Cobalt recovery from low cobalt, high iron, oxide slag - by selective redn. using solid reductant in electric furnace

摘要

Oxide slag, having a low Co content and a high Fe content and opt. contg. small amts. of other metal values such as Cu and Ni, is selectively reduced to recover a Co-rich alloy by continuously feeding a mixt. of the slag and a solid reductant (in amt. insufficient to reduce all the oxides) into an electrical furnace, having C electrodes and walls and hearth made of non carbonaceous material, to form a bottom layer of molten metal and a top layer of oxide slag. Heat, required for melting the mixt. and for redn., is produced in the upper part of the slag layer to avoid overheating of the metal layer. Periodically, part of the metal and part of the slag are tapped off so that the two layers are maintained permanently in the furnace. Process can be used to treat slags (contg. e.g. 0.5-3% Co) from processing lean Co ores and ores contg. Co as impurity, e.g. certain Cu ores. Process is continuous, employs a single furnace, and gives a non-carburised alloy prod. Temp. control of the metal layer avoid attack on the furnace refractories.