CAKING MECHANISM OF FERTILIZER AND METHODS OF ITS CONTROL

Since the start of the industrial production of fertilizers about one hundred years ago, the fertilizer industry has made tremendous progress in developing ever more efficient fertilizers and improved production methods.In spite of these improvements certain problems are still encountered in the manufacture, handling and application of industrial fertilizers. The main problems can be listed as caking, dusting and moisture pick-up, and have attracted a great deal of attention in the past, but although progress has been made, the task of finding cost-effective solutions will still continue. The tendency of solid fertilizers to cake and form large stiff masses is one the principal problems associated with their manufacture, handling and application.The cause of caking of most fertilizers is the growth of crystal bonds between fertilizer particles. These crystals develop during storage due to continuing internal chemical reaction or thermal effects, which in the deposition of crystals, from minute amount of salt solutions present in fertilizer. Inter-growth of such crystals between granules or between particles of non-granular product result in caking.The scope of this paper covers the mechanisms of caking, factors affecting caking, and methods of their prevention. In addition to, the various potential anti-caking additives are surveyed, and their mode of action reconsidered in the light of the proposed mechanisms of caking.