酸性矿山废水中锌铁锰的分离及回收

Separation and recovery of Zn,Fe and Mn in acid mine drainage

采用机械活化硫精矿吸附,氧化沉淀以及氢氧化钠沉淀处理酸性矿山废水,使废水中锌、铁、锰得到分离与回收。当酸性矿山废水pH为1.83,锌、铁和锰质量浓度分别为150,2 900和315 mg/L时,在10 L酸性矿山废水中加入活化硫精矿975 g,反应20 min后,锌残留质量浓度为1.33 mg/L,锌去除率达到99.08%。废水经除锌后,取10 L废水,当废水pH为6.92,空气流量为500 mL/min,反应时间为2.5 h时,铁和锰残留质量浓度分别为97.96和290.55 mg/L,铁、锰去除率分别为98.28%和18.45%。XRD分析表明:氧化沉淀渣为Fe3O4和α-FeOOH,渣中铁含量为52.73%;废水经除铁后用氢氧化钠溶液调节pH至11.01,反应时间为30 min时,废水中锰残留质量浓度为1.15 mg/L,所得锰渣锰含量达到34.47%;除锰废水经硫酸调节pH为7后达GB 8978—1996排放标准。

Separation and recovery of Zn,Fe and Mn from acid mine drainage was researched by applying absorption with mechanically activated pyrite,oxidation-precipitation and sodium hydroxide neutralization.The mass concentration of residual Zn is 1.33 mg/L,and the removal rate of Zn is up to 99.08% when pH of the acid mine drainage is 1.83,the mass concentrations of Zn,total iron and Mn are 150,2 900 and 315 mg/L,respectively,the dosage of activated pyrite is 975 g in 10 L wastewater,reaction time is 20 min.In 10 L wastewater after removing Zn,the residual Fe and Mn are 97.96 mg/L and 290.55 mg/L,respectively,and the removal rates of Fe and Mn are 98.28% and 18.45%,respectively when pH of the wastewater is 6.92,airflow is 500 mL/min,reaction time is 2.5 h.X-ray diffraction（XRD） analysis shows that the products of oxidation-precipitation are Fe3O4 and α-FeOOH,in which the content of Fe is 52.73%.Then the residual Mn is 1.15 mg/L,and the Mn content in the sediment is 34.47% when pH of the wastewater is adjusted to about 11.01 with sodium hydroxide solution,and reaction time is 30 min.The effluent quality can meet the Chinese standards of wastewater discharge（GB 8978-1996） after pH of the Mn removing wastewater is adjusted to 7 with sulfuric acid.