Smelting reduction of lean pyrite cynder of complex mineralogy for the production of low silicon ferro-alloys

The physical characteristics and mineralogy of reddish brown pyrite cinder material reveal that the recovery of metal value from this material by any physical means or by acid/ alkali leaching treatment is difficult due to complex mode of association of gangue materials with iron oxide minerals. However, smelting reduction of as received lean pyrite cinder material in induction furnace produces a low silicon (around 180/0) ferro-alloy. Use of petroleum coke or non-coking coal as the carbonaceous reducing agent showed a satisfactory performance in extracting the metal value. The process is almost smooth and trouble free although a little of foaming of slag is observed due to the use of fine materials. This, however, is controlled efficiently during experimentations. A little loss of charge materials is observed as some fine materials are carried away with the outgoing product gases. A proper monitoring of the process and use of pellets in place of fines could very well improve the recovery of metal value.