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实验所用原料为含锗的锌冶炼真空炉渣,该物料主要含有锌和铅,此外还含有砷、锗、铟、银等元素,主要以金属或金属间化合物的形式存在。采用氧化浸出工艺浸出物料中的有价元素,回收有价元素后的废液通过化学沉淀法进行除砷,达到排放标准后排放。实验结果表明,氧化浸出的最优工艺条件为:游离酸浓度5 mol·L-1;双氧水过剩系数αH2O2=1.5;浸出时间1 h;液固比5∶1。在此条件下,Ge和As的平均浸出率分别为99.64%和99.43%。含砷废液除砷未达标严禁排放,以石灰为沉淀剂,废液经过化学沉淀法除砷处理,得到的砷酸钙废渣用水泥固化技术进行稳定化处理,避免造成二次砷污染;除砷后的废液运用氢化物发生-原子荧光光谱法(HG-AFS)测定残留的砷含量,检测得到溶液中的砷含量(0.008 mol·L-1)低于饮用水排放标准(0.01 mol·L-1),并进一步用石灰中和使废液pH达到9左右,达到排放标准。
The raw materials used in the experiment are zinc smelting vacuum slag containing germanium. The material mainly contains zinc and lead. In addition, it contains arsenic, germanium, indium and silver, which are mainly in the form of metal or intermetallic compounds. Oxidation leaching process leaching material with the value of the elements, after the recovery of valuable elements of the waste by chemical precipitation arsenic, to discharge standards after discharge. The experimental results show that the optimum conditions for the leaching process are as follows: free acid concentration 5 mol·L-1; hydrogen peroxide excess coefficient αH2O2 = 1.5; leaching time 1 h; liquid-solid ratio 5: 1. Under these conditions, the average leaching rates of Ge and As were 99.64% and 99.43%, respectively. Arsenic-containing waste arsenic was not discharged within the arsenic standard is not strictly prohibited, with lime as a precipitating agent, the waste liquid after chemical precipitation method of arsenic treatment, obtained calcium arsenate waste cement stabilized with cement curing technology to avoid secondary arsenic pollution; The residual arsenic content was determined by hydride generation-atomic fluorescence spectrometry (HG-AFS). The content of arsenic (0.008 mol·L-1) was lower than that of drinking water (0.01 mol · L-1) L-1), and further use of lime and waste liquid pH reaches about 9, to meet emission standards.