Bauxites, upgrading

The production of aluminum begins with the mining and beneficiation of bauxite. At the mine (usually of the surface type), bauxite ore is removed to a crusher. The crushed ore is then screened and stockpiled, ready for delivery to an alumina plant. In some cases, ore is upgraded by beneficiation (washing, size classification, and separation of liquids and solids) to remove unwanted materials such as clay and silica. 

RON and MON of the Hydrocol Fe-HTFT Syncrude before and after Upgrading over Bauxite, and with Different Levels of Tetraethyl Lead (TEL) Addition... 

In an attempt to upgrade the siliceous bauxites and other aluminous materials, such as clay where the alumina usually is in the form of complex silicates, Skow and Conley (Si 9) considered the removal of the silica by caustic digestion. Prior to leaching, the aluminuous materials were calcined at 970°C, resulting in an optimal removal of silica with little loss in alumina content in the subsequent leaching step. The desilication step is necessary prior to using the raw materials as feed to the standard Bayer process (E3). The pilot plant operation to extract alumina from an anorthosite ore has been reported by St. Clair et al. (S24). 

Among the largest users of agglomeration technologies are iron and steel mills and their raw material suppliers, the cement industry and fertilizer producers. In the first area flotation concentrates and ores that were upgraded by other methods, fine or dusty pyrite cinders, red mud from bauxite processing, filter... 

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