| The production of copper smelting slag was very huge,because of the low recovery rate and poor comprehensive utilization efficiency of the current treatment technology,most of them were unemployed and stocked open in the environment,which posed potential dangers for the atmosphere,soil,water environment and human health.Therefor the research of exploring the processing technology for the slag with high efficiency,clean environmental protection was urgent and necessary.In this paper,the typical water quenched copper slag is taken as the research object,and the wet extraction process of oxygen pressure sulfuric acid selective leaching of the water quenched copper slag is proposed and optimized.By means of ICP-AES,XRD,SEM,filtration rate measurement and other analysis,detection and characterization means,the ore of copper smelting slag and leaching slag is studied physical characteristics;through the study of the transformation behavior of silicon and iron in the copper smelting slag under the condition of acid leaching under pressure,the influence mechanism of the filtration performance of the leaching pulp and the selective leaching mechanism of sulfuric acid under oxygen pressure are revealed,and optimize the results by controllable conditions;through the study of the leaching kinetics of copper in the copper smelting slag under oxygen pressure sulfuric acid system,the influence mechanism of the mineral leaching efficiency and the phase of copper and ferrosilicon are clarified The reconstruction mechanism provides theoretical basis for harmless treatment of copper smelting slagThe results show that the treatment of copper smelting slag by the selective leaching process of oxygen pressure sulfuric acid can destroy the inlay structure of copper and iron in the slag.The analysis of the composition and phase of the leach residue shows that the leach residue is mainly composed of hematite(?-Fe2O3)and amorphous SiO2,in which there is almost no s and the content of valuable metal is less than 0.1 wt%.The leach residue can be used as high-quality raw material for ironmaking or further treatment.And the process does not produce sulfur dioxide and greenhouse gases,the process is environmentally friendly,and the energy consumption is low.The reaction process is characterized by low acidity,small corrosion to equipment,mild operating conditions and easy industrialization.Under the condition of initial acid concentration 0.4 mol/L,leaching temperature 200?,Liquid-Solid ratio 6 mL/g,oxygen partial pressure 600 kPa,leaching time 60 min,the leaching rate of Cu is more than 95 wt%,the leaching rate of Fe is less than 0.6 wt%,the leaching rate of Si is less than 2 wt%,and the filtration rate of leaching pulp can reach 378.54 L/(m~2·h).Using response surface method adaptive weight particle swarm optimization to optimize the selective leaching process of copper smelting slag oxygen pressure sulfuric acid,the model of selective leaching rate and Pulp Filtration Performance of copper smelting slag can be established,and the fitting degree of the model is high,and the optimization result is credible.The optimum conditions of the optimized leaching process are as follows:temperature 204.1?,sulfuric acid concentration 0.46 mol/L,Liquid-Solid ratio 6.9 mL/g.under this condition,the selective leaching rate is 96.95 wt%,and the filtration rate is 399.42 L/(m~2·h).The results of the process are obviously improved compared with those before optimization.The kinetics of copper leaching was in accordance with the unreacted shrinking core model.The leaching process was controlled by chemical reaction in the early stage,then by solid product layer diffusion.The apparent activation energy of chemical reaction control and solid product layer diffusion control processes were 47.3 kJ/mol and 11.35 kJ/mol,respectively.The leaching rate of copper is mainly determined by the chemical reaction control stage,in this control process,the reaction orders of sulfuric acid concentration,oxygen partial pressure and initial radius of particles are 0.83,0.92 and-1,respectively.Therefore,the kinetics equation of copper leaching can be summarized as follows:(?)... |
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