Effect Of Blast Furnace Dust On Desulfurization And Valuable Metal Enrichment Of Stainless-steel Pickling Sludge

Stainless steel pickling sludge contains Fe,Cr,Ni,CaO,CaF₂,etc.There is still a lack of recycling and utilization methods with large amount of consumption,high efficiency and no secondary pollution.The dust collection from blast furnace contains Fe,Zn,C and CaO,MgO,SiO₂,Al₂O₃,etc.Currently,it is mainly used as sintering ingredients,pellet raw materials,direct reduction,etc.There are certain problems in the utilization process.This paper is based on the technical idea of desulfurization treatment of pickling sludge for steelmaking auxiliary material.Meanwhile,the blast furnace dust is used as the desulfurizer for pickling sludge,to achieve synergistic treatment of two kinds of solid waste.The thermodynamic conditions of carbonation reduction of pickling sludge components,the effect of carbonation on the decomposition reaction of calcium sulfate in pickling sludge,and stainless steel were studied by means of FactSage thermodynamics software,thermal mass spectrometry and calcination reduction under inert atmosphere,respectively.The law of co-heat desulfurization and the influence mechanism of blast furnace dust composition on the conversion of sulfur-containing substances in pickling sludge have the following conclusions:?1?The pickling sludge has the same trend of TG-DTG curve under different carbon content conditions,all of which are weight loss in three stages and different gas generation during heating;with the increase of the proportion of carbon,the weight loss and weight loss of rate sample roasting is increasing continuously.When the carbon content is twice of the carbon requirement,the weight loss is the highest,which is 13.94g,and the weight loss rate reaches 40.42%.?2?The pickling sludge with different proportions of blast furnace dust has a larger weight loss than the pure sludge.When the ratio of dust removal ash in the high sulfuric picking sludge bag is 8:2,the maximum weight loss is 39.055%;when the ratio of low sulfuric picking sludge to gravity dust removal ash is 2:8,the weight loss is the largest,which is 36.66%;When the ratio of pickling sludge to blast furnace dust is 2:8,the difference between theoretical weight loss and actual weight loss is greater than 9%;the minimum temperature of SO2 escaping is 700°C The ratio of high sulfuric picking sludge to bag dust is 8:2 and at 1200?C for 3.5h.The desulfurization rate after calcination in Ar atmosphere is 75.07%,and the recovery rates of Fe,Cr and Ni are 91.24%,70.68%,and67.11%,respectively.the removal rate of Zn is 99%.?3?The addition of Fe₂O₃,SiO₂ and Na₂CO₃ can reduce the decomposition temperature of carbon-reduced calcium sulfate,of which 5%Fe₂O₃,8%SiO₂ and 3%Na₂CO₃ promote the reaction better.The research of the paper provides a foundation for the return of stainless steel pickling sludge and blast furnace dust in steel enterprises.