Study On The Effect Of Simulated Waste Oil Cracking Gas Products On The Depletion Effect Of Copper Slag

Copper slag cleaning usually adds reductant such as coal,coke,oil and gas.However,with the shortage of energy and the intensification of environmental problems,it is particularly important to find a sustainable,less polluting reductant to replace the traditional reductant.Waste cooking oil as a waste biomass resource has the characteristics of low carbon emissions and waste to reuse.The pyrolysis of waste cooking oil at high temperature will produce small molecules with strong reducing ability such as hydrocarbons,CO,H₂,and the composition is similar to that of reductant commonly used in the metallurgical industry.If waste cooking oil can be used as a reductant for copper slag cleaning,it can not only reduce the consumption of non-renewable energy sources such as coal,coke,natural gas,diesel,but also reduce greenhouse gas emissions and occurrence of environmental pollution.The resource utilization of waste cooking oil opens up new ideas.Based on the characteristics of high-temperature pyrolysis of waste cooking oil,this paper proposes using waste cooking oil as the reductant for the cleaning of copper slag,and explore the feasibility of applying waste cooking oil to the cleaning of copper slag.Based on the characteristics of high-temperature pyrolysis gas products of waste cooking oil,three kinds of mixed gases were used to simulate the cleaning of copper slag,so as to reduce the content of magnetic iron and reduce the loss of copper in the slag,thus providing a new idea for the low carbonization of copper slag cleaning.First,Factsage was used to calculate and analyze the relevant thermodynamics of the waste cooking oil as a reductant cleaning copper slag process.The magnetic iron in slag can be reduced by H₂,CO and CH₄.The degree of difficulty of spontaneous reduction reaction in spontaneous reduction temperature range is:C<CH₄<H₂<CO.The calculation results of the chemically dissolved copper content in the slag show that the slag always contains a certain amount of chemically dissolved copper.With the decrease of Fe₃O₄ content,the content of chemically dissolved copper in the slag decreased.When the Fe₃O₄content is less than 2%,further reducing the Fe₃O₄ content has little effect on chemically dissolving copper in the slag.Then,70%H₂-30%N₂,70%H₂-10%CO-20%N₂ and 70%H₂-10%CO-10%CH₄-10%N₂ are used to simulate the pyrolysis products of the waste cooking oil at high temperature.The effect of gaseous gas products on the cleaning of copper slag was experimentally studied.The cleaning effect is best when using 70%H₂-10%CO-10%CH₄-10%N₂ gas mixture as reductant.At1250?,the gas flow rate is 0.2 L/min and the blowing time is 20 min,the copper content in the slag can be reduced to 0.52%.Finally,the distribution and characteristics of copper and iron components in the process of cleaning were discussed.During the melting process(stage I),the viscosity of the slag decreases with increasing temperature.At the same time,matte began to accumulate and settle.In stage(II),the matte and magnetic iron contents in the slag are significantly reduced.In the settlement stage(stage III),the remaining matte in the slag continued to settle,and the number of matte particles gradually increased from the top to the bottom of the slag.The slag viscosity remains unchanged.In stage(IV),due to the high initial temperature of cooling,matte still has sedimentation behavior.At the same time,slag viscosity increases with decreasing temperature and precipitation of magnetic iron.In addition,a clear boundary is formed between the slag and matte.There is a large amount of magnetite above the matte layer,and some magnetite reacts with matte to form FeO.A large amount of magnetite above the matte layer will lead to increased copper loss in the slag.