钙矾石法去除离子型稀土矿尾水中硫酸根研究

Research on the Removal of Sulfate from Ionic Rare Earth Mine Tail Water by Ettringite Precipitation Method

为了降低离子型稀土矿山尾水中硫酸根浓度,实验研究了钙矾石沉淀法去除硫酸根离子的最佳参数,用偏铝酸钠(NaAlO_(2))、铝酸钙(约含Al_(2)O_(3)49%)和聚合氯化铝(约含Al_(2)O_(3)40%)3种铝盐进行对比实验研究。实验结果表明:采用钙矾石沉淀法去除离子型稀土矿山尾水中硫酸根离子时,偏铝酸钠在pH值=11.5,按照Ca^(2+)∶SO_(4)^(2-)∶Al^(3+)=6∶3∶2的摩尔比计算,按0.8的过量比投加药剂,充分反应60min后,将硫酸根离子浓度从1400mg/L降至418.29mg/L,达到相应排放标准。该方法经工业实验验证稳定可靠。

In order to reduce the concentration of sulfate in the tail water of ionic rare earth mines,the optimal condition of ettringite precipitation method to remove sulfate ions were studied experimentally.Three kinds of aluminum salts,namely sodium metaaluminate(NaAlO_(2)),calcium aluminate(containing about 49%Al_(2)O_(3))and polyaluminium chloride(containing about 40%Al_(2)O_(3)),were reserched in the comparative experiments.The results show that for the ionic rare earth mine tail water,under the following conditions:pH=11.5,molar ratio Ca^(2+)∶SO_(4)^(2-)∶Al^(3+)=6∶3∶2,overdose ratio 0.8,and reaction time 60 min,the concentration of sulfate ions can reduce from 1400 mg/L to 418.29 mg/L,reaching the corresponding emission standard.It is proved by industrial experiments that this method is stable and reliable.