膜蒸馏-结晶处理高浓度硫酸锌溶液的研究  

Treatment of Highly Concentrated Zinc Sulfate Solution by Membrane Distillation and Crystallization

作　　者：娄向阳 纪仲光[1] 徐政[1] 王巍[1] 李岩[1] Lou Xiangyang;Ji Zhongguang;Xu Zheng;Wang Wei;Li Yan(National Engineering Laboratory of Biohydrometallurgy, General Reasearch Institute for Nonferrous Metals, Beifing 100088, China)

机构地区：[1]北京有色金属研究总院生物冶金国家工程实验室

出　　处：《稀有金属》2018年第3期299-306,共8页Chinese Journal of Rare Metals

基　　金：国家国际科技合作专项(2014DFA90920)资助

摘　　要：电镀等行业进行锌消费会产生高浓度锌废液,此类废液具有酸度高、腐蚀性强等特点,传统处理方法处理成本高且对设备耐腐蚀要求极高。本研究利用管式膜蒸馏-结晶技术处理高浓度ZnSO_4溶液,首先比较了不同流速、温度、pH条件下稀（0.2%,质量分数）、浓（20%,质量分数）ZnSO_4溶液膜蒸馏性能的差异,然后在优化条件下进行了浓ZnSO_4溶液膜蒸馏-结晶探索研究。研究结果表明,与稀溶液相比,浓ZnSO_4溶液的膜蒸馏通量略低,这主要是溶液蒸汽压下降以及浓差极化共同作用的结果。在高酸度条件下,浓ZnSO_4溶液膜蒸馏产水水质更容易恶化。此外,高浓度并未对ZnSO_4溶液的膜蒸馏性能产生显著的特殊影响。膜蒸馏-结晶操作过程中,膜通量由初始的2.81降至1.86kg·m-2·h-1,降幅为37%,产水电导率始终维持在10μS·cm-1以下,重金属盐截留率达到99.99%以上。冷却结晶得到的产品晶体形状规则,ZnSO_4溶液一次膜蒸馏-结晶理论回收率48.10%,实际回收率46.28%。采用合适的操作方式,膜蒸馏-结晶耦合工艺处理高浓度ZnSO_4溶液直接得到晶体产品可行。Highly concentrated zinc waste liquid is produced in electroplating and other industries. This liquid is characterized by high acidity,strong corrosion and so on. It costs a lot to deal with this kind of waste by traditional methods,and processing equipment needs a good resistance of corrosion. In this work,membrane distillation by tube membrane combined with crystallization was used to treat highly concentrated ZnSO_4 solution. Firstly,the performance differences of dilute（0. 2%,mass fraction） and concentrated（20%,mass fraction） ZnSO_4 solution in membrane distillation under different flow rates,temperatures and pH values were investigated. Then,the treatment of concentrated ZnSO_4 solution by membrane distillation and crystallization was studied under optimized conditions. The results showed that membrane distillation flux of concentrated ZnSO_4 solution was slightly lower than that of the dilute solution,which was mainly caused by the combined action of solution vapor pressure drop and concentration polarization. Under the condition of high acidity,the yield water quality of concentrated ZnSO_4 solution was easier to deteriorate. In addition,high concentration did not have a special effect on the membrane distillation performance of ZnSO_4 solution. During the operating processes of membrane distillation and crystallization,the membrane flux dropped from 2. 81 to 1. 86 kg·m-2·h-1,with a 37% decline. The conductivity of permeate remained below 10 μS·cm-1. The rejection rate of heavy metal salt reached 99. 99%. The products obtained by cooling crystallization had a good crystal morphology. The theory recovery rate of ZnSO_4 solution by primary membrane distillation and crystallization was 48. 10%,while the actual recovery rate was 46. 28%. The coupling process of membrane distillation and crystallization to treat high concentrated ZnSO_4 solution with appropriate operation was feasible to obtain crystal products directly.

关 键 词：管式膜 膜蒸馏 结晶 硫酸锌 

分 类 号：X758[环境科学与工程—环境工程]