Pyrometallurgical process for smelting nickel and nickel-copper concentrates including slag treatment

摘要

Process for recovering nickel and nickel-copper from molten smelter-type slags or other highly oxidized sources of nickel and nickel-copper containing 7 to 30 percent by weight of magnetite (Fe3O4). The magnetite in the slag is reduced with carbonaceous materials or other solid reductants such as sulfides, metals or carbides. While the slag is mixed with a fluid cooled, metal-bladed mechanical stirrer, the reductant is reacted with the slag. As a result of stirring the reductant into the slag, the rate of magnetite reduction is highly accelerated. With the reduction, the nickel or nickel-copper (as well as cobalt, if present) separates into a phase as either immiscible metal, a sulfide, or a nickel-copper-iron-sulfide matte, depending upon the initial composition of the slag.