Patent ID: 11897783
Assignee: RHODIA OPERATIONS
Field: Chemical engineering (Chemistry)
Classification: CPC C  B | IPC C

Claim 10:
11. A process for preparing the aluminum hydrate as claimed in claim 1, the process comprising the following steps:
(a) introducing the following into a stirred tank containing an aqueous nitric acid solution:
an aqueous solution (A) comprising aluminum sulfate, optionally the additional element(s) in nitrate form, and nitric acid;
an aqueous sodium aluminate solution (B);

the aqueous solution (A) being introduced continuously throughout step (a) and the flow rate of introduction of the solution (B) being regulated so that the mean pH of the reaction mixture is equal to a target value of between 4.0 and 6.0;
(b) when the entire aqueous solution (A) has been introduced, continuing the introduction of the aqueous solution (B) until a target pH of between 8.0 and 10.5 is reached;
(c) filtering the reaction mixture to recover the solid and washing said solid with water;
(d) drying the solid resulting from step (c) to form the aluminum hydrate of claim 1.