Distribution and leaching characteristics of La element in oxyapatite glass-ceramic derived from uranium tailings

Distribution and leaching characteristics of La element in oxyapatite glass-ceramic derived from uranium tailings | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Distribution and leaching characteristics of La element in oxyapatite glass-ceramic derived from uranium tailings Pingping Huang, Mingfeng Chen, Jiajun Wang, Wanrong Zou, Zhitao Hu This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7702366/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 03 Feb, 2026 Read the published version in Journal of Radioanalytical and Nuclear Chemistry → Version 1 posted You are reading this latest preprint version Abstract Due to their high waste loading capacity and excellent chemical durability, rare earth (RE) - oxyapatites are a potential material for the immobilization of nuclear waste. In this work, NaLa 9 (SiO 4 ) 6 O 2 glass-ceramics (GCs) and La 2 Si 2 O 7 GCs derived from different contents of uranium tailings were synthesized by the solid-state method to immobilize lanthanides (La). The effect of uranium tailings content and sintering temperature on the phase evolution and chemical durability of the solidified samples was systematically investigated. Rietveld refinement analysis was used to obtain the ratios of crystalline-glass phases in the GCs, and the La element distribution between different phases before and after the leaching test was characterized by TEM-EDS. Results demonstrated that U20 (20 wt% uranium tailing addition) samples were an ideal waste form to immobilize La. The U20 sample had a 63.80 wt% proportion of crystalline phase, and the proportion of La element on the crystalline phase was 69.95 wt%, which was obviously larger than the La content of 3.53–5.81 wt% on the vitreous part. ASTM Product Consistency Test (PCT) results indicated that U20 samples had the lowest La leaching rate over the 28-day leaching period, U40, U50, and U60 samples with La 2 Si 2 O 7 as the main crystalline phase had similar leaching values with U70 samples, which were pure glass phase. After the leaching test, no lattice distortion or phase change happened on the NaLa 9 (SiO 4 ) 6 O 2 crystalline phase. Oxyapatite glass-ceramics Lanthanides Uranium tailings Phase evolution chemical durability Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 1 Introduction High-level nuclear waste (HLW) includes fission products (e.g., 129 I, 137 Cs, 90 Sr), transuranic elements (e.g., 239 Pu, 237 Np), rare-earth elements (RE), actinides, noble metals, alkali and transition elements [ 1 ] . Borosilicate glass is commonly used as a waste form in several countries, including France, the USA, Great Britain, Germany, and Japan, to immobilize nuclear waste, because the glass structure can accommodate a wide range of components (e.g., fission products), and it has good glass-forming ability and chemical durability [ 2 ] . However, some fission products such as MoO 3 , rare earth elements (RE), and noble metals (e.g., Pd, Rh, Ru) have poor solubility in borosilicate glass [ 3 ] , and also owing to their metastable phase structure with inferior thermodynamic [ 4 ] , uncontrolled crystallization happens in the glass matrix during long-time disposal [ 2 ] . Fortunately, by controlled crystallization of amorphous glasses either during the cooling of melts or after reheating of parent glasses [ 2 ] , a new waste form glass-ceramics (GCs) has been generated, which is a kind of polycrystalline ceramic material with an amorphous phase, and one or more crystalline phases [ 5 ] . Compared to the borosilicate glass waste form, the GC waste form possesses higher mechanical properties, thermal stability, and chemical durability [ 6 , 7 , 8 ] . Meanwhile, the GCs are expected to have higher waste loadings (45 mass% vs 18 mass%) with an increased solubility of troublesome components in durable crystalline phases [ 9 ] . In particular, RE oxyapatites have a general chemical formula of (AE, RE) 10 (SiO 4 , PO 4 ) 6 X 2 where X is an anion, e.g. O 2− , OH − , F − , which contain 56 wt%-77 wt% RE elements in the structure, and the waste loading of the oxyapatites GC waste forms ranges from 45 wt%-55 wt% [ 10 ] . Also, the oxyapatite GCs are known to exhibit thermal stability, chemical stability [ 5 ] , and resistance toward radiation [ 6 ] . Significant research efforts have been devoted to exploring the immobilization of lanthanides or simulated actinides in oxyapatite GC matrices. Miae Kim fabricated GC containing calcium neodymium(cerium) oxide silicate [Ca 2 Nd 8 − x Ce x (SiO 4 ) 6 O 2 ] crystals by controlled crystallization of alkali borosilicate glasses with heating at T ≥ 750 ℃ for 3 h to immobilize radioactive wastes that contain large portions of rare-earth ions. The maximum lanthanide oxide waste loading was greater than 26.8 wt.%, and the normalized release values performed by a product consistency test were 2.64×10 − 6 g·m − 2 for Ce ion and 2.19×10 − 6 g·m − 2 for Nd ion [ 6 ] . Choosing granite wastes as a matrix for loading simulated actinide waste, a series of oxyapatite GCs were synthesized via the solid-state sintering method. A maximum doping amount of 76 mass % of Nd 2 O 3 was loaded in the Ca 2 Nd 8 (SiO 4 ) 6 O 2 GCs, Nd is uniformly distributed in the crystalline-amorphous two-phased matrix [ 11 ] . For Eu 2 O 3 as simulated radionuclides, the main phase oxyapatite (Ca 2 Eu 8 (SiO 4 ) 6 O 2 ) is dispersed homogenously in glass matrix, the GCs containing 40 wt % of Eu 2 O 3 possess the optimal mechanical properties and excellent chemical durability, and the leaching rate of Eu 3+ is 3.6×10 − 8 g·m − 2 ·d − 2[ 12 ] . Also, Oxyapatite (Ca 2 Nd 8 (SiO 4 ) 6 O 2 ) GCs derived from coal fly ash (CFA) [ 13 ] , radioactive sludge, and silicate glass particles [ 14 ] were fabricated via microwave heating to immobilize simulated trivalent actinides. The Ca 2 Nd 8 (SiO 4 ) 6 O 2 GCs prepared from CFA show high bulk density (3.24 g·cm − 3 ), superior leaching resistance (the leaching rate of Nd element was 4.29×10 − 8 g·m − 2 ·d − 1 ), and the normalized leaching rate of Nd in the GC derived from radioactive sludge was at a low level of 10 − 6 g·m − 2 ·d − 1 . The above study suggests that oxyapatite GCs are promising immobilization substrates for the immobilization of simulated radionuclides. Uranium mill tailings (UMT) are the crushed ore residues from the extraction of uranium (U) from ores [ 15 ] , containing numerous radioactive pollutants, whose migration into water or air is a huge threat to the biosphere and humans. Moreover, the main composition of uranium mill tailings in Hunan, China, is SiO 2 (87.78%), Al 2 O 3 (7.76%), and K 2 O (2.52%), which is an ideal raw material to synthesize aluminosilicate glass [ 16 ] . Therefore, it is a promising strategy to use UMT as a matrix material to immobilize radioactive waste, which could not only effectively immobilize radioactive wastes for long-term geological disposal but also greatly reduce the amount of UMT for protecting the environment. In this work, we aim to synthesize oxyapatite GCs to immobilize lanthanides, using uranium tailings and Na 2 CO 3 as starting materials, the La 2 O 3 as the lanthanides. The conventional and easy solid-state sintering method is used to prepare oxyapatite GCs. The phase evolution, microstructure, element distribution, and chemical durability of as-prepared sintered forms were systematically investigated by XRD, SEM-EDS, and ICP-OES. Quantitative analysis of the phase composition of glass-ceramics was conducted by internal standard powder XRD and Rietveld refinement. TEM-EDS was used to study the distribution of La in amorphous-crystalline two phases before and after the leaching test. This research provides an experimental and theoretical analysis to deepen the knowledge of oxyapatite GCs derived from uranium mill tailings as the waste host matrix. 2 Experimental 2.1 Materials The uranium tailing sample, used in this work, was collected from a uranium tailings pond in Hunan Province, China. After drying at 105°C for 24 h and sifting through a 200-mesh sieve, the powder samples were heated at 600℃ for 6 h in a muffle furnace to remove organic matter and volatiles. The composition of the uranium tailings determined by X-ray fluorescence is given in Table 1 [ 17 ] . Table 1 Oxide composition of uranium tailings Oxide SiO 2 Al 2 O 3 K 2 O Na 2 O Fe 2 O 3 SO 3 MgO CaO ZnO TiO 2 U 3 O 8 Content, wt.% 87.78 7.76 2.52 0.554 0.941 0.191 0.180 0.163 0.151 0.132 0.0045 2.2 Preparation of samples Based on the same outermost electronic structure, similar ionic radius and similar chemical properties, La 3+ (La 2 O 3, grade, Shanghai Maclin Biochemical Technology Co.) was selected as the simulated ion of U 3+[ 18 ] . The addition of uranium tailings powders was set as 20 wt% %, 40 wt% %, 50 wt% %, 60 wt% % 70 wt% %, respectively. Na 2 CO 3 (AR grade, Tianjin Tianli Chemical Reagent Co., Ltd) was added with a mass fraction ratio of 8:2 (uranium tailings: Na 2 CO 3 ) to lower the sintering temperature of Na 2 O-Al 2 O 3 -SiO 2 glass [ 16 ] . The detailed formula and corresponding sample labels are listed in Table 2 . A sample made as U20 refers to the 20 wt% % uranium tailings that were doped. The raw materials were mixed in an agate mortar. Subsequently, the mixed powders were placed into alumina crucibles and dried in a 100°C electric thermostatic drying oven for 6 hours. Finally, the dried powders were sintered at temperatures of 1100, 1200, and 1300℃ for 3 h with a heating rate of 10°C/min in muffle furnace (KSL-1700X-A2,50GHz,5.2kW). The entire sintering process was performed in an air environment, and the sintered samples were natural cooling to room temperature. Figure 1 shows the preparation process of oxyapatite GCs. Table 2 Detailed formula and corresponding sample labels of pre-sintering samples (wt.%) Samples Percentage of uranium tailings (%) La 2 O 3 /SiO 2 (mol) Additive amount of raw materials, g La 2 O 3 Na 2 CO 3 Uranium tailings U20 U40 U50 U60 U70 20 0.75 3.00 0.21 0.84 40 0.26 2.02 0.41 1.62 50 0.16 1.51 0.51 2.03 60 0.09 1.01 0.61 2.43 70 0.04 0.50 0.71 2.84 2.3 Characterization The phases and compositions of sintered samples were identified by X-ray diffraction (XRD, Rigaku SmartLab SE, Japan, Cu, Kα radiation, λ = 1.5406Å). The scanning range of 2θ was set from 10° to 80° with a scanning rate of 5°/min. Scanning electron microscopy (SEM, MIRA4 LMH, TESCAN) equipped with an energy dispersive spectroscopy (EDS; One Max 50, Britain) was utilized to explore the morphology of sintered samples and the distribution features of elements. The concentration of lanthanum ions in the leaching solution was identified using an inductively coupled plasma Optical Emission Spectrometer (ICP-OES, Agilent 5110 ICP-OES, USA). 2.4 Static leaching experiment The chemical stability of the sintered specimens was evaluated via static leaching experiments (i.e., product consistency tests; PCT) with deionized water as leachate at a controlled temperature of 90 ± 1 ℃ over 28 days [ 19 ] . Firstly, the five samples sintered at 1300℃ were crushed into powders and sieved between 100 and 200 mesh. Then,1g sample powders were immersed in 10 ml deionized water in a stainless steel container consisting of polytetrafluoroethylene, and the sealed stainless steel containers were placed in an oven at 90 ± 1°C. The leaching agent was replaced with a new one at regular intervals (1, 3, 7, 14, and 28 days) and centrifugation of the leachate was carried out to ensure the clarification of the extracted leachate sample and the accuracy of the test data. The concentration of La (C La ) in the leachate was analyzed by an inductively coupled plasma Optical Emission Spectrometer (ICP-OES, Agilent 5110icpoes, USA). The normalized leaching rate (LRi, g· m − 2 d − 1 ) of La was calculated by Eq. (1) $$\:\begin{array}{c}{\text{L}\text{R}}_{\text{i}}=\frac{{\text{C}}_{\text{i}}}{{\text{f}}_{\text{i}}\bullet\:\left(\frac{\text{S}\text{A}}{\text{V}}\right)\bullet\:\text{t}} \left(1\right) \end{array}$$ 3 Results and discussion 3.1 Analyses using XRD Figure 2 shows the XRD pattern of samples with increasing uranium tailing sand (20–70 wt%) after solid-phase sintering at 1100 ℃, 1200 ℃, and 1300 ℃. When the uranium tailing sand addition is 20 wt%, La oxyapatite (NaLa 9 (SiO 4 ) 6 O 2 , PDF#74-2430) appears as the crystalline phase. Compared to a lower temperature (1100 ℃), the diffraction peak of La 2 O 3 disappears after sintering at 1200 ℃ and 1300 ℃, indicating that higher temperatures promote the solid phase reaction. With the uranium tailing sand increasing to 40 wt%, a new high-temperature monoclinic phase crystal (G-La 2 Si 2 O 7 , PDF#82–0729) forms as the primary crystalline phase. When the uranium tailing sand content further increases to 50 wt% and 60 wt%, the La 2 Si 2 O 7 is detected as the only crystal. However, as seen in Fig. 2 , the proportion of low-temperature tetragonal modification (A-La 2 Si 2 O 7 ) and high-temperature monoclinic phase (G-La 2 Si 2 O 7 ) is affected by the uranium tailing sand content and sintered temperatures (1100, 1200, 1300 ℃). The G-La 2 Si 2 O 7 is mostly decreased when more uranium tailing sand is used in the starting reagent, and a higher heat treatment temperature promotes the formation of the G-La 2 Si 2 O 7 phase. For the U50 sample, the diffraction peak intensity of G-La 2 Si 2 O 7 at 2θ = (26.1°) increases with the sintering temperature from 1100 ℃ to 1200 ℃; for a higher temperature of 1300 ℃, the diffraction peak intensity barely changes. For the U60 sample, the primary crystalline phase changes from A-La 2 Si 2 O 7 to G-La 2 Si 2 O 7 from 1100 ℃ to 1300 ℃. When the uranium tailing sand proportion is 70 wt%, the XRD spectrogram of sintered products exhibits obvious amorphous features with the hump between 20–35°. An additional 10 wt% of Al 2 O 3 was added as an internal standard, employing Rietveld refinement to quantify the weight fractions of the components (including crystalline and amorphous phases) of the GCs [ 20 ] . The fitting is plotted in Fig. 3 and the main refinement parameters of the processing [ 21 ] , the corresponding crystallographic data, and the quantitative fractions of sintered glass-ceramics are given in Table 3 . The difference profile was nearly flat, signifying that the observed and calculated profiles were in very good agreement with an acceptable χ 2 (χ 2 represents goodness of fit of parameter refinement) value of 5.62 and 5.20, respectively. The Rietveld analysis shows that the content of crystalline phase (NaLa 9 (SiO 4 ) 6 O 2 ) and amorphous phases in the U20 samples was 63.80 wt% and 26.2 wt%, respectively. For U50 samples, the content of crystalline phase (La 2 Si 2 O 7 ) gradually decreased to 34.96 wt%, and on the contrary, the content of the amorphous phases increased to 55.04 wt%. The structure refining showed that the amorphous phases continue to grow with the Uranium tailings. Table 3 Phase quantification of U20 and U50 samples calcined at 1300℃/3 h by the Rietveld method. Sample U20 U50 Chemical formula NaLa 9 (SiO 4 ) 6 O 2 La 2 Si 2 O 7 Space group P63/m P21/c Crystalline phases, % 63.80 34.96 Al 2 O 3 , % 10.00 10.00 Amorphous, % 26.20 55.04 Calculated multiplicity(g/cm 3 ) 5.274 4.730 a, Å 9.69089 5.40655 b, Å 9.69089 8.79787 c, Å 7.19094 14.19003 α, ° 90 90 β, ° 90 112 γ, ° 120 90 V(Å3) 584.849 626.312 Reliability factors, % Rwp = 15.5, RB = 6.36, χ 2 = 5.62, Rexp = 6.55, Rp = 11.50 Rwp = 13.4, RB = 10.7, χ 2 = 5.20, Rexp = 5.88, Rp = 10.40 *The reliability factors of the refinement are Rwp, R-Bragg, the chi-squared χ2 = (Rwp/Rexp) 2 , Rexp, Rp, where Rwp indicates the success of the refinement, R-Bragg is the crystallographic model to fit the experimental data, χ2 represents the goodness of fit of parameter refinement, Rexp is the best residual in theory, and Rp is the average deviation between fitted and experimental curves. 3.2 Analyses using SEM and EDS The SEM images, EDS surface scanning images and EDS spectra of samples with various uranium tailing sand (20–70 wt%) after heat treatment at 1300 ℃ are presented in Fig. 4 . For samples of U20, figure (a) indicates that the micron size rod-shaped crystals with a hexagonal cross-section are precipitated [ 18 ] , which is confirmed to be NaLa 9 (SiO 4 ) 6 O 2 . The EDS surface scanning analysis (Fig. 4 (a2)) shows that the La is enriched in the crystalline phases. For U40 samples (Fig. 4 (b, b5)), some irregularly shaped grains and small particles appear, and La is enriched in the crystals compared to the glass substrate. The SEM micrograph of U50 and U60 glass-ceramic specimens (Fig. 4 (c-d)) shows that disorder-distributed needle-like growth forms are developed. La is predominantly fixed within the crystalline structure (Fig. 4 (c5, d5). For U70 samples (Fig. 4 (e, e4)), no grain forms, the La element is evenly distributed in the smooth and amorphous glass matrix. The corresponding EDS spectra results for the glass-ceramic forms of U20, U40, U50, U60, U70 presented in Fig. 4 (a6, b9, c9, d8, e7) show that the weight ratios of La are 69.95%, 30.14%, 18.12%, 19.41% and 10.12%, respectively. This result indicates that the glass-ceramic product obtained from 20 wt% uranium tailing sand addition with La oxyapatite (NaLa 9 (SiO 4 ) 6 O 2 ) as the primary phase is an ideal matrix to immobilize La. 3.3 Chemical durability Figure 5 shows the normalized leaching rate of La over time in the lanthanum-containing glass ceramics sintered at 1300℃ with various amounts of uranium tailings. It is observed that the normalized leaching rate curves of La in the series of solidified bodies decrease sharply in the initial 7 days, then flatten out with the prolongation of leaching time. After 28 days, the LR La of all sintered samples are expected to remain relatively stable (i.e., they all fell below 6.52×10 − 4 g·m − 2 ·day − 1 ). Throughout the entire leaching process, the normalized leaching rate of La in the U20 sample is the lowest among various glass-ceramics of U20-U70. This is because of the high proportion of crystalline phase (NaLa 9 (SiO 4 ) 6 O 2 ) in the U20 sample. However, glass-ceramics with La 2 Si 2 O 7 as the primary crystal phase (U40, U50, U60) have comparable leaching rates of La to the amorphous glass waste form (U70). This indicates that the crystalline phase (NaLa 9 (SiO 4 ) 6 O 2 ) is a more ideal matrix to immobilize La element compared to La 2 Si 2 O 7 [ 14 ] . Table 4 presents a comparison of the leaching rate of the La element of specific waste forms. The leaching rate of La in U20 sample is 1.6×10 − 5 g·m − 2 ·day − 1 (28d), which is lower than the values reported as 4×10 − 4 g·m − 2 ·day − 1 [ 22 ] and 2.5×10 − 5 g·m − 2 ·day − 1 [ 23 ] . And the one-step cooling procedure used in our study is simpler than the secondary heat treatment for crystallization [ 23 ] . Compared to the value reported as 4.9×10 − 8 g·m − 2 ·day − 1 [ 24 ] , our leaching result may not be good, but U20 samples have a higher La solid solubility of 69.95wt% than the basaltic glasses with La capacity of 16.29 wt% [ 24 ] . So then oxyapatite GCs derived from uranium mill tailings in our study have considerable chemical durability [ 25 ] . Table 4 LR La of specific waste forms according to the literature Solidification forms Precursors Treatment Leaching rate of La 3+ (g·m − 2 ·d − 1 ) Ref Sodium borosilicate glass matrix incorporated with simulated HLW. A sodium borosilicate glass matrix with composition of 2SiO 2 -B 2 O 3 -Na 2 O (in mol%) and 19 wt% waste oxide (Rb 2 O, Cs 2 O, SrO, BaO, ZrO 2 , MoO 3 and La 2 O 3 ) Conventional sintering (950℃ 30min) 4×10 − 4 [ 22 ] Glass-ceramics with CaLa 4 (SiO 4 ) 3 O as the main phase Parent glass with the chemical composition of 9Na 2 O-15CaO-9La 2 O 3 -15B 2 O 3 -52SiO 2 (in mol%) Melt cooling method (1300℃ 2h) and queching for base glass, then 900 ℃ 2h for crystalization to glass-ceramic 2.5×10 − 5 (14d) [ 23 ] The simulated actinides basaltic glass The mixture of 68 wt% basaltic glass 10.30 wt% Nd 2 O, 3.41wt% CeO 2 and 16.29wt% La 2 O 3 oxides The solid-state melt method (1400℃ 3h) 4.9×10 − 8 (56d) [ 24 ] La-containing glass— ceramics The mixture of uranium tailings, La 2 O 3 and Na 2 CO 3 oxides High-temperature solid-state method (1300℃ 3h) 1.6×10 − 5 (28d) this work 3.4 Micromorphology analysis To further identify the La elements' leaching characteristics in crystal and amorphous structures, the surfaces of U20 samples prepared at 1300℃ before and after the 28-day leaching test were characterized through transmission electron microscopy (TEM). The TEM image, selected area electron diffraction (SAED) analysis, and element mapping images are shown in Fig. 6 . From the micro-topography of Fig. 6 (a) and (d), no changes were found in the powder particles before and after leaching. The observed zone of U20 sample particles exhibited clear lattice fringes; the measured interplanar spacing (d) was found to be 0.42 nm, which was well matched with the spacing of the (2 0 0) plane of NaLa 9 (SiO 4 ) 6 O 2 crystal. And the interplanar spacing values are the same and in good agreement with Rietveld refinement results before and after the leaching, indicating that no lattice distortion or phase change of NaLa 9 (SiO 4 ) 6 O 2 occurred during the leaching test. Expect the crystalline region, it was seen from Fig. 6 (b) and (e) that an amorphous phase with a disordered structure marked as Region B and D also existed. The SAED diagrams of U20 samples before and after leaching are shown in Fig. 6 (c) and (f), and the crystal plane parameters were calibrated as shown in these figures. It showed both a weak amorphous diffraction ring and a crystal diffraction spot, which further verified that the U20 sample was a typical glass-ceramic structure. Concerning the distribution of elements, it can be found from Fig. 6 (g) and (h) that the Na, O, and Si elements were evenly distributed, and the mapping images hardly changed before and after leaching. The La element enrichment in the crystalline phase was easy to find in the TEM-EDS measurements of areas A, B, C, and D; the detailed information is listed in the Table. 5. No matter before or after leaching, it was interesting to identify from Energy dispersive spectroscopy (EDS) of regions A and C in Fig. 6 (b) and (e) that the mass fraction of La (49.2 wt% and 54.6wt%) was lower than the result (69.95%) from SEM-EDS in Fig. 4 (a6). This was mainly attributed to the fact that the La element scanned by the TEM-EDS was composed of the crystalline section and amorphous region. A theoretical value of La content can be calculated from a formula as follows: $$\:\text{L}\text{a}\:\text{r}\text{a}\text{t}\text{i}\text{o}\:\text{i}\text{n}\:\text{G}\text{C}=\text{w}\text{t}\text{%}\:\text{o}\text{f}\:\text{c}\text{r}\text{y}\text{s}\text{t}\text{a}\text{l}\times\:\text{W}1+\text{w}\text{t}\text{%}\:\text{o}\text{f}\:\text{g}\text{l}\text{a}\text{s}\text{s}\times\:\text{W}2$$ Where wt% of crystal = crystalline phase/0.9, wt% of glass = amorphous/0.9, the quantitative mass ratio of crystalline and amorphous phases in the GCs obtained from the rietveld refinement results in Table 3 , but an extra step is needed because 10 wt% Al 2 O 3 is in testing sample; W1: the La weight ratios in the NaLa 9 (SiO 4 ) 6 O 2 crystal from SEM-EDS in Fig. 4 (a6); W2: the La weight ratios in the glass from TEM-EDS in Fig. 6 (b2). After a simple calculation, a value of 50.61 wt% was obtained, which was near the result (49.2 wt% and 54.6wt%) from the TEM-EDS characterization analysis. Furthermore, the increase of La content in both the crystalline (54.6wt% vs 49.2 wt%) and amorphous phases (5.81wt% vs 3.53wt%) after the leaching test may be attributed to two reasons: one was the region marked as A and C were not composed of the same grains, region A may include more amorphous section and less crystalline phase, and region C was the opposite; the second was the U20 samples had an excellent chemical durability due to no obvious La depletion after the leaching. Table 5 The mass fraction of La in crystalline and amorphous regions in the selected area of U20 samples before and after leaching Mass fraction of lanthanum (%) Crystal Amorphous Before leaching Area A Area B 49.20 3.53 After leaching Area C Area D 54.60 5.81 4 Conclusion In this work, the effect of uranium tailings content on the phase evolution, microstructure, morphology, and chemical durability of the solidified samples prepared by the high-temperature solid-state method was systematically investigated. The XRD results indicated that the primary crystalline phase of the glass-ceramics transitioned from oxyapatite to the high-temperature monoclinic phase crystal (G-La 2 Si 2 O 7 ) forms with increasing uranium tailings content. When the uranium tailing sand proportion was 70 wt%, the XRD spectrogram of sintered products exhibited obvious amorphous features. The weight fractions of the components (including crystalline and amorphous phases) of the GCs were quantitatively investigated using Rietveld refinement. Within a 20–50 wt% range, the proportion of crystalline phase in the samples decreased from 63.80% to 34.96% with rising uranium tailings content, while the glassy phase proportion increased. The SEM-EDS test results indicated that when the content of uranium tailings was between 20 and 60 wt%, La was enriched in the crystalline phases. A maximum 69.95% weight ratio of La was verified in the crystalline region of U20 samples, which indicated that the U20 glass-ceramic product with La oxyapatite (NaLa 9 (SiO 4 ) 6 O 2 ) as the primary phase is an ideal matrix to immobilize La. The TEM-EDS test results indicated that no lattice distortion or phase change of NaLa 9 (SiO 4 ) 6 O 2 occurred during the leaching test. Through theoretical calculation, the overall content of La in the GCs was consistent with the experimental value, confirming that La oxyapatite GCs could load 49wt%-55wt% La. For the U20 sample, the normalized element leaching rate of La(1.6×10 − 5 g·m − 2 ·d − 1 after 28 days) indicated good chemical durability of the solidified body. The high loading capacity for the immobilization of lanthanides and excellent chemical durability of the solidified body with uranium mill tailings as raw materials bring novel ideas for solving radioactive wastes with low levels and high levels. Declarations Funding Declaration This work was supported by the Project Approved by the Natural science foundation of Hunan Province (Grant Nos. 2021JJ40463; 2020JJ5463); the Provincial Education Department of Hunan Province, China (No.19A420). Author Contribution Huang Pingping and Chen Mingfeng: Data curation, Investigation, Writing – original,draft, Writing – review & editing. 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Cite Share Download PDF Status: Published Journal Publication published 03 Feb, 2026 Read the published version in Journal of Radioanalytical and Nuclear Chemistry → Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7702366","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":534037401,"identity":"bee52aab-3979-4c3f-80d5-b5953b887fa2","order_by":0,"name":"Pingping Huang","email":"","orcid":"","institution":"University of South China","correspondingAuthor":false,"prefix":"","firstName":"Pingping","middleName":"","lastName":"Huang","suffix":""},{"id":534037402,"identity":"6d0c9673-7b2c-4e0f-b4a3-c888d257bad8","order_by":1,"name":"Mingfeng Chen","email":"","orcid":"","institution":"University of South 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14:44:40","extension":"xml","order_by":15,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":99631,"visible":true,"origin":"","legend":"","description":"","filename":"f05612056b4a464a9e4d5e607359548d1structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-7702366/v1/bf7df69293fd0d2c66b7c3eb.xml"},{"id":94456615,"identity":"fa79662c-d435-4125-a920-c29ebac52114","added_by":"auto","created_at":"2025-10-27 14:44:49","extension":"html","order_by":16,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":99328,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-7702366/v1/d10ba2ee7063a83b7773492a.html"},{"id":94457043,"identity":"b67e670e-a30b-44bb-b48b-63b979d4f854","added_by":"auto","created_at":"2025-10-27 14:45:26","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":1239866,"visible":true,"origin":"","legend":"\u003cp\u003eThe schematic of the preparation process of oxyapatite GCs.\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7702366/v1/84c4b6136191bd09e2bf3c92.jpeg"},{"id":94457007,"identity":"6c638238-fde0-4477-ac66-d8fe0a64360c","added_by":"auto","created_at":"2025-10-27 14:45:22","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":1006742,"visible":true,"origin":"","legend":"\u003cp\u003eXRD patterns of samples with various uranium tailing sand (20-70 wt%) after heat treatment at (a) 1100 ℃, (b) 1200 ℃, and (c) 1300 ℃\u003c/p\u003e","description":"","filename":"floatimage2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7702366/v1/27279adcf542da611ae030a1.jpeg"},{"id":94456610,"identity":"2760a9be-4bbf-42c7-9cad-c1a4cc1dacbc","added_by":"auto","created_at":"2025-10-27 14:44:48","extension":"jpeg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":878891,"visible":true,"origin":"","legend":"\u003cp\u003eRietveld refinement of samples (a) U20, and (b) U50, using Al\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e as an internal standard for each of the phases in the samples. Data are shown as a black cross and the solid red curve is the best fit obtained from the data. The blue dashed curve represents the difference between the observed and calculated profiles. The yellow and red tick marks above the x-axis indicate the positions of allowed diffraction maxima of the NaLa\u003csub\u003e9\u003c/sub\u003e(SiO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e6\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e(3-a)、La\u003csub\u003e2\u003c/sub\u003eSi\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e(3-b) and Al\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e oxides, respectively.\u003c/p\u003e","description":"","filename":"floatimage3.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7702366/v1/744997cb857e9ad4f83b502e.jpeg"},{"id":94456754,"identity":"5ebfc09f-1261-40ad-9ca8-eb826de003fb","added_by":"auto","created_at":"2025-10-27 14:45:06","extension":"jpeg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":1329496,"visible":true,"origin":"","legend":"\u003cp\u003eSEM-EDS results of various samples after heat treatment at 1300 ℃; a, U20; b, U40; c, U50; d, U60; e, U70\u003c/p\u003e","description":"","filename":"floatimage4.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7702366/v1/0134c959dcf65a27fd1d39ef.jpeg"},{"id":94456320,"identity":"8783a189-5ebd-4a4a-8b52-aa2d168a80e4","added_by":"auto","created_at":"2025-10-27 14:44:27","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":745822,"visible":true,"origin":"","legend":"\u003cp\u003eThe 28-day normalized leaching rates (LRi) of La for samples sintered at 1300 ℃.\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-7702366/v1/56f92be4e4806fecdbaa7e2e.png"},{"id":94456938,"identity":"b6153725-ab84-433b-9ee3-05cd142a151b","added_by":"auto","created_at":"2025-10-27 14:45:15","extension":"jpeg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":910007,"visible":true,"origin":"","legend":"\u003cp\u003eTransmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) image, selected area electron diffraction (SAED) and element mapping images of U20 samples sintering at 1300 ℃: (a-c, g) before the leaching test, (d-f, h) after the leaching test. (b1-b2, e1-e2) The corresponding EDS of the selected area.\u003c/p\u003e","description":"","filename":"floatimage6.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7702366/v1/cfefe49a11cbfdcee21833c0.jpeg"},{"id":102234353,"identity":"4dd326d8-1f43-4454-b83c-35e16e573445","added_by":"auto","created_at":"2026-02-09 16:10:14","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":7057429,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7702366/v1/0f3b39a1-a942-45e7-97a8-5239c0c3dc37.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Distribution and leaching characteristics of La element in oxyapatite glass-ceramic derived from uranium tailings","fulltext":[{"header":"1 Introduction","content":"\u003cp\u003eHigh-level nuclear waste (HLW) includes fission products (e.g.,\u003csup\u003e129\u003c/sup\u003eI, \u003csup\u003e137\u003c/sup\u003eCs, \u003csup\u003e90\u003c/sup\u003eSr), transuranic elements (e.g., \u003csup\u003e239\u003c/sup\u003ePu, \u003csup\u003e237\u003c/sup\u003eNp), rare-earth elements (RE), actinides, noble metals, alkali and transition elements\u003csup\u003e[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]\u003c/sup\u003e. Borosilicate glass is commonly used as a waste form in several countries, including France, the USA, Great Britain, Germany, and Japan, to immobilize nuclear waste, because the glass structure can accommodate a wide range of components (e.g., fission products), and it has good glass-forming ability and chemical durability\u003csup\u003e[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]\u003c/sup\u003e. However, some fission products such as MoO\u003csub\u003e3\u003c/sub\u003e, rare earth elements (RE), and noble metals (e.g., Pd, Rh, Ru) have poor solubility in borosilicate glass\u003csup\u003e[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]\u003c/sup\u003e, and also owing to their metastable phase structure with inferior thermodynamic\u003csup\u003e[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]\u003c/sup\u003e, uncontrolled crystallization happens in the glass matrix during long-time disposal\u003csup\u003e[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]\u003c/sup\u003e. Fortunately, by controlled crystallization of amorphous glasses either during the cooling of melts or after reheating of parent glasses\u003csup\u003e[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]\u003c/sup\u003e, a new waste form glass-ceramics (GCs) has been generated, which is a kind of polycrystalline ceramic material with an amorphous phase, and one or more crystalline phases\u003csup\u003e[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]\u003c/sup\u003e. Compared to the borosilicate glass waste form, the GC waste form possesses higher mechanical properties, thermal stability, and chemical durability\u003csup\u003e[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/sup\u003e. Meanwhile, the GCs are expected to have higher waste loadings (45 mass% vs 18 mass%) with an increased solubility of troublesome components in durable crystalline phases\u003csup\u003e[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]\u003c/sup\u003e. In particular, RE oxyapatites have a general chemical formula of (AE, RE)\u003csub\u003e10\u003c/sub\u003e(SiO\u003csub\u003e4\u003c/sub\u003e, PO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e6\u003c/sub\u003eX\u003csub\u003e2\u003c/sub\u003e where X is an anion, e.g. O\u003csup\u003e2\u0026minus;\u003c/sup\u003e, OH\u003csup\u003e\u0026minus;\u003c/sup\u003e, F\u003csup\u003e\u0026minus;\u003c/sup\u003e, which contain 56 wt%-77 wt% RE elements in the structure, and the waste loading of the oxyapatites GC waste forms ranges from 45 wt%-55 wt%\u003csup\u003e[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]\u003c/sup\u003e. Also, the oxyapatite GCs are known to exhibit thermal stability, chemical stability\u003csup\u003e[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]\u003c/sup\u003e, and resistance toward radiation\u003csup\u003e[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/sup\u003e. Significant research efforts have been devoted to exploring the immobilization of lanthanides or simulated actinides in oxyapatite GC matrices. Miae Kim fabricated GC containing calcium neodymium(cerium) oxide silicate [Ca\u003csub\u003e2\u003c/sub\u003eNd\u003csub\u003e8\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003eCe\u003csub\u003ex\u003c/sub\u003e(SiO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e6\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e] crystals by controlled crystallization of alkali borosilicate glasses with heating at T\u0026thinsp;\u0026ge;\u0026thinsp;750 ℃ for 3 h to immobilize radioactive wastes that contain large portions of rare-earth ions. The maximum lanthanide oxide waste loading was greater than 26.8 wt.%, and the normalized release values performed by a product consistency test were 2.64\u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;6\u003c/sup\u003e g\u0026middot;m\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e for Ce ion and 2.19\u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;6\u003c/sup\u003e g\u0026middot;m\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e for Nd ion\u003csup\u003e[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/sup\u003e. Choosing granite wastes as a matrix for loading simulated actinide waste, a series of oxyapatite GCs were synthesized via the solid-state sintering method. A maximum doping amount of 76 mass % of Nd\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e was loaded in the Ca\u003csub\u003e2\u003c/sub\u003eNd\u003csub\u003e8\u003c/sub\u003e(SiO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e6\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e GCs, Nd is uniformly distributed in the crystalline-amorphous two-phased matrix\u003csup\u003e[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]\u003c/sup\u003e. For Eu\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e as simulated radionuclides, the main phase oxyapatite (Ca\u003csub\u003e2\u003c/sub\u003eEu\u003csub\u003e8\u003c/sub\u003e(SiO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e6\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e) is dispersed homogenously in glass matrix, the GCs containing 40 wt % of Eu\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e possess the optimal mechanical properties and excellent chemical durability, and the leaching rate of Eu\u003csup\u003e3+\u003c/sup\u003e is 3.6\u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;8\u003c/sup\u003eg\u0026middot;m\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e\u0026middot;d\u003csup\u003e\u0026minus;\u0026thinsp;2[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]\u003c/sup\u003e. Also, Oxyapatite (Ca\u003csub\u003e2\u003c/sub\u003eNd\u003csub\u003e8\u003c/sub\u003e(SiO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e6\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e) GCs derived from coal fly ash (CFA) \u003csup\u003e[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]\u003c/sup\u003e, radioactive sludge, and silicate glass particles\u003csup\u003e[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]\u003c/sup\u003e were fabricated via microwave heating to immobilize simulated trivalent actinides. The Ca\u003csub\u003e2\u003c/sub\u003eNd\u003csub\u003e8\u003c/sub\u003e(SiO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e6\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e GCs prepared from CFA show high bulk density (3.24 g\u0026middot;cm\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e), superior leaching resistance (the leaching rate of Nd element was 4.29\u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;8\u003c/sup\u003e g\u0026middot;m\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e\u0026middot;d\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e), and the normalized leaching rate of Nd in the GC derived from radioactive sludge was at a low level of 10\u003csup\u003e\u0026minus;\u0026thinsp;6\u003c/sup\u003e g\u0026middot;m\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e\u0026middot;d\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. The above study suggests that oxyapatite GCs are promising immobilization substrates for the immobilization of simulated radionuclides. Uranium mill tailings (UMT) are the crushed ore residues from the extraction of uranium (U) from ores\u003csup\u003e[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]\u003c/sup\u003e, containing numerous radioactive pollutants, whose migration into water or air is a huge threat to the biosphere and humans. Moreover, the main composition of uranium mill tailings in Hunan, China, is SiO\u003csub\u003e2\u003c/sub\u003e (87.78%), Al\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e (7.76%), and K\u003csub\u003e2\u003c/sub\u003eO (2.52%), which is an ideal raw material to synthesize aluminosilicate glass\u003csup\u003e[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]\u003c/sup\u003e. Therefore, it is a promising strategy to use UMT as a matrix material to immobilize radioactive waste, which could not only effectively immobilize radioactive wastes for long-term geological disposal but also greatly reduce the amount of UMT for protecting the environment.\u003c/p\u003e\u003cp\u003eIn this work, we aim to synthesize oxyapatite GCs to immobilize lanthanides, using uranium tailings and Na\u003csub\u003e2\u003c/sub\u003eCO\u003csub\u003e3\u003c/sub\u003e as starting materials, the La\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e as the lanthanides. The conventional and easy solid-state sintering method is used to prepare oxyapatite GCs. The phase evolution, microstructure, element distribution, and chemical durability of as-prepared sintered forms were systematically investigated by XRD, SEM-EDS, and ICP-OES. Quantitative analysis of the phase composition of glass-ceramics was conducted by internal standard powder XRD and Rietveld refinement. TEM-EDS was used to study the distribution of La in amorphous-crystalline two phases before and after the leaching test. This research provides an experimental and theoretical analysis to deepen the knowledge of oxyapatite GCs derived from uranium mill tailings as the waste host matrix.\u003c/p\u003e"},{"header":"2 Experimental","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e2.1 Materials\u003c/h2\u003e\u003cp\u003eThe uranium tailing sample, used in this work, was collected from a uranium tailings pond in Hunan Province, China. After drying at 105\u0026deg;C for 24 h and sifting through a 200-mesh sieve, the powder samples were heated at 600℃ for 6 h in a muffle furnace to remove organic matter and volatiles. The composition of the uranium tailings determined by X-ray fluorescence is given in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e\u003csup\u003e[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eOxide composition of uranium tailings\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"12\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c12\" colnum=\"12\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eOxide\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eAl\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eK\u003csub\u003e2\u003c/sub\u003eO\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eNa\u003csub\u003e2\u003c/sub\u003eO\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eFe\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003eSO\u003csub\u003e3\u003c/sub\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003eMgO\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c9\"\u003e\u003cp\u003eCaO\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c10\"\u003e\u003cp\u003eZnO\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c11\"\u003e\u003cp\u003eTiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c12\"\u003e\u003cp\u003eU\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e8\u003c/sub\u003e\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eContent, wt.%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e87.78\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e7.76\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e2.52\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.554\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.941\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0.191\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e0.180\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e0.163\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e0.151\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e0.132\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cp\u003e0.0045\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e2.2 Preparation of samples\u003c/h2\u003e\u003cp\u003eBased on the same outermost electronic structure, similar ionic radius and similar chemical properties, La\u003csup\u003e3+\u003c/sup\u003e (La\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3,\u003c/sub\u003e grade, Shanghai Maclin Biochemical Technology Co.) was selected as the simulated ion of U\u003csup\u003e3+[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]\u003c/sup\u003e. The addition of uranium tailings powders was set as 20 wt% %, 40 wt% %, 50 wt% %, 60 wt% % 70 wt% %, respectively. Na\u003csub\u003e2\u003c/sub\u003eCO\u003csub\u003e3\u003c/sub\u003e (AR grade, Tianjin Tianli Chemical Reagent Co., Ltd) was added with a mass fraction ratio of 8:2 (uranium tailings: Na\u003csub\u003e2\u003c/sub\u003eCO\u003csub\u003e3\u003c/sub\u003e) to lower the sintering temperature of Na\u003csub\u003e2\u003c/sub\u003eO-Al\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e-SiO\u003csub\u003e2\u003c/sub\u003e glass\u003csup\u003e[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]\u003c/sup\u003e. The detailed formula and corresponding sample labels are listed in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. A sample made as U20 refers to the 20 wt% % uranium tailings that were doped. The raw materials were mixed in an agate mortar. Subsequently, the mixed powders were placed into alumina crucibles and dried in a 100\u0026deg;C electric thermostatic drying oven for 6 hours. Finally, the dried powders were sintered at temperatures of 1100, 1200, and 1300℃ for 3 h with a heating rate of 10\u0026deg;C/min in muffle furnace (KSL-1700X-A2,50GHz,5.2kW). The entire sintering process was performed in an air environment, and the sintered samples were natural cooling to room temperature. Figure\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e shows the preparation process of oxyapatite GCs.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eDetailed formula and corresponding sample labels of pre-sintering samples (wt.%)\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"6\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eSamples\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003ePercentage of uranium tailings (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eLa\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e/SiO\u003csub\u003e2\u003c/sub\u003e (mol)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"3\" nameend=\"c6\" namest=\"c4\"\u003e\u003cp\u003eAdditive amount of raw materials, g\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eLa\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eNa\u003csub\u003e2\u003c/sub\u003eCO\u003csub\u003e3\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eUranium tailings\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"4\" rowspan=\"5\"\u003e\u003cp\u003eU20\u003c/p\u003e\u003cp\u003eU40\u003c/p\u003e\u003cp\u003eU50\u003c/p\u003e\u003cp\u003eU60\u003c/p\u003e\u003cp\u003eU70\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.75\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e3.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.21\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.84\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e40\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.26\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e2.02\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.41\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e1.62\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.16\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.51\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.51\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e2.03\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e60\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.09\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.01\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.61\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e2.43\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e70\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.04\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.71\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e2.84\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\u003ch2\u003e2.3 Characterization\u003c/h2\u003e\u003cp\u003eThe phases and compositions of sintered samples were identified by X-ray diffraction (XRD, Rigaku SmartLab SE, Japan, Cu, Kα radiation, λ\u0026thinsp;=\u0026thinsp;1.5406\u0026Aring;). The scanning range of 2θ was set from 10\u0026deg; to 80\u0026deg; with a scanning rate of 5\u0026deg;/min. Scanning electron microscopy (SEM, MIRA4 LMH, TESCAN) equipped with an energy dispersive spectroscopy (EDS; One Max 50, Britain) was utilized to explore the morphology of sintered samples and the distribution features of elements. The concentration of lanthanum ions in the leaching solution was identified using an inductively coupled plasma Optical Emission Spectrometer (ICP-OES, Agilent 5110 ICP-OES, USA).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\u003ch2\u003e2.4 Static leaching experiment\u003c/h2\u003e\u003cp\u003e\u003cul\u003e\u003cli\u003e\u003cp\u003eThe chemical stability of the sintered specimens was evaluated via static leaching experiments (i.e., product consistency tests; PCT) with deionized water as leachate at a controlled temperature of 90\u0026thinsp;\u0026plusmn;\u0026thinsp;1 ℃ over 28 days \u003csup\u003e[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e\u003c/li\u003e\u003c/ul\u003e\u003c/p\u003e\u003cp\u003eFirstly, the five samples sintered at 1300℃ were crushed into powders and sieved between 100 and 200 mesh. Then,1g sample powders were immersed in 10 ml deionized water in a stainless steel container consisting of polytetrafluoroethylene, and the sealed stainless steel containers were placed in an oven at 90\u0026thinsp;\u0026plusmn;\u0026thinsp;1\u0026deg;C. The leaching agent was replaced with a new one at regular intervals (1, 3, 7, 14, and 28 days) and centrifugation of the leachate was carried out to ensure the clarification of the extracted leachate sample and the accuracy of the test data. The concentration of La (C\u003csub\u003eLa\u003c/sub\u003e) in the leachate was analyzed by an inductively coupled plasma Optical Emission Spectrometer (ICP-OES, Agilent 5110icpoes, USA). The normalized leaching rate (LRi, g\u0026middot; m\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e d\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) of La was calculated by Eq.\u0026nbsp;(1)\u003cdiv id=\"Equa\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equa\" name=\"EquationSource\"\u003e\n$$\\:\\begin{array}{c}{\\text{L}\\text{R}}_{\\text{i}}=\\frac{{\\text{C}}_{\\text{i}}}{{\\text{f}}_{\\text{i}}\\bullet\\:\\left(\\frac{\\text{S}\\text{A}}{\\text{V}}\\right)\\bullet\\:\\text{t}} \\left(1\\right) \\end{array}$$\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e"},{"header":"3 Results and discussion","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003e3.1 Analyses using XRD\u003c/h2\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e shows the XRD pattern of samples with increasing uranium tailing sand (20\u0026ndash;70 wt%) after solid-phase sintering at 1100 ℃, 1200 ℃, and 1300 ℃. When the uranium tailing sand addition is 20 wt%, La oxyapatite (NaLa\u003csub\u003e9\u003c/sub\u003e(SiO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e6\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e, PDF#74-2430) appears as the crystalline phase. Compared to a lower temperature (1100 ℃), the diffraction peak of La\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e disappears after sintering at 1200 ℃ and 1300 ℃, indicating that higher temperatures promote the solid phase reaction. With the uranium tailing sand increasing to 40 wt%, a new high-temperature monoclinic phase crystal (G-La\u003csub\u003e2\u003c/sub\u003eSi\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e, PDF#82\u0026ndash;0729) forms as the primary crystalline phase. When the uranium tailing sand content further increases to 50 wt% and 60 wt%, the La\u003csub\u003e2\u003c/sub\u003eSi\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e is detected as the only crystal. However, as seen in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, the proportion of low-temperature tetragonal modification (A-La\u003csub\u003e2\u003c/sub\u003eSi\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e) and high-temperature monoclinic phase (G-La\u003csub\u003e2\u003c/sub\u003eSi\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e) is affected by the uranium tailing sand content and sintered temperatures (1100, 1200, 1300 ℃). The G-La\u003csub\u003e2\u003c/sub\u003eSi\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e is mostly decreased when more uranium tailing sand is used in the starting reagent, and a higher heat treatment temperature promotes the formation of the G-La\u003csub\u003e2\u003c/sub\u003eSi\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e phase.\u003c/p\u003e\u003cp\u003eFor the U50 sample, the diffraction peak intensity of G-La\u003csub\u003e2\u003c/sub\u003eSi\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e at 2θ = (26.1\u0026deg;) increases with the sintering temperature from 1100 ℃ to 1200 ℃; for a higher temperature of 1300 ℃, the diffraction peak intensity barely changes. For the U60 sample, the primary crystalline phase changes from A-La\u003csub\u003e2\u003c/sub\u003eSi\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e to G-La\u003csub\u003e2\u003c/sub\u003eSi\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e from 1100 ℃ to 1300 ℃. When the uranium tailing sand proportion is 70 wt%, the XRD spectrogram of sintered products exhibits obvious amorphous features with the hump between 20\u0026ndash;35\u0026deg;.\u003c/p\u003e\u003cp\u003eAn additional 10 wt% of Al\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e was added as an internal standard, employing Rietveld refinement to quantify the weight fractions of the components (including crystalline and amorphous phases) of the GCs\u003csup\u003e[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]\u003c/sup\u003e. The fitting is plotted in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e and the main refinement parameters of the processing\u003csup\u003e[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]\u003c/sup\u003e, the corresponding crystallographic data, and the quantitative fractions of sintered glass-ceramics are given in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. The difference profile was nearly flat, signifying that the observed and calculated profiles were in very good agreement with an acceptable χ\u003csup\u003e2\u003c/sup\u003e (χ\u003csup\u003e2\u003c/sup\u003e represents goodness of fit of parameter refinement) value of 5.62 and 5.20, respectively.\u003c/p\u003e\u003cp\u003eThe Rietveld analysis shows that the content of crystalline phase (NaLa\u003csub\u003e9\u003c/sub\u003e(SiO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e6\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e) and amorphous phases in the U20 samples was 63.80 wt% and 26.2 wt%, respectively. For U50 samples, the content of crystalline phase (La\u003csub\u003e2\u003c/sub\u003eSi\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e) gradually decreased to 34.96 wt%, and on the contrary, the content of the amorphous phases increased to 55.04 wt%. The structure refining showed that the amorphous phases continue to grow with the Uranium tailings.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003ePhase quantification of U20 and U50 samples calcined at 1300℃/3 h by the Rietveld method.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"3\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSample\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eU20\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eU50\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eChemical formula\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNaLa\u003csub\u003e9\u003c/sub\u003e(SiO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e6\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eLa\u003csub\u003e2\u003c/sub\u003eSi\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSpace group\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eP63/m\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eP21/c\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCrystalline phases, %\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e63.80\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e34.96\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAl\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e, %\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e10.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e10.00\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAmorphous, %\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e26.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e55.04\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCalculated multiplicity(g/cm\u003csup\u003e3\u003c/sup\u003e)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e5.274\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4.730\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ea, \u0026Aring;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e9.69089\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e5.40655\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eb, \u0026Aring;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e9.69089\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e8.79787\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ec, \u0026Aring;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e7.19094\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e14.19003\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eα, \u0026deg;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e90\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e90\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eβ, \u0026deg;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e90\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e112\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eγ, \u0026deg;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e120\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e90\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eV(\u0026Aring;3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e584.849\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e626.312\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eReliability factors, %\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eRwp\u0026thinsp;=\u0026thinsp;15.5, RB\u0026thinsp;=\u0026thinsp;6.36,\u003c/p\u003e\u003cp\u003eχ\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;5.62, Rexp\u0026thinsp;=\u0026thinsp;6.55,\u003c/p\u003e\u003cp\u003eRp\u0026thinsp;=\u0026thinsp;11.50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eRwp\u0026thinsp;=\u0026thinsp;13.4, RB\u0026thinsp;=\u0026thinsp;10.7,\u003c/p\u003e\u003cp\u003eχ\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;5.20, Rexp\u0026thinsp;=\u0026thinsp;5.88,\u003c/p\u003e\u003cp\u003eRp\u0026thinsp;=\u0026thinsp;10.40\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e*The reliability factors of the refinement are Rwp, R-Bragg, the chi-squared χ2 = (Rwp/Rexp)\u003csup\u003e2\u003c/sup\u003e, Rexp, Rp, where Rwp indicates the success of the refinement, R-Bragg is the crystallographic model to fit the experimental data, χ2 represents the goodness of fit of parameter refinement, Rexp is the best residual in theory, and Rp is the average deviation between fitted and experimental curves.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e\u003ch2\u003e3.2 Analyses using SEM and EDS\u003c/h2\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe SEM images, EDS surface scanning images and EDS spectra of samples with various uranium tailing sand (20\u0026ndash;70 wt%) after heat treatment at 1300 ℃ are presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e. For samples of U20, figure (a) indicates that the micron size rod-shaped crystals with a hexagonal cross-section are precipitated\u003csup\u003e[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]\u003c/sup\u003e, which is confirmed to be NaLa\u003csub\u003e9\u003c/sub\u003e(SiO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e6\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e. The EDS surface scanning analysis (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e(a2)) shows that the La is enriched in the crystalline phases. For U40 samples (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e(b, b5)), some irregularly shaped grains and small particles appear, and La is enriched in the crystals compared to the glass substrate. The SEM micrograph of U50 and U60 glass-ceramic specimens (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e(c-d)) shows that disorder-distributed needle-like growth forms are developed. La is predominantly fixed within the crystalline structure (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e(c5, d5). For U70 samples (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e(e, e4)), no grain forms, the La element is evenly distributed in the smooth and amorphous glass matrix.\u003c/p\u003e\u003cp\u003eThe corresponding EDS spectra results for the glass-ceramic forms of U20, U40, U50, U60, U70 presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e(a6, b9, c9, d8, e7) show that the weight ratios of La are 69.95%, 30.14%, 18.12%, 19.41% and 10.12%, respectively. This result indicates that the glass-ceramic product obtained from 20 wt% uranium tailing sand addition with La oxyapatite (NaLa\u003csub\u003e9\u003c/sub\u003e(SiO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e6\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e) as the primary phase is an ideal matrix to immobilize La.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e\u003ch2\u003e3.3 Chemical durability\u003c/h2\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e shows the normalized leaching rate of La over time in the lanthanum-containing glass ceramics sintered at 1300℃ with various amounts of uranium tailings. It is observed that the normalized leaching rate curves of La in the series of solidified bodies decrease sharply in the initial 7 days, then flatten out with the prolongation of leaching time. After 28 days, the LR\u003csub\u003eLa\u003c/sub\u003e of all sintered samples are expected to remain relatively stable (i.e., they all fell below 6.52\u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;4\u003c/sup\u003e g\u0026middot;m\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e\u0026middot;day\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e). Throughout the entire leaching process, the normalized leaching rate of La in the U20 sample is the lowest among various glass-ceramics of U20-U70. This is because of the high proportion of crystalline phase (NaLa\u003csub\u003e9\u003c/sub\u003e(SiO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e6\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e) in the U20 sample. However, glass-ceramics with La\u003csub\u003e2\u003c/sub\u003eSi\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e as the primary crystal phase (U40, U50, U60) have comparable leaching rates of La to the amorphous glass waste form (U70). This indicates that the crystalline phase (NaLa\u003csub\u003e9\u003c/sub\u003e(SiO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e6\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e) is a more ideal matrix to immobilize La element compared to La\u003csub\u003e2\u003c/sub\u003eSi\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e\u003csup\u003e[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e presents a comparison of the leaching rate of the La element of specific waste forms. The leaching rate of La in U20 sample is 1.6\u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;5\u003c/sup\u003eg\u0026middot;m\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e\u0026middot;day\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e (28d), which is lower than the values reported as 4\u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;4\u003c/sup\u003eg\u0026middot;m\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e\u0026middot;day\u003csup\u003e\u0026minus;\u0026thinsp;1 [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]\u003c/sup\u003e and 2.5\u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;5\u003c/sup\u003eg\u0026middot;m\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e\u0026middot;day\u003csup\u003e\u0026minus;\u0026thinsp;1 [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]\u003c/sup\u003e. And the one-step cooling procedure used in our study is simpler than the secondary heat treatment for crystallization \u003csup\u003e[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]\u003c/sup\u003e. Compared to the value reported as 4.9\u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;8\u003c/sup\u003eg\u0026middot;m\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e\u0026middot;day\u003csup\u003e\u0026minus;\u0026thinsp;1 [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]\u003c/sup\u003e, our leaching result may not be good, but U20 samples have a higher La solid solubility of 69.95wt% than the basaltic glasses with La capacity of 16.29 wt% \u003csup\u003e[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]\u003c/sup\u003e. So then oxyapatite GCs derived from uranium mill tailings in our study have considerable chemical durability\u003csup\u003e[\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eLR\u003csub\u003eLa\u003c/sub\u003e of specific waste forms according to the literature\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSolidification forms\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePrecursors\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eTreatment\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eLeaching rate of La\u003csup\u003e3+\u003c/sup\u003e (g\u0026middot;m\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e\u0026middot;d\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eRef\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSodium borosilicate glass matrix incorporated with simulated HLW.\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eA sodium borosilicate glass matrix with composition of 2SiO\u003csub\u003e2\u003c/sub\u003e-B\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e-Na\u003csub\u003e2\u003c/sub\u003eO (in mol%) and 19 wt% waste oxide (Rb\u003csub\u003e2\u003c/sub\u003eO, Cs\u003csub\u003e2\u003c/sub\u003eO, SrO, BaO, ZrO\u003csub\u003e2\u003c/sub\u003e, MoO\u003csub\u003e3\u003c/sub\u003e and La\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eConventional sintering (950℃ 30min)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e4\u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;4\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u003csup\u003e[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eGlass-ceramics with CaLa\u003csub\u003e4\u003c/sub\u003e(SiO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003eO as the main phase\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eParent glass with the chemical composition of 9Na\u003csub\u003e2\u003c/sub\u003eO-15CaO-9La\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e-15B\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e-52SiO\u003csub\u003e2\u003c/sub\u003e (in mol%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eMelt cooling method (1300℃ 2h) and queching for base glass, then 900 ℃ 2h for crystalization to glass-ceramic\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e2.5\u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;5\u003c/sup\u003e(14d)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u003csup\u003e[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eThe simulated actinides basaltic glass\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eThe mixture of 68 wt% basaltic glass\u003c/p\u003e\u003cp\u003e10.30 wt% Nd\u003csub\u003e2\u003c/sub\u003eO, 3.41wt% CeO\u003csub\u003e2\u003c/sub\u003e and 16.29wt% La\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e oxides\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eThe solid-state melt method (1400℃ 3h)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e4.9\u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;8\u003c/sup\u003e(56d)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u003csup\u003e[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eLa-containing glass\u0026mdash; ceramics\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eThe mixture of uranium tailings, La\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e and Na\u003csub\u003e2\u003c/sub\u003eCO\u003csub\u003e3\u003c/sub\u003e oxides\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eHigh-temperature solid-state method (1300℃ 3h)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.6\u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;5\u003c/sup\u003e(28d)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003ethis work\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\u003ch2\u003e3.4 Micromorphology analysis\u003c/h2\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eTo further identify the La elements' leaching characteristics in crystal and amorphous structures, the surfaces of U20 samples prepared at 1300℃ before and after the 28-day leaching test were characterized through transmission electron microscopy (TEM). The TEM image, selected area electron diffraction (SAED) analysis, and element mapping images are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e. From the micro-topography of Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e (a) and (d), no changes were found in the powder particles before and after leaching. The observed zone of U20 sample particles exhibited clear lattice fringes; the measured interplanar spacing (d) was found to be 0.42 nm, which was well matched with the spacing of the (2 0 0) plane of NaLa\u003csub\u003e9\u003c/sub\u003e(SiO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e6\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e crystal. And the interplanar spacing values are the same and in good agreement with Rietveld refinement results before and after the leaching, indicating that no lattice distortion or phase change of NaLa\u003csub\u003e9\u003c/sub\u003e(SiO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e6\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e occurred during the leaching test. Expect the crystalline region, it was seen from Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e (b) and (e) that an amorphous phase with a disordered structure marked as Region B and D also existed. The SAED diagrams of U20 samples before and after leaching are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e (c) and (f), and the crystal plane parameters were calibrated as shown in these figures. It showed both a weak amorphous diffraction ring and a crystal diffraction spot, which further verified that the U20 sample was a typical glass-ceramic structure.\u003c/p\u003e\u003cp\u003eConcerning the distribution of elements, it can be found from Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e (g) and (h) that the Na, O, and Si elements were evenly distributed, and the mapping images hardly changed before and after leaching. The La element enrichment in the crystalline phase was easy to find in the TEM-EDS measurements of areas A, B, C, and D; the detailed information is listed in the Table. 5.\u003c/p\u003e\u003cp\u003eNo matter before or after leaching, it was interesting to identify from Energy dispersive spectroscopy (EDS) of regions A and C in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e (b) and (e) that the mass fraction of La (49.2 wt% and 54.6wt%) was lower than the result (69.95%) from SEM-EDS in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e(a6). This was mainly attributed to the fact that the La element scanned by the TEM-EDS was composed of the crystalline section and amorphous region. A theoretical value of La content can be calculated from a formula as follows:\u003cdiv id=\"Equb\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equb\" name=\"EquationSource\"\u003e\n$$\\:\\text{L}\\text{a}\\:\\text{r}\\text{a}\\text{t}\\text{i}\\text{o}\\:\\text{i}\\text{n}\\:\\text{G}\\text{C}=\\text{w}\\text{t}\\text{%}\\:\\text{o}\\text{f}\\:\\text{c}\\text{r}\\text{y}\\text{s}\\text{t}\\text{a}\\text{l}\\times\\:\\text{W}1+\\text{w}\\text{t}\\text{%}\\:\\text{o}\\text{f}\\:\\text{g}\\text{l}\\text{a}\\text{s}\\text{s}\\times\\:\\text{W}2$$\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eWhere wt% of crystal\u0026thinsp;=\u0026thinsp;crystalline phase/0.9, wt% of glass\u0026thinsp;=\u0026thinsp;amorphous/0.9, the quantitative mass ratio of crystalline and amorphous phases in the GCs obtained from the rietveld refinement results in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e, but an extra step is needed because 10 wt% Al\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e is in testing sample; W1: the La weight ratios in the NaLa\u003csub\u003e9\u003c/sub\u003e(SiO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e6\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e crystal from SEM-EDS in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e(a6); W2: the La weight ratios in the glass from TEM-EDS in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e(b2). After a simple calculation, a value of 50.61 wt% was obtained, which was near the result (49.2 wt% and 54.6wt%) from the TEM-EDS characterization analysis.\u003c/p\u003e\u003cp\u003eFurthermore, the increase of La content in both the crystalline (54.6wt% vs 49.2 wt%) and amorphous phases (5.81wt% vs 3.53wt%) after the leaching test may be attributed to two reasons: one was the region marked as A and C were not composed of the same grains, region A may include more amorphous section and less crystalline phase, and region C was the opposite; the second was the U20 samples had an excellent chemical durability due to no obvious La depletion after the leaching.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eThe mass fraction of La in crystalline and amorphous regions in the selected area of U20 samples before and after leaching\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"3\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eMass fraction of lanthanum (%)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCrystal\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eAmorphous\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eBefore leaching\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eArea A\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eArea B\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e49.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3.53\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eAfter leaching\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eArea C\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eArea D\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e54.60\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e5.81\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e"},{"header":"4 Conclusion","content":"\u003cp\u003eIn this work, the effect of uranium tailings content on the phase evolution, microstructure, morphology, and chemical durability of the solidified samples prepared by the high-temperature solid-state method was systematically investigated. The XRD results indicated that the primary crystalline phase of the glass-ceramics transitioned from oxyapatite to the high-temperature monoclinic phase crystal (G-La\u003csub\u003e2\u003c/sub\u003eSi\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e) forms with increasing uranium tailings content. When the uranium tailing sand proportion was 70 wt%, the XRD spectrogram of sintered products exhibited obvious amorphous features. The weight fractions of the components (including crystalline and amorphous phases) of the GCs were quantitatively investigated using Rietveld refinement. Within a 20\u0026ndash;50 wt% range, the proportion of crystalline phase in the samples decreased from 63.80% to 34.96% with rising uranium tailings content, while the glassy phase proportion increased. The SEM-EDS test results indicated that when the content of uranium tailings was between 20 and 60 wt%, La was enriched in the crystalline phases. A maximum 69.95% weight ratio of La was verified in the crystalline region of U20 samples, which indicated that the U20 glass-ceramic product with La oxyapatite (NaLa\u003csub\u003e9\u003c/sub\u003e(SiO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e6\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e) as the primary phase is an ideal matrix to immobilize La. The TEM-EDS test results indicated that no lattice distortion or phase change of NaLa\u003csub\u003e9\u003c/sub\u003e(SiO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e6\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e occurred during the leaching test. Through theoretical calculation, the overall content of La in the GCs was consistent with the experimental value, confirming that La oxyapatite GCs could load 49wt%-55wt% La. For the U20 sample, the normalized element leaching rate of La(1.6\u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;5\u003c/sup\u003e g\u0026middot;m\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e\u0026middot;d\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e after 28 days) indicated good chemical durability of the solidified body. The high loading capacity for the immobilization of lanthanides and excellent chemical durability of the solidified body with uranium mill tailings as raw materials bring novel ideas for solving radioactive wastes with low levels and high levels.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cb\u003eFunding Declaration\u003c/b\u003e This work was supported by the Project Approved by the Natural science foundation of Hunan Province (Grant Nos. 2021JJ40463; 2020JJ5463); the Provincial Education Department of Hunan Province, China (No.19A420).\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eHuang Pingping and Chen Mingfeng: Data curation, Investigation, Writing \u0026ndash; original,draft, Writing \u0026ndash; review \u0026amp; editing. Wang Jiajun: Investigation, Methodology, Software. Zou Wanrong:Data curation,Software.Hu Zhitao: Conceptualization, Formal analysis, Methodology, Project administration, Supervision, Writing \u0026ndash; review \u0026amp; editing.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eRavikumar R, Gopal B, Sekar JK, Sriram S, Vijayalakshmi S (2020) Chemical durability studies on multi-rare earths immobilized simulated oxysilicate apatite wasteforms CaLa\u003csub\u003e3.4\u003c/sub\u003eCe\u003csub\u003e0.1\u003c/sub\u003ePr\u003csub\u003e0.1\u003c/sub\u003eNd\u003csub\u003e0.1\u003c/sub\u003eSm\u003csub\u003e0.1\u003c/sub\u003eGd\u003csub\u003e0.1\u003c/sub\u003eY\u003csub\u003e0.1\u003c/sub\u003e(SiO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003eO and Ca\u003csub\u003e0.8\u003c/sub\u003eSr\u003csub\u003e0.1\u003c/sub\u003ePb\u003csub\u003e0.1\u003c/sub\u003eLa\u003csub\u003e3.4\u003c/sub\u003eCe\u003csub\u003e0.1\u003c/sub\u003ePr\u003csub\u003e0.1\u003c/sub\u003eNd\u003csub\u003e0.1\u003c/sub\u003eSm\u003csub\u003e0.1\u003c/sub\u003eGd\u003csub\u003e0.1\u003c/sub\u003eY\u003csub\u003e0.1\u003c/sub\u003e(SiO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003eO. 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J Clean Prod, 268\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003e傅茂洋 廖其龙 (2022) 王辅, 胥有利, 何泽旭, 竹含真, CaO含量对镧硼硅酸盐玻璃陶瓷晶相和化学稳定性的影响[J], vol 41. 硅酸盐通报, pp 3861\u0026ndash;3869\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003e童钦 (2023) 玄武岩玻璃及玻璃陶瓷固化模拟锕系核素的研究[D], 西南科技大学, 98\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLi L, Shu X, Tang H, Chen S, Huang W, Wei G, Shao D, Xie Y, Lu X (2021) Immobilize CeO\u003csub\u003e2\u003c/sub\u003e as simulated nuclear waste in natural magmatic granite: maximum solid solubility. J Radioanal Nucl Chem 328:795\u0026ndash;803\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Oxyapatite glass-ceramics, Lanthanides, Uranium tailings, Phase evolution, chemical durability","lastPublishedDoi":"10.21203/rs.3.rs-7702366/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7702366/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eDue to their high waste loading capacity and excellent chemical durability, rare earth (RE) - oxyapatites are a potential material for the immobilization of nuclear waste. In this work, NaLa\u003csub\u003e9\u003c/sub\u003e(SiO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e6\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e glass-ceramics (GCs) and La\u003csub\u003e2\u003c/sub\u003eSi\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e GCs derived from different contents of uranium tailings were synthesized by the solid-state method to immobilize lanthanides (La). The effect of uranium tailings content and sintering temperature on the phase evolution and chemical durability of the solidified samples was systematically investigated. Rietveld refinement analysis was used to obtain the ratios of crystalline-glass phases in the GCs, and the La element distribution between different phases before and after the leaching test was characterized by TEM-EDS. Results demonstrated that U20 (20 wt% uranium tailing addition) samples were an ideal waste form to immobilize La. The U20 sample had a 63.80 wt% proportion of crystalline phase, and the proportion of La element on the crystalline phase was 69.95 wt%, which was obviously larger than the La content of 3.53\u0026ndash;5.81 wt% on the vitreous part. ASTM Product Consistency Test (PCT) results indicated that U20 samples had the lowest La leaching rate over the 28-day leaching period, U40, U50, and U60 samples with La\u003csub\u003e2\u003c/sub\u003eSi\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e as the main crystalline phase had similar leaching values with U70 samples, which were pure glass phase. After the leaching test, no lattice distortion or phase change happened on the NaLa\u003csub\u003e9\u003c/sub\u003e(SiO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e6\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e crystalline phase.\u003c/p\u003e","manuscriptTitle":"Distribution and leaching characteristics of La element in oxyapatite glass-ceramic derived from uranium tailings","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-10-27 11:42:07","doi":"10.21203/rs.3.rs-7702366/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"a8ff6494-5c17-42bb-b4fe-d1bd8031a0a3","owner":[],"postedDate":"October 27th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-02-09T16:05:32+00:00","versionOfRecord":{"articleIdentity":"rs-7702366","link":"https://doi.org/10.1007/s10967-026-10727-0","journal":{"identity":"journal-of-radioanalytical-and-nuclear-chemistry","isVorOnly":false,"title":"Journal of Radioanalytical and Nuclear Chemistry"},"publishedOn":"2026-02-03 15:57:52","publishedOnDateReadable":"February 3rd, 2026"},"versionCreatedAt":"2025-10-27 11:42:07","video":"","vorDoi":"10.1007/s10967-026-10727-0","vorDoiUrl":"https://doi.org/10.1007/s10967-026-10727-0","workflowStages":[]},"version":"v1","identity":"rs-7702366","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7702366","identity":"rs-7702366","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}