Experimental Study On High-efficiency Extraction Of Scattered Metals By Pressure Leaching Of Scrap Copper Anode Slime

With the progress and development of society,the demand for resources exploitation of human,Are continues to increase.And at the same time,the proportion of recycling and utilization of scrap metal resources is increasing.Scrap copper is usually rich in a large amount of copper and rare precious metals such as selenium,tellurium,gold,silver.When smelting and recovering copper,it produces an intermediate product-anode slime,and the rare precious metals are enriched in Scrap copper anode slime.copper anode slime is one of the important materials for production the rare and precious metals.In order to solve the problem of the dispersion of rare metals in the traditional copper anode slime treatment process,this article by low-acid pressure leaching copper and selenium-two-stage strong acid pressure leach tellurium ways to treat scrap copper anode slime,Achieved efficient recovery of copper,selenium and tellurium.The preferred process conditions for the atmospheric pressure sulfuric acid leach of scrap copper anode slime: the sulfuric acid concentration of the leaching agent was 1mol/L,the liquid-solid ratio was 10:1,the reaction temperature was 80?,the reaction time was 4h,and the amount of hydrogen peroxide was 0.5 mL H₂O₂/g copper anode slime,the copper leaching rate can reach 90.66%,and selenium can not be leached into the solution,and the tellurium leaching rate is only 24.29%.The first stage pressure acid leach process conditions: the sulfuric acid concentration of the leaching agent was 0.5mol/L,the liquid-solid ratio was 10:1,the reaction temperature was 150?,the oxygen partial pressure was 1.5MPa,the stirring speed was 500 rpm,The reaction time was 2h,and the leaching rates of copper and selenium were 99.54% and 96.54%,respectively,and the leaching rate of tellurium was 68.54%.The better conditions for the two-stage pressurized acid leaching process are: the sulfuric acid concentration of the leaching agent was 1mol/L,the liquid-solid ratio was 20:1,the reaction temperature was 150?,the oxygen partial pressure was 1.5MPa,the stirring speed is 500 rpm,and the reaction time was 2h.In the second-stage leaching residue,the contents of tellurium,copper and selenium are 0.12%,0.016% and 0.28%.After two stages of pressure leaching,the leaching rates of copper,selenium and tellurium were 99.97%,99.33% and 94.39%.The leaching experiment of scrap copper anode slime by the oxygen pressure acid leaching process,The results show that the concentration of sulfuric acid has a significant effect on the leaching rate of selenium.Cu₂Se_O3 was formed in the low acidity,and Se was formed in the high acidity.Enrichment of selenium and tellurium from pressure leaching solution.The effects of reaction temperature,reaction time,copper powder dosage or Na₂SO₃ dosage on the reduction rate of selenium and tellurium were studied.The results show that the copper powder replacement process can obtain a higher reduction rate of selenium and tellurium.At the reaction temperature of 80?,adding twice the theoretical amount of copper powder,the reaction time of 2h,the reduction rates of selenium and tellurium can reach 95.5% and 97.45%,respectively.Na₂SO₃ as a reducing agent can selectively reduce Se(?)in the pressure leaching solution,while tellurium is not substantially reduced,thereby achieving effective separation and extraction of selenium and tellurium in the pressure leaching solution.