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论文类型：期刊论文

发表时间：2018-12-20

发表刊物：CONSTRUCTION AND BUILDING MATERIALS

收录刊物：SCIE、Scopus

卷号：192

页面范围：584-592

ISSN号：0950-0618

关键字：Mineralogical alterations; pH; Leaching; Accelerated carbonation; Basic oxygen furnace slag

摘要：Basic oxygen furnace slag (BOFS) contains different alkaline Ca-bearing minerals that lead to high CO2 sequestration and high pH. The high alkalinity of BOFS is an environmental issue. In this study, we investigated the relationship between accelerated carbonation, pH, and leaching by analyzing changes in mineral composition during carbonation process. Results indicate that carbonation of Ca-bearing minerals in BOFS was mainly from, from highest to lowest, Ca(OH)(2), beta-C2S and C(4)AF. Ca(OH)(2) was most likely to be carbonated because of its high solubility. Carbonation greatly reduced the alkalinity of BOFS, from an initial pH of 12.73 (non-carbonated BOFS) to a final pH of 9.36. When the pH value was <10, carbonation was hindered by lack of CO32-. The increase in the degree of carbonation greatly reduced Ca leaching but significantly increased Si leaching. The pH value and Ca leaching from non-carbonated BOFS were determined by Ca(OH)(2). The pH value and Ca leaching from carbonated BOFS tended to equilibrate with a saturated CaCO3 solution, and Si leaching was determined by amorphous SiO2 generated during carbonation. (C) 2018 Elsevier Ltd. All rights reserved.