Or Low In The Control Potential Selective Chlorination Process Separation And Recovery Of Wealth Antimony Metal Production Practices

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.