Influence of the amount and fineness of grinding of ammonium sulfate on the properties of sulfate-containing urea

Abstract

The objective of this work is to determine the optimal technological mode for obtaining sulfated urea with a balanced content of nitrogen and sulfur by adding ammonium sulfate to the urea melt before granulation. The article presents the results of a study of the dependence of the properties of sulfated urea on the degree of grinding and on the amount of ammonium sulfate, expressed by the mass ratio of CO (NH2)2: (NH4)2SO4 = 100 : (2.5-50). Methods for obtaining, granulating and studying the properties of sulfated urea samples are presented. In fertilizers obtained with the addition of ammonium sulfate to the urea melt at the studied ratios, the strength of the granules increases from the initial 2,53 to 4,80 MPa, the gyroscopic point decreases from 58,4% to 52,3. It was also revealed that when ammonium sulfate is added to the urea melt, the density and viscosity of the melt increase with an increase in the amount of ammonium sulfate introduced. At 135 ° C, an increase in the addition of ammonium sulfate from 2,5 to 50,0 mass parts per 100 mass parts of urea leads to an increase in density from 1,162 to 1,412 g/cm3, viscosity from 2,56 to 7,91 cΠɜ. It was found that the smaller the particle size of ammonium sulfate, the higher the strength of the urea granules. With a decrease in the dispersion of ammonium sulfate particles from 0,25 to 0,04 mm, the strength of sulfated urea granules increases, the presence of ammonium sulfate in the composition of urea reduces the dissolution rate, which makes it possible to prolong their action, in addition, it lowers the pH of the product, which prevents the release of ammonia during storage and transportation sulfated urea.