无机酸对金尾矿中多种重金属的去除效果研究

Removal Effect of Inorganic Acid on Multiple Heavy Metals from Gold Tailings

以金尾矿为研究对象,通过振荡试验研究了硝酸溶液和盐酸溶液在不同浓度、液固比、淋洗时间和淋洗次数条件下对金尾矿中重金属的去除效果,并分析了金尾矿的重金属全量和重金属各种形态的含量。结果表明:硝酸溶液和盐酸溶液在浓度分别为1 mol/L和2 mol/L、液固比同为15∶1、淋洗时间同为6 h、淋洗次数同为1次的条件下可以达到最佳的去除效果。硝酸溶液对Cu、As、Ni、Sr、Co、Pb的去除率为39.80%、27.77%、24.57%、65.80%、17.17%、26.87%,盐酸溶液对上述元素的去除率为43.29%、42.23%、28.57%、56.67%、18.48%、31.54%。重金属全量及形态分析表明,金尾矿中As、Sr、Ni等元素的含量较高,分别达到1 930.25、315.25、40.90 mg/kg;硝酸溶液和盐酸溶液对乙酸可提取态、可还原态、可氧化态等移动能力及生物有效性高的形态的重金属有良好的去除效果,而对残渣态含量高的重金属去除效果不明显。

The oscillated test was conducted to study the removal effect of different concentrations, liquid -solid ratios,leaching time and leaching number of nitric acid and hydrochloric acid respectively on heavy metals in the gold tailings.Then the contents of total heavy metals and their speciation were analyzed. The results showed that the optimal leaching conditions were nitric acid of 1 mol /L and hydrochloric acid of 2 mol /L,liquid -solid ratio of 1 5∶1 ,leaching 6 h and 1 time.Under these conditions,the removal rate of ni-tric acid to Cu,As,Ni,Sr,Co and Pb were 39.80%,27.77%,24.57%,65.80%,1 7.1 7% and 26.87%respectively,and the removal rates of hydrochloric acid to the above elements were 43.29%,42.23%, 28.57%,56.67%,1 8.48% and 31 .54% respectively.The results of total heavy metals and their speciation analysis showed that the contents of As,Sr and Ni in gold tailings were higher with the concentrations of 1 930.25,31 5.25 and 40.90 mg/kg;the removal effects of nitric acid and hydrochloric acid on heavy metals with the forms of high locomotivity and bio -availability were higher,but that on residual form of heavy metals was not obvious.