Determination of extraction equilibria for several metals in the development of a process designed to recover aluminum and other metals from coal combustion ash
| Autor: | B.Z. Egan, A.D. Kelmers, F.G. Seeley, L.K. Felker, W.J. McDowell |
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| Rok vydání: | 1981 |
| Předmět: |
Ammonium sulfate
Extraction (chemistry) Inorganic chemistry technology industry and agriculture Metals and Alloys Sulfuric acid Industrial and Manufacturing Engineering Flue-gas desulfurization chemistry.chemical_compound chemistry Fly ash Sodium sulfate Materials Chemistry medicine Ferric Sulfate medicine.drug |
| Zdroj: | Hydrometallurgy. 6:277-290 |
| ISSN: | 0304-386X |
| DOI: | 10.1016/0304-386x(81)90045-1 |
| Popis: | Laboratory-scale tests of several methods for the recovery of resource materials from fly ash have led to the development of a sinter/dilute acid leach method (Calsinter process) in which fly ash is sintered with a source of calcium oxide (CaCO3, CaSO4, CaO, and/or limestone flue-gas desulfurization scrubber sludge) at 1000–1200°C, followed by a two-stage leach of the sintered solids with dilute sulfuric acid. Recovery of aluminum from this leach solution in a relatively pure form requires that several contaminants, particularly iron, must be separated from the aluminum before it can be precipitated. Therefore, distribution coefficients for iron (III) and 16 other metal ions have been determined in the liquid—liquid extraction system: Primene JM-T—toluene versus aqueous ammonium sulfate (and sodium sulfate) as a function of sulfate, acid, metal ion, and amine sulfate concentration. A study of iron (III) loading equilibria as a function of time indicated that equilibrium was essentially achieved in 1 h; however, some changes, probably in the nature of the extracted species, occurred over a period of approximately 20 h. Iron (III) extraction results obtained under various sulfate concentration matrix conditions suggested the formation of an aqueous complex of ferric ammonium sulfate, which depressed iron distribution to the organic phase. Extraction isotherms for Ag, As, Cd, Cr, and Fe all exhibit linearity at low loading conditions with unit slopes, indicating the same degree of association of the metal ion species in both the organic and the aqueous phase. Other metal ions for which distribution coefficients are reported are: Ba, Mg, Mn, Na, K, P, Pb, Th, Ti, and U. |
| Databáze: | OpenAIRE |
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