The Experiment Of The Dephosphorization Without Chromiumloss Of Stainless Steels Under The Condition Of Renewable Resources

Due to the dephosphorization using the scraps smelt stainless steels that cause the chromium loss. In this paper, the experiment of the oxidating dephossphorization without chromium loss, which adopts the multiple slag system with BaO and CaO for 9Cr18Ni1 Mo stainless steels is carried out. On the basis of thermodynamic calculation s, through deploying the BaO content, carbon content atmosphere and steel processing temperature, during the dephosphorization process,it gets the best slag system is 20 %CaO-45%BaO-15%Fe2O3-10Cr2O3-10%BaCl2,and the dephos pho rization rate is fro m 35.67% to 57.3%.And chromium oxide content is from 3.10% to 7.86%. Experim ental studies show that the initial carbon content in liquid stainless steels has a great effect on dephosphorization rate and chromium oxide rate.With the increase of carbon content in the molten steel, the dephosphorizatio rate is increased and the loss of cromium is decreased.The smelting temperature of stainless steels has a great effect on dephospho riz ation rate and chromium oxide rate. As the temperature increases, the dephosphorizat ion rate is increased and the loss of the chromium is decreased. When the temperature is 1750 K, it obtains the best of the dephosphorization rate.The smelting temperature of stainless steels using IF vacuum induction melting furnace is high. And with the increase of smelting temperature, the trend of carbon-oxygen reaction is increased. During the 5 minutes of reaction, the process of dephosphorization is relatively violent. The dephosphorization in liquid stainless steels is oxidized into the slag. After the 10 minutes of dephosphorization reaction, the phosphorus in liquid stainless steels tends to be stable. In the early dephosphorization, the silicon is quickly reduced. After 5 minutes of reaction, it is reduced from 0.585% to 0.198%. After that, iy is reached equilibrium with oxygen potential, and it is on longer reduced. Although sulfur has some degree of decline, the range of decline is small. The change of manganese and nickel are not significant.The dephosphorus is mainly oxidized to P5+, and then polarize O2- to from PO3-4 in slag interface. PO3-4. PO3-4 combine with Ba2+ and Ca2+ to generate Ba3(PO4)2 and Ca3(PO4)2, which will exist in slag system. The chromium are oxidized to Cr2O3 into slag.Dynamic studies show that the restrictive step of phosphorization is deph osp h o rus mass transfer in liquid stainless steels. And the initial dephosphorus content in liquid stainless steels has a very great effect on dephosphorization reaction. However the slag content which is added during the process of dephosphorization has little effect on dephosphorization reaction.