Physical desulfurization of Iowa coal

Technical Report · Wed Jun 30 04:00:00 EDT 1976

DOI:https://doi.org/10.2172/7119916· OSTI ID:7119916

Min, S

An investigation to determine the effectiveness of different physical beneficiation methods for desulfurization included separation and recovery of clean coal by float-sink (gravity) separation in dense liquids, froth flotation, and selective oil agglomeration. Since the effectiveness of these separation methods depends on first liberating or freeing the mineral matter from the coal through fragmentation or breakage, the effects of size reduction and method of comminution were also investigated. The effects of other parameters on the separation efficiency were also studied. Various combinations of comminution and separation methods were applied in order to determine the overall effectiveness of different treatment sequences. Since a significant percentage of the pyrites in some coals consists of finely disseminated crystallites, these coals have to be ground rather finely to free and subsequently separate the pyrites effectively. It proved helpful to chemically comminute the coal by soaking in liquid anhydrous ammonia before crushing and grinding. One of the most effective treatment sequences involved soaking lump coal in liquid ammonia, crushing to /sup 1///sub 4/ in. top size, separating float and sink fractions at a gravity of 1.6, pulverizing and grinding the float fraction, and recovering the fine coal by selective oil agglomeration. As a result of this treatment sequence the pyritic sulfur content of two coals was reduced 85 to 86 percent and the ash content 70 to 84 percent while obtaining an overall weight yield of 82 to 84 percent. The separation of coal and pyrite by either froth flotation or selective oil agglomeration was improved significantly by chemically pretreating the pulverized coal to oxidize the surface of the pyrite to render the surface hydrophilic and distinctly different from the hydrophobic surface of the coal.

• Research Organization: Iowa State Univ. of Science and Technology, Ames (USA). Energy and Mineral Resources Research Inst.
• OSTI ID: 7119916
• Report Number(s): IS-ICP-35
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010402* -- Coal
Lignite
& Peat-- Purification & Upgrading
013000 -- Coal
Lignite
& Peat-- Transport
Handling
& Storage
AGGLOMERATION
AMMONIA
CARBONACEOUS MATERIALS
CHALCOGENIDES
CHEMICAL REACTIONS
COAL
COAL PREPARATION
COMMINUTION
DESULFURIZATION
ENERGY SOURCES
FLOTATION
FOSSIL FUELS
FUELS
GRINDING
HYDRIDES
HYDROGEN COMPOUNDS
IOWA
IRON COMPOUNDS
IRON SULFIDES
MACHINING
MIDWEST REGION
MINERALS
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NORTH AMERICA
ORES
OXIDATION
PYRITE
PYRITES
REMOVAL
SEPARATION PROCESSES
SULFIDES
SULFUR COMPOUNDS
SULFUR ORES
TRANSITION ELEMENT COMPOUNDS
USA