Study On MgO Injection From Tuyeres Of Cheng Gang Blast Furnace

High Al2O3 content in iron-making blast furnace burden may cause blast furnace slag viscosity increasing,which leads to bad liquidity,so many companies add MgO used in sintering and pelletizing additive to solve the problem in current time.However this method can bring many negative effects such as: reduce sinter drum strength and deteriorate charge droplet performance.To avoid the effects,investigation,including physical and chemical properties of Magnesite,effects of magnesite addition on pulverized coal combustion rate,effects of MgO Content on soft-melt dripability of Blast Furnace and spouting of the magnesite powder to the slag in hearth area has been conducted in the background of Chengde Iron-Making Factory.The main conclusions are as follows:1)The HGI of magnesite used as MgO additives is 66,and the HGI of the coal is 70 and 56,which indicates that the magnesite can be milled and mixed with the coal;2)As the density of magnesium and coal respectively is 2.88 g/cm3 and 1.44 g/cm3,it can be conveyed at the speed of 5.84m/s.3)Tests on the burning rate of coal containing MgO additive show that MgO additive can improve the burning rate of coal to about 10% in comparison with the coal without MgO;4)Pyrolysis rate of pulverized coal mixed with MgO additive could be promoted by about 15%;5)The maximum pressure difference ?Pmax increases when the MgO content increases in the charge.?Pmax of S-0 # is only 2.04 kPa and the total characteristic of S value is only 59 kPa·?,so the charge of its droplet property is excellent;6)The difference between the upper and lower of MgO slag samples is only 0.1%,in the slag test at 1500 ?,which indicates that under the blast furnace smelting conditions MgO-containing additives can complete blast furnace slagging.