Abstract
A new technology for hot metal pretreatment with the modified BOF has been developed at Kobe Works. This technology has been successfully applied to mass production of high-grade steel since November 1983. The furnace for hot metal pretreatment has an 80 t capacity and is equipped with two lances for flux injection and oxygen top blowing. Hot metal is desiliconized and dephosphorized with oxygen and lime-iron oxide based flux in the first stage of refining, and desulphurization with soda ash injection is followed without deslagging.
This paper describes the pretreatment technology and results of the operation. Features of this process are as follows:
(1) Excellent reaction efficiency and reaction rate because of the suitable furnace shape for refining.
(2) Sequential and rapid dephosphorization and desulphurization treatment within about fifteen minutes.
(3) Low treatment cost by using cheap submaterials, such as lumpy burnt lime, BOF slag.
(4) Increase of the manganese content in the hot metal and dephosphorization reaction efficiency by the addition of manganese ore.
(5) Treatment of hot metal with high silicon content(Si ≈ 0.40%) in reasonably short time and with low cost.
