STUDY OF THE PROPERTIES OF UREA-AMMONIUM SULFATE (UAS) PELLETS

The effects of pressure on the crushing strength of UAS pellets, produ ced by a laboratory pressing machine were investigated. Physico-chemic al properties of UAS pellets were studied by Electron Microscope (EMS) , X-ray, Infra-Red Derivatography with a view to identifying the reaso ns for improvement in physico-mechanical properties. It was proved tha t there are some structural changes in UAS pellets due to application of pressure and because of this a higher crushing strength could be ob tained. As a result of pelletization the average crystallites size is lower. Secondly, the main chemical groups are the same, but there are some evidences that a new co-ordination between NH2 and SO4 structures is occurring. So the higher crushing strength is due not only to the mechanical compacting but also to the chemical co-ordination. The addi tion of ZnO accelerates those changes.