THEORY ANALYSIS ON THE NEW GENERATION OF CLEAN STEEL PRODUCTION PROCESS

Based on the thermodynamic analysis on the selective oxidation of the main elements in the new generation of clean steel production process, and the production practices of hot metal treatment in the new process of clean steel production accumulated by the Jing Tang Iron and Steel Corporation, the control of the main elements such as S, P, C, etal., were investigated, and the main characteristics of the new generation of clean steel. production process were analyzed. We indicate that several production problems must be solved. The research results show that, by using KR desulphurization technology, the S content of hot metal can be steadily controlled to less than 0.0020%. The final S control of the new production process of clean steel depends mainly on the resulfurization content in the dephosphorization furnace. Increasing the slag basicity and reducing the content of S from scrap and slag forming materials can reduce the resulfurization of hot metal. The formation of proper slag basicity at relatively lower hot metal pretreatment temperature (1300-1350 degrees C) and at relatively higher oxygen potential is the key to solving the problem of removing P at high C content. The P content in dephosphorization furnace, when producing common low P steel (P <= 0.006%), may be controlled at less than 0.03%, whereas the P content should be below 0.008% when producing ultra low P steel (P <= 0.002%). Less-slag smelting, lower Fe losing and high carbon tapping of decarburization furnace are the important technological characteristics of the new generation of clean steel production process.