Fly ash: an economic source of Al/sub 2/O/sub 3/ and Fe/sub 2/O/sub 3/

Conference · Fri Jan 01 04:00:00 EST 1982

OSTI ID:5521396

Gilliam, T M; Canon, R M

In 1980, over 55 million tons of fly ash were collected in the United States. The quantity of ash generated is expected to rise significantly with the increased emphasis on the use of coal for both power and fuels production. Although treated primarily as a waste, fly ash represents a premined source of several metals, some of which are largely imported. Economic recovery of these metals would significantly reduce our dependence on foreign suppliers. Since 1976, the Oak Ridge National Laboratory has been involved in basic studies on methods for metal recovery from coal combustion residue. Initial efforts concentrated on maximizing the recoveries of alumina (the primary material of interest) and iron oxide. However, recent results indicate that the cost of processing this type of material is relatively independent of the extraction obtained in the leach step and is primarily incurred in the subsequent metal separation steps. This fact has led to renewed interest in direct acid leach processes (minimum-treatment processes which remove the acid-soluble portion of the metals). Studies of direct acid leach with HC1, HC0/sub 3/, and H/sub 2/SO/sub 4/ have shown the HC1 system to be the most attractive. An economic analysis using this system for the treatment of 1 million tons per year of an eastern US ash would require a capital investment of $38.2 million, resulting in a yearly cash flow of $15.2 million. In addition, the metals in the leach residue would remain in a form which is expected to be relatively inert to normal environmental conditions.

• Research Organization: Oak Ridge National Lab., TN (USA)
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 5521396
• Report Number(s): CONF-820333-1; ON: DE82008804
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010800* -- Coal
Lignite
& Peat-- Waste Management
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
320305 -- Energy Conservation
Consumption
& Utilization-- Industrial & Agricultural Processes-- Industrial Waste Management
AEROSOL WASTES
ALUMINIUM
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
ASHES
CHALCOGENIDES
CHEMICAL COMPOSITION
COST
DATA
DISSOLUTION
ECONOMICS
ELEMENTS
FINANCIAL DATA
FLY ASH
HYDROCHLORIC ACID
HYDROGEN COMPOUNDS
INFORMATION
INORGANIC ACIDS
IRON
IRON COMPOUNDS
IRON OXIDES
LEACHING
METALS
NITRIC ACID
OXIDES
OXYGEN COMPOUNDS
RECOVERY
RESIDUES
SEPARATION PROCESSES
SULFURIC ACID
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
WASTE PRODUCT UTILIZATION
WASTES