Lime-sinter process for production of alumina from fly ash
A substantial background of literature on methods of extracting alumina from aluminous-siliceous raw materials shows that alumina may be released by addition of calcium oxide (lime) in a high-temperature treatment to produce a sinter or slag from which alumina is extracted using a sodium carbonate solution, the silica being converted to dicalcium silicate. The calcium oxide has a stronger affinity for silica than does alumina, thus leading to release of the alumina for extraction. Work on application of the lime-sinter process to fly ash has resulted in yields of over 50 percent of the alumina present. The primary variables are temperature, time, and ratio of lime to fly ash. Tests have been run using a small number of pellets of lime-fly ash mixtures in a tube furnace at temperatures ranging up to 1400/sup 0/C. The majority of the iron oxide in the ash is removed by magnetic separation prior to addition of lime. A solid phase transformation leads to a self-disintegrating sinter with proper selection of processing conditions.
- Research Organization:
- Ames Lab., Iowa (USA); Iowa State Univ. of Science and Technology, Ames (USA)
- DOE Contract Number:
- W-7405-ENG-82
- OSTI ID:
- 7365894
- Report Number(s):
- IS-M-64; CONF-760322-1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
010500* -- Coal
Lignite
& Peat-- Products & By-Products
010800 -- Coal
Lignite
& Peat-- Waste Management
AEROSOL WASTES
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
AQUEOUS SOLUTIONS
CALCIUM COMPOUNDS
CALCIUM OXIDES
CARBON COMPOUNDS
CARBONATES
CHALCOGENIDES
DISPERSIONS
FABRICATION
FLY ASH
IRON COMPOUNDS
IRON OXIDES
MANAGEMENT
MIXTURES
OXIDES
OXYGEN COMPOUNDS
PROCESSING
PRODUCTION
RECOVERY
REMOVAL
SINTERING
SLAGS
SODIUM CARBONATES
SODIUM COMPOUNDS
SOLUTIONS
TRANSITION ELEMENT COMPOUNDS
WASTE MANAGEMENT
WASTE PROCESSING
WASTES