摘要 |
Metal oxides are applied to the surface of urea particles and chemically bonded to the urea by a heat-induced reaction. The product of this reaction is a free-flowing, relatively non-hygroscopic nitrogenous chemical fertilizer. By selecting metal oxides corresponding to a particular soil deficiency, beneficial micronutrients can be supplied simultaneously with nitrogen. Other materials, such as elemental sulfur, can be incorporated into the metal oxides prior to coating or can be liquefied and applied as a separate additional coating to the metal oxide-urea particles. In another embodiment, fertilizer particles are coated with metal oxides, covered with molten urea, and heated to induce a reaction. The formed reaction product remains as a layer on the exterior of the particle.
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