How to prevent nutrient loss in fertilizer granules made by disc granulators?

Fertilizer granules can easily lose nutrients during production if the process isn't right, affecting how well the fertilizer works. When using a disc granulator, how can we minimize nutrient loss?

1.Control Raw Material Ratio and Mixing Uniformity

Before granulation, ensure nitrogen, phosphorus, potassium, and trace elements are thoroughly mixed. Avoid areas with too high or too low nutrient levels. Use a pre-mixing step and efficient mixers for a uniform blend.

2.Adjust Tilt Angle and Rotation Speed

The disc granulator's tilt angle (usually 35°-55°) and rotation speed (10-25 rpm) directly affect how well the granules form. Adjust these settings based on the material to make sure the granules are dense and smooth, reducing powdering off.

3.Optimize Binder Choice

Binders (like humic acid or bentonite) strengthen the granules, reducing breakage and nutrient loss.

Spray Evenly: Use misting nozzles to avoid spots that are too wet or too dry, ensuring stable granule structure.

4.Control Drying Temperature

When drying fertilizer granules, temperatures that are too high (above 80°C) can cause nitrogen to evaporate (like urea breaking down) or some trace elements to oxidize. Use low-temperature drying in stages:

Stage 1 (60-70°C): Remove surface moisture to prevent granules sticking together.

Stage 2 (50-60°C): Slowly dry out internal moisture to reduce nutrient damage.

5.Proper Screening and Coating

After granulation, screen out fine powder and oversized granules. Also, consider coating techniques (like sulfur coating or polymer coating) to slow down fertilizer dissolution and improve nutrient use efficiency.

In summary, preventing nutrient loss in granules made by disc granulators requires optimizing multiple steps: raw material mixing, granulation settings, binder use, drying process, and post-processing.