摘要
由于氰化物具有高毒性,研究人员正在寻找一种环境友好和可持续的贵金属浸出工艺。硫代硫酸盐被认为是最有前途的替代浸出体系之一。传统的硫代硫酸盐浸出液一般由硫酸铜和氨组成,其中硫酸铜作为氧化剂,氨作为铜离子稳定剂。然而,氨也是有毒试剂。为此,本文研究了一种新型的、环保的硫酸铜-酒石酸盐-硫代硫酸盐体系用于硫化银的浸出,并考察了转速、温度、初始pH值、硫酸铜、酒石酸盐和硫代硫酸盐浓度以及不同气氛对硫化银溶解速率的影响。在硫酸铜-酒石酸盐-硫代硫酸盐溶液中,硫化银的溶解过程受化学反应控制,其表观活化能为43.49 kJ/mol。硫化银浸出的反应级数与硫酸铜、酒石酸盐和硫代硫酸盐浓度的关系分别为0.491、1.366和0.916。对比Ag_(2)S浸出前、后的XRD分析结果,提出了Ag_(2)S在硫酸铜-酒石酸盐-硫代硫酸盐溶液中可能的溶解路线,即Ag_(2)S被Cu(Ⅰ)-S_(2)O_(3)^(2-)逐步取代,生成中间产物Ag_(3)CuS_(2)、AgCuS和(Ag,Cu)_(2)S,最终以Ag(S_(2)O_(3))_(2)^(3-)的形式进入溶液。XPS分析结果表明单质S是Ag_(2)S中硫离子的最终氧化产物。
Due to the high toxicity of cyanide,researchers are trying to find an environmentally friendly and sustainable leaching process for precious metals.Thiosulfate is considered one of the most promising alternative leaching systems.Nevertheless,a traditional thiosulfate leaching solution generally consists of copper sulfate and ammonia,in which copper sulfate acts as oxidant and ammonia acts as copper ion stabilizer.However,ammonia is another toxic reagent.For this reason,a novel and eco-friendly system of copper sulfate-tartrate-thiosulfate was investigated for silver sulfide leaching in this work.The effects of rotation speed,temperature,initial pH,copper sulfate,tartrate and thiosulfate concentrations and different atmospheres on the dissolution rate of Ag_(2)S were examined.The process of silver sulfide dissolution is controlled by chemical reactions with an apparent activation energy of 43.49 kJ/mol.The reaction orders of silver sulfide leaching with respect to copper sulfate,tartrate,and thiosulfate concentrations in copper sulfate-tartratethiosulfate solutions are 0.491,1.366,and 0.916,respectively.A detailed dissolution route of Ag_(2)S was proposed based on XRD analysis of intermediate products such as Ag_(3)CuS_(2),AgCuS and(Ag,Cu)2S.XPS analysis indicated that elemental sulfur was determined to be the final oxidant product of sulfur ions from Ag_(2)S.
作者
陈俊南
谢锋
王伟
符岩
王剑
徐斌
CHEN Jun-nan;XIE Feng;WANG Wei;FU Yan;WANG Jian;XU Bin(Key Laboratory for Ecological Metallurgy of Multimetallic Ores(Ministry of Education),Northeastern University,Shenyang 110819,China;School of Metallurgy,Northeastern University,Shenyang 110819,China;Faculty of Materials,Metallurgy and Chemistry,Jiangxi University of Science and Technology,Ganzhou 341000,China;School of Minerals Processing and Bioengineering,Central South University,Changsha 410083,China)
基金
Project(N182502044) supported by the Fundamental Research Funds for Central Universities of China。
