ABSTRACT

The unit operation "oxidation of a solid phase" is applied exclusively to sulfide ores. Oxidation of sulfides is an exothermic process. This unit operation has undergone numerous changes caused by the same reasons that changed the construction of furnaces, which can be summarized as follows: the supply of rich lump ore gave way to fine flotation concentrates and the desire to avoid handling fine powders by using agglomerating techniques. It also include: air pollution has to be kept to minimum. Development was first aimed at finding a mechanical means to move the hearth of a furnace continuously rather than to move the ore. The improvement was in two directions: the rotating hearth furnace and the moving grate machines. Oxidation of sulfides in a moving grate furnace is a continuous process and can be completely automated. Flash oxidation process which was introduced in the later 1950's finely divided sulfide concentrate is sprayed in a heated chamber in a stream of air.