Research And Application Of Duplex Converter Steelmaking Dephosphorization Technology

Along with the rapid development of modern iron and steel technology, more and more high to the requirement of P content in the steel, high-quality steel demand phosphorus content < 0.015%; Low temperature with special steel, tin plates for phosphorus content in the steel < 0.010%; Aviation materials, atomic energy with phosphorus content in steel demand steel sinosteel < 0.005% [1]; Into the 1990 s, says Cleffs Inc proposed iron ore concentrate phosphorus content should be < 0.024%[2].Harsh on phosphorus content, conventional converter process is difficult to organize production at low cost[3].The continuous improvement of the hot metal pretreatment technology and mature, converter steelmaking has developed from the original "blast furnace ? converter ? pouring" to "blast furnace ? Hot metal pretreatment ? converter ? secondary refining ? pouring" [4]. At present, there are mainly three types of dephosphorization methods: single slag, double slag, and duplex steelmaking. Method of single slag dephosphorization liquid steel smelting end[5];Method of double slag dephosphorization liquid steel smelting end < 0.010%[6];Duplexing dephosphorization liquid steel smelting end can stability control under0.005%[7].A factory in order to improve the dephosphorization efficiency of dephosphorization and decarburization of furnace efficiency of furnace steelmaking,and decarburization of dephosphorization furnace furnace are analyzed in the experiment, through formal ion model calculation and slag- gold thermodynamic experiment, analysis of slag composition, temperature and composition of the molten iron of the effect of dephosphorization and found the optimal dephosphorization of hot metal composition and temperature.The results show that the dephosphorization rate increased with the increase of slag basicity, but when the alkalinity increased to a certain value, the dephosphorization rate began to fall. In order to meet the requirements of the first half of the steel dephosphorization and slag basicity control at around 2.5 ~ 3.0; Increased with the increase of slag oxidizing dephosphorization rate increased, but too much can increase the iron losses. Therefore, control the oxidizing slag between 20%~30%;Dephosphorization rate and decreased with the increase of temperature, low temperature is advantageous to the dephosphorization reaction, but the temperature is too low will affect dephosphorization reaction kinetics. Therefore, dephosphorization furnace temperature should be controlled between 1320 ℃ ~ 1360 ℃.Industrial test results show that the double D- P phase control of converter, bychanging the burden structure, slag quantity, low intensity, oxygen blowing gun position, oxygen pressure strength, caused the phosphorus furnace slag material consumption to an average of 20.23 kg/t and the dephosphorization rate was 83.34%;In the double D C phase control of converter, through the optimization of oxygen supply system and slag making system, makes the dephosphorization furnace slag quantity of 13.56 kg/t, the average consumption dephosphorization rate was 95.26%.