{"title":"Direct carbonation of magnesium slag after salt lake lithium extraction for use as a cementitious material","authors":"Zhen Li , Ying Hua , Zhichao Zhang , Yongbo Huang , Pengyu Zhang , Jueshi Qian","doi":"10.1016/j.conbuildmat.2025.140545","DOIUrl":null,"url":null,"abstract":"<div><div>Carbonation of MgO and Mg(OH)<sub>2</sub> for the preparation of cementitious materials has attracted much attention due to the rapid strength gain and high CO<sub>2</sub> sequestration. This paper investigated the potential use of lithium extraction by-product magnesium slag from salt lake as MgO and Mg(OH)<sub>2</sub> sources to prepare construction material through carbonation. Calcium hydroxide and dipotassium hydrogen phosphate were used to promote the hardening and carbonation of magnesium slag. Properties of magnesium slag moulded by casting and compacting under 100 % CO<sub>2</sub> and 0.1 MPa pressure condition were compared and the phase changes were also analyzed. Results indicated that the cast moulding magnesium slag yielded uniform carbonation of the specimen, resulting in 1 h strength of 20 MPa. Compacted magnesium slag leads to the uneven carbonation but continuous strength development due to the internal moisture. Brucite in magnesium slag was the main reactant while hydromagnesite and amorphous hydrated magnesium carbonates were confirmed as the main carbonation products by combining XRD, FTIR, TGA analysis. In addition, K<sub>2</sub>HPO<sub>4</sub> promoted the carbonation of Mg(OH)<sub>2</sub>, leading to the uniform carbonation of specimens and increased 8 h strength to 49.4 MPa. This study builds foundation for use carbonation of Mg-based solid wastes as construction materials.</div></div>","PeriodicalId":288,"journal":{"name":"Construction and Building Materials","volume":"471 ","pages":"Article 140545"},"PeriodicalIF":7.4000,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Construction and Building Materials","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0950061825006932","RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CONSTRUCTION & BUILDING TECHNOLOGY","Score":null,"Total":0}
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Abstract
Carbonation of MgO and Mg(OH)2 for the preparation of cementitious materials has attracted much attention due to the rapid strength gain and high CO2 sequestration. This paper investigated the potential use of lithium extraction by-product magnesium slag from salt lake as MgO and Mg(OH)2 sources to prepare construction material through carbonation. Calcium hydroxide and dipotassium hydrogen phosphate were used to promote the hardening and carbonation of magnesium slag. Properties of magnesium slag moulded by casting and compacting under 100 % CO2 and 0.1 MPa pressure condition were compared and the phase changes were also analyzed. Results indicated that the cast moulding magnesium slag yielded uniform carbonation of the specimen, resulting in 1 h strength of 20 MPa. Compacted magnesium slag leads to the uneven carbonation but continuous strength development due to the internal moisture. Brucite in magnesium slag was the main reactant while hydromagnesite and amorphous hydrated magnesium carbonates were confirmed as the main carbonation products by combining XRD, FTIR, TGA analysis. In addition, K2HPO4 promoted the carbonation of Mg(OH)2, leading to the uniform carbonation of specimens and increased 8 h strength to 49.4 MPa. This study builds foundation for use carbonation of Mg-based solid wastes as construction materials.
期刊介绍：
Construction and Building Materials offers an international platform for sharing innovative and original research and development in the realm of construction and building materials, along with their practical applications in new projects and repair practices. The journal publishes a diverse array of pioneering research and application papers, detailing laboratory investigations and, to a limited extent, numerical analyses or reports on full-scale projects. Multi-part papers are discouraged.
Additionally, Construction and Building Materials features comprehensive case studies and insightful review articles that contribute to new insights in the field. Our focus is on papers related to construction materials, excluding those on structural engineering, geotechnics, and unbound highway layers. Covered materials and technologies encompass cement, concrete reinforcement, bricks and mortars, additives, corrosion technology, ceramics, timber, steel, polymers, glass fibers, recycled materials, bamboo, rammed earth, non-conventional building materials, bituminous materials, and applications in railway materials.
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