1. Raw material processing: Pre-crush clumped raw materials (such as urea and ammonium phosphate), automatically weigh and blend them, then mix the raw materials to ensure uniform mixing. Resin coating materials: Prepare resin, such as polyurethane, solvents such as toluene, and modifiers such as plasticisers. Mix the resin, solvent and additives in the correct proportions and stir evenly to produce a coating liquid suitable for spraying.
2. Granulation: Feed the uniformly mixed powdered material into the granulation equipment to form primary fertiliser granules. Granulation methods can include disc granulation, extrusion granulation, or drum granulation.
Name |
Capacity |
Advantages |
Rotary Granulation |
5-30 tons/h |
High yield, most suitable for large-scale industrial production, with good particle uniformity. |
Double Roll Granulation |
1-8 tons/h |
Usually no drying process, extremely high particle strength. |
Disc Granulation |
1-10 tons/h |
Simple structure, intuitive operation, easy to adjust. |
3. Drying and Cooling: Granules after granulation typically contain high moisture content and must enter a drying and cooling machine. Hot air is used to evaporate moisture from the granules, achieving the specified moisture content to ensure granule strength and prevent adhesion during subsequent coating. Drying and cooling temperatures must be strictly controlled to avoid melting or decomposition of core fertilisers like urea.
4. Screening and Recirculation: The dried and cooled granules are graded using a screening machine. Qualified granules proceed to the next process, while oversized granules or fine powders are returned for re-mixing or re-granulation.
5. Resin Coating and Curing Preheated granules enter the drum coating machine, where a spray gun atomises the prepared resin coating solution into fine droplets, uniformly spraying them onto the surface of the tumbling granules. Simultaneously, hot air at a controlled temperature and flow rate is introduced into the drum. This forms a thin, uniform, continuous, and dense resin film. The residence time within the coating machine is extended to ensure complete resin film reaction, achieve final strength, and thoroughly remove residual solvents.
6. Product Storage and Packaging: Qualified resin-coated composite fertiliser particles are sent to the finished product warehouse for storage. Finally, they are processed through an automatic packaging machine for weighing, bagging, sealing, and coding, resulting in the final product.