ABSTRACT
The metallurgical industry used to emit waste gases directly at ground level, for example in roasting of sulfide ores in heaps or making of coke by the beehive method. The major pollution problems arise in iron and steelmaking and in the treatment of nonferrous sulfide ores. Pollution in the iron and steel industry is severe because of the large tonnage of material treated. Coke is an essential raw material for the manufacture of iron in the blast furnace; about 0.6 ton is needed for making 1 ton pig iron. Ferroalloys are used as additives to steel. They are manufactured by the simultaneous reduction of iron ore and another oxide ore mixture. In the 1940's extensive research was done, pilot plants were built, and commercial scale plants went into operation to utilize SO2 instead of emitting it in the environment.
