Means to cope with the higher alumina burden in the blast furnace

The stability of the blast furnace (BF) process depends on the quality of raw materials charged into the BF. Apart from various process variables, slag viscosity and slag fluidity are key parameters that require due attention for the stable BF operation. The varying Al2O3 content in slag increases the viscosity of slag and thus hinders the separation of slag from hot metal during the casting process. This leads to the deterioration of hot metal quality because of the entrapment of slag during the slag-metal interfacial reaction. In this work, an attempt is made to utilize the high alumina content raw materials and to reduce the Al2O3 content in the final slag. The high alumina content in slag increases the liquidus temperature and viscosity of slag and causes an adverse effect on BF operations. To countermeasure the effect of alumina, slag volume is increased and basicity along with MgO was increased. It has been demonstrated that MgO addition as a flux is effective for compensating the effect of a high alumina burden. By increasing the MgO in slag, fluidity was maintained to ensure easy separation of slag from hot metal.