Effect of integration of mechanical ball milling and flue gas desulfurization gypsum on dealkalization of bauxite residue
(1. School of Metallurgy and Environment, Central South University, Changsha 410083, China;
2. Zhengzhou Non-ferrous Metals Research Institute Co., Ltd. of CHALCO, Zhengzhou 450041, China;
3. College of Environment and Resources, Xiangtan University, Xiangtan 411105, China;
4. School of Resources and Safety Engineering, Central South University, Changsha 410083, China)
2. Zhengzhou Non-ferrous Metals Research Institute Co., Ltd. of CHALCO, Zhengzhou 450041, China;
3. College of Environment and Resources, Xiangtan University, Xiangtan 411105, China;
4. School of Resources and Safety Engineering, Central South University, Changsha 410083, China)
Abstract: The synergistic impact of mechanical ball milling and flue gas desulfurization (FGD) gypsum on the dealkalization of bauxite residue was investigated through integrated analyses of solution chemistry, mineralogy, and microtopography. The results showed a significant decrease in Na2O content (>30 wt.%) of FGD gypsum-treated bauxite residue after 30 min of mechanical ball milling. Mechanical ball milling resulted in differentiation of the elemental distribution, modification of the minerals in crystalline structure, and promotion in the dissolution of alkaline minerals, thus enhancing the acid neutralization capacity of bauxite residue. 5 wt.% FGD gypsum combined with 30 min mechanical ball milling was optimal for the dealkalization of bauxite residue.
Key words: bauxite residue; alkalinity regulation; flue gas desulfurization gypsum; mechanical activation; soil formation of bauxite residue