Recovery of heavy metals from intractable wastes: A thermal approach
- Univ. of Toronto (Canada)
The generation of industrial solid wastes containing leachable species of environmental concern is a problem for developing and developed nations alike. These materials arise from direct processing of mineral ores, from production of metals and minerals, from manufacturing operations, and from air and water pollution treatment processes. The general characteristics that make these wastes intractable is that their content of hazardous species is not easily liberated from the waste yet is not bound so tightly that they are safe for landfill disposal or industrial use. The approach taken in this work is a thermal treatment that separates the inorganic contaminants from the wastes. The objective is to provide recovery and reuse of both the residual solids and liberated contaminants. The results from operating this technique using two very different types of waste are described. The reasons that the process will work for a wide variety of wastes are explored. By using the knowledge of the thermodynamic stability of the phases found from the characterization analyses, a thermal regime was found that allowed separation of the contaminants without capturing the matrix materials. Bench scale studies were carried out using a tube furnace. Samples of the wastes were heated in crucible boats from 750 to 1150{degrees}C in the presence of various chlorinating agents. The offgas contained 90{sup +}% of the targeted contaminants despite their complex matrix form. The residue was free of contamination. As a result of the efficient concentrating mechanism of the process, the contaminants in the offgas solids are attractive for reuse in metallurgical industries. As an additional benefit, the organic contaminants of the residues were eliminated. Dioxin traces in the solids before treatment were absent after treatment. 15 refs., 4 figs., 4 tabs.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- OSTI ID:
- 567697
- Report Number(s):
- CONF-9611157-; ON: DE97009015; TRN: 98:000722-0015
- Resource Relation:
- Conference: 1996 Pacific Basin conference on hazardous waste, Kuala Lumpur (Malaysia), 4-8 Nov 1996; Other Information: PBD: [1996]; Related Information: Is Part Of Pacific Basin conference on hazardous waste: Proceedings; PB: 706 p.
- Country of Publication:
- United States
- Language:
- English
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