Enhanced dealkalization of bauxite residue through calcium-activated desulfurization gypsum  

钙活化脱硫石膏强化赤泥脱碱

作　　者：Yu-jun WU Sheng-guo XUE Li-ping LIU Feng LI Graeme J.MILLAR Fei GE Jiang TIAN 吴玉俊;薛生国;刘丽坪;李峰;Graeme J.MILLAR;葛飞;田江(湘潭大学环境与资源学院,湘潭411105;中南大学冶金与环境学院,长沙410083;School of Mechanical,Medical and Process Engineering,Faculty of Engineering,Queensland University of Technology,Brisbane,Queensland 4000,Australia)

机构地区：[1]College of Environment and Resources,Xiangtan University,Xiangtan 411105,China [2]School of Metallurgy and Environment,Central South University,Changsha 410083,China [3]School of Mechanical,Medical and Process Engineering,Faculty of Engineering,Queensland University of Technology,Brisbane,Queensland 4000,Australia

出　　处：《Transactions of Nonferrous Metals Society of China》2024年第10期3412-3424,共13页中国有色金属学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(No.42307521);the China Postdoctoral Science Foundation(No.2023M742934)。

摘　　要：A novel integrated approach to remove the free alkalis and stabilize solid-phase alkalinity by controlling the release of Ca from desulfurization gypsum was developed.The combination of recycled FeCl_(3)solution and EDTA activated desulfurization gypsum lowered the bauxite residue pH to 7.20.Moreover,it also improved the residual Ca state,with its contribution to the total exchangeable cations increased(68%-92%).Notably,the slow release of exchangeable Ca introduced through modified desulfurization gypsum induced a phase transition of the alkaline minerals.This treatment stabilized the dealkalization effect of bauxite residue via reducing its overall acid neutralization capacity in abating pH rebound.Hence,this approach can provide guidance for effectively utilizing desulfurization gypsum to achieve stable regulation of alkalinity in bauxite residue.提出一种通过控制脱硫石膏中钙的释放行为来去除赤泥游离碱和稳定结合碱的新方法。结果表明,利用FeCl_(3)结合EDTA活化脱硫石膏(钙离子活化剂)能够有效降低赤泥碱性(pH值稳定在7.20),显著提高钙离子交换容量饱和度,进而增加Ca对可交换阳离子总量的贡献(68%~92%)。交换性钙从改性脱硫石膏中缓慢释放后,使碱性矿物发生相转变。该方法通过降低赤泥整体酸中和能力抑制pH回升,最终稳定赤泥碱性调控效果,为脱硫石膏在赤泥碱性调控中的高效应用提供科学指导。

关 键 词：bauxite residue desulfurization gypsum EDTA activation alkalinity regulation recycled FeCl_(3) 

分 类 号：X758[环境科学与工程—环境工程] TQ177.375[化学工程—硅酸盐工业]