Mineralogical characterization of steel industry hazardous waste and refractory sulfide ores for zinc and gold recovery processing
- Univ. of Missouri, Rolla, MO (United States). Geology Geophysics Dept.
The steel industry generates dust as a waste product from high temperature electric arc furnaces (EAF), which is a major step in processing scrap metal into steel. The Environmental Protection Agency (EPA) has classified EAF dust as KO61 hazardous waste, due to its lead, cadmium, and chromium content. The dust also contains valuable zinc, averaging 19%. Detailed mineralogical characterization show the zinc is present as crystals of franklinite-magnetite-jacobsite solid solutions in calcium-iron-silicate glass spheres and as zincite mostly as very small individual spheres. Much of the chromium is present in an insoluble form in solid solution in the iron spinels. This microscopic research is a valuable tool in determining treatment processes for the 600,000 tons of dust generated annually in the US. Refractory gold ores, pyrite and arsenopyrite, have been studied to determine additional, cost-effective methods of processing. One technique under investigation involves roasting sulfide mineral particles to hematite to create porosity through which a leach can permeate to recover the gold. Portlandite, Ca(OH)[sub 2], is added to the roast for retention of hazardous sulfur and arsenic. Modern microscopic and spectroscopic techniques, such electron spectroscopy for chemical analysis, cathodoluminescence microscopy, and electron microprobe, have been applied, as well as reflected light and dark field microscopy, and scanning electron microscopy to determine the mineralogy of the sulfur, arsenic, and iron phases, and the extent of porosity, permeability, and oxidation state of the ore particles at various roasting temperatures. It is concluded that mineralogical techniques can be effectively applied to the solution of environmental problems.
- OSTI ID:
- 6924600
- Report Number(s):
- CONF-9404217-; CODEN: GAAPBC
- Journal Information:
- Geological Society of America, Abstracts with Programs; (United States), Vol. 26:5; Conference: 27. annual conference of the North-Central Section of the Geological Society of America (GSA), Kalamazoo, MI (United States), 28-29 Apr 1994; ISSN 0016-7592
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
GOLD ORES
MINERALOGY
ORE PROCESSING
METAL INDUSTRY
WASTE MANAGEMENT
MINERAL WASTES
WASTE PRODUCT UTILIZATION
ZINC ORES
HAZARDOUS MATERIALS
HEALTH HAZARDS
SCRAP METALS
SMELTERS
WASTE PROCESSING
ELEMENTS
HAZARDS
INDUSTRY
MANAGEMENT
MATERIALS
METALS
ORES
PROCESSING
SCRAP
SOLID WASTES
WASTES
580000* - Geosciences
320305 - Energy Conservation
Consumption
& Utilization- Industrial & Agricultural Processes- Industrial Waste Management