Spray calcination and drying process to produce high-purity alumina

Abstract

Processes for preparing high-purity aluminum oxide include providing an aluminum feedstock, reacting the aluminum feedstock with one or more acids to form a hydrated aluminum salt solution, and calcining the hydrated aluminum salt to form an aluminum oxide powder. Other processes for preparing high-purity aluminum oxide include providing an aluminum feedstock and reacting it with one or more acids to form a first hydrated aluminum salt solution, precipitating hydrated aluminum salt from the first hydrated aluminum salt solution to produce a mixture of precipitated hydrated aluminum salt crystals and a mother liquor, separating precipitated hydrated aluminum salt crystals from the mother liquor, dissolving the hydrated aluminum salt crystals in a solvent to form a second hydrated aluminum salt solution, and calcining hydrated aluminum salt of the second hydrated aluminum salt solution to form an aluminum oxide powder. Also described herein are various furnaces for preparing high-purity aluminum oxide.

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