摘要 |
To prepare nickel laterite ore for selective reduction of its nonferrous metal oxides, it is comminuted (preferably to 85% minus 200 mesh) and is mixed with comminuted (preferably 100% minus 65 mesh) high volatile, high ash waste coal and a non-gaseous sulfur material. Carbon content of the coal is 50% to 150% of the amount of carbon needed for stoichiometric complete reduction of nonferrous metal oxides in the ore and partial reduction of its iron oxide content. The sulfur content of the sulfur material is such that, together with the sulfur content of the coal, the weight of sulfur is 1% to 1.5% of the weight of the ore. The mixture, preferably pelletized with water, is heated out of contact with air to bring it to 550 DEG C. (requiring 20 to 25 minutes) and is then passed to an aquatic quench. Volatiles in the coal provide reducing gas, and the ash content facilitates wet grinding after quench and provides a good filter bed for subsequent leaching to recover nonferrous metal values. |