METHOD OF PRODUCING UREA HAVING IMPROVED LOOSINESS,TRANSFER AND STORAGE CHARACTERISTICS

摘要

Prodn. of urea with improved flow, transition and storage properties and virtual freedom from dust, comprises treating urea with 0.01-0.2 (pref. 0.05-0.1) wt.% of a 5-40 wt.% soln. of bitumen in mineral oil. The oil has viscosity of is not >50 cst at 50 degrees C; pour point is not >10 degrees C and resin content is not >3%. The bitumen is an extraction bitumen (e.g. propane bitumen) with softening point 60-80 degrees C; penetration is not >15 x 101mm and paraffin content is not >2%. The anticaking agent is added to the urea melt or to the granules; in the latter case the anticaking agent temp. is not 40 degrees C and the granules is not 10 degrees C. Treated urea remains free flowing after is not >12 months storage and is useful as fertiliser or feed additive. Smaller amts. of anti-caking agent are needed so prodn. costs are reduced.