A granulating method for a round-particle potassium fertilizer

Abstract

The invention relates to the technical field of agricultural fertilizers and particularly relates to a granulating method for a straight round-particle potassium fertilizer. The method includes crushing the potassium fertilizer with a ball mill into particles the granularity of which is 80 meshes, wetting the potassium fertilizer with water the weight of which is 5-7% of the weight of the potassium fertilizer, fully mixing, adding the potassium fertilizer into a screw extruder, extruding to obtain cylindric small segments the diameter of which is 3-4 mm and the length of which is 2-4 mm to preform the potassium fertilizer, rounding the potassium fertilizer small segments and improving strength in a revolving drum with the time being 10 min or above to achieve certain strength, drying the potassium fertilizer in a mesh-belt type drying machine with the drying temperature being controlled to be 120-200 DEG C, drying time being 40-60 min, and moisture removing temperature being 70-80 DEG C, and cooling the dried material in a revolving drum cooler until the temperature is 60 DEG C or below to obtain the round-particle potassium fertilizer. The degree of particle circularity of a prepared product is 95%, a product yield is 90% or above and strength is 30-40 N.

Description

technical field [0001] The invention relates to the technical field of agricultural fertilizers, in particular to a granulation method of simple round particle potassium fertilizer. Background technique [0002] my country is a large agricultural country, and the nutrients needed by crops are mainly nitrogen, phosphorus and potassium. There are two main methods of fertilization at this stage: the first is the application of compound fertilizer or compound fertilizer, which is characterized by round particles and the combination of three elements. and crops are inconsistent, the compound fertilizer is difficult to meet the needs of crops in various places, which not only affects the yield, but also wastes the content. Therefore, developed countries rarely use compound fertilizers, and the domestic demand is also on the decline; the second is to apply Blended fertilizer (BB fertilizer), which is characterized in that the three elements of nitrogen (urea), phosphorus (diammoni...

AI Technical Summary

Problems solved by technology

Dry extrusion granulation is the most popular method at present. This method has simple process flow, simple technology, low equipment investment, low energy consumption, and high granule strength. The disadvantage is that the product yield is low, and the return rate reaches 70%. The shape of the particles is irregular. After being used to make blended fertilizers, the particle flow velocity of urea and diammonium is inconsistent during the fertilization process, resulting in uneven fertilization. To a certain extent, the yield of crops is affected due to element deviation; spraying The granule is made by dissolving or partially dissolving potassium chloride or potassium sulfate in water to make a saturated solution or suspension, and then spraying the saturated solution or suspension on the masterbatch, and drying it while spraying, so that the granule grows gradually and sieved Particles with a qualified particle size are separated into finished products. Small particles are re-granulated as master batches, and large particles are broken and dissolved. The roundness of the particles produced by this method is better, but the yield is low, the process is complicated, and the energy consumption is high. It is not suitable for actual industrial production. At present, there are relatively few manufacturers using this method to produce round potash fertilizer particles

Due to the high melting point and poor cohesiveness of inorganic salts such as potassium chloride and potassium sulfate, it is impossible to use general pelletizing methods such as disc granulation and drum granulation to form balls directly.