Abstract: Floride and aluminum values, as well as carbon, are recovered from waste cathode liner material from aluminum electrolytic cells by leaching of the liner at ambient temperature with a caustic solution, followed by precipitation of sodium fluoride by saturating the leach liquor with a compound which suppresses the solubility of sodium fluoride in the leach liquor. Ammonia is a preferred compound. Aluminum compounds, as well as the carbon values, are also recovered. Treating chemicals used in the process are recycled. The process is essentially a closed-cycle process with substantially no discharge of effluent.
Type:
Grant
Filed:
October 2, 1975
Date of Patent:
September 12, 1978
Assignee:
National Fluoride and Chemical Corporation