Przemysl Chemiczny, Vol.94, No.7, 1147-1155, 2015
Chemical reactions in the phosphorite-sulfuric acid-urea-water system in relation to process security and product quality. Part 1. System CO(NH2)(2)-H2SO4-H2O
Mixts. of H2SO4, urea, H2O and phosphorite were prepd. and studied by thermogravimetry and differential thermal anal. up to 500 degrees C to study reactions occurring and products formed (NH2SO3NH4, NH2SO3H, (NH4)(2)SO4,CaHPO4). The formation of unwanted by-products was limited at temps. below 110 degrees C and at low H2SO4 concn.