Abstract Large amounts of iron– and steelmaking slag and greenhouse gas are annually produced by the steel industry worldwide. Using Ca/Mg in the slag to capture and store the CO2 via mineral carbonation is a promising approach to the reduction of waste emissions. Since iron– and steelmaking slags are a mixture of numerous types of minerals, understanding the dissolution behavior of various phases in solution system is of critical importance for Ca/Mg recovery. In this work, seven Ca/Mg–bearing phases and four typical solutions were prepared and studied. Theoretical results indicated that the order of mineral solubility in aqueous solution is as follows: (CaO and Ca2SiO4) > (Ca3MgSi2O8, Ca2MgSi2O7, and MgO) > Ca2Al2SiO7 > MgCr2O4. A batch of leaching tests was conducted at room temperature, and the recovery yield of Ca/Mg was investigated. It was found that minerals show different dissolution behavior in various systems, and the metallic oxide phases exhibited a relatively higher solubility than silicate phases. The solubility of minerals in various systems was illustrated by radar plots. Moreover, leaching tests for silicate briquettes were performed to investigate the transformation mechanism. On the basis of the results, it was proposed that a silicic acid layer generated on the surface of briquettes in the leaching process, and could transform into porous silica phase via dehydration process. The formed Si–rich layer obstructed the dissolution of inner mineral leading to a low recovery efficiency of Ca/Mg.

中文翻译：

---

从炼铁和炼钢炉渣中回收含钙和镁相以封存 CO2

摘要 世界范围内的钢铁工业每年都会产生大量的炼铁和炼钢炉渣和温室气体。在炉渣中使用 Ca/Mg 通过矿物碳酸化来捕获和储存 CO2 是减少废物排放的一种有前途的方法。由于炼铁和炼钢炉渣是多种矿物质的混合物，因此了解溶液系统中各相的溶解行为对于 Ca/Mg 的回收至关重要。在这项工作中，制备和研究了七个含 Ca/Mg 的相和四个典型的溶液。理论结果表明，矿物在水溶液中的溶解度顺序为：(CaO和Ca2SiO4)>(Ca3MgSi2O8、Ca2MgSi2O7和MgO)>Ca2Al2SiO7>MgCr2O4。在室温下进行了一批浸出试验，考察了Ca/Mg的回收率。发现矿物在不同体系中表现出不同的溶解行为，金属氧化物相的溶解度高于硅酸盐相。各种系统中矿物质的溶解度由雷达图说明。此外，对硅酸盐压块进行浸出试验以研究转化机制。在此基础上，提出了在浸出过程中煤球表面生成了一层硅酸层，可以通过脱水过程转化为多孔二氧化硅相。形成的富硅层阻碍了内部矿物的溶解，导致 Ca/Mg 的回收效率低。各种系统中矿物质的溶解度由雷达图说明。此外，对硅酸盐压块进行浸出试验以研究转化机制。在此基础上，提出了在浸出过程中煤球表面生成了一层硅酸层，可以通过脱水过程转化为多孔二氧化硅相。形成的富硅层阻碍了内部矿物的溶解，导致 Ca/Mg 的回收效率低。各种系统中矿物质的溶解度由雷达图说明。此外，对硅酸盐压块进行浸出试验以研究转化机制。在此基础上，提出了在浸出过程中煤球表面生成了一层硅酸层，可以通过脱水过程转化为多孔二氧化硅相。形成的富硅层阻碍了内部矿物的溶解，导致 Ca/Mg 的回收效率低。并可以通过脱水过程转化为多孔二氧化硅相。形成的富硅层阻碍了内部矿物的溶解，导致 Ca/Mg 的回收效率低。并可以通过脱水过程转化为多孔二氧化硅相。形成的富硅层阻碍了内部矿物的溶解，导致 Ca/Mg 的回收效率低。