Release of aluminum, arsenic, cadmium, chromium, copper, iron, lead, and zinc in a coal leachate, and their removal from solution undergoing neutralization

Miscellaneous · Wed Jan 01 00:00:00 EST 1992

OSTI ID:5627967

Tatum, T L

Whole coal contains significant amounts of iron pyrite which is oxidized ultimately to ferric acid sulfate. As a result, trace elements are released from the coal and other minerals in potentially hazardous concentrations. The purpose of this research was to: (1) study the release and mobility of selected trace elements during the weathering of coal; (2) seek to understand factors controlling solubility of trace elements in a synthetic, acidic leachate undergoing gradual neutralization; and (3) develop a chemical thermodynamic computer model to predict the effects of dilution and neutralization of leachate on trace element mobility and speciation. Samples collected periodically from a slurry of whole ground coal in water were filtered and analyzed for dissolved sulfate (by ion chromatography), iron (by flame atomic absorption spectrophotometry), and Al, Zn, Cd, Cu, Cr, Pb, As, and Se (by graphite furnace AAS). Iron, copper, and probably arsenic tracked the production of sulfate, while aluminum, zinc, chromium, and cadmium concentrations were stable or rose slightly. A synthetic leachate of ferric sulfate and sulfuric acid was doped with trace levels of Al, Zn, Cu, Cd, Cr, Pb, As, and Se. Slow injection of sodium bicarbonate solution neutralized the stirred system, though hydrolysis of iron buffered the pH and 2.5.

• Research Organization: Maryland Univ., College Park, MD (United States)
• OSTI ID: 5627967
• Resource Relation: Other Information: Thesis (Ph.D)
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
COAL
WEATHERING
LEACHATES
CHEMICAL ANALYSIS
ALUMINIUM
ARSENIC
CADMIUM
CHROMIUM
COPPER
IRON
LEAD
MINERALS
PYRITE
SOLUBILITY
TRACE AMOUNTS
ZINC
CARBONACEOUS MATERIALS
DISPERSIONS
ELEMENTS
ENERGY SOURCES
FOSSIL FUELS
FUELS
MATERIALS
METALS
MIXTURES
SEMIMETALS
SOLUTIONS
SULFIDE MINERALS
TRANSITION ELEMENTS
010900* - Coal
Lignite
& Peat- Environmental Aspects
400100 - Analytical & Separations Chemistry