Recovery of carbon and cryolite from spent pot lining of aluminium reduction cells by chemical leaching

doi:10.1016/S1003-6326(11)61164-3

Transactions of Nonferrous Metals Society of China

Volume 22, Issue 1, January 2012, Pages 222-227

https://doi.org/10.1016/S1003-6326(11)61164-3 Get rights and content

Abstract

A two-step alkaline-acidic leaching process was conducted to separate the cryolite from spent pot lining and to purify the carbon. The influencing factors of temperature, time, and the ratio of liquid to solid in alkaline and acidic leaching were investigated. The results show that the recovery of soluble compounds of Na₃AlF₆ and Al₂O₃ dissolving into the solution during the NaOH leaching is 65.0%, and the purity of carbon reaches 72.7%. During the next step of HCl leaching, the recovery of soluble compounds of CaF₂ and NaAl₁₁O₁₇ dissolving into the HCl solution is 96.2%, and the carbon purity increases to 96.4%. By mixing the acidic leaching solution and the alkaline leaching solution, the cryolite precipitates under a suitable conditions of pH value 9 at 70°C for 2 h. The cryolite precipitating rate is 95.6%, and the purity of Na₃AlF₆ obtained is 96.4%.

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: Foundation item: Project (50804010) supported by the National Natural Science Foundation of China

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Recovery of carbon and cryolite from spent pot lining of aluminium reduction cells by chemical leaching

Abstract

Transactions of the Institution of Chemical Engineers

Geochimica et Cosmochimica Acta

Journal of Molecular Liquids

Transactions of Nonferrous Metals Society of China

Transactions of Nonferrous Metals Society of China

Journal of Molecular Structure: Theochem

Applying flotation to separate electrolyte from spent carbon cathode of aluminum electrolysis [J]

Nonferrous Metals

Co-processing at cement plant of spent potlining from the aluminum industry [C]