Converter smelting can be divided into three main processes: single slag process, double slag process and double coupling process. The lime consumption of single slag method is closely related to the initial silicon content of molten iron, which is generally in the range of 30 ~ 50kg/t. Double slag smelting is usually used when the content of molten iron and silicon is high, and the consumption of converter auxiliary materials is higher than that of single slag smelting. Although the double method can reduce the consumption of raw materials, it needs to increase the converter specially used for dephosphorization, and the iron temperature drop after dephosphorization increases, which increases the burden of the subsequent process. The purpose of the converter process of slag reduction at SHAsteel is to greatly reduce the consumption of converter auxiliary materials and slag and reduce the production cost of steelmaking on the premise of meeting the requirement of molten steel W (P) < 0.02% without adding new equipment.
Scholars have developed a bof steelmaking process to reduce slag by studying the slag dumping time and blowing process parameters in the early stage of bof. The bof blowing process is divided into two stages, respectively dephosphorization stage and decarbonization stage. After the end of the dephosphorization stage, part of the phosphorous rich slag is removed, and then a small amount of slag is decarbonized. The end point of the blowing process retains the decarbonization slag with the following furnace dephosphorization. The practical results show that compared with the conventional smelting process, the consumption of lime and the consumption of light burned dolomite decreases from 26kg/t to less than 17kg/t and from 13kg/t to less than 9kg/t, which reduces the production cost of converter. The w(P) of molten steel at the end of blowing is controlled from 0.0080% to 0.0182%, with an average of 0.0126%.