Suppression of pyritic sulfur during flotation tests using the bacterium Thiobacillus ferrooxidans
Environmental concern about sulfur dioxide emissions has led to the examination of the possibility of removing pyritic sulfur from coal prior to combustion during froth flotation. The bacterium Thiobacillus ferrooxidans was effective in leaching 80% and 63% -53 ..mu..m pyrite at 2% and 6% pulp density in shake flasks in 240 and 340 h, respectively. The natural floatability of pyrite was significantly reduced in the Hallimond tube following 2.5 min of conditioning in membrane-filtered bacteria liquor prior to flotation. The suppression effect was greatly enhanced in the presence of Thiobacillus ferrooxidans. A bacterial suspension in pH 2.0 distilled water showed 85% suppression, whereas in spent growth liquor this value was 95%. The optimum bacterial density was 3.25 x 10/sup 10/ cells/g pyrite in 230-ml distilled water in the Hallimond tube. The degree of suppression by the cells was related to particle size but not to pH or temperature. The sulfur content of a synthetic coal/pyrite mixture was reduced from 10.9 to 2.1% by flotation after bacterial preconditioning. It is postulated that pyrite removal in coals which are cleaned by froth flotation could be significantly reduced using a bacterial preconditioning stage with a short residence time of 2.5 min.
- Research Organization:
- North Staffordshire Polytechnic, Stoke-on-Trent, England
- OSTI ID:
- 5703238
- Journal Information:
- Biotechnol. Bioeng.; (United States), Vol. 30:1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
COAL
DESULFURIZATION
PYRITE
BIODEGRADATION
THIOBACILLUS FERROXIDANS
GROWTH
LEACHING
PARTICLE SIZE
REMOVAL
SULFUR DIOXIDE
BACILLUS
BACTERIA
CARBONACEOUS MATERIALS
CHALCOGENIDES
CHEMICAL REACTIONS
DECOMPOSITION
DISSOLUTION
ENERGY SOURCES
FOSSIL FUELS
FUELS
IRON COMPOUNDS
IRON SULFIDES
MATERIALS
MICROORGANISMS
MINERALS
OXIDES
OXYGEN COMPOUNDS
SEPARATION PROCESSES
SIZE
SULFIDE MINERALS
SULFIDES
SULFUR COMPOUNDS
SULFUR OXIDES
SULFUR-OXIDIZING BACTERIA
TRANSITION ELEMENT COMPOUNDS
010800* - Coal
Lignite
& Peat- Waste Management
560300 - Chemicals Metabolism & Toxicology