IMPROVEMENT OF MN YIELD IN LESS SLAG BLOW ING AT BOF BY USE OF SINTERED MANGANESE ORE

In order to improve manganese recovery by smelting reduction of mangan ese ore during less slag blowing at BOF, the effects of sintered manga nese ore on reduction behavior have been studied both in 100kg laborat ory scale and in 340t industrial scale tests. Results obtained in this work are summarized as follows. 1) The oxidation of Mn! during addit ion of manganese ore is suppressed by using sintered manganese ore, be cause the active oxygen in manganese ore can be decreased to one third by sintering. 2) Addition of CaO to sinter is very effective for incr easing the reduction rate of (MnO). Especially, it is most effective w hen CaO/SiO2 of sinter is more than 3. 3) Using the sinter with CaO/Si O2 of 3.05, manganese recovery in industrial converter can be increase d to 70-80%, when the amount of sinter is 12-13kg/t and also end-point C! is 0.10-0.18%. (65% for raw manganese ore) 4) These effects of hi gh basicity sinter are due to both early slagging and decreasing (%MnO )/%Mn!.