OPTIMIZING THE PROCESS OF DESULFURIZATION BY POWDER INJECTION IN RH BY COMMERCIAL TEST

摘要

Desulfurization by powder injection in RH is an important process to produce ultra-low-sulfur steel which has been widely applied to marine industry, aviation industry and petroleum transportation industry. In this paper, the motion trajectory of desulfurizer in RH was analyzed in detail to reach the conclusion that the desulfurization efficiency could be improved through reducing the quantity of desulfurizer inhaled into hot bends and increasing the desulfurizer staying time in liquid steel. Furthermore, commercial tests were carried out to study the relationships of desulfurization efficiency and RH process parameters including desulfurizer composition, top lance height, and driving gas flow rate when desulfurization was proceeding. Based on the relationships, finally, the optimal parameters, CaO/CaF_2 was 90/10, top lance height was 1.3 m, driving gas flow was 50 Nm~3/h, were found, which could ensure that the sulfur content in steel after RH process was less than 15×10~(-4)%.