Mintek business develop-ment and technology commer-cialisation GM Dr Nic Barcza reports that, in January last year, the pyrometallurgy division first took up the challenge to investigate the possibilities of substantially increasing power supply to large single-electrode furnaces of 40 MW.
“A few months later, it was decided that sufficient potential benefits, and hence market demand, existed to warrant the development of a twin-electrode dc furnace that would double furnace power supply to 80 MW,” Barcza explains.
Studies have been carried out on chromite-, ilmenite- and nickel-ore smelting, where it is increasingly apparent that the need for these furnaces exists.
He points out that, as a by-product of platinum refining, some 20-million tons of chromite ore are generated which, in turn, could yield several million tons of chrome alloys – enough to meet the world’s yearly demand.
Barcza discusses some of the six dc furnaces in operation around the country.
The 30 MW Mogale Alloys furnace, in Krugersdorp, which produces a nickel-chrome-iron alloy – partly through recycling of stainless-steel dusts – has no need to convert to a twin-electrode system, he says.
On the other hand, the Samancor operation, in Middelburg, would likely benefit from a chromite-smelting furnace providing between 60 MW and 80 MW of power, in place of its current 40 MW to 45 MW unit.
Feasibility studies are under way for ferrochrome smelting, in which ore is preheated to 1 000