Study On The Recovery Of Metal Values From Copper Converter Slag

Copper slag,the main by-product in the copper smelting process,which cantains a certain amount of copper,zinc,cobalt,iron and some other metal values,is a kind of potential secondary resources.If the copper slag is not comprehensive recycling and utilization,it will not only cause waste of resources,but also cause serious pollution to the environment.The consumed of mine's resource is high while secondary utilization of the mine's resource is low in the industry of copper metallurgy.It is of great theoretical and practical significance to recover metal values from copper slag by proper process.The copper converter slag and tailings discharged from a copper smelter were studied in the thesis.The leaching behaviors of copper from tailings in ammonia system were analyzed.Copper,cobalt and zinc in converter slag were leached into the solution by sulfuric acid;excess iron was removed by the processes of oxidization,neutralization and hydrolyzafion;copper was extracted by Lix984 after cobalt was recovered by oxidizing precipitation,zinc in the copper-raffinate was extracted by P204;through the above analysis,the conclusions were as follows:?1?Leaching of copper in NH₃·H₂O–NH₄Cl system from flotation tailings has been studied.The optimum leaching condition was determined that slag particle size of–0.045mm,leaching temperature of 60?,concentration of NH₃·H₂O of 3.0mol/L,concentration of NH₄Cl of 2.5mol/L,usage amount of H₂O₂ of 0.2mL/g,liquid to solid ratio of 6:1mL/g,copper leaching rate under this condition was 62.22%.Kinetics studies indicated that the leaching process of copper was controlled by the inner diffusion of reactants,the apparent activation energy was 11.56kJ/mol,apparent reaction order of NH₃·H₂O concentration was 0.93883.?2?The converter slag was leached by sulfuric acid after crushing,grinding and screening,the optimum leaching condition was determined that stirring speed of500r/min,sulfuric acid concentration of 3.5mol/L,leaching temperature of 75?,usage amount of H2O2 of 1.2mL/g,liquid to solid ratio of 5:1mL/g,leaching time of 120min;under the condition,the leaching rate of copper,zinc,cobalt was 92.91%,89.21%,93.44%,respectively.?3?Iron in the leaching solution was removed by means of oxidization,neutralization with H2O2 as oxidant and NaOH as neutralizer.The optimum condition for removing iron was determined that temperature of 80?,usage amount of H₂O₂ of 20mL/L,system pH of 5.0 and reaction time of 120min.Iron removal rate was up to 99.45%.?4?Na₂S₂O₈ was used as oxidant to recover cobalt in the solution,cobalt was enriched under the conditon:dosage of Na₂S₂O₈ of 4 times of theoretical cobalt consumptions,temperature of 80?,pH of the system of 4.5,reaction time of 120min.99.57%of the cobalt was precipitated and the cobalt content in the residue was 12.47%.?5?Lix984 was used to extract copper after cobalt removal.The optimum extraction condition was determined that initial pH of the solution of 2.0,concentration of Lix984 of6%,O:A of 1:1.The extraction rate of copper was 98.32%and 99.47%of the copper in the loaded organic phase was extracted by sulphuric acid of 2.0mol/L when O:A was 5:1.?6?P204 was used to extract zinc from the copper-raffinate.The optimum extraction condition was determined that initial pH of the solution of 3.0,concentration of P204 of20%,O:A of 1:2.The extraction rate of zinc was 91.84%,and 97.54%of the zinc in the loaded organic phase was extracted by sulphuric acid of 2.0mol/L when O:A was 3:1.