Trace-element and phase relations in fly ash

Technical Report · Fri May 01 04:00:00 EDT 1981

OSTI ID:6184448

Hulett, L D; Weinberger, A J; Ferguson, N M; Northcutt, K J; Lyon, W S

Chemical forms of elements have been studied in fly ash specimens collected from four Tennessee Valley Authority steam plants. Matrix components have been isolated and individually analyzed to determine trace element distributions. After particle sizing and extraction of magnetic components, the aluminosilicate phases were etched in 1% HF to remove glasses comingled with mullite and quartz. Neutron activation and atomic absorption analyses showed that most of the +1- and +2-valent elements, rare earths, and certain transition metals were concentrated in the glass phases. Cr, V, Ti, Fe, Ga, and Zr, which are trivalent and tetravalent, were concentrated in the crystal phases. X-ray diffraction and elemental analyses show that the main components of the magnetic phase are ferrite compounds with compositions of approximately Fe/sub 2/ /sub 3/Al/sub 0/ /sub 7/O/sub 4/. First-row transition elements, V, Cr, Mn, Co, Cu, Ni, and Zn are concentrated by factors as high as 50 in the magnetic phases. This infers that they occur as isomorphic substitutions in the magnetic spinel lattice since such compounds are well known. Because the spinel is magnetic, a magnetic separation could be used to remove spinel, along with its associated transition metals. Scanning electron microscopy studies of mullite phases remaining after 1% etching suggest that they have resource value. As mullite and quartz crystallize during the solidification of fly ash particles, they purify themselves of trace elements by freezing them out into interstitial glass phases. An analytic scheme for routine chemical specification and pollution hazard assessment of fly ash is suggested. Studies of fly ash exposed to sluice pond waters show tht iron in the magnetic spinel phases is oxidized and subsequently adsorbed on alumino-silicate and other particles. Arsenic and molybdenum are translocated and concentrated into these iron-rich surface phases.

• Research Organization: Oak Ridge National Lab., TN (USA)
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 6184448
• Report Number(s): EPRI-EA-1822; ON: DE81028555
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010600* -- Coal
Lignite
& Peat-- Properties & Composition
010800 -- Coal
Lignite
& Peat-- Waste Management
20 FOSSIL-FUELED POWER PLANTS
200202 -- Fossil-Fueled Power Plants-- Waste Management-- Noxious Gas & Particulate Emissions
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400101 -- Activation
Nuclear Reaction
Radiometric & Radiochemical Procedures
400104 -- Spectral Procedures-- (-1987)
ABSORPTION SPECTROSCOPY
ACTINIDES
ACTIVATION ANALYSIS
AEROSOL WASTES
ALKALI METALS
ALKALINE EARTH METAL COMPOUNDS
ALKALINE EARTH METALS
ALUMINIUM
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
ALUMINIUM SILICATES
ANTIMONY
ARSENIC
ASHES
BARIUM
BARYON REACTIONS
CADMIUM
CALCIUM
CARBONACEOUS MATERIALS
CERIUM
CESIUM
CHALCOGENIDES
CHEMICAL ANALYSIS
CHEMICAL REACTIONS
CHEMICAL STATE
CHROMIUM
COAL
COBALT
COHERENT SCATTERING
COMBUSTION
COPPER
DATA
DIFFRACTION
DYSPROSIUM
ELECTRON MICROSCOPY
ELEMENTS
ENERGY SOURCES
EUROPIUM
EXPERIMENTAL DATA
EXTRACTION
FLY ASH
FOSSIL FUELS
FOSSIL-FUEL POWER PLANTS
FUELS
GALLIUM
HADRON REACTIONS
HAFNIUM
HYDROFLUORIC ACID
HYDROGEN COMPOUNDS
INDIUM
INFORMATION
INORGANIC ACIDS
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
IRON
LANTHANUM
LEAD
MAGNESIUM
MAGNESIUM COMPOUNDS
MAGNESIUM OXIDES
MANGANESE
MATERIALS
METALS
MICROSCOPY
MINERALS
MOLYBDENUM
MULLITE
NEUTRON REACTIONS
NICKEL
NUCLEAR REACTIONS
NUCLEON REACTIONS
NUMERICAL DATA
OXIDATION
OXIDES
OXYGEN COMPOUNDS
POTASSIUM
POWER PLANTS
QUANTITATIVE CHEMICAL ANALYSIS
QUARTZ
RARE EARTHS
REFRACTORY METALS
RESIDUES
RUBIDIUM
SCANDIUM
SCANNING ELECTRON MICROSCOPY
SCATTERING
SELENIUM
SEMIMETALS
SEPARATION PROCESSES
SILICATES
SILICON COMPOUNDS
SILICON OXIDES
SODIUM
SPECTROSCOPY
SPINELS
STRONTIUM
TANTALUM
TERBIUM
THERMAL POWER PLANTS
THERMOCHEMICAL PROCESSES
THORIUM
TITANIUM
TRACE AMOUNTS
TRANSITION ELEMENTS
TUNGSTEN
URANIUM
VANADIUM
WASTES
X-RAY DIFFRACTION
YTTERBIUM
ZINC
ZIRCONIUM