Method for increased mine recovery and upgrading of lignite
A process is described for upgrading lignite ores to remove a substantial proportion of the non-combustible ash content associated with the lignite which comprises: (1) sizing by crushing to a maximum top size of less than about 6 inches in two directions (axis's) (2) separating the clay and/or rock (gangue) which are discarded and lignite from each other in a float-sink gravity separator, (3) directing the float containing the lignite and some small particles of clay to a screen deck to size the float into at least three portions, (4) washing the first two screen proportions to free them of clays, (5) collecting the third portion consisting of fines and water as an underflow from the deck, (6) treating the underflow in a hydrocyclone to recover a substantial quantity of the lignite associated with some clays as the overflow and an aqueous stream containing the remainder of the clays and some lignite as the underflow and discarding. (7) treating overflow to effectuate a size separation of the lignite substantially free of clays as underflow and the clays with some fine lignites as the overflow. (8) seive bend dewatering and washing and drying the underflow and combining the resultant product with the +28 mesh lignite product, (9) flocculating (clarifier-thickener) the refuse from the seive bend and the overflow from (7) to about 35% solids, (10) further concentrating the refuse, as by filtration, to a discardable solid.
- Assignee:
- Dow Chemical Co., Midland, MI
- Patent Number(s):
- US 4619669
- OSTI ID:
- 6964291
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
010300* -- Coal
Lignite
& Peat-- Preparation-- (1987-)
AQUEOUS SOLUTIONS
ASH CONTENT
BROWN COAL
CARBONACEOUS MATERIALS
CLAYS
CLEANING
COAL
COAL MINING
COAL PREPARATION
COMMINUTION
CONCENTRATORS
CRUSHING
CYCLONE SEPARATORS
DEASHING
DISPERSIONS
DRYING
ENERGY SOURCES
EQUIPMENT
FILTRATION
FLOCCULATION
FOSSIL FUELS
FUELS
INERTIAL SEPARATORS
LIGNITE
MATERIALS
MINING
MIXTURES
PARTICLE SIZE
POLLUTION CONTROL EQUIPMENT
PRECIPITATION
REMOVAL
SCREENS
SEPARATION EQUIPMENT
SEPARATION PROCESSES
SIZE
SIZING
SOLUTIONS
WASHING
WATER REMOVAL