Alumina from coal wastes by the lime-soda sinter process

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1984

OSTI ID:5950571

Padilla, R

The lime-soda sinter process for alumina extraction from domestic coal wastes was investigated. The three main basic steps - sintering, leaching and desilication - were studied to obtain optimal operating conditions for the highest yield of alumina. The recovery of alumina up to 80% was obtained by sintering coal waste mixtures having molar ratios of Na/sub 2/O/Al/sub 2/O/sub 3/ = 1.3 and CaO/SiO/sub 2/ = 1.8 at 1200 to 1250/sup 0/C for 20 to 30 min. The corresponding optimum conditions for water leaching of the sinters are temperatures of 60 to 70/sup 0/C for 30 to 40 minutes. The sodium aluminate responds readily to desilication with Ca(OH)/sub 2/ suspensions at room temperature. In the sintering stage, the kinetics of carbon combustion and sodium aluminate formation are also discussed. A mathematical model based on simultaneous mass and heat transport is formulated and applied to the carbon combustion process. The model predicts the combustion rate well.

• OSTI ID: 5950571
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010800* -- Coal
Lignite
& Peat-- Waste Management
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
ALUMINATES
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CALCIUM COMPOUNDS
CALCIUM OXIDES
CARBONACEOUS MATERIALS
CHALCOGENIDES
CHEMICAL REACTION KINETICS
COAL
COMBUSTION KINETICS
DISSOLUTION
ENERGY SOURCES
FABRICATION
FOSSIL FUELS
FUELS
KINETICS
LEACHING
MANAGEMENT
MATERIALS
MATERIALS RECOVERY
OXIDES
OXYGEN COMPOUNDS
PROCESSING
REACTION KINETICS
RECOVERY
SEPARATION PROCESSES
SILICON COMPOUNDS
SILICON OXIDES
SINTERING
SODIUM COMPOUNDS
SODIUM OXIDES
SOLID WASTES
WASTE MANAGEMENT
WASTE PROCESSING
WASTES