Separation of flue-gas scrubber sludge into marketable products. Fourth year, first quarterly technical progress report, September 1, 1996--December 31, 1996 (Quarter No. 13)
To reduce their sulfur emissions, many coal-fired electric power plants use wet flue-gas scrubbers. These scrubbers convert sulfur oxides into solid sulfate and sulfite sludge, which must then be disposed of. This sludge is a result of reacting limestone with sulfur dioxide to precipitate calcium sulfite and calcium sulfate. It consists of calcium sulfite (CaSO{sub 3}{circ}0.5H{sub 2}O), gypsum (CaSO{sub 4}{circ}2H{sub 2}O), and unreacted limestone (CaCO{sub 3}) or lime (Ca(OH)2), with miscellaneous objectionable impurities such as iron oxides, silicates, and magnesium, sodium, and potassium oxides or salts. These impurities prevent many sludges from being utilized as a replacement for natural gypsum, and as a result they must be disposed of in landfills, which presents a serious disposal problem. Knowledge of scrubber sludge characteristics is necessary for the development of purification technologies which will make it possible to directly utilize scrubber sludges rather than landfilling them. This project is studying the use of minimal-reagent froth flotation as the purification process, using the surface properties of the particles of unreacted limestone to remove them and their associated impurities from the material, leaving a purified calcium sulfite/gypsum product.
- Research Organization:
- Michigan Technological Univ., Houghton, MI (United States). Dept. of Metallurgical and Materials Engineering
- Sponsoring Organization:
- USDOE Assistant Secretary for Fossil Energy, Washington, DC (United States)
- DOE Contract Number:
- FG22-93PC93214
- OSTI ID:
- 477736
- Report Number(s):
- DOE/PC/93214--T13; ON: DE97051576
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
20 FOSSIL-FUELED POWER PLANTS
CALCIUM COMPOUNDS
COAL
FLOTATION
FLUE GAS
FOSSIL-FUEL POWER PLANTS
GYPSUM
IRON OXIDES
LIMESTONE
MAGNESIUM
MARKET
POTASSIUM OXIDES
PROGRESS REPORT
SALTS
SEPARATION PROCESSES
SILICATES
SLUDGES
SURFACE PROPERTIES
WASTE PROCESSING
WASTE PRODUCT UTILIZATION