Development of an accelerated caking test for urea

Abstract

A new accelerated caking test for use with urea has been developed and used in screening potential conditioning agents. The urea sample is held under pressure in a perforated cylindrical mold while temperature and relative humidity are cycled, to cause alternate absorption and loss of moisture. The degree of caking was measured by a penetrom-eter and was expressed as a caking index: hardness of unconditioned urea divided by the hardness of conditioned urea.Tests of 31/-2 days duration were satisfactorily correlated with 1-and 3-month bag storage tests run at two different urea producing plants.