How to improve the compressive strength of products through drum granulation
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Experts, are there any effective methods for drum granulation that can improve the compressive strength of the product, thereby reducing the problem of the product crumbling due to low compressive strength? Steam granulation is currently used in production, with common raw materials including urea, monoammonium phosphate, potassium chloride, ammonium chloride, sulfuric acid an, ammonium bicarbonate, and attapulgite powder
Keep the product moisture content below 1.6
1. In production, try to use steam to adjust the amount of liquid phase, in order to avoid the formation of water clumps in the granulator. 2. Among the several NPK ingredients you mentioned, choose those that can undergo complex chemical reactions; for example, use ammonium carbonate and ammonium chloride to produce viscous diammonium compounds that can be used for granulation. 3. Do not add too much clay just in order to achieve a high output rate from the granulator. 4. During granulation, aim to form small particles which then grow into larger ones over time. 5. The temperature inside the granulator should be appropriate, usually between 60-70°C; utilize urea to soften sandy materials and help them form balls. 6. Control the temperatures at the inlet and outlet of the dryer properly, and make use of the secondary granulation function provided by the dryer’s light tube section. Excessively high temperatures can cause the raw materials to decompose, resulting in many pores in the fertilizer and reducing its density – this is especially true in the case of ammonium carbonate decomposition. 7. Optimize the combination of raw materials, and conduct more preliminary experiments before production. Some formulations, such as 16-16-16, are difficult to granulate when there is a small difference in the ratio of urea to ammonium chloride; the resulting balls have poor strength, and they tend to disintegrate over time when stored.
In short, ensuring the quality of fertilizer products is a systematic task that requires consideration of various factors. The answers provided above are merely intended to serve as a starting point; I hope that more experienced experts and veterans can offer their guidance.