冶炼烟气洗涤污酸废水气液硫化除锌

Technique,thermodynamics and kinetics of zinc removal from acidic wastewater via gas-liquid sulfidation reaction

采用气液硫化法对模拟含锌污酸废水进行处理,考察pH值、H2S气体分压、反应温度、反应时间、Zn^(2+)初始浓度等条件对Zn^(2+)去除效果的影响。在单因素实验的基础上进行五因素五水平的正交实验,并对采用该工艺处理冶炼烟气洗涤污酸废水效果进行验证。研究Zn^(2+)硫化分离的热力学,及其气液反应动力学过程,并对锌沉渣进行分析与表征。结果表明:在最佳工艺条件为模拟溶液初始pH值3、反应时间80 min、温度35℃、H2S气体的体积分数为30%、Zn^(2+)初始浓度100 mg/L时,Zn^(2+)脱除率为99.54%,沉渣主要物相为ZnS,锌的质量分数达63.84%;实际污酸废水锌浓度为569和216.7 mg/L时,去除率分别达到99.79%和99.49%。

Sulfide precipitation via gas-liquid reaction was used to treat the simulated acidic wastewater containing zinc ion. The effects ofpH value, H2S volume fraction, temperature, reaction time, initial concentration of Zn2＋ on the removal rate of zinc were investigated. The orthogonal experiments with five factors and five levels were designed based on the results of single factor experiments, which was applied to the treatment of acidic wastewater generated from smelting flue gas washing. The thermodynamic of Zn2＋ sulfidation and kinetics of gas-liquid reaction were studied. And then, the sediments were analyzed and characterized. The results show that the optimum operation conditions are as follows pH value of 3, the time for reaction of 80 min, the temperature controlled at 25℃, H2S volume fraction of 30%, and the initial concentration of Zn2＋ of 100 mg/L. The removal rate of Zn2＋ can reach 99.54% under the optimum operation condition. The sediments mainly consists of ZnS with zinc content of 63.84%. When concentrations of Zn2＋ in acidic wastewater are 569 and 216.7 mg/L, the removal rates of Zn2＋ are 99.79% and 99.49%, respectively.