The effects and production methods of compound fertilizers containing three types of nitrogen

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At present, with the development of modern agriculture, the production of compound fertilizers both domestically and internationally plays a dominant role in the fertilizer industry. In countries where this industry is well-developed, compound fertilizers account for 70% to 80% of total fertilizer usage. Compound fertilizers are primarily made by mixing basic fertilizers containing nitrogen, phosphorus, and potassium, such as urea, ammonium chloride, ammonium phosphate, and potassium chloride. In a granulator, these materials are agglomerated into pellets at certain temperatures and with a specific amount of liquid, either due to their own adhesive properties or by the addition of an appropriate amount of binder. After that, the pellets are dried, cooled, and screened to produce the final compound fertilizer product. The granulation production method mentioned above is a widely used technique in China. The products produced contain either one type of nitrogen (ammonium nitrogen) or two types of nitrogen (ammonium nitrogen and amide nitrogen), or (ammonium nitrogen and nitrate nitrogen). Ammonium nitrogen comes primarily from ammonium chloride, nitrate nitrogen from phosphatic nitrates, and amide nitrogen from urea. Potassium is usually supplied in the form of potassium chloride. These products have a high content of chloride ions, classifying them as dichlorinated products. Long-term use of such products on field crops can lead to soil compaction, reduced crop yields, and they are not suitable for cash crops such as vegetables, fruit trees, and tobacco. Products containing three forms of nitrogen, namely nitrate nitrogen, ammonium nitrogen, and amide nitrogen. Among them, nitrate nitrogen and ammonium nitrogen are readily available nitrogen, while amide nitrogen is slowly released nitrogen. It has a wider range of applicable crops; it can be used not only for field crops but also for economic crops such as vegetables, fruit trees, and tobacco. After the fertilizer is applied to the soil, nitrate nitrogen begins to be released after 5–7 days, ammonium nitrogen starts to be released after 10–15 days, and amide nitrogen begins to be released after 15 days. This ensures a continuous supply of nutrients to the crops, improves the efficiency of fertilizer use, and reduces nutrient loss. A production method for a compound fertilizer containing three types of nitrogen: raw materials containing nitrate nitrogen, ammonium nitrogen, and amide nitrogen are added to the mixture; no ammonium chloride is used in the production process, but phosphoric acid nitrate fertilizer and urea are added. Phosphoric acid nitrate fertilizer contains both nitrate nitrogen and ammonium nitrogen in a ratio of approximately 1:1.1. The product contains three types of nitrogen, including both rapidly available nitrogen and slowly released nitrogen. Urea is added in solid form and serves as a masterbatch needed for granulation; it is surrounded by other materials layer by layer. The chemical reactions between these materials enhance the strength of the particles, making the shell surrounding the urea more robust, and this helps to control the rate at which ammonia nitrogen is released, thereby giving the product a better slow-release effect. What is difficult to control in the aforementioned production process is urea nitrate, which is produced by the reaction between urea and phosphoric acid fertilizer. Urea nitrate has high viscosity; on the one hand, it serves as a good source of liquid phase for granulation, but on the other hand, an excessive amount of urea nitrate causes the material to become viscous or form large particles, preventing the production process from proceeding. To prevent the reaction between urea and phosphoric nitrate fertilizers that leads to an excessive amount of urea nitrate, ammonia gas must be introduced during the granulation process, depending on the specific mixing ratios, in order to ammoniate the phosphoric nitrate fertilizers, thereby reducing the formation of urea nitrate and increasing the neutralization degree of monoammonium phosphate. Full use is made of the large amount of heat generated when nitric acid phosphate fertilizer decomposes upon heating, as well as the heat of neutralization resulting from the reaction between ammonia gas and monoammonium phosphate, to heat the material and raise the granulation temperature. The viscosity of urea nitrate and the increased solubility of ammonium phosphates are utilized to ensure an adequate amount of liquid phase for granulation; thus, no additional binders are needed, resulting in a high balling rate and cost reduction. The moisture content of the material used for granulation is significantly reduced, which lowers the drying load and saves a considerable amount of energy. The other powdered base fertilizers containing nitrogen, phosphorus, and potassium, such as ammonium phosphate, ordinary calcium carbonate, ammonium sulfate, potassium chloride, and potassium sulfate, can be used in combination; the type and amount of these base fertilizers to be added depend on the nutrient and moisture content of the final product. If the resulting product is to be a monochloride product, then ammonium chloride is not added. The final product contains nitrate nitrogen, ammonia nitrogen, and amide nitrogen. If the phosphoric acid fertilizer is in granular form, it needs to be crushed before being added. QQ number: 2369226565 Email: lyl7110@126.com We can also provide the Category B safety production standardization manual for the compound fertilizer industry (suitable for enterprises using the amino acid-based production process). Exchange production process formulas and equipment technology for compound fertilizers.