In order to produce ultra-low phosphorus steel, the deep dephosphorization experiment of steel containing phosphorus about 0.01 % outside BOF was carried out by high basic slag of CaO-CaF_2-FeO at 1 600 ℃.
The process route, composing of the deep DeP process in HM vessel-the mother liquid melting in EAF-AOD strong stirring with top lance-VOD strong stirring, featured the applicability for steelmaking both with high HM ratio and scrap, as well as for the new products of ultra-pure ferritic stainless steel by 3-step/2-step and 1-step process respectively, and the ferritic stainless steel as well.
The final phosphorous content in the liquid steel is reduced to about 10ppm by deeply dephosphorzing the liquid steel in an induction furnace using the appropriately selected slag and the proportional of the phosphor in between the iron and slag determined in the experiment and the actual dephosphorization quantity compared with the theoretical dephosphorization quantity.