How to use double roller extrusion granulator to make 20:10:10 npk fertilizer


Double roller extrusion granulators are a popular choice in the fertilizer industry for producing NPK (Nitrogen, Phosphorus, and Potassium) fertilizers due to their efficiency, flexibility, and cost-effectiveness. The 20:10:10 NPK fertilizer blend, which contains 20% nitrogen, 10% phosphorus, and 10% potassium, is widely used to promote robust plant growth. This passage will guide you through the step-by-step process of using a double roller extrusion granulator to manufacture 20:10:10 NPK fertilizer.

double roller granulation plant

double roller granulation plant

Raw Material Preparation

Selecting and Measuring Raw Materials

The first step in the production process is selecting and measuring the raw materials. To create a 20:10:10 NPK fertilizer, you will need sources of nitrogen, phosphorus, and potassium. Common sources include urea or ammonium sulfate (for nitrogen), superphosphate or diammonium phosphate (for phosphorus), and potassium chloride or potassium sulfate (for potassium). Accurate measurement of these raw materials is crucial to ensure the correct nutrient balance in the final product.

Mixing the Raw Materials

Once the raw materials are measured, they need to be thoroughly mixed to create a uniform blend. Mixing can be done using a rotary drum mixer, paddle mixer, or even manually for smaller-scale operations. Ensuring a homogenous mixture is important for the consistency and quality of the final fertilizer granules.

Granulation Process

Feeding the Mixture into the Granulator

The homogenous mixture of raw materials is then fed into the double roller extrusion granulator. This machine works by pressing the material between two rollers, which have corresponding mold cavities. As the rollers rotate, the material is compressed and shaped into granules.

Extrusion and Shaping

The extrusion process is where the magic happens. The mixture is forced through the roller molds, forming compacted granules. These granules need to have a consistent size and shape for easy application and better performance in the field. Adjustments to roller pressure and mold design can help in achieving the desired granule characteristics.

Drying and Cooling

Drying the Granules

Freshly extruded granules contain moisture that needs to be removed to ensure stability and longevity. The drying process can be done using a rotary dryer, fluidized bed dryer, or other drying equipment. Proper drying is essential to prevent caking and ensure the granules remain free-flowing.

Cooling the Granules

After drying, the granules are hot and need to be cooled to ambient temperature. Cooling can be achieved using a rotary cooler or other cooling equipment. This step not only brings the granules to a manageable temperature but also further hardens them, improving their durability and handling properties.

Screening and Coating

Screening for Size Uniformity

Once the granules are dried and cooled, they are passed through a screening machine to separate oversized and undersized particles. Only granules of the desired size range are collected, while others are returned to the granulator for reprocessing. This ensures uniformity in the final product, which is important for even nutrient distribution when applied to crops.

Applying a Coating

To enhance the performance and storage properties of the granules, a coating can be applied. Coatings can include anti-caking agents, slow-release additives, or protective layers to improve the granules’ resistance to moisture and abrasion. The coating process involves spraying the granules with the coating material and allowing them to dry.

Packaging and Storage

Packaging the Final Product

The final step in the production process is packaging the 20:10:10 NPK fertilizer granules. Packaging can be done in bags, bulk containers, or other suitable forms depending on market requirements. Proper packaging ensures the product remains free from contamination and maintains its quality during storage and transportation.

Storing the Fertilizer

The packaged fertilizer should be stored in a cool, dry place to prevent moisture absorption and degradation. Proper storage conditions extend the shelf life of the fertilizer and maintain its effectiveness for when it is applied to crops.


Using a double roller extrusion granulator to produce 20:10:10 NPK fertilizer involves several critical steps, including raw material preparation, mixing, granulation, drying, cooling, screening, coating, and packaging. By following these steps and paying attention to detail at each stage, high-quality fertilizer granules can be produced to support healthy plant growth. This method not only ensures efficient nutrient delivery but also promotes sustainable agricultural practices.

This entry was posted in compound fertilizer making, Fertilizer Dry Granulator, fertilizer granulation machine, Fertilizer granulation with less water, NPK Fertilizer Production Line, NPK Fertilizer Production Process and tagged . Bookmark the permalink.