Recovery and utilization of gypsum and limestone from scrubber sludge. Final technical report, September 1, 1992--August 31, 1993
- Michigan Technological Univ., Houghton, MI (United States). Dept. of Metallurgical and Materials Engineering
Wet flue-gas desulfurization units in coal-fired power plants produce a large amount of sludge which must be disposed of, and which is currently landfilled in most cases. Increasing landfill costs are gradually forcing utilities to find other alternatives. In principle, this sludge can be used to make gypsum (CaSO{sub 4}{center_dot}2H{sub 2}O) for products such as plaster-of-Paris and wallboard, but only if impurities such as unreacted limestone and soluble salts are removed, and the calcium sulfite (CaSO{sub 3}) is oxidized to calcium sulfate (CaSO{sub 4}). This project investigated methods for removing the impurities from the sludge so that high-quality, salable gypsum products can be made. Two processes were studied, both separately and in combination: Water-only cycloning, and froth flotation. A large fraction (30--40%) of the impurities in the sludge are contained in the coarser, higher-density particles, which are readily removed using a water-only cyclone. Much of the remaining impurities are hydrophobic, and can be removed by froth flotation. A combined cyclone/froth flotation process has been found to be suitable for producing a high-purity product from scrubber sludge at low cost.
- Research Organization:
- Illinois Dept. of Energy and Natural Resources, Springfield, IL (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- FC22-92PC92521
- OSTI ID:
- 10132205
- Report Number(s):
- DOE/PC/92521-T75; ON: DE94008017; TRN: 94:003528
- Resource Relation:
- Other Information: PBD: [1993]
- Country of Publication:
- United States
- Language:
- English
Similar Records
Recovery and utilization of gypsum and limestone from scrubber sludge. Technical report, December 1, 1992--February 28, 1993
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Related Subjects
20 FOSSIL-FUELED POWER PLANTS
GYPSUM
PURIFICATION
MATERIALS RECOVERY
COAL-FIRED GAS TURBINES
SLUDGES
SCRUBBERS
WASTE PRODUCT UTILIZATION
PROGRESS REPORT
LIMESTONE
GAS TURBINE POWER PLANTS
CHEMICAL PREPARATION
CYCLONE SEPARATORS
FLOTATION
010800
200202
WASTE MANAGEMENT
NOXIOUS GAS AND PARTICULATE EMISSIONS