Abstract

A new method for curing electrolytic manganese residue (EMR) using the biocarbonization of reactive MgO (r-MgO) is presented in this paper. This method uses microbial technology to provide CO₂ to react with r-MgO then strengthen the EMR and reduce its heavy-metal content, which combines the advantage of r-MgO solidification technology and microbial technology. Several parameters include the content of r-MgO and urea, initial moisture content, and age that affect the moisture content, dry density, pH, unconfined compressive strength, stress–strain curve, and microstructure of solidified EMR are studied, and the solidification mechanism of EMR using the biocarbonization of r-MgO is discussed. The results show that the hydration of r-MgO generates brucite can reduce the moisture content and increase the dry density and pH. The CO₂ produced by the hydrolysis of urea with bacteria reacts with brucite to produce nesquehonite, hydromagnesite, and other carbonized products that further reduce the moisture content and increase the dry density. This process can bridge particles and fill pores, consequently improving the EMR strength. At early age, the biocarbonated EMR samples can reach 5.22 MPa at 12 h. This shows the biocarbonization of r-MgO is effective for solidifying EMR.

摘要

本文提出了一种利用活性氧化镁 (r-MgO) 的生物碳化来固化电解锰渣 (EMR) 的新方法。该方法使用微生物技术提供 CO ₂与r-MgO反应，增强EMR，降低其重金属含量，结合了r-MgO固化技术和微生物技术的优势。几个参数包括r-MgO和尿素的含量、初始含水量和影响含水量的年龄、干密度、pH值、无侧限抗压强度、应力-应变曲线和凝固EMR的微观结构，并研究了凝固机制讨论了使用 r-MgO 生物碳化的 EMR。结果表明，r-MgO水合生成水镁石可以降低含水量，提高干密度和pH值。二氧化碳₂尿素与细菌水解产生的水镁石与水镁石反应生成三水镁石、水菱镁矿和其他碳化产物，进一步降低水分含量并增加干密度。该过程可以桥接颗粒并填充孔隙，从而提高 EMR 强度。在早期，生物碳酸化 EMR 样品在 12 小时时可达到 5.22 MPa。这表明 r-MgO 的生物碳化对于固化 EMR 是有效的。