Unie Van Kunstmestfabrieken B.v.

Johan W Hoogendonk

Servatius J Lucassen

Storage-stable nitrogen-phosphorous-potassium fertilizer granules and prills are made by adding to a molten or aqueous solution mixture of ammonium nitrate and ammonium phosphate, a particulate potassium salt, typically potassium chloride, in which the particles have an average size no greater than 55 microns and less than 1% by weight of the particles are larger than 150 microns. The potassium salt is added without the need for preheating and at a temperature of between 5.degree. and 40.degree. C. to the mixture where it is simultaneously converted. The resulting mixture is granulated or prilled into NPK fertilizer particles.

Process for the preparation of a granular NPK fertilizer and granular

Mineral-enriched urea prills for addition to maize silage are prepared using conventional urea prilling equipment by rapidly mixing a urea melt with a mineral enrichment composition containing up to 22% weight of sodium chloride in a rapid manner such that at most only about one-third of the total sodium chloride content is dissolved, the balance remaining in suspension, mixing typically requires no more than about 7 seconds, then the melt is sprayed to prills and cooled.

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Geleen, Netherlands

Johan W Hoogendonk