Gas quantity and composition from the hydrolysis of salt cake from secondary aluminum processing

• Published in: International journal of environmental science and technology (Tehran) 2019-04, Vol.16 (4), p.1955-1966
• Main Authors: Huang, X.-L., Tolaymat, T.
• Format: Article
• Language: English
• Subjects: Aquatic Pollution; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Science and Engineering; Original Paper; Soil Science & Conservation; Waste Water Technology; Water Management; Water Pollution Control
• ISSN: 1735-1472; 1735-2630
• DOI: 10.1007/s13762-018-1820-x

A systematic approach to understanding the hydrolysis of salt cake from secondary aluminum production in municipal solid waste landfill environment was conducted. Thirty-nine (39) samples from 10 Aluminum recycling facilities throughout the USA were collected. A laboratory procedure to assess the gas productivity of SC from SAP under anaerobic conditions at 50 °C to simulate a landfill environment was developed. Gas quantity and composition data indicate that on average 1400 µmol g −1 (35 mL g −1 ) of gas resulted from the hydrolysis of SC. Hydrogen was the dominant gas generated (79% by volume) followed by methane with an average of 190 µmol g −1 (21% by volume). N 2 O was detected at a much lower concentration (1.2 ppmv). The total ammonia released was 680 µmol g −1 , and because of the closed system nature of the experimental setup, the vast majority of ammonia was present in the liquid phase (570 mg L −1 ). In general, the productivity of both hydrogen and total ammonia (the sum of gas and liquid forms ammonia) was a fraction of that expected by stoichiometry indicating an incomplete hydrolysis and a potential for re-hydrolysis when conditions are more favorable. The result provides substantial evidence that SC can be hydrolyzed to generate a gas with relative long-lasting implications for municipal solid waste landfill operations.