Phosphorus Distribution Equilibrium Between Hot Metal Demanganization Pretreatment Slag-Hot Metal And BOF Slag-Molten Steel

In order to meet the increasingly strict requests of steel users for steel qualities, the content and range of impurities containing in steel, especially those of phosphorus, is therefore required to be as low as possible. In order to meet the production requests of steel works,demanganization pretreatment is required to taken to hot metal containing 0.3% [Mn] and 0.1% [P] after desilication. Demanganization demand low basicity oxidizing slags, which is in contradiction with dephosphorization and desulphurization pretreatment. So for the sake of knowing the change of content of [p] and factors affecting it during the demanganization and determining the high efficiency slags and slag-forming system of converter, the study about phosphorus distribution ratio between demanganization slag and carbon saturation hot metal is very important. In addition, it is necessary to measure the phosphorus distribution ratio between converter slag and low-manganese molten steel, as the minimum phosphorus content of low-manganese liquid steel with which the converter blowing end can reach hasn't been reported.In this paper, according to the problem of actual production, the phosphorus distribution equilibrium has been measured between different slags and hot metal or molten steel during the process of demanganization. The manganese or phosphorus distribution ratio between slags and Ag and solid iron achieved at 1573K,1623K,1673K have been transformed into distribution ratio between slags and carbon saturation hot metal through related thermodynamic parameter. So the relation between P equilibrium content of hot metal and slag component & temperature have been gained. At the same time, the study of factors affecting phosphorus distribution ratio between converter slag and low-manganese molten steel have been carried out.The conclusions are summed up as following:1. The phosphorus distribution ratio between demanganization slag and carbon saturation hot metal increase with basicity. The manganese distribution ratio reach the highest value as 650.12 with basicity is 0.19 at 1573K while phosphorus distribution ratio is 11.28.2. The phosphorus distribution ratio between demanganization slag and carbon saturation hot metal increase with the content of FetO, especially as basicity is at the range of 0.26~0.27.3. The increase of Al2O3 has very little effect on the phosphorus distribution ratio between demanganization slag and carbon saturation hot metal while MgO make it bigger.4. The phosphorus distribution ratio reaches the highest value as 92.35 while the manganese distribution ratio is 197.15 and [Mn] of carbon saturation hot metal is 0.021%.5. The connection between phosphorus distribution ratio and slag component & temperature can be describe as follow: P , R e g r e s s t 22 5 = - 3 9 2 .5 2 + 0 .1 4 6 2 + 1 .5 4 1 ( % F e O ) + 1 .7 2 1 ( % M n O ) + 0 .2 4 9 ( % S i O ) + 3 .7 9 9 ( % C a O ) + 2 6 .6 6 ( % P O ) L T6. The manganese or phosphorus distribution ratio between converter slag and low-manganese molten steel increase with FetO content, as long as its value less than 35%.7. The manganese distribution ratio between converter slag and molten steel reach the highest value 183.10 while [Mn] is 0.011% and [P] is 0.0012%, it's good to satisfy the needs of demanganization.