Process for preparing Compound Fertilizer Granules

摘要

The invention relates to a process for the preparation of compound fertilizer granules containing at least two of the plant nutrients nitrogen, phosphorous and potassium, said process comprising the steps of: (a) mixing solid fertilizer raw materials and recycled oversize material, (b) crushing the mixture, (c) optionally mixing the crushed mixture with recycled undersize material to provide a solid feed material having a desired composition, (d) feeding the feed material to a melter and introducing hot air into said melter for heating the feed material and for melting a desired portion thereof and keeping said portion in molten state, (e) feeding the partly molten feed material from the melter to a granulator to obtain a granulated product, and (f) cooling and screening the granulated product to obtain dry compound fertilizer granules having a desired size distribution.