a process for treating massive pyritic kies that are composed of pyrite (FeS2) in association with some amount of chalcopyrite (CuFeS2).
The theory of pyritic smelting was developed in the late 1920’s by A. A. Baikov and V. Ia. Mostovich. Pyritic smelting is carried out in a shaft furnace; the coke consumption ranges from 2 to 4 percent, mainly because of the thermal effect of the oxidation reactions of the molten iron sulfide in the tuyeres and the slagging of the resultant ferrous oxide. The oxidation of iron sulfides proceeds according to the following equation:
Pyritic smelting is not feasible when the ore contains less than 36 percent sulfur. Quartz flux and limestone are added to the charge. The optimal size of the chunks of ore, fluxes, and fuel ranges from 30 to 100 mm. Liquid matte and slag form during pyritic smelting.
In modern pyritic smelting, furnace gases are additionally treated with fine coke in order to simultaneously produce elemental sulfur in addition to the matte. The air that is introduced into the furnace is enriched with oxygen to accelerate the smelting process.