The production process of compound fertilizer is a complex and refined process, usually including the following main steps:

1、 Raw material preparation

The main raw materials for compound fertilizers include basic fertilizers such as nitrogen, phosphorus, potassium, and other trace elements. These raw materials can be chemically synthesized fertilizer components such as urea, ammonium chloride, potassium sulfate, etc., as well as natural ores or organic matter such as phosphate ore, potassium ore, etc. Before production, it is necessary to screen, grind, and mix these raw materials to ensure that their quality and proportion meet the requirements.

2、 Ingredients and Mixing

According to the formula ratio of compound fertilizer, various raw materials are put into the mixing equipment in a certain proportion. Mixing equipment can be rotary drums, mixers, or sprayers, etc. Its purpose is to thoroughly mix various raw materials evenly, ensuring that each particle contains the corresponding nutrients. This step is crucial for the quality of compound fertilizers, as uneven mixing may lead to uneven distribution of nutrients and affect fertilizer efficiency.

3、 Granulation

Granulation is a crucial step in the production of compound fertilizers, which determines the particle shape, size, and strength of the compound fertilizer. According to different production processes, granulation methods can be divided into wet and dry methods:

Wet granulation: During the wet granulation process, a paste is formed by adding an appropriate amount of water or solution to the evenly mixed raw materials. Then, the paste is granulated through a granulator or a spray tower to form granular compound fertilizer. The advantages of wet granulation are regular particle shape and uniform size, but the disadvantages are high energy consumption and the need for subsequent drying treatment. Common wet granulation processes include drum granulation, disc granulation, and spray granulation.

Drum granulation: By using a certain amount of water or steam to humidify the base fertilizer inside the drum, a chemical reaction occurs fully, and the material particles are compressed and agglomerated into balls through the rotational motion of the drum. The rotary drum granulator is the most widely used equipment in the production of compound fertilizers.

Disc granulation: After all the raw materials are mixed, they enter the disc granulator, and the disc rotates to agglomerate the materials into balls. The disc granulation process is simple and requires less investment, but it is only suitable for small-scale production and has low efficiency.

Spray granulation: Using evaporation to directly produce small particles from a solution or slurry, often referring to urea spray. Melt urea and spray it into the compound fertilizer granulation device to reduce the urea crushing process. Spray granulation fertilizer dissolves quickly, but the process conditions are relatively special, making it suitable for the production of compound fertilizers with high nitrogen formulas.

Dry granulation: In the process of dry granulation, the uniformly mixed raw materials are granulated by special granulation machinery, such as drum granulators or tablet presses. There is no need to add water or solution during this process, so the energy consumption is low and there is no need for subsequent drying treatment. But the particle shape and size of dry granulation may not be as good as those of wet granulation rules. High tower granulation is a typical dry granulation process.

High tower granulation: The raw materials are melted into high-temperature slurry or transformed into a slurry mixture, which is then scattered from a high altitude. During the scattering process, they are cooled and agglomerated into granules, which are then sieved. The composite fertilizer particles produced by high tower granulation technology are crystal clear, have good appearance, and are not easily clumped. But this technology requires high purity of raw materials and formulation. Bulk blending fertilizer production line