Soluble sulfur species extracted from coal by chemical leaching. [MS thesis; mineral and coal-derived pyrite; 114 references]
The nature of the soluble sulfur-containing reaction products from the desulfurization of pyrite was studied. The rate of oxydesulfurization of the two varieties of pyrite was studied under the leaching conditions of the Ames process. Concentrations of soluble sulfur species were determined for oxydesulfurization using leach solutions of sodium carbonate, sodium bicarbonate, distilled water, and dilute sulfuric acid and for alkaline leaching without oxygen using sodium carbonate. Mineral grade pyrite was found to be much less reactive towards oxydesulfurization than coal-derived pyrite, although the mechanism of sulfur removal was apparently the same. The sulfur containing products of oxydesulfurization were found to be thiosulfate, sulfite, and sulfate for alkaline leach solutions, and elemental sulfur and sulfuric acid when neutral or acidic solutions were used. For the Ames process, thiosulfate was usually the major sulfur containing product, although oxidation to sulfite and sulfate was found to take place. Oxidation of thiosulfate did not occur with oxygen alone, but did occur in the presence of oxygen and partially reacted pyrite. Higher temperatures and higher oxygen partial pressures favored formation of sulfate at the expense of both thiosulfate and sulfite. With neutral and acidic leach solutions, sulfuric acid accounted for most of the sulfur, although measurable quantities of elemental sulfur were present.Higher oxygen partial pressures and higher temperatures favored the formation of sulfuric acid at the expense of elemental sulfur. Pyrite oxidized faster under alkaline conditions than under neutral or acidic conditions. Pyrite was also leached at high temperatures in a sodium carbonate solution in the absence of oxygen.
- Research Organization:
- Ames Lab., IA (USA)
- DOE Contract Number:
- W-7405-ENG-82
- OSTI ID:
- 6650076
- Report Number(s):
- IS-T-1003; ON: DE83004974
- Resource Relation:
- Other Information: Thesis
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
LEACHATES
CHEMICAL COMPOSITION
PYRITE
LEACHING
SULFUR
CHEMICAL STATE
ACID CARBONATES
AMES WET OXIDATION PROCESS
AQUEOUS SOLUTIONS
CHEMICAL ANALYSIS
EXPERIMENTAL DATA
OXIDATION
OXYGEN
PARTIAL PRESSURE
SODIUM CARBONATES
SULFATES
SULFITES
SULFURIC ACID
TEMPERATURE DEPENDENCE
THIOSULFATES
WATER
ALKALI METAL COMPOUNDS
CARBON COMPOUNDS
CARBONATES
CHALCOGENIDES
CHEMICAL REACTIONS
DATA
DISPERSIONS
DISSOLUTION
ELEMENTS
HYDROGEN COMPOUNDS
INFORMATION
INORGANIC ACIDS
IRON COMPOUNDS
IRON SULFIDES
MINERALS
MIXTURES
NONMETALS
NUMERICAL DATA
OXYGEN COMPOUNDS
SEPARATION PROCESSES
SODIUM COMPOUNDS
SOLUTIONS
SULFIDE MINERALS
SULFIDES
SULFUR COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
010600* - Coal
Lignite
& Peat- Properties & Composition