控电位选择性氯化工艺分离和回收富贵锑中贵贱金属的生产实践

【作者】 刘勇；

【导师】 杨天足；

【作者基本信息】 中南大学 ， 有色金属冶金， 2007， 硕士

【摘要】 本论文针对我国金锑精矿冶炼产物富贵锑中提金工艺存在的问题,将实验室规模下控电位选择性氯化分离和回收富贵锑中贵贱金属技术应用于工业生产。论文介绍了“盐酸+硫酸体系”和“盐酸+氯化钠体系”两个不同体系的富贵锑控电位选择性氯化的工业试验。在盐酸+硫酸体系选择性氯化浸出过程中虽然金、银能与锑、铜、镍分离,但铅在后续工序脱除不理想,造成金的品位只有16.7%,没有达到预期的目标。盐酸+氯化钠体系可以初步分离贵金属和贱金属,富集渣通过进一步处理可以得到品位高于70%的粗金粉,效果理想。所以,在工业生产中选择“盐酸+氯化钠体系”控电位选择性氯化工艺。工业实践中盐酸+氯化钠体系中控电位选择性氯化条件为:富贵锑粉100kg、盐酸浓度[HCl]=4.5mol·L^-1、氯化钠[NaCl]=1.0mol·L^-1、液固比L:S=4:1、双氧水加入量1:1（与富贵锑重量比）、终点电位350～380mV、温度80～90℃、反应时间3～5h、搅拌速度100r·min^-1下,各贱金属的浸出率均在≥99%,金的入渣率≥99.83%。浸出渣中的银通过氨浸——水合肼还原的工序提取,氨浸后可得品位高于70%的粗金粉。浸出液中的银、铅、锑、铜和镍可以逐一回收,浸出液中的铅主要以氯化铅的形式结晶产出,铅的结晶率92%。选用富贵锑粉还原进入溶液中的银,在富贵锑粉用量为浸出时用量的20%、温度80℃、时间1.5h的条件下,溶液中银的还原率≥98%。溶液中的锑可以通过水解制备氯氧锑并与其他离子分离,氯氧锑与氨水反应制备氧化锑,所得氧化锑含锑80%以上,锑的回收率99%以上。溶液中的铜以碱式碳酸铜的形式回收,当控制pH为4时,反应时间为3h可以得到过滤性能良好含镍2.2%以下的碱式碳酸铜渣,铜的沉淀率可达99%。溶液中的镍以碳酸镍的形式回收,回收率98%。控电位选择性氯化分离贵贱金属工艺,工艺流程短,无环境污染、操作简单、能耗低、无金属返渣,金属直收率高、主产品金品位高。富贵锑选择性氯化分离贱金属生产线的设计规模是年产5t黄金,处理能力年处理富贵锑420t。项目总投资400万元。新工艺比原有火法处理工艺在节约成本方面有明显优势,单从加工成本方面,年节约成本70万元,若将直回收率的提高计算进去,较原工艺年增加效益2000万元。更多还原

【Abstract】 The technology of selective chlorination leaching by controlling potential—metals recovery in the lab was applied to the industry for the present problem of extracting gold from antimony-gold alloy.Industrial experiments were carried out in the system of the combination of sulfuric acid & hydrochloric acid and the system of hydrochloric acid & sodium chloride.The industrial experiment in the system of combination of sulfuric acid & hydrochloric acid indicated:the base metals of antinomy, copper and nickle could be separated from the precious metals of gold and silver effectively by chlorination leaching under controlled potential, but the lead removing fell flat in the following step,as a result,the content of gold in the residue was just 16.7%,which was under the prospective level.For the system of hydrochloric acid & sodium chloride, the base metals could be separated from the precious metals firstly, through the following steps the content of gold in the residue reached up to 70%,which met the prospective aim,so the process in the system of hydrochloric acid & sodium chloride was chosen for the industrialization. In the system of combination of hydrochloric acid & sodium chloride of the industrial experiment,under the following operation conditions: [HCl]=4.0mol·L^-1,[NaCl]=1.0mol·L^-1,liquid-solid ratio L:S=4:1, leaching temperature 80～90℃,leaching time 3～5h,the oxidation potential 350～380mV,mixing speed 100r·min^-1,the leaching efficiencies of copper,nickel and antimony were over 99%,and 99.83% of gold was still in the residue.The silver in the leaching residue could be obtained through leaching by NH₃·H₂O and reduction by N₂H₄,the content of gold in the residue could be reached 70%.Silver,lead, antimony,copper,and nickel in the leaching solution could be recovered one by one.PbCl₂ crystallized from the solution,and the crystallizing ratio was above 92%.The powder of gold-antimony alloys was adopted to reduce silver contained in the leaching solution.Under the follow operation conditions:the dosage of gold-antimony alloys 20%, temperature 80℃and time 1.5h,the reducing ratio of silver could reach to 98%.Antimony trichloride contained in the solution in which silver had been reduced was got as Sb₄O₅Cl₂ by hydrolysis,followed by ammonia dissolving,then Sb₂O₃ can be received and the recovery ratio was above 98%.Cooper was got in the form of Cu（OH）₂CO₃ with nickel content below 2.2%when pH value of 4,reaction time of 3hours,and precipitation ratios of copper was 98%.Nickel was recovered as NiCO₃ and the recovery ratio was 98%.The technology of selective chlorination leaching by controlling potential—metals recovery has fewer processes,no pollution,no recycling residue,higher metal recovery,higher gold content,and is easy to handle,low energy consuming.The design scale of this line is 5t gold per year,and 420t gold-antimony alloy could be dealed with.The whole investment of the program is 4 000 000 yuan.The new process is better at saving cost,and it cuts down the process cost 700 000 each year,if taking the increasing recovering rate into account,it gains more 20 000 000 yuan than the old process.更多还原