针对尾矿重金属危害及电动修复研究现状，进行了某含锌尾矿解吸-电动-硫化钠沉淀联合修复试验研究，实现尾矿锌的去除及电极液循环再用。不同解吸试剂试验结果表明，柠檬酸解吸率较优达到63.33%，其具有酸性、络合作用双重特性，可用作该尾矿解吸剂。电动修复试验结果表明较高电压梯度有助于增大电流，加快离子移动，提升去除率，但电压梯度过高却会带来更大能耗，电压梯度选1.5V/cm为宜，柠檬酸作解吸剂，最终锌去除率可达67.32%。修复后锌形态分析表明，尾矿中锌的弱酸可提取态和铁锰氧化态去除率分别为93.18%和63.16%，均有大幅度去除。SEM手段考察了尾矿微观变化，发现了尾矿颗粒晶体及表面在修复后遭到了破坏，这利于离子移动和修复指标的提升。最后，经Na2S 0.006mol/L沉淀除锌后，阴极液可再次用作阳极补充液。
关键词：
锌; 解吸; 电动修复; 沉淀; 联合方法
Based on the damage of heavy metals contained in tailings and research status of electrokinetic remediation, a desorption-electrokinetic-precipitation remediation method was designed on a tailing containing zinc metal. Results of desorption with different reagents showed that a better index of 63.33% was provided by citric acid, which has a double characteristic of acidic and complexation and could be chosen as desorbing reagent for the tailings. Results of electrokinetic remediation showed that a better removal rate was provided by a higher voltage gradient, which can contribute to the increase of current and movement speed of the ions in solution. However, a greater energy consumption appeared with an excessive voltage gradient. Therefore, voltage gradient of 1.5 V/cm was chosen for electrokinrtic remediation and zinc removal rate reached to 67.32% with desorption of citric acid. Zinc contained in the tailings can be removed effectively using the pre-desorption method. Results of speciation analysis showed that removal rate of weak acid form and Fe-Mn oxides form in zinc were 93.18% and 63.16%, respectively. Meanwhile, microstructure change of tailings particles after remediation was analyzed by means of SEM. Results showed that crystal and surface of tailings particles were damaged after remediation, which is helpful to accelerating movement of ions in solution and increasing remediation index. The cathode liquid containing zinc precipitated with 0.006mol/L sodium sulfide would be used as the anode electrolyte.
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