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Anti-Caking in the production of water-soluble fertilizers

release time:2024-04-22

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1、 Caking problem

 

The problem of fertilizer caking generally occurs during the processing, storage, and transportation of fertilizers, mainly due to the moisture absorption, surface dissolution (deliquescence), evaporation, and recrystallization of microscopic fertilizer grains. During this process, crystal bridges are formed, causing small particles to turn into large particles and clump.

Firstly, the materials commonly used in the production of fertilizers are:; Ammonium salts, phosphates, micronutrients salts, potassium salts, etc., most of which contain crystalline water and are prone to moisture absorption and caking. For example, ammonium sulfate is prone to caking, while phosphates and trace elements are prone to caking and becoming insoluble substances. Urea is prone to precipitation of water and caking when it encounters trace element salts, mainly by replacing the crystalline water in the trace element salts with urea to form a paste, which then clumps.

Secondly, fertilizer production is generally non enclosed. During the production process, the higher the air humidity, the more likely the fertilizer is to absorb moisture and clump. When the weather is dry or raw materials are dried, the fertilizer is less likely to clump.

Thirdly, the higher the room temperature, the more conducive it is to dissolution. Generally, raw materials dissolve in their own crystalline water, leading to caking. When the temperature is higher, the water evaporates and is less prone to caking. This temperature is usually above 50 ℃, and we usually need to heat it to reach this temperature.

Fourthly, the greater the pressure applied to the fertilizer, the easier it is for the crystals to come into contact and clump together; The smaller the external pressure, the less likely it is to clump.

Fifthly, the longer the storage time of the produced fertilizer, the easier it is to clump, while the shorter the storage time, the less likely it is to clump.

 

2. How to prevent caking

 

Firstly, make a reasonable selection of raw materials, that is, choose materials that are not prone to caking as the raw materials for our production, such as trace element foliar fertilizers, which use iron, copper, manganese, zinc, sulfate, boric acid, and ammonium molybdate as raw materials, and magnesium sulfate as the main additive. When the main selected material is dry and the air is not too humid, the fertilizer produced is not prone to caking. Fertilizers mainly made from humic acid and amino acids are not prone to caking. Also, choose materials that are as dry as possible.

Secondly, choose the appropriate production time. As most parts of China belong to the northern temperate zone, the rainy season is mostly concentrated in June, July, and August, and the time with higher temperatures is also concentrated at this time. Therefore, the probability of fertilizer production and caking in spring, late autumn, and winter is also lower. This is because the air humidity is low and the temperature is not high, which is not conducive to caking.

Thirdly, add some anti caking agents, such as talc powder, humic acid and other powders that are not easily caking, and they play a bridging role in the middle. Special anti caking blocks can also be added,

Fourthly, reasonable packaging should be adopted to prevent squeezing. Packaging materials should mainly prevent moisture absorption and breathability, and prevent excessive squeezing during transportation and storage, which can also effectively prevent agglomeration problems.