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US 6,576,204 B2Granted
Process for the production of alumina
AssigneeHaldor Topsoe A/S
InventorKeld Johansen
Life of this patent
Estimating the term…
Abstract
A process for the production of alumina is performed by dissolving gibbsite Al2O3.3H2O in nitric acid to provide an acid solution containing aluminum nitrate; decomposing the acid solution at 300-700° C. with a free air supply to form alumina and Nox by spraying onto the inner surface of one or more rotary kilns, drying in a fluid bed, or drying in a steel belt conveyor furnace; regenerating the formed NOx into concentrated nitric acid and recycling the nitric acid to be used for the dissolving of gibbsite; and recovering the alumina formed upon decomposing the acid solution.
Claims4
A process for the production of alumina comprising:
- a. dissolving gibbsite in nitric acid to provide an acid solution containing aluminum nitrate;
- b. decomposing the acid solution at 350-700° C. with a free air supply to obtain alumina and a NOx by spraying the acid solution onto the inner surface of one or more rotary kilns, drying the acid solution in a fluid bed, or drying the acid solution in a steel band conveyor furnace;
- c. regenerating the formed NOx to concentrated nitric acid and recycling the concentrated nitric acid to be used for dissolving gibbsite in process segment (a);
- and
- d. recovering the alumina formed upon decomposing the acid solution.
2 more elements
Dependencies are inferred from the claim text.