Ammonium sulfate Merseburg

Some companies have used the Merseburg process to manufacture ammonium sulfate from gypsum, but the process is only economically attractive where sulfur is unavailable or very expensive (32), and is thus not used in the United States. Ammonium carbonate, formed by the reaction of ammonia and carbon dioxide in an aqueous medium, reacts with suspended, finely ground gypsum. Insoluble calcium carbonate and an ammonium sulfate solution are formed. 

Merseburg A process for making ammonium sulfate fertilizer from gypsum. The gypsum is slurried with water and ammonium carbonate solution added. Calcium carbonate precipitates and is removed, any excess of ammonium carbonate is neutralized with sulfuric acid, and the solution is concentrated until it crystallizes ... 

OSAG A process for making ammonium sulfate from gypsum. Developed by Osterre-ichische Stickstoff-Werke, Linz, Austria, and offered by Power-Gas. See also Merseburg. 

A few companies have used the Merseburg process to recover sulfur values from gypsum as ammonium sulfate. This process is based on the reaction of gypsum with ammonium carbonate. 

The most obvious advantage of the Merseburg process was the ability to produce ammonium sulfate without any sulfuric acid. High energy intensity, due to the large volume of steam needed to recover solid sulfate from a relatively dilute solution, was the main drawback. Nevertheless, the process has been used in a number of European and Asian countries see UNIDO and IFDC. 1998. Fertilizer Manual. Dordrecht Kluwer Academic, pp. 246-247. Its steps are... 

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