| 摘要 |
Process for the production of technical grade biuret, readily in a form suitable for use as animal feed, by the controlled pyrolysis of urea in two stages, the first stage involving the partial pyrolysis of urea at a temperature above the melting point of urea to produce a first stage intermediate reaction product containing from about 20% to about 60% urea, and not more than about 25% cyanuric acid by weight, such reaction product being then cooled and comminuted, the comminuted product then being subjected, in solid form and in the absence of a liquid carrier, to a temperature at or slightly below the softening point of the solid particulate (suitable at a temperature of from about 100 DEG C. to about 140 DEG C.) with forced air circulation through the comminuted product for a sufficient time to lower its urea content by partial sublimation of the urea and partial further reaction thereof to biuret with only minimal further conversion of urea to cyanuric acid. Crystallization and cooling of the molten intermediate product resulting from the first stage of pyrolyzation is advantageously accelerated by addition thereof of a powdered seed material, preferably including powdered feed grade biuret from a previous run, which additive serves to also increase the melting point of the product and thus increase the temperature at which it may be heated during the solid state pyrolyzation.
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