Composite fertilizer and method for its manufacture
AssigneeJ. R. Simplot Company
InventorsJack Lee Smith, Charles Raymond Crowley, Roger Benton Humberger
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Abstract
This invention relates to novel fertilizer particles having an inner core and an outer water permeable sulfur coating; to a method of preparing these fertilizer particles by contacting a particulate core material in a fluidized bed, or other suitable coating apparatus, with molten sulfur which solidifies upon the core material; the process preferably being conducted in a fluidized bed having an inert atmosphere in the material contacting zone. This invention is particularly useful in preparing triple superphosphate fertilizers with a water permeable coating of elemental sulfur.
Claims10
A composite fertilizer particle having a fertilizer particle core selected from the group consisting of normal superphosphate, enriched superphosphate, triple superphosphate, monocalcium phosphate, monoammonium phosphate, diammonium phosphate, and ammonium polyphosphate and a non-uniform, discontinuous particulate water-permeable coating comprising sulfur.
A composite fertilizer particle comprising a core comprising a calcium or ammonium phosphate fertilizer having a non-uniform water-permeable coating of sulfur, said coating having dispersed therein a minor amount of a particulate modifier material which swells in the presence of water, or which is more water soluble than sulfur, said amount being sufficient to promote the release of the core fertilizer.
A method of forming a composite fertilizer particle comprising a core of a calcium or ammonium phosphate having a non-uniform, discontinuous water permeable coating comprising sulfur which method comprises:
- contacting a particulate calcium or ammonium phosphate fertilizer particle with a particulate molten coating material comprising sulfur at a temperature such that the molten coating material does not flow on the surface of the core so as to form a non-uniform water-permeable coating.
Dependencies are inferred from the claim text.