Use of Diatomaceous Earth to Accelerate Drying of Ammonium Nitrate

Abstract

The drying characteristics of ammonium nitrate prills coated with diatomaceous earth were compared to those of noncoated material using both a tray and small rotary dryer. Nitrate with 3 to 4% coating agent dried from 2.5 or 3.Oy0 to 0.2y0 moisture, dry basis, in about one third the time required for noncoated material. This amount of coating agent gave the! greatest increase in drying rate. The relative difference in drying rate between coated and uncoated material increased as the moisture content decreased. Air velocity had no significant effect. In the rotary dryer less fines were formed during the drying of coated material. A mechanism to account for the phenomena observed is postulated and supported by photomicrographs of individual prill cross sections.