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US 3,937,793 AGranted
Process for the continuous manufacture of crystallized ammonium thiosulfate
AssigneeHoechst Aktiengesellschaft
InventorsAdolf Metzger, Karl-Heinz Henke, Horst Schreiber
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Abstract
Crystallized ammonium thiosulfate is manufactured by converting ammonia with oxygen containing sulfur dioxide in ammonium thiosulfate solution to ammonium bisulfite and ammonium sulfite in a first step, while maintaining a pH of from 5.5 to 7.0 and a reaction temperature of up to 80.degree.C. In a second step, the ammonium bisulfite and ammonium sulfite in the solution are converted with ammonia and sulfur to ammonium thiosulfate.
Claims3
A process for the continuous manufacture of crystallized ammonium thiosulfate which comprises:
- reacting ammonia with oxygen containing sulfur dioxide in an ammonium thiosulfate solution to form ammonium bisulfite and ammonium sulfite at a pH of from 5.5 to 7.0 and a temperature of up to 80.degree.C;
- and, in a second step, converting the ammonium bisulfite and ammonium sulfite in the solution formed with ammonia and sulfur to ammonium thiosulfate at a temperature of 105.degree.C, said temperature being obtained by heating, if necessary.
Dependencies are inferred from the claim text.