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U.S. Department of Energy
Office of Scientific and Technical Information

Column leaching teats of coal combustion by-products

Book ·
OSTI ID:257016
;  [1]
  1. Bureau of Mines, Pittsburgh, PA (United States). Pittsburgh Research Center

Coal combustion by-products (fly ash, bottom ash, and flue gas desulfurization sludge) are classified as residual wastes, and their disposal is regulated by the states. When coal combustion by-products are placed in abandoned or inactive surface and underground coal mines, they may react chemically with naturally occurring fluids, such as rain, ground water and acid mine drainage. The US Bureau of Mines is investigating possible reactions with a series of column leaching tests. Approximately 1 kg of material is placed in each of seven 5-cm by 1 m acrylic columns. The material is leached at a nominal rate of 250 mL/d for 60 days. Lixiviants include deionized water, artificial ground water, synthetic precipitation, and dilute solutions of acetic acid, ammonium hydroxide, sulfuric acid, and ferric chloride. Leachate is analyzed for pH, acidity/alkalinity, iron, calcium, aluminum, manganese, magnesium and heavy metals. Leaching tests have so far been completed on four fly ash samples. Eleven heavy metals were detected in at least 1% of the leachate samples; the average dissolution rate varied between 0.1 and 70 ppb per day.

OSTI ID:
257016
Report Number(s):
CONF-950952--
Country of Publication:
United States
Language:
English