Copper Dust Wet Processing New Technology For Recovery Of Valuable Metals

At present, the copper smelting capacity has been more than three million tons/year in our country, mainly of which was smelted by fuel fired smelting. No matter what melting method was selected, the dust was produced in the process because of the volatile substances in sport and will have substantial smoke, there was much valuable elenments in one of enrichment. The copper dust was mainly disposaled with fuel fired smelting, but there were low recovery ratio, bad working conditions, pollution problems. The hydrometallurical processing was developed because the new methods of treatment was studied at home and abroad. It is difficult to have a unified process for copper dust, because of the different composition of raw materials, process methods, process conditions.An technics processing for using hydrometallurical processing treated the dust mixture of blast furnace and reverberatory furnace, recovering copper, zinc, tin and lead was described in this article. The grade of copper concentrate obtained was more than 50% and the contents of harmful impurity were less than smelting standard of copper concentrate; The purity of zinc sulphate was more than 95%, which reached the standard of industry in our country; lead, tin and silver were well enriched in lead dross, content of which was 28%,10% and 1.425%. All these show that this technology lays a good basis for the next recovery of the above valuable elements.The mainly teche of experimental treatment flow includes neutral leaching,acid leaching, acid leach liquor eliminating tin, sulphide precipitation and precipitation translation. During neutral leaching process, the effects of leaching liquid-solid ratio, leaching temperature and leaching time on leaching rate of copper and zinc were explored. The experimental results show the optimized conditions to obtain leaching rate of 40.71% and 93.42% for copper and zinc are:liquid-solid ratio being 4/1, leaching temperature at 25℃, leaching time of 1h. The effects of sulphate acidity, leaching temperature, leaching liquid-solid ratio,and leaching time on leaching rate of copper, zinc, tin were explored for using orthogonal experiment in acid leaching process. The experimental results show the optimized conditions to obtain leaching rate of 97.33%,79.36% and 9.83% for copper, zinc and tin are:sulphate acidity being lmol/L(98g/L), leaching temperature in 50℃, liquid-solid ratio being 5/1, leaching time of 2h. Neutral leached mud could eliminate tin in the solution during acid leaching liquor outing tin, if the pH was controled. The experimental results show the optimized conditions to obtain solution, which the content of tin was less than O.Olg/L, were:liquid-solid ratio being 2/1, precipitating time of 2h, precipitating temperature in 50℃. Sodium sulphide was used for precipiting the copper ion and zinc ion in solution during sulphide precipitating process. The experimental results and theory show the contents of copper and zinc was less than 10-8mol/L, if the content of sulphur ion was 10-8mol/L in solution, sodium sulphate were made Glauber's salt and precipitation were the mixture of the copper sulphide and zinc sulphide. The above mixture of the copper sulphide and zinc sulphide was used for treating the leaching liquor containing the copper and zinc in precipitation translating process. The effect of copper recovery ratio benefited from excessive percent of zinc sulphide was considered. The experimental results show the optimized conditions to obtain copper recovery ratio of 98.40% were:the excessive percent being 10%, precipitation translating time of 2h.The total recoveries of copper and zinc reach 96.85% and 92.69% in entire treatment process.lead, tin and silver basiccal were entered and enriched in lead residue, the material input-output ratio is 1:2.22 in economy.This process was fitted with the copper dust contented soluble copper, zinc compounds. There were the following characteristics using this process:the use of wet treatment method to eradicate the fire treatment of lead poisoning, the whole process without solid waste, no harmful gas and liquid emissions; there were a greater economic advantage process for using sulfide precipitation and sedimentation separation conversion solution of copper and zinc; the flow was short, the equipment was simple, the main chemical materials consumed less, have greater technical and economic advantages.