The economics of salt cake recycling
The Process Evaluation Section at Argonne National Laboratory (ANL) has a major program aimed at developing cost-effective technologies for salt cake recycling. This paper addresses the economic feasibility of technologies for the recovery of aluminum, salt, and residue-oxide fractions from salt cake. Four processes were assessed for salt recovery from salt cake: (1) base case: leaching in water at 25{degree}C, with evaporation to crystallize salts; (2) high-temperature case: leaching in water at 250{degree}C, with flash crystallization to precipitate salts; (3) solventlantisolvent case: leaching in water at 25{degree}C, concentrating by evaporation, and reacting with acetone to precipitate salts; and (4) electrodialysis: leaching in water at 25{degree}C, with concentration and recovery of salts by electrodialysis. All test cases for salt recovery had a negative present value, given current pricing structure and 20% return on investment. Although manufacturing costs (variable plus fixed) could reasonably be recovered in the sales price of the salt product, capital costs cannot. The economics for the recycling processes are improved, however, if the residueoxide can be sold instead of landfilled. For example, the base case process would be profitable at a wet oxide value of $220/metric ton. The economics of alternative scenarios were also considered, including aluminum recovery with landfilling of salts and oxides.
- Research Organization:
- Argonne National Lab., IL (United States). Energy Systems Div.
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 224304
- Report Number(s):
- ANL/ES/CP--88051; CONF-960202--5; ON: DE96006901
- Country of Publication:
- United States
- Language:
- English
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