Effect of integration of mechanical ball milling and flue gas desulfurization gypsum on dealkalization of bauxite residue

机械球磨与烟气脱硫石膏联用对赤泥脱碱的影响

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 Na_(2)O 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.

结合溶液化学、矿物学和微观形貌分析,研究机械球磨和烟气脱硫石膏联用对赤泥碱性调控的影响。结果表明,经机械球磨30 min后用烟气脱硫石膏处理的赤泥中Na_(2)O含量降低了30%(质量分数)以上;机械球磨改变了赤泥矿物表面元素分布和晶型结构,促进了赤泥碱性矿物的溶解,从而提高了脱碱后赤泥的酸中和能力。5%(质量分数)烟气脱硫石膏和30 min球磨时间可实现赤泥脱碱。