Comprehensive Utilization Of Ironmaking Precipitator Dust And Steelmaking Sludge

To improve the comprehensive utilization level of precipitator dust(sludge)pro-duced in iromaking and steelmaking processes of Dazhou Iron&Steel Co.,Ltd,the extrac-tion of potassium chloride from sintering precipitator dust,the extraction of alkali metals and zinc from blast furnace dust,and influence of mixed dust and sludge on sintering production and blast furnace smelting was analyzed in this paper.The appropriate opera-tion control parameters were determined through experiments.The fineness and recover-ies of potassium chloride and zinc,the removal rate of alkali,the grade and recoveries of carbon and iron concentrate were investigated.The influence of mixed dust and sludge on the output and quality index of the sinter was studied at a 320m~2 sinter machine,and the change of alkali load,zinc load,fuel ratio and blast furnace production index was examined in a 1780m~3 blast furnace.The results showed that 7626-ton potassium chloride whose recovery rate can reach92.3%with a purity 91.65%could be extracted from sintering precipitator dust every year,7207-ton zinc ingot whose recovery rate can reach 90.12%with a purity 98.61%could be extracted from blast furnace dust.The recycling of hazardous elements has been real-ized.The annual sales of KCl and zinc ingots can reach 135 million yuan,which is of high economic value.After alkali metal and zinc extracted from precipitator dust(sludge),the problems that high alkali metals load and zinc load of blast furnace during precipitator dust(sludge)'s recycling were solved.The alkali and zinc load of blast furnace were de-creased by 0.7 and 0.2kg/ton iron.After sludge powder added into 320m~2 sintering ma-chine,the sintering productivity had increased from 1.32t/(m~2.h)to 1.45t/(m~2.h),the sinter production had been raised 296,600t/a.The problem that the proportion of sludge powder is low and cannot be used in time were solved,and the dosage of sludge powder is in-creased by about 50%.After applying in 1780m~3 blast furnace,the blast furnace produc-tivity had increased from 2.47t/(m~3.d)to2.58t/(m~3.d),the production of hot metal was increased 72,000t/a.At the same time,the pollution problem during precipitator dust(sludge)treatment process and the period of circulation use were solved,obviously obtaining society and environmental benefit.