CO Injection Reduction Of Copper Converter Slag And Its Kinetics

As an important secondary resource,copper slag increases by more than 15 million t per year in China,among which copper content reaches more than 750,000 t.Therefore,it is very important to carry out deep dilution of copper slag,reduce the content of copper in the slag and improve the recovery rate of copper in the slag to promote the recovery and utilization of secondary resources in China.Biomass fuels such as biodiesel,gutter oil and rubber seed oil are often used as reducing agents to participate in the dilution of copper slag.Since the pyrolysis products of biomass fuel at high temperature are mainly carbon monoxide and hydrogen,the reduction of carbon monoxide plays a certain role in the lean copper slag with biomass fuel.Therefore,the study of carbon monoxide reduction of copper converter slag and the analysis of reduction process kinetics,to determine the reaction type of carbon monoxide and iron oxide reaction,reaction mechanism and the speed limit link,for the study of carbon reductant,biomass oil,natural gas as a reducing agent of copper slag depletion mechanism has an important role.Firstly,the thermodynamics of copper to slag reduction by CO-CO₂ mixed gas injection was studied.It is found that the reactions during the reduction of copper to slag by CO-CO₂ mixed gas injection are as follows:the decomposition of CO produces CO₂ and C,the reaction of reducing Fe₃O₄ to FeO and CO₂ by C,and the reaction of CO reducing Fe₃O₄ to FeO and CO₂.From the point of view of the standard free energy of reaction,the increase of temperature has little effect on the reaction rate of CO-CO₂mixed gas injection reduction copper converter slag.Secondly,magnetic analyzer and SEM-EDS were used to analyze the copper converter slag after the reduction of CO-CO₂ mixed gas.The results show that the magnetic iron content of converter slag decreases with the increase of reduction temperature and time.In 1250?¹325?temperature range,the same temperature of CO,the utilization rate of change is not big.At 1350?,the initial CO utilization rate is higher,as the reaction of CO utilization gradually reduce.When the reduction temperature is high,the deposition of copper in converter slag is favorable.The reduction effect of higher CO ratio on copper converter slag is better,and more copper particles grow and accumulate.Finally,the kinetic process of CO reduction of copper slag at 1250?¹350?was studied by means of the results of copper slag injection reduction.It is found that the reaction of CO with magnetic iron in copper slag is a regional chemical reaction on the surface of magnetic iron phase and in the second stage of regional chemical reaction,[-ln?1-X?]^2/3=kt accords with the kinetic reaction equation of copper slag reduction by CO injection.The apparent activation energy of copper slag reduced by CO injection is 313.263kJ/mol.The reaction rate of copper slag reduction by CO injection at 1250?¹350? is controlled by both chemical process and mass transfer process.Increasing the temperature or increasing the gas flow rate can increase the reaction rate.