Process for producing biuret from urea

A process for the production of biuret from urea comprising:

• a) ammonia and carbon dioxide are reacted in a synthesis section at a synthesis pressure to form urea and obtaining a reaction effluent containing urea, water and unconverted reagents;
• b) said reaction effluent is processed in a recovery section to recover unconverted reagents contained therein;
• c) a urea aqueous solution, withdrawn from the recovery section, is processed to remove water and obtain a concentrated urea melt;
• said urea aqueous solution containing no more than 100 ppm by weight of formaldehyde;
• d) said urea melt is processed under biuret-forming conditions to decompose urea into biuret and ammonia and obtain a biuret urea melt;
• e) said biuret urea melt is diluted with water or with an aqueous stream obtaining a solution;
• f) the solution obtained at step e) is subject to a process of crystallization including precipitation of a solid phase containing biuret and obtaining a slurry including precipitated solid phase and a mother liquor;
• g) the slurry obtained at step f) is processed to obtain a biuret-containing solid product and a mother liquor.