title: Characterization of salt cake from secondary aluminum production.
abstract: Salt cake is a major waste component generated from the recycling of secondary aluminum processing (SAP) waste. Worldwide, the aluminum industry produces nearly 5 million tons of waste annually and the end-of-life management of these wastes is becoming a challenge in the U.S. and elsewhere. In this study, the mineral phases, metal content and metal leachability of 39 SAP waste salt cake samples collected from 10 different facilities across the U.S. were determined. The results showed that aluminum (Al), aluminum oxide, aluminum nitride and its oxides, spinel and elpasolite are the dominant aluminum mineral phases in salt cake. The average total Al content was 14% (w/w). The overall percentage of the total leachable Al in salt cake was 0.6% with approximately 80% of the samples leaching at a level less than 1% of the total aluminum content. The extracted trace metal concentrations in deionized water were relatively low (μgL(-1) level). The toxicity characteristic leaching procedure (TCLP) was employed to further evaluate leachability and the results indicated that the leached concentrations of toxic metals from salt cake were much lower than the EPA toxicity limit set by USEPA.
authors.affiliation: Pegasus Technical Services, Inc., 46 E. Hollister Street, Cincinnati, OH 45219. USA.
authors.forename: Xiao-Lan
authors.initials: XL
authors.lastname: Huang
authors.affiliation: Pegasus Technical Services, Inc., 46 E. Hollister Street, Cincinnati, OH 45219. USA.
authors.forename: Amro El
authors.initials: AE
authors.lastname: Badawy
authors.affiliation: Pegasus Technical Services, Inc., 46 E. Hollister Street, Cincinnati, OH 45219. USA.
authors.forename: Mahendranath
authors.initials: M
authors.lastname: Arambewela
authors.affiliation: Office of Research and Development, U.S. EPA, Cincinnati, OH 45224, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Ford
authors.affiliation: Department of Civil, Construction & Environmental Engineering, North Carolina State University, Raleigh, NC 27695, USA.
authors.forename: Morton
authors.initials: M
authors.lastname: Barlaz
authors.affiliation: Office of Research and Development, U.S. EPA, Cincinnati, OH 45224, USA. Electronic address: tolaymat.thabet@epamail.epa.gov.
authors.forename: Thabet
authors.initials: T
authors.lastname: Tolaymat
mesh_terms: D007220:Industrial Waste / Q000032:analysis*; D008670:Metals / Q000032:analysis*; D008903:Minerals / Q000032:analysis; D012492:Salts; D014874:Water Pollutants, Chemical / Q000032:analysis
chemical_list: D007220:Industrial Waste; D008670:Metals; D008903:Minerals; D012492:Salts; D014874:Water Pollutants, Chemical
keywords: Aluminum; Leachability; Mineral phase; Salt cake; Secondary aluminum production (SAP); Toxicity characteristic leaching procedure (TCLP)