Qualitative Assessment of PC88A and HBTA Extractants in Lithium Recovery Processes Using Solvent Extraction

Qualitative Assessment of PC88A and HBTA Extractants in Lithium Recovery Processes Using Solvent Extraction | 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 Qualitative Assessment of PC88A and HBTA Extractants in Lithium Recovery Processes Using Solvent Extraction Junhyung Seo, Thang Toan Vu, Seungu Cho, Jieun Cha, Yeongeun Choi, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4593022/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 26 Nov, 2024 Read the published version in Korean Journal of Chemical Engineering → Version 1 posted 5 You are reading this latest preprint version Abstract This study compares the solvent extraction behavior of lithium (Li) using the cost-effective extractant PC88A and the more expensive extractant HBTA. PC88A achieved an optimal extraction rate of 37.6% at pH 5.43, with a maximum rate of 41.4% at pH 7.80. It required six stages at a 5/1 O/A ratio for 98% extraction and three stages at a 15/1 ratio for 100% extraction. In contrast, HBTA showed an optimal extraction rate of 86.2% at pH 6.23 and a maximum rate of 92.9% at pH 11.95. HBTA achieved 100% extraction with three stages at a 1/1 O/A ratio and one stage at a 5/1 ratio. These findings reveal HBTA's striking superiority over PC88A in terms of efficiency. Future studies should include evaluations of equipment and extractant costs, and overall efficiency. Waste battery recycling Solvent extraction Lithium PC88A HBTA Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 1. Introduction Electric vehicles (EVs) have recently gained attention as a revolutionary means to significantly reduce greenhouse gas emissions [ 1 ]. Consequently, governments are proposing subsidies for electric vehicles and charging infrastructure, expanding support for eco-friendly vehicle development policies [ 2 ]. The implementation of these government initiatives has resulted in a significant rise in the number of electric vehicle (EV) registrations. By the end of 2021, EV registrations increased by 71.5% compared to the previous year. As a result, there is an expected surge in demand for lithium-ion batteries (LiBs), which are used in EVs. [ 3 ]. Nevertheless, the typical lifespan of an EV battery is limited to a range of 5 to 10 years, indicating a potential significant problem of accumulating discarded EV batteries [ 4 ]. Additionally, lithium-ion batteries primarily use metals such as lithium, cobalt, and nickel as key raw materials. However, 82% of lithium reserves are concentrated in Chile, Australia, Argentina, and China, meaning that countries like ours rely heavily on imports for metal resource supply [ 5 ]. This dependence highlights the need for a stable supply of raw materials and has spurred research into processes for separating and recovering rare metals from waste batteries. Recycling end-of-life batteries as a circular resource not only addresses raw material shortages but also mitigates environmental issues from battery landfill disposal [ 6 ]. Various methods such as evaporation, precipitation, and solvent extraction are used to recover valuable metals from LiBs [ 7 ]. Among these, solvent extraction is frequently employed in metal recovery technology due to its high recovery efficiency and low energy consumption [ 8 ]. Solvent extraction involves a continuous process in which manganese, cobalt, nickel, and lithium are sequentially extracted from the cathode material of LiBs [ 9 ]. Typically, the extraction efficiency increases when the pH of the aqueous phase containing metal ions increases. Therefore, it is necessary to employ a saponification process utilizing sodium hydroxide (NaOH) in order to neutralize the extractant. Manganese, cobalt, and nickel, which are extracted before lithium, achieve nearly 100% extraction rates using D2EHPA, Cyanex 272, and PC88A extractants, respectively [ 9 – 13 ]. During the extraction process, the concentration of sodium ions in the liquid phase increases, leading to a higher concentration of sodium ions compared to lithium ions in the final liquid phase [ 10 ]. The disparity in concentration poses a challenge to the extraction of lithium ions with conventional extractants [ 14 ]. Therefore, new extractants like ether crowns or combinations of existing extractants such as β-diketones and neutral ligands are being researched to improve lithium extraction efficiency [ 15 – 16 ]. The typical extractants in metal extraction processes are phosphorus-based, containing P-OH or P-SH groups [ 17 ]. Phosphorus-based extractants are also preferred for their cost-effectiveness compared to other extractants. One of the most studied phosphorus-based extractants is PC88A, which can applied widely in Mn, Co, and Ni extraction. However, using PC88A in lithium extraction results in an extraction rate of about 50% at optimal pH, which is significantly lower than for other metals [ 18 ]. In contrast, HBTA, a type of β-diketone extractant, forms chelates more easily with lithium ions than with sodium, resulting in higher lithium selectivity [ 14 ]. Additionally, TOPO, a neutral ligand, acts as a strong electron donor when combined with HBTA, leading to higher lithium extraction rates than using HBTA alone [ 14 ]. Hence, the combination of HBTA and TOPO overcomes the drawbacks of phosphorus-based extractants, making it suitable for recovering lithium from solutions with high Na/Li molar ratios [ 19 ]. However, β-diketones and neutral ligands like HBTA and TOPO are more expensive than phosphorus-based extractants [ 7 ]. The trade-off between the cost of the extractant and the cost of the entire extraction system is unaddressed. Although research has made progress in creating new extractants to improve the efficiency of lithium extraction, there is still an absence of assessments that compare the commonly employed extractants, taking into account their strengths and weaknesses. This study presents a comparative analysis of two commonly employed extractants: PC88A, a phosphorus-based extractant, and the HBTA-TOPO combination, which consists of a β-diketone and a neutral ligand. This research establishes the optimal operating conditions for each extractant by standardizing the concentration conditions, using pH isotherms and McCabe-Thiele experimental data. The main contribution of this study lies in its assessment of the economic and operational efficiencies of these two extractants. It provides important insights into their practical use and offers guidance for future endeavors in improving lithium recovery processes. 2. Experimental Materials and Methods To investigate the lithium (Li) extraction behavior under feed conditions with a low Li concentration relative to sodium (Na), an aqueous solution with the composition shown in Table 1 was used[ 17 ]. The aqueous phase was prepared by dissolving lithium sulfate monohydrate (Li 2 SO 4 ∙H 2 O) and sodium sulfate (Na 2 SO 4 ) in distilled water. The solution was stirred thoroughly for approximately 20 minutes using a magnetic stirrer. Table 1 Concentration of Feed Li Na g/L 1.85 31.2 To compare the Li extraction rates, the extractants used were PC88A (2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester), a phosphorus-based extractant, HBTA (benzoyltrifluoroacetone), a β-diketone extractant, and TOPO (tri-n-octyl phosphine oxide), a neutral ligand used with β-diketones. D80 was used as a diluent to adjust the concentration of the extractants. The organic phase, comprising HBTA, TOPO, and D80, was also thoroughly stirred for about 20 minutes using a magnetic stirrer. The saponification of the organic phase involved adding NaOH and stirring again for approximately 20 minutes. The prepared aqueous and organic phases were introduced into a 250 mL separatory funnel in appropriate volumes according to the O/A (organic-to-aqueous) ratio. The phases were then mixed at 350 RPM in a shaking incubator for 10 minutes, followed by a stabilization period of 6 minutes to allow phase separation. During the stabilization period, any small droplets of the organic phase attached to the inside of the funnel's aqueous phase were removed by partially draining the aqueous phase and reintroducing it at the top of the funnel. This process was repeated three times. All experiments were conducted at room temperature. After the 6-minute stabilization period, complete phase separation was observed, and the aqueous phase was filtered to measure the equilibrium pH. The aqueous phase was then diluted, and the concentrations of metals were measured using inductively coupled plasma optical emission spectroscopy(ICP-OES). The extraction rate was calculated using the following Eq. (1): $$Extraction\left(\text{%}\right)= \frac{{C}_{0}-{C}_{eq}}{{C}_{0}} \times 100 \cdots \left(1\right)$$ where C 0 is the initial Li concentration in the aqueous phase, and C eq is the Li concentration in the aqueous phase after extraction. 3. Results and Discussion 3.1 Lithium Extraction Behavior According to Equilibrium pH The lithium (Li) extraction process using each extractant proceeds according to equations (2) and (3): $$HA\left(org\right)+ NaOH\left(aq\right)\to NaA\left(org\right)+ {H}_{2}O \cdots \left(2\right)$$ $${Li}^{+}\left(aq\right)+ NaA\left(org\right)\to LiA\left(org\right)+ {Na}^{+}\left(aq\right)\cdots \left(3\right)$$ During continuous solvent extraction, the hydrogen ions from the extractant (HA) cause the pH of the aqueous phase to decrease, reducing the driving force for extraction. To prevent this, the extractant must be saponified in advance, as shown in Eq. (2). The lithium extraction process using the saponified extractant proceeds as shown in Eq. (3). We analyzed the lithium extraction behavior (pH isotherm) according to the equilibrium pH for 0–100% saponification of 0.4M PC88A and 0.4M HBTA-TOPO under equal organic-to-aqueous phase ratio (O/A ratio) conditions of 1/1. The results are presented in Figs. 1 and 2 . Both extractants showed an increase in lithium extraction rate as the equilibrium pH increased. For PC88A (Fig. 1 ), the extraction rate rose sharply from an equilibrium pH of 3.11 (0% saponification) to 5.43 (40% saponification). However, beyond an equilibrium pH of 5.43, further increases in pH did not significantly affect the extraction rate. Consequently, an equilibrium pH of 5.43, with a noticeable extraction rate of approximately 37.6%, was deemed optimal. For HBTA (Fig. 2 ), the extraction rate increased sharply from an equilibrium pH of 2.84 (0% saponification) to 6.23 (70% saponification). Similarly, beyond an equilibrium pH of 6.23, further increases in pH did not significantly affect the extraction rate. Thus, an equilibrium pH of 6.23, with a prominent extraction rate of approximately 86.2%, was considered optimal. 3.2 Lithium Extraction Behavior According to O/A Ratio To identify the optimal O/A ratio, we investigated lithium extraction behavior at various O/A ratios under the optimal pH conditions for each extractant. The volumes of the aqueous and organic phases were adjusted within the range of 10 mL to 90 mL, considering the size of the separatory funnel and mixing efficiency. Experiments were conducted at O/A ratios ranging from 1/15 to 10/1. However, the condition of O/A ratio 15/1 was excluded due to the high viscosity, which significantly reduced mixing efficiency. PC88A experiments were conducted within a pH range of 5.33 to 5.53, and HBTA experiments within a pH range of 6.13 to 6.33, reflecting a pH error margin of ± 0.1. The saponification rate was adjusted by controlling the amount of NaOH to meet these pH ranges. Figures 3 and 4 present the lithium extraction rate behavior according to O/A ratio. For both extractants, the lithium extraction rate increased with the O/A ratio. PC88A (Fig. 3 ) showed a continuous increase in extraction rate as the O/A ratio changed from 1/15 to 10/1, without identifying an optimal O/A ratio. However, HBTA (Fig. 4 ) exhibited a significant increase in extraction rate from an O/A ratio of 1/15 to 1/1, beyond which no further substantial increase was observed. Thus, the optimal O/A ratio for HBTA was determined to be 1/1. Figures 3 and 4 indicate that there are significant differences in the O/A ratio operating conditions needed to achieve similar lithium extraction rates for PC88A and HBTA. For instance, PC88A achieved a 63.7% extraction rate at an O/A ratio of 5/1, while HBTA achieved a 64.7% extraction rate at an O/A ratio of 1/2. Therefore, assuming the same volume of the aqueous phase, approximately ten times the amount of extractant is required for PC88A to achieve similar lithium extraction rates as HBTA. 3.3 Qualitative Economic Evaluation Using McCabe-Thiele Diagram In continuous solvent extraction processes, the theoretical number of extraction stages is typically determined using the McCabe-Thiele Diagram. We used the lithium extraction rate data according to O/A ratio from Figs. 3 and 4 to plot McCabe-Thiele Diagrams based on the Li concentrations in the aqueous and organic phases after extraction. The curve represents the equilibrium line, derived from experimental data at O/A ratios ranging from 1/15 to 10/1. The straight line represents the operating line, with its slope corresponding to the A/O ratio. By adjusting the slope of the operating line to reflect the respective O/A ratios, we compared the number of extraction stages required for each extractant. Figure 6 shows the McCabe-Thiele Diagram for HBTA under its optimal operating condition of 1/1 O/A ratio. To achieve 100% extraction of 1.85 g/L Li present in the initial aqueous phase, three extraction stages are required. For comparison, the McCabe-Thiele Diagram for PC88A achieving three stages is shown in Fig. 5 at a 15/1 O/A ratio. Achieving 100% Li extraction using three extraction stages requires HBTA at 0.4M concentration, 70% saponification, and a 1/1 O/A ratio. In contrast, PC88A requires a 0.4M concentration, 40% saponification, and a 15/1 O/A ratio. The 15-fold difference in O/A ratio implies that, under the same aqueous phase volume, the mixer-settler unit volume for PC88A must be more than 15 times larger than that for HBTA. Additionally, such a large O/A ratio as 15/1 can decrease mixing efficiency. Figures 7 and 8 compare the number of extraction stages required for both extractants under the same O/A ratio condition. PC88A could not generate a proper McCabe-Thiele Diagram at lower O/A ratios like 1/1 and 3/2, so the comparison was made at 5/1. Figure 7 indicates that at a 5/1 O/A ratio, achieving approximately 98% Li extraction requires six stages for PC88A. Conversely, Fig. 8 shows that at the same 5/1 O/A ratio, HBTA requires only one stage for approximately 98% Li extraction and two stages for 100% extraction. Thus, at a 5/1 O/A ratio, PC88A requires six times more extraction stages than HBTA to achieve similar lithium extraction rates. 4. Conclusion This study compared the solvent extraction behavior of lithium (Li) from an aqueous solution with a low Li concentration relative to sodium (Na) using two different extractants: the cost-effective phosphorus-based extractant PC88A and the more expensive β-diketone extractant HBTA. Both extractants demonstrated an increase in Li extraction rate with the increase in equilibrium pH and O/A ratio. For 0.4M PC88A, the extraction rate was 37.6% at an equilibrium pH of 5.43, which was determined to be the optimal pH condition. The maximum extraction rate was 41.4% at an equilibrium pH of 7.80. The Li extraction rate continued to increase with O/A ratios ranging from 1/15 to 10/1, preventing the determination of an optimal O/A ratio. The McCabe-Thiele Diagram indicated that 98% Li extraction could be achieved with six stages at an O/A ratio of 5/1, and 100% Li extraction could be achieved with three stages at an O/A ratio of 15/1. For 0.4M HBTA, the extraction rate was 86.2% at an equilibrium pH of 6.23, identified as the optimal pH condition. The maximum extraction rate was 92.9% at an equilibrium pH of 11.95. The Li extraction rate did not significantly increase beyond an O/A ratio of 1/1, establishing this as the optimal O/A ratio. The McCabe-Thiele Diagram showed that 100% Li extraction could be achieved with three stages at an O/A ratio of 1/1, and 100% Li extraction could be achieved with one stage at an O/A ratio of 5/1. Therefore, when comparing the two extractants at the same concentration of 0.4M, it was found that to achieve similar extraction efficiencies, the O/A ratio for PC88A was 15/1 compared to 1/1 for HBTA, resulting in a 15-fold difference in organic phase volume. Similarly, at the same O/A ratio of 5/1, PC88A required six stages compared to just one stage for HBTA, indicating a six-fold difference in the number of extraction stages. Consequently, this qualitative evaluation suggests that HBTA is significantly more advantageous than PC88A in terms of operational efficiency at the same extractant concentration of 0.4M. Future quantitative evaluations should consider the electrical efficiency and equipment costs when using large-volume mixer-settlers, as well as the bulk extractant prices, to provide a more comprehensive economic comparison. Declarations Acknowledgments This work was supported the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. 2021R1F1A1048416), and the Graduate School of Chemical Characterization hosted by the Korean Ministry of Environment. References Korea Energy Economics Institute., (2018). 전기차 사용후 배터리 거래시장 구축을 위한 정책연구. (18-16) Wang, Dangyang., (2022) A Comparative Study on the Technological inovation bewtween Chinese and Korean Battery Industry: Focusing on CATL and LG Chemistry. (Master's Thesis, Department of Management of Technology and Innovation, Korea University of Technology Education) MINISTRY OF LAND, INFRASTRUCTURE AND TRANSPORT. 05.24, Total Registered Motor Vehicles., http://stat.molit.go.kr. 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Cite Share Download PDF Status: Published Journal Publication published 26 Nov, 2024 Read the published version in Korean Journal of Chemical Engineering → Version 1 posted Editorial decision: Major Revisions Needed 02 Aug, 2024 Reviewers agreed at journal 30 Jun, 2024 Reviewers invited by journal 30 Jun, 2024 Editor assigned by journal 19 Jun, 2024 First submitted to journal 17 Jun, 2024 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-4593022","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":320790046,"identity":"811a20a5-2d64-43c9-ab6c-561a50d01dad","order_by":0,"name":"Junhyung Seo","email":"","orcid":"","institution":"Chonnam University: Chonnam National University","correspondingAuthor":false,"prefix":"","firstName":"Junhyung","middleName":"","lastName":"Seo","suffix":""},{"id":320790047,"identity":"d83cb6d3-8bd4-49ad-87dc-1972f03fbe4a","order_by":1,"name":"Thang Toan Vu","email":"","orcid":"","institution":"Chonnam University: Chonnam National 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4","display":"","copyAsset":false,"role":"figure","size":40711,"visible":true,"origin":"","legend":"\u003cp\u003e0.4M HBTA Li extraction rate vs. O/A ratio\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-4593022/v1/b4b0f0c14f645c3dae1f4ba9.png"},{"id":61017666,"identity":"d3e7c8b6-3f86-4c83-a1af-b96342876fad","added_by":"auto","created_at":"2024-07-24 15:36:54","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":60458,"visible":true,"origin":"","legend":"\u003cp\u003e0.4M PC88A McCabe-Thiele Diagram at 15/1 O/A ratio\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-4593022/v1/057988bb1be3228c4468e304.png"},{"id":61018270,"identity":"2489bc32-f349-4592-bfc6-d9e1ba54704f","added_by":"auto","created_at":"2024-07-24 15:44:55","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":60726,"visible":true,"origin":"","legend":"\u003cp\u003e0.4M HBTA-TOPO McCabe-Thiele Diagram at 1/1 O/A ratio\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-4593022/v1/0713c22a376216aa44e3f355.png"},{"id":61018272,"identity":"ab17bec6-5b31-4d9e-9b05-b09b5ad41ccb","added_by":"auto","created_at":"2024-07-24 15:44:55","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":60428,"visible":true,"origin":"","legend":"\u003cp\u003e0.4M PC88A McCabe-Thiele Diagram at 5/1 O/A ratio\u003c/p\u003e","description":"","filename":"floatimage7.png","url":"https://assets-eu.researchsquare.com/files/rs-4593022/v1/21ee65ff5c38721e4acfeb02.png"},{"id":61017674,"identity":"0313c568-85a7-4d05-bb70-a522d0ba0277","added_by":"auto","created_at":"2024-07-24 15:36:55","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":56313,"visible":true,"origin":"","legend":"\u003cp\u003e0.4M HBTA-TOPO McCabe-Thiele Diagram at 5/1 O/A ratio\u003c/p\u003e","description":"","filename":"floatimage8.png","url":"https://assets-eu.researchsquare.com/files/rs-4593022/v1/c284eac0df1d9e6e6e3bd926.png"},{"id":70389198,"identity":"dcef5cb3-7068-4a38-8b0b-2e3fbe472a08","added_by":"auto","created_at":"2024-12-02 17:28:17","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":664062,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4593022/v1/b6a76a12-d3f1-4663-870b-cb3d8c005288.pdf"}],"financialInterests":"","formattedTitle":"Qualitative Assessment of PC88A and HBTA Extractants in Lithium Recovery Processes Using Solvent Extraction","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eElectric vehicles (EVs) have recently gained attention as a revolutionary means to significantly reduce greenhouse gas emissions [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Consequently, governments are proposing subsidies for electric vehicles and charging infrastructure, expanding support for eco-friendly vehicle development policies [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. The implementation of these government initiatives has resulted in a significant rise in the number of electric vehicle (EV) registrations. By the end of 2021, EV registrations increased by 71.5% compared to the previous year. As a result, there is an expected surge in demand for lithium-ion batteries (LiBs), which are used in EVs. [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Nevertheless, the typical lifespan of an EV battery is limited to a range of 5 to 10 years, indicating a potential significant problem of accumulating discarded EV batteries [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Additionally, lithium-ion batteries primarily use metals such as lithium, cobalt, and nickel as key raw materials. However, 82% of lithium reserves are concentrated in Chile, Australia, Argentina, and China, meaning that countries like ours rely heavily on imports for metal resource supply [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. This dependence highlights the need for a stable supply of raw materials and has spurred research into processes for separating and recovering rare metals from waste batteries. Recycling end-of-life batteries as a circular resource not only addresses raw material shortages but also mitigates environmental issues from battery landfill disposal [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eVarious methods such as evaporation, precipitation, and solvent extraction are used to recover valuable metals from LiBs [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Among these, solvent extraction is frequently employed in metal recovery technology due to its high recovery efficiency and low energy consumption [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Solvent extraction involves a continuous process in which manganese, cobalt, nickel, and lithium are sequentially extracted from the cathode material of LiBs [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Typically, the extraction efficiency increases when the pH of the aqueous phase containing metal ions increases. Therefore, it is necessary to employ a saponification process utilizing sodium hydroxide (NaOH) in order to neutralize the extractant. Manganese, cobalt, and nickel, which are extracted before lithium, achieve nearly 100% extraction rates using D2EHPA, Cyanex 272, and PC88A extractants, respectively [\u003cspan additionalcitationids=\"CR10 CR11 CR12\" citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. During the extraction process, the concentration of sodium ions in the liquid phase increases, leading to a higher concentration of sodium ions compared to lithium ions in the final liquid phase [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. The disparity in concentration poses a challenge to the extraction of lithium ions with conventional extractants [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Therefore, new extractants like ether crowns or combinations of existing extractants such as β-diketones and neutral ligands are being researched to improve lithium extraction efficiency [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe typical extractants in metal extraction processes are phosphorus-based, containing P-OH or P-SH groups [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Phosphorus-based extractants are also preferred for their cost-effectiveness compared to other extractants. One of the most studied phosphorus-based extractants is PC88A, which can applied widely in Mn, Co, and Ni extraction. However, using PC88A in lithium extraction results in an extraction rate of about 50% at optimal pH, which is significantly lower than for other metals [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. In contrast, HBTA, a type of β-diketone extractant, forms chelates more easily with lithium ions than with sodium, resulting in higher lithium selectivity [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Additionally, TOPO, a neutral ligand, acts as a strong electron donor when combined with HBTA, leading to higher lithium extraction rates than using HBTA alone [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Hence, the combination of HBTA and TOPO overcomes the drawbacks of phosphorus-based extractants, making it suitable for recovering lithium from solutions with high Na/Li molar ratios [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. However, β-diketones and neutral ligands like HBTA and TOPO are more expensive than phosphorus-based extractants [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. The trade-off between the cost of the extractant and the cost of the entire extraction system is unaddressed.\u003c/p\u003e \u003cp\u003eAlthough research has made progress in creating new extractants to improve the efficiency of lithium extraction, there is still an absence of assessments that compare the commonly employed extractants, taking into account their strengths and weaknesses. This study presents a comparative analysis of two commonly employed extractants: PC88A, a phosphorus-based extractant, and the HBTA-TOPO combination, which consists of a β-diketone and a neutral ligand. This research establishes the optimal operating conditions for each extractant by standardizing the concentration conditions, using pH isotherms and McCabe-Thiele experimental data. The main contribution of this study lies in its assessment of the economic and operational efficiencies of these two extractants. It provides important insights into their practical use and offers guidance for future endeavors in improving lithium recovery processes.\u003c/p\u003e"},{"header":"2. Experimental Materials and Methods","content":"\u003cp\u003eTo investigate the lithium (Li) extraction behavior under feed conditions with a low Li concentration relative to sodium (Na), an aqueous solution with the composition shown in Table \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e was used[\u003cspan class=\"CitationRef\"\u003e17\u003c/span\u003e]. The aqueous phase was prepared by dissolving lithium sulfate monohydrate (Li\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e∙H\u003csub\u003e2\u003c/sub\u003eO) and sodium sulfate (Na\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e) in distilled water. The solution was stirred thoroughly for approximately 20 minutes using a magnetic stirrer.\u003c/p\u003e\u0026nbsp;\u003ctable id=\"Tab1\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eConcentration of Feed\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eLi\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eNa\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eg/L\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.85\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e31.2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eTo compare the Li extraction rates, the extractants used were PC88A (2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester), a phosphorus-based extractant, HBTA (benzoyltrifluoroacetone), a \u0026beta;-diketone extractant, and TOPO (tri-n-octyl phosphine oxide), a neutral ligand used with \u0026beta;-diketones. D80 was used as a diluent to adjust the concentration of the extractants. The organic phase, comprising HBTA, TOPO, and D80, was also thoroughly stirred for about 20 minutes using a magnetic stirrer. The saponification of the organic phase involved adding NaOH and stirring again for approximately 20 minutes.\u003c/p\u003e\n\u003cp\u003eThe prepared aqueous and organic phases were introduced into a 250 mL separatory funnel in appropriate volumes according to the O/A (organic-to-aqueous) ratio. The phases were then mixed at 350 RPM in a shaking incubator for 10 minutes, followed by a stabilization period of 6 minutes to allow phase separation. During the stabilization period, any small droplets of the organic phase attached to the inside of the funnel\u0026apos;s aqueous phase were removed by partially draining the aqueous phase and reintroducing it at the top of the funnel. This process was repeated three times.\u003c/p\u003e\n\u003cp\u003eAll experiments were conducted at room temperature. After the 6-minute stabilization period, complete phase separation was observed, and the aqueous phase was filtered to measure the equilibrium pH. The aqueous phase was then diluted, and the concentrations of metals were measured using inductively coupled plasma optical emission spectroscopy(ICP-OES). The extraction rate was calculated using the following Eq.\u0026nbsp;(1):\u003c/p\u003e\n\u003cdiv id=\"Equa\" class=\"Equation\"\u003e\n \u003cdiv class=\"mathdisplay\" id=\"FileID_Equa\" name=\"EquationSource\"\u003e$$Extraction\\left(\\text{%}\\right)= \\frac{{C}_{0}-{C}_{eq}}{{C}_{0}} \\times 100 \\cdots \\left(1\\right)$$\u003c/div\u003e\u003c/div\u003e\u003cp\u003ewhere \u003cem\u003eC\u003c/em\u003e\u003csub\u003e\u003cem\u003e0\u003c/em\u003e\u003c/sub\u003e is the initial Li concentration in the aqueous phase, and \u003cem\u003eC\u003c/em\u003e\u003csub\u003e\u003cem\u003eeq\u003c/em\u003e\u003c/sub\u003e is the Li concentration in the aqueous phase after extraction.\u003c/p\u003e"},{"header":"3. Results and Discussion","content":"\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Lithium Extraction Behavior According to Equilibrium pH\u003c/h2\u003e \u003cp\u003eThe lithium (Li) extraction process using each extractant proceeds according to equations (2) and (3):\u003cdiv id=\"Equb\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equb\" name=\"EquationSource\"\u003e\n$$HA\\left(org\\right)+ NaOH\\left(aq\\right)\\to NaA\\left(org\\right)+ {H}_{2}O \\cdots \\left(2\\right)$$\u003c/div\u003e\u003c/div\u003e\u003cdiv id=\"Equc\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equc\" name=\"EquationSource\"\u003e\n$${Li}^{+}\\left(aq\\right)+ NaA\\left(org\\right)\\to LiA\\left(org\\right)+ {Na}^{+}\\left(aq\\right)\\cdots \\left(3\\right)$$\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eDuring continuous solvent extraction, the hydrogen ions from the extractant (HA) cause the pH of the aqueous phase to decrease, reducing the driving force for extraction. To prevent this, the extractant must be saponified in advance, as shown in Eq.\u0026nbsp;(2). The lithium extraction process using the saponified extractant proceeds as shown in Eq.\u0026nbsp;(3). We analyzed the lithium extraction behavior (pH isotherm) according to the equilibrium pH for 0\u0026ndash;100% saponification of 0.4M PC88A and 0.4M HBTA-TOPO under equal organic-to-aqueous phase ratio (O/A ratio) conditions of 1/1. The results are presented in Figs.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e and \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eBoth extractants showed an increase in lithium extraction rate as the equilibrium pH increased. For PC88A (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e), the extraction rate rose sharply from an equilibrium pH of 3.11 (0% saponification) to 5.43 (40% saponification). However, beyond an equilibrium pH of 5.43, further increases in pH did not significantly affect the extraction rate. Consequently, an equilibrium pH of 5.43, with a noticeable extraction rate of approximately 37.6%, was deemed optimal. For HBTA (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e), the extraction rate increased sharply from an equilibrium pH of 2.84 (0% saponification) to 6.23 (70% saponification). Similarly, beyond an equilibrium pH of 6.23, further increases in pH did not significantly affect the extraction rate. Thus, an equilibrium pH of 6.23, with a prominent extraction rate of approximately 86.2%, was considered optimal.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Lithium Extraction Behavior According to O/A Ratio\u003c/h2\u003e \u003cp\u003eTo identify the optimal O/A ratio, we investigated lithium extraction behavior at various O/A ratios under the optimal pH conditions for each extractant. The volumes of the aqueous and organic phases were adjusted within the range of 10 mL to 90 mL, considering the size of the separatory funnel and mixing efficiency. Experiments were conducted at O/A ratios ranging from 1/15 to 10/1. However, the condition of O/A ratio 15/1 was excluded due to the high viscosity, which significantly reduced mixing efficiency. PC88A experiments were conducted within a pH range of 5.33 to 5.53, and HBTA experiments within a pH range of 6.13 to 6.33, reflecting a pH error margin of \u0026plusmn;\u0026thinsp;0.1. The saponification rate was adjusted by controlling the amount of NaOH to meet these pH ranges. Figures\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e and \u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e present the lithium extraction rate behavior according to O/A ratio.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFor both extractants, the lithium extraction rate increased with the O/A ratio. PC88A (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e) showed a continuous increase in extraction rate as the O/A ratio changed from 1/15 to 10/1, without identifying an optimal O/A ratio. However, HBTA (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e) exhibited a significant increase in extraction rate from an O/A ratio of 1/15 to 1/1, beyond which no further substantial increase was observed. Thus, the optimal O/A ratio for HBTA was determined to be 1/1. Figures\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e and \u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e indicate that there are significant differences in the O/A ratio operating conditions needed to achieve similar lithium extraction rates for PC88A and HBTA. For instance, PC88A achieved a 63.7% extraction rate at an O/A ratio of 5/1, while HBTA achieved a 64.7% extraction rate at an O/A ratio of 1/2. Therefore, assuming the same volume of the aqueous phase, approximately ten times the amount of extractant is required for PC88A to achieve similar lithium extraction rates as HBTA.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e3.3 Qualitative Economic Evaluation Using McCabe-Thiele Diagram\u003c/h2\u003e \u003cp\u003eIn continuous solvent extraction processes, the theoretical number of extraction stages is typically determined using the McCabe-Thiele Diagram. We used the lithium extraction rate data according to O/A ratio from Figs.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e and \u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e to plot McCabe-Thiele Diagrams based on the Li concentrations in the aqueous and organic phases after extraction. The curve represents the equilibrium line, derived from experimental data at O/A ratios ranging from 1/15 to 10/1. The straight line represents the operating line, with its slope corresponding to the A/O ratio. By adjusting the slope of the operating line to reflect the respective O/A ratios, we compared the number of extraction stages required for each extractant.\u003c/p\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e shows the McCabe-Thiele Diagram for HBTA under its optimal operating condition of 1/1 O/A ratio. To achieve 100% extraction of 1.85 g/L Li present in the initial aqueous phase, three extraction stages are required. For comparison, the McCabe-Thiele Diagram for PC88A achieving three stages is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e at a 15/1 O/A ratio. Achieving 100% Li extraction using three extraction stages requires HBTA at 0.4M concentration, 70% saponification, and a 1/1 O/A ratio. In contrast, PC88A requires a 0.4M concentration, 40% saponification, and a 15/1 O/A ratio. The 15-fold difference in O/A ratio implies that, under the same aqueous phase volume, the mixer-settler unit volume for PC88A must be more than 15 times larger than that for HBTA. Additionally, such a large O/A ratio as 15/1 can decrease mixing efficiency.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFigures \u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e and \u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e compare the number of extraction stages required for both extractants under the same O/A ratio condition. PC88A could not generate a proper McCabe-Thiele Diagram at lower O/A ratios like 1/1 and 3/2, so the comparison was made at 5/1. Figure\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e indicates that at a 5/1 O/A ratio, achieving approximately 98% Li extraction requires six stages for PC88A. Conversely, Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e shows that at the same 5/1 O/A ratio, HBTA requires only one stage for approximately 98% Li extraction and two stages for 100% extraction. Thus, at a 5/1 O/A ratio, PC88A requires six times more extraction stages than HBTA to achieve similar lithium extraction rates.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"4. Conclusion","content":"\u003cp\u003eThis study compared the solvent extraction behavior of lithium (Li) from an aqueous solution with a low Li concentration relative to sodium (Na) using two different extractants: the cost-effective phosphorus-based extractant PC88A and the more expensive β-diketone extractant HBTA. Both extractants demonstrated an increase in Li extraction rate with the increase in equilibrium pH and O/A ratio.\u003c/p\u003e \u003cp\u003eFor 0.4M PC88A, the extraction rate was 37.6% at an equilibrium pH of 5.43, which was determined to be the optimal pH condition. The maximum extraction rate was 41.4% at an equilibrium pH of 7.80. The Li extraction rate continued to increase with O/A ratios ranging from 1/15 to 10/1, preventing the determination of an optimal O/A ratio. The McCabe-Thiele Diagram indicated that 98% Li extraction could be achieved with six stages at an O/A ratio of 5/1, and 100% Li extraction could be achieved with three stages at an O/A ratio of 15/1.\u003c/p\u003e \u003cp\u003eFor 0.4M HBTA, the extraction rate was 86.2% at an equilibrium pH of 6.23, identified as the optimal pH condition. The maximum extraction rate was 92.9% at an equilibrium pH of 11.95. The Li extraction rate did not significantly increase beyond an O/A ratio of 1/1, establishing this as the optimal O/A ratio. The McCabe-Thiele Diagram showed that 100% Li extraction could be achieved with three stages at an O/A ratio of 1/1, and 100% Li extraction could be achieved with one stage at an O/A ratio of 5/1.\u003c/p\u003e \u003cp\u003eTherefore, when comparing the two extractants at the same concentration of 0.4M, it was found that to achieve similar extraction efficiencies, the O/A ratio for PC88A was 15/1 compared to 1/1 for HBTA, resulting in a 15-fold difference in organic phase volume. Similarly, at the same O/A ratio of 5/1, PC88A required six stages compared to just one stage for HBTA, indicating a six-fold difference in the number of extraction stages. Consequently, this qualitative evaluation suggests that HBTA is significantly more advantageous than PC88A in terms of operational efficiency at the same extractant concentration of 0.4M.\u003c/p\u003e \u003cp\u003eFuture quantitative evaluations should consider the electrical efficiency and equipment costs when using large-volume mixer-settlers, as well as the bulk extractant prices, to provide a more comprehensive economic comparison.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAcknowledgments\u003c/h2\u003e \u003cp\u003eThis work was supported the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. 2021R1F1A1048416), and the Graduate School of Chemical Characterization hosted by the Korean Ministry of Environment.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eKorea Energy Economics Institute., (2018). 전기차 사용후 배터리 거래시장 구축을 위한 정책연구. 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Bogacki., The effect of tributyl phosphate on the extraction of nickel(ii) and cobalt(11) ions with di(2-ethylhexyl)phosphoric acid. Physicochemical Problems of Mineral Processing. \u003cstrong\u003e41\u003c/strong\u003e, 145 (2007).\u003c/li\u003e\n\u003cli\u003eAhn, H.J., (2014) A study of lithium recovery from lithium-containing waste solution by solvent extraction (Master\u0026apos;s Thesis, Dept. of Advanced materials Science \u0026amp; Engineering, Dae-jin University). http://www.riss.kr/link?id=T13775593 \u003c/li\u003e\n\u003cli\u003eLicheng Zhang, Lijuan Li, Dong Shi, Xiaowu Peng, Fugen Song, Feng Nie, Wensheng Hana., Recovery of lithium from alkaline brine by solvent extraction with \u0026beta;-diketone. Hydrometallurgy. \u003cstrong\u003e175\u003c/strong\u003e, 35 (2018).\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":true,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"korean-journal-of-chemical-engineering","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"kjce","sideBox":"Learn more about [Korean Journal of Chemical Engineering](http://link.springer.com/journal/11814)","snPcode":"11814","submissionUrl":"https://www.editorialmanager.com/kjce/default2.aspx","title":"Korean Journal of Chemical Engineering","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Subscription","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Waste battery recycling, Solvent extraction, Lithium, PC88A, HBTA","lastPublishedDoi":"10.21203/rs.3.rs-4593022/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4593022/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis study compares the solvent extraction behavior of lithium (Li) using the cost-effective extractant PC88A and the more expensive extractant HBTA. PC88A achieved an optimal extraction rate of 37.6% at pH 5.43, with a maximum rate of 41.4% at pH 7.80. It required six stages at a 5/1 O/A ratio for 98% extraction and three stages at a 15/1 ratio for 100% extraction. In contrast, HBTA showed an optimal extraction rate of 86.2% at pH 6.23 and a maximum rate of 92.9% at pH 11.95. HBTA achieved 100% extraction with three stages at a 1/1 O/A ratio and one stage at a 5/1 ratio. These findings reveal HBTA's striking superiority over PC88A in terms of efficiency. Future studies should include evaluations of equipment and extractant costs, and overall efficiency.\u003c/p\u003e","manuscriptTitle":"Qualitative Assessment of PC88A and HBTA Extractants in Lithium Recovery Processes Using Solvent Extraction","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-07-24 15:36:50","doi":"10.21203/rs.3.rs-4593022/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Major Revisions Needed","date":"2024-08-02T12:41:23+00:00","index":"","fulltext":""},{"type":"reviewerAgreed","content":"","date":"2024-07-01T02:16:51+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-06-30T12:52:21+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-06-19T06:56:15+00:00","index":"","fulltext":""},{"type":"submitted","content":"Korean Journal of Chemical Engineering","date":"2024-06-17T05:06:17+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"korean-journal-of-chemical-engineering","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"kjce","sideBox":"Learn more about [Korean Journal of Chemical Engineering](http://link.springer.com/journal/11814)","snPcode":"11814","submissionUrl":"https://www.editorialmanager.com/kjce/default2.aspx","title":"Korean Journal of Chemical Engineering","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Subscription","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"ab4f66e7-995e-41c9-b572-534ceca22e12","owner":[],"postedDate":"July 24th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2024-12-02T17:23:57+00:00","versionOfRecord":{"articleIdentity":"rs-4593022","link":"https://doi.org/10.1007/s11814-024-00341-9","journal":{"identity":"korean-journal-of-chemical-engineering","isVorOnly":false,"title":"Korean Journal of Chemical Engineering"},"publishedOn":"2024-11-26 15:58:24","publishedOnDateReadable":"November 26th, 2024"},"versionCreatedAt":"2024-07-24 15:36:50","video":"","vorDoi":"10.1007/s11814-024-00341-9","vorDoiUrl":"https://doi.org/10.1007/s11814-024-00341-9","workflowStages":[]},"version":"v1","identity":"rs-4593022","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4593022","identity":"rs-4593022","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}