Preparation Of Copper-Containing Austenitic Antibacterial Stainless Steel By Reduction Of Hot Metal From Copper Slag

With the rapid development of China’s economy,copper output is increasing.Copper slag is a by-product of fire smelting,with an annual output of up to 20 million tons.The Cu content in copper slag is between 0.4%and 4.6%,and the Fe content is between 29%and 46%,which is much higher than the grade of the corresponding ore.Therefore,the recovery of valuable resources in copper slag has been a hot topic of research.The research group proposed a new idea of "moderate depletion of copper slag,deep reduction,and direct smelting of copper-containing antibacterial stainless steel with coppercontaining molten iron".Based on the above new ideas and the preliminary research basis of the research group,this article will carry out copper smelting of copper-containing smelting.Research on direct smelting of molten iron containing copper austenite antibacterial stainless steel with molten iron.In this thesis,a thermodynamic analysis of a CO2 decarburization steelmaking system for preparing copper-containing molten iron by copper slag is performed.The effects of reaction temperature,CO2 flow,CO2 partial pressure,and reaction time on the decarburization process are investigated using single-factor experiments.The effect of O2 ratio on the thermal balance of decarburization reaction;etc.The chemical composition and metallographic analysis were used to analyze the composition and micromorphology of the obtained copper-containing stainless steel and copper-containing austenitic stainless steel after heat treatment.The main conclusions are as follows:(1)The thermodynamic calculation of the carbon dioxide decarburization system shows that between 1400～2000K,the elements involved in the reaction mainly include:C,Fe,Cr,Mn,Si,etc.Among them,the reaction of carbon dioxide with C and with Cr,Mn,There are intersection points in the oxidation reactions of Si element,which indicates that CO2 has selectivity to the oxidation of alloy elements,and reacts in the order of Si,Mn,and Cr.The calculation of lg(pCO/Pθ)and the equilibrium w[C],w[Cr],w[Ni]in the melt shows that when w[C]drops below 0.1%,reducing pCO is beneficial to "decarbonization and chromium preservation";When w[Cr]is between 17%and 19%,the reduction in pco partial pressure is conducive to the decarbonization process;when w[Ni]is between 8%and 11%,the CO2 decarbonization process is almost It has no effect on w[Ni],that is,the copper-containing molten iron prepared by copper slag is decarburized with CO2,which can achieve "decarbonization and nickel retention".(2)The dephosphorization calculation shows that:between 1600 and 1950 K,when the temperature is 1623K,the LP is 2048.35,indicating that low temperature is beneficial for dephosphorization;when the temperature is 1623K,and the FeO content is 20%,the LP is 22460.64,indicating Increasing the FeO content in the slag is beneficial to dephosphorization;when the temperature is 1623K and CaO content is 35%,the LP is 18241.71,which indicates that increasing the CaO content in the slag is beneficial to dephosphorization.(3)The energy balance calculation of the copper-containing molten iron decarburization steelmaking system for copper slag smelting in this paper shows that:the overall heat absorption of the CO2 system is injected,and the temperature of the molten pool is reduced;while the overall heat dissipation of the O2 steelmaking system,only decarbonization is considered Reaction,such as 13.70%O2 in CO2,the system can achieve the thermal equilibrium of the decarbonization reaction.(4)Single factor experimental study of CO2 decarburization and steelmaking shows that high temperature is beneficial for decarburization,increasing the flow of CO2 is beneficial for decarburization,mixing inert gas argon to reduce the partial pressure of CO2,and extending the time for CO2 blowing is beneficial for decarburization.carbon.The suitable reaction conditions obtained in this study are:reaction temperature of 1923K,CO2 flow rate of 940 mL/min,CO2 partial pressure of 80%,and reaction time of 50 min.The copper-containing stainless steels smelted under these conditions are:w[C]:0.053%,w[Si]:0.040%,w[Nn]:<0.01%,w[P]:0.031%,w[s]:0.019%,w[Ni]:10.33%,w[Cr]:19.2%,w[Cu]:2.55%,achieving the goal of "decarbonizing copper and nickel",the composition of molten steel meets the target steel grade 06Cr18Ni9Cu2 Ingredient requirements.(5)Hold the solution at 1050℃ for 30 minutes for solution treatment,and perform water cooling and air cooling respectively.Observation of the microstructure shows that austenite phase is precipitated in the steel.The grains are coarse;the average hardness of air-cooled samples is 194 HBW,and the average hardness of water-cooled samples is 212 HBW.