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Electrowinning aluminum from aluminum chloride: operation of a single-compartment cell.

Kirby DE; Singleton EL; Sullivan TA
Boulder City, NV: U.S. Department of the Interior, Bureau of Mines, RI 7353, 1970 Jan; :1-24
The electrochemical reduction of AlCl3 was investigated as a process for the production of aluminum. An externally heated, single-compartment cell with a rammed refractory lining was used with molten KCl-NaCl-AlCl3 electrolyte. Aluminum was deposited at 700 deg. to 760 deg. C with a current of 100 to 200 amperes on a molten aluminum cathode. Chloride was evolved at a graphite anode and collected and measured to provide a quantitative evaluation of the AlCl3 reduction. Aluminum was removed from the cell by siphoning or ladling. Granular AlCl3 was added periodically to replenish that depleted from the electrolyte. Concentrations of 7.5 to 17.5 percent AlCl3 in the electrolyte were optimum for operation. Anode current efficiencies of 83 to 85 percent were attained, using anode current densities of 5.9 amperes per square inch and an anode-cathode distance of 4 inches. The chemically bonded, alumina liner was resistant to attack by aluminum and chlorine but susceptible to erosion at the surface of the electrolyte. Titanium diboride proved suitable for the electrical connection to the molten aluminum cathode. Aluminum of a purity equal to or better than 1100 series metal was electrowon continuously from commercial AlCl3 for a period of 4 1/2 months.
Aluminum compounds; Electrochemical reactions; Metallurgical processes; Aluminum; Refining; Metallurgy; Chlorides; Reduction; Chemistry; Electrolytic cells; Electrolytes; Potassium compounds; Sodium compounds; Aluminum chlorides; Aluminum; Electrolysis; Electrowinning
Publication Date
Document Type
IH; Report of Investigations
Fiscal Year
NTIS Accession No.
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Identifying No.
RI 7353
NIOSH Division
Source Name
Boulder City, NV: U.S. Department of the Interior, Bureau of Mines, RI 7353
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division