Mextral V10–Mextral 973H体系脱除酸性矿山废水中重金属的研究

矿山选、冶废水成分复杂、水量大，目前所用方法对重金属的脱除效果不理想、成本高，为解决矿山废水重金属污染问题，开发适用于酸度较高、重金属浓度较低、对钙、镁离子有抑萃作用的协同萃取法脱除并回收废水中的重金属。通过绘制萃取等温线、FT-IR及紫外吸收光谱对Mextral V10–Mextral 973H协同萃取体系进行分析，研究了萃取剂浓度、有机相和水相体积比(简称相比，O/A)和Mextral V10皂化率对废水中重金属分离影响。结果表明，Mextral V10–Mextral 973H协同萃取体系能有效脱除酸性废水中Cu2+, Pb2+, Cd2+和Zn2+。在10vol% (Mextral V10+Mextral 973H)+90vol% Mextral DT100，Mextral V10:Mextral 973H=1:1的最佳实验条件下连续萃取六次，萃后废水中Cu2+, Cd2+, Zn2+, Pb2+, Mg2+和Ca2+的萃取率分别为99.1%±0.1%, 99.9%±0.02% 99.5%±0.05%, 97.6%±0.03%, 10.11%±0.1%和18.3%±0.05%，废水中残留Cu2+, Zn2+, Cd2+和Pb2+浓度分别为1.720±0.10, 0.256±0.03, 0.054±0.01和0.929±0.01 mg/L，低于GB8978-1996中第一类污染物最高允许排放标准值。

Study of removing heavy metals from acid mine wastewater with solvent extracting system of Mextral V10–Mextral 973H

The mine drainage from mineral and metallurgical processing has complex composition and large amount of water. At present, the effect is not ideal and high cost of heavy metal removal method. In order to solve the problem of heavy metal pollution in mine drainage, a synergistic extraction method has been developed to remove and recover heavy metals from mine drainage, which could be used to the solution with the high acidity and low heavy metal concentration, and inhibit calcium and magnesium ions enter into extractant. A synergistic extractant of Mextral V10–Mextral 973H was obtained for the effective removal of Cu2+, Pb2+, Cd2+ and Zn2+ from the acidic wastewater by the analysis of metal extraction pH isotherms, FT-IR spectrum and UV–vis absorption spectra. The volume ratio of organic phase and water phase (O/A), the saponification rate of Mextral V10 and extracting agent concentration has been studied on the effect of metal ions extraction. The extractability percentage of Cu2+, Cd2+, Zn2+, Pb2+, Mg2+ and Ca2+ were 99.1%±0.1%, 99.9%±0.02%, 99.5%±0.05%, 97.6%±0.03%, 10.11%±0.1% and 18.3%±0.05% respectively after sixth extraction continuously under the optimum experimental conditions of 10vol% (Mextral V10 and Mextral 973H) diluted in Mextral DT100 and Mextral V10:Mextral 973H=1:1, the residual concentration of Cu2+, Zn2+, Cd2+ and Pb2+ in wastewater were 1.720±0.10, 0.256±0.03, 0.054±0.01 and 0.929±0.01 mg/L respectively, which were lower than the maximum allowable emission standard value of class Ⅰ pollutant in GB8978-1996.