Decomposition of aluminum nitrate

摘要

There is described a method for the decomposition of aluminum nitrate crystals to alumina comprising the steps of: (a) melting the aluminum nitrate crystals; (b) evaporating from the melted crystals in a once through evaporator at the boiling temperature of the mixture and for a time sufficient to remove water and associated nitric acid and to provide a fluid having an alumina concentration of at least about 18% by weight; (c) decomposing the product of step (b) at a temperature of between about 150 DEG and about 200 DEG C. and recovering the heat of condensation of the resultant vapors; (d) further decomposing the product of step (c) in a fluidized bed decomposer at a temperature of between about 300 DEG and about 400 DEG C. to reduce the residual nitrate concentration in the product to between about 5 and about 10 weight percent; (e) decomposing the product of step (d) in a fluidized bed decomposer at a temperature of between about 500 DEG and about 800 DEG C. to reduce the residual nitrate concentration in the product to below about 3 percent by weight; and (f) calcining the product of step (e) at a temperature of at least about 1000 DEG C.