Production of Aluminum-Silicon Alloy and Ferrosilicon and Commercial Purity Aluminum by the Direct Reduction Process. Second Quarterly Progress Report, December 1, 1977--February 28, 1978

摘要

Revised heat and mass balance calculations predicted a 36% increase in O sub 2 and fuel carbon to offset reactant sensible heats and estimated unit heat losses. Preliminary calculations of heat and mass flows for the conceptual pilot reactor design indicated critical zones at the bottom due to high heat input requirements, and at the top due to excess heat generation by formation of CO sub 2 and C from CO. Binderless agglomerates were made from bauxite, clay and metallurgical coke, fired and measured for important physical properties. Extrudates tested at operating conditions maintained integrity up to 1800 exp 0 C. Additional reaction mechanism runs resulted in production of competing reactions at the higher temperatures. It was determined that heat input rate effected product formation. Mathematical modeling of kinetic expressions for predicted reactions was initiated. Several improved versions of crucible type, self-heated reactors were built and operated to evaluate O sub 2 tuyere assemblies, raceway formation and O sub 2 distribution to a coke bed. The design of a bench scale, self-heated shaft reactor was initiated. The effects of Fe and Ti impurities on fractional crystallization were determined in the bench scale unit. Reduction of Si from 27.6% to 14% was attained in a pilot crystallizer. Design of pilot crystallizer components was started and a site layout was made for the purification equipment. Preliminary designs of alternative holding furnaces were completed. Bench scale tests on purification to commercial grade Al were continued. Feed materials containing Al-Si-Fe and Al-Si-Fe-Ti were used. Efficiencies of 98% and Al purities of 99.9% were attained. Compositions of intermetallic compounds in the residue phase were identified. (ERA citation 03:041037)