FERTILIZER CAKING - MECHANISMS, INFLUENTIAL FACTORS, AND METHODS OF PREVENTION

Most fertilizers have some tendency to form lumps or agglomerates (caking) during storage. The mechanism of caking in fertilizers is most often attributed to the formation of salt bridges and/or capillary adhesion. The severity of caking can be influenced by a number of factors, such as chemical composition, moisture content, particle structure, mechanical strength, hygroscopic properties, product temperature, ambient conditions, storage time, and storage pressure. The various methods of reducing or eliminating caking in fertilizers basically involve process control, storage/packaging conditions, and/or addition of anticaking agents. Caking mechanisms, factors that influence caking, and methods of prevention are discussed in this paper. Particular attention is given to the various types of anticaking agents and their modes of action. The paper also provides a fairly comprehensive list of commercially available anticaking agents and their producers.