Chemical leaching of coal to remove ash, alkali and vanadium
A process is described for upgrading powdered coal to improve the usefulness thereof as a fuel for internal combustion engines which consists of: (a) pressure-leaching powdered coal having a particle size ranging from about 28 mesh to about 200 mesh in an aqueous caustic solution at a temperature ranging from about 175/sup 0/C, to about 350/sup 0/C., the amount of caustic in the solution ranging from about 5% to about 30% by weight, the amount of coal being sufficient to form a slurry comprising about 10% to 30% by weight of solids, (b) hydrochloric acid leaching the caustic leached coal to dissolve acid-soluble constituents resulting from the caustic leach, (c) pressure leaching the acid-leached coal with a liquid from the group consisting of water and dilute aqueous ammonia to remove sodium and chlorine, and thereafter (d) filtering and washing the pressure leached coal, whereby the coal is characterized by up to about 0.85% by weight of ash, up to about 150 ppm of alkali metals and up to about 4 ppm vanadium.
- Assignee:
- AMAX Inc., Greenwich, CT
- Patent Number(s):
- US 4582512
- OSTI ID:
- 5789063
- Country of Publication:
- United States
- Language:
- English
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33 ADVANCED PROPULSION SYSTEMS
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ALKALI METALS
AMMONIA
AQUEOUS SOLUTIONS
CHLORINE
CLEANING
COAL FINES
DEASHING
DEMETALLIZATION
DISPERSIONS
DISSOLUTION
ELEMENTS
ENGINES
FILTRATION
FUEL SLURRIES
FUEL SUBSTITUTION
FUELS
HALOGENS
HEAT ENGINES
HIGH TEMPERATURE
HYDRIDES
HYDROCHLORIC ACID
HYDROGEN COMPOUNDS
INORGANIC ACIDS
INTERNAL COMBUSTION ENGINES
LEACHING
METALS
MIXTURES
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NONMETALS
OXYGEN COMPOUNDS
PARTICLE SIZE
POTASSIUM
PRESSURE DEPENDENCE
SEPARATION PROCESSES
SIZE
SLURRIES
SODIUM
SOLUTIONS
SUSPENSIONS
WASHING
WATER