Chemie Linz Aktiengesellschaft

Karlheinz Wegleitner

Ferdinand Weinrotter

Alfred Schmidt

Rudolf Sykora

Josef Herbert Hatzl

Alfred Garber

Walter Muller

Melon is prepared by heating, in the solid form, preferably as granules, a mixture of dicyandiamide and melamine, or a mixture of one or both thereof with urea and/or biuret and/or triuret and/or guanidine carbonate at a temperature from 450.degree. to 600.degree. C.

Process for the preparation of melon

Guanidine carbonate is isolated from dilute aqueous solutions containing guanidine, urea, pyrolysis products of urea, ammonia and carbon dioxide, by evaporation of the solution at a temperature of 80.degree. to 130.degree. C until a guanidine carbonate content of 20g/l and a pyrolysis products content of not more than 28g/l at 80.degree. C or not more than 128.degree. g/l at 30.degree. C is achieved, without exceeding a heating time of 6 hours at the upper temperature limit, separation of the precipitated pyrolysis products, subsequent cooling to not more than 45.degree. C, addition of ammonia to an ammonia content of 15 to 30 % by weight and separation of the precipitated guanidine carbonate.

Recovery of guanidine carbonate from aqueous solutions

Process for obtaining guanidine carbonate from aqueous solutions in which it is present with urea and its pyrolysis products as well as ammonia and carbon dioxide, which comprises heating the aqueous solution to a temperature of at most 80.degree.C at atmospheric pressure, evaporating the resulting solution, which contains an amount of carbon dioxide equal to the guanidine content, until it is saturated with urea, separating the solid precipitate, suspending the mother liquor in liquid ammonia and separating the resulting guanidine carbonate.

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Linz (Danube), undefined

Karlheinz Wegleitner