Spray pelleting process of compound fertilizer

Abstract

This invention relates to a method for spray granulation of composite fertilizers, that is, potassium chloride and oil of vitriol react with each other to produce potassium hydrosulphate solution. The potassium hydrosulphate solution is homogeneously mixed with ammonium dihydrophosphate and reacts with ammonia to produce neutralization paste containing ammonium sulphate, potassium sulphate and diammonium hydrophosphate. The neutralization paste is then granulated, dried, cooled and screened to obtain composite fertilizers. This spray granulation of composite fertilizers has the advantages of low production cost and smooth particle surfaces.

Description

technical field

[0001] The invention relates to a preparation method of compound fertilizer, more specifically a spray granulation method of compound fertilizer. Background technique

[0002] Common compound fertilizer granulation methods include agglomeration granulation, extrusion granulation and ammoniation granulation. The agglomeration granulation method is to agglomerate basic fertilizers containing nitrogen, phosphorus and potassium nutrients, such as monoammonium phosphate, potassium sulfate, urea, ammonium sulfate or ammonium chloride, etc., into granules with a drum granulator after stirring evenly; The granulation method is to extrude the above-mentioned raw materials into granules with an extrusion granulator. The disadvantage of the above two methods is that potassium sulfate, urea, ammonium sulfate or ammonium oxide in the raw materials used are all basic fertilizers prepared into finished products, and compound fertilizers are reproduced with these basic fert...