Carbothermic prodn. of aluminium (alloy) - with separate feed of alumina and reductant giving rapid prod. removal from reaction zone

摘要

The process comprises supplying carbonaceous material along a path separate from the supply path of alumina (opt. mixed with other oxides) and contacting the carbonaceous material and alumina in a zone to which electrical energy is supplied to attain a high temp. and effect carbothermic reduction. Pref. The carbonaceous material is placed in carbonaceous material containers stacked on each other with a tight fit and positioned in a shaft on the top of which is a supply of alumina which is gravity fed by a guiding shell, electrodes being positioned in and extending through the alumina. The carbonaceous material is supplied by ascending movement to the reaction zone. The process is used in the prodn. of aluminium or its alloys, e.g. aluminium-silicon alloys. The process is energy efficient and the liquid metal is immediately drained from the vicinity of the electrodes so that the build-up of a molten metal pool is prevented and heat generation takes places in the arcs between the electrodes and the top layer of carbon and in the alumina-carbon mixt. where the heat is needed for reaction.