Sodium carbonate oxygen pulping of softwood for various yield levels

Sodium carbonate oxygen pulping of softwood for various yield levels | 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 Sodium carbonate oxygen pulping of softwood for various yield levels Hertta Seppälä, Marjo Määttänen, Ilkka Nurminen, Stina Grönqvist, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8229751/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 9 You are reading this latest preprint version Abstract Alkaline oxidation using sodium carbonate (Na 2 CO 3 ) and oxygen (O 2 ) provides a sulfur free pulping process for wood, presenting a simpler alternative to conventional kraft pulping in terms of chemical recovery. This process also yields water-soluble lignin with application potential distinct from that of kraft lignin. The purpose of this study was to evaluate the potential of alkaline oxidized pulps for paper and paperboard applications. The pulps were produced by adjusting pre-hydrolysis levels and oxygen pulping conditions to obtain pulps with distinct total pulping yields. Before the alkaline oxidation stage, the wood chips and the pre-hydrolyzed wood chips were defibrated using a pressurized disc-refiner to enhance oxygen reactions. The pulps were beaten to various drainability levels using a PFI refiner, and 150 g/m² handsheets were produced to evaluate their structural and mechanical properties. Strength, bulk, and air resistance varied with pre-hydrolysis severity and pulping yield. Typically, pulp strength properties improved with decreased total pulping yield, particularly between pulps with similar pre-hydrolysis treatment. While most pulps showed consistent tensile strength at SR 30, some of them achieved significantly higher values. A negative correlation was observed between internal bonding strength and bulk, and tensile strength increased with sheet density. The pulp, prepared without a separate pre-hydrolysis step but mechanically defibrated before alkaline oxidation, with a pulping yield of 65–70% indicated a high potential for a strong medium-high yield pulp for paperboard making. The findings highlight the potential of sodium carbonate oxygen pulps and suggest further optimization through combined pre-treatment and pulping strategies. oxygen pulping sodium carbonate pre-hydrolysis yield handsheet characteristics Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 15 Mar, 2026 Reviews received at journal 07 Mar, 2026 Reviewers agreed at journal 25 Feb, 2026 Reviews received at journal 23 Feb, 2026 Reviewers agreed at journal 17 Feb, 2026 Reviewers invited by journal 17 Feb, 2026 Editor assigned by journal 15 Feb, 2026 Submission checks completed at journal 29 Nov, 2025 First submitted to journal 28 Nov, 2025 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. 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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-8229751","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":594165099,"identity":"cd33bfda-f293-4955-a25e-78b8e0b81c0a","order_by":0,"name":"Hertta Seppälä","email":"","orcid":"","institution":"VTT Technical Research Centre of Finland Ltd","correspondingAuthor":false,"prefix":"","firstName":"Hertta","middleName":"","lastName":"Seppälä","suffix":""},{"id":594165101,"identity":"b2cddbe9-358a-46d9-8493-c8b3e02ac7ab","order_by":1,"name":"Marjo Määttänen","email":"","orcid":"","institution":"VTT Technical Research Centre of Finland Ltd","correspondingAuthor":false,"prefix":"","firstName":"Marjo","middleName":"","lastName":"Määttänen","suffix":""},{"id":594165102,"identity":"3b4e2677-394b-467b-b4b4-ccb405cc580c","order_by":2,"name":"Ilkka Nurminen","email":"","orcid":"","institution":"VTT Technical Research Centre of Finland Ltd","correspondingAuthor":false,"prefix":"","firstName":"Ilkka","middleName":"","lastName":"Nurminen","suffix":""},{"id":594165104,"identity":"83a199ba-3e82-4092-bad2-44afdeb5c015","order_by":3,"name":"Stina Grönqvist","email":"","orcid":"","institution":"VTT Technical Research Centre of Finland Ltd","correspondingAuthor":false,"prefix":"","firstName":"Stina","middleName":"","lastName":"Grönqvist","suffix":""},{"id":594165105,"identity":"9bac5c2a-bfbb-46fb-8505-e30adedd250e","order_by":4,"name":"Jari Sirviö","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAzklEQVRIiWNgGAWjYBACxgYGhgMMDBIMDMwMjA9AIuzNJGhhNmBIMGDgOUyCjWwSYC0HCChjbj/78ADDH4t8g+PMx6p5f/xh4GEn5LCedIMDjG0SlhsOs6Xd5gHZwkxIS0MawwHGBgkDyWYes5szgFrsCWrpfwb0/h+IlsIZRNkyA2gL0OMG/Mw8ZgwfiNMCtCWxDaSFLVniQ5oxD0Ethv1pzB8+/KkzYOM/fPBDgo2cHA//AQJaGoBEApIADwE7GBjkCaoYBaNgFIyCUQAAdNY1jJMEKsMAAAAASUVORK5CYII=","orcid":"","institution":"VTT Technical Research Centre of Finland Ltd","correspondingAuthor":true,"prefix":"","firstName":"Jari","middleName":"","lastName":"Sirviö","suffix":""}],"badges":[],"createdAt":"2025-11-28 11:08:21","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8229751/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8229751/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":103505873,"identity":"9eaac6ed-5954-4221-bf20-09c0c1076d45","added_by":"auto","created_at":"2026-02-26 13:33:20","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1276243,"visible":true,"origin":"","legend":"","description":"","filename":"SeppletalSodiumcarbonateoxygenpulpingofsoftwoodforvariousyieldlevels.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8229751/v1_covered_82c7bc02-d058-4141-9cd7-89752f622abc.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Sodium carbonate oxygen pulping of softwood for various yield levels","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"cellulose","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"cels","sideBox":"Learn more about [Cellulose](https://www.springer.com/journal/10570)","snPcode":"10570","submissionUrl":"https://submission.nature.com/new-submission/10570/3","title":"Cellulose","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"oxygen pulping, sodium carbonate, pre-hydrolysis, yield, handsheet characteristics","lastPublishedDoi":"10.21203/rs.3.rs-8229751/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8229751/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eAlkaline oxidation using sodium carbonate (Na\u003csub\u003e2\u003c/sub\u003eCO\u003csub\u003e3\u003c/sub\u003e) and oxygen (O\u003csub\u003e2\u003c/sub\u003e) provides a sulfur free pulping process for wood, presenting a simpler alternative to conventional kraft pulping in terms of chemical recovery. This process also yields water-soluble lignin with application potential distinct from that of kraft lignin. The purpose of this study was to evaluate the potential of alkaline oxidized pulps for paper and paperboard applications. The pulps were produced by adjusting pre-hydrolysis levels and oxygen pulping conditions to obtain pulps with distinct total pulping yields. Before the alkaline oxidation stage, the wood chips and the pre-hydrolyzed wood chips were defibrated using a pressurized disc-refiner to enhance oxygen reactions. The pulps were beaten to various drainability levels using a PFI refiner, and 150 g/m\u0026sup2; handsheets were produced to evaluate their structural and mechanical properties. Strength, bulk, and air resistance varied with pre-hydrolysis severity and pulping yield. Typically, pulp strength properties improved with decreased total pulping yield, particularly between pulps with similar pre-hydrolysis treatment. 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