Production of Aluminum-Silicon Alloys from Sand and Clay in Hall Cells

Abstract

Sand and clay mixed with metallurgical alumina were reduced in alumina reduction cells to produce silicon-aluminum alloy. It was demonstrated that these methods of producing silicon-aluminum alloy were viable alternates to the use of silicon produced in electric-arc furnaces. Additions of SiO₂ containing material to the reduction cell resulted in loss of production and decreased ampere efficiency; typically, a 0.5% ampere efficiency loss was found to occur per weight percent silicon metal produced from the silica material. A procedure or practice is discussed for the planned and carefully controlled operation of reduction cells using additions of silica by effectively regulating the total distributive oxide concentration in the electrolyte.