Analysis and control for desiliconization process of low niobium hot metal by experimental approach

摘要

To clarify selective oxidation of silicon prior to the other elements such as niobium，the pre-desiliconization process of low niobium hot metal has been experimentally investigated. Desiliconization experiments were carried out in a medium frequency induction furnace with bottom- soft- blowing for promoting selective oxidation. The effect of initial slag addition was taken into account. It has been found that selective oxidization of silicon in preference to the other elements including niobium occurs under the good dynamical condition and with initial basic slag. In effective thermodynamic and dynamical conditions for selective oxidation, niobium may be oxidized prior to manganese. The initial basic slag addition was conducive to selective oxidation of elements in hot metal, which gave good conditions for improving silicon oxidation and suppressing of the oxidization of niobium and manganese. The bottom-soft-blowing might cause that the partial oxygen pressure in bath lowed down with the bath height rising, which could be a good dynamical condition for selective oxidation. The pretreatment process of low niobium hot metal could be divided into three stages: the desiliconization, extraction of niobium and manganese and dephosphorization.