Extrusion granulation process for NPK fertilizer production
Extrusion granulation is a relatively new process for dry granulation to produce NPK compound fertilizers. The principle of the roller press granulator is: the dry material is agglomerated into a dense and hard mass (cake material) under the action of pressure, which is called the extrusion process, and the cake material is crushed and sieved to become a pellet material, which is called granulation process. The effect of the extrusion is to squeeze out the air between the particles, and to make the particle spacing close enough to produce attractive forces such as van der Waals force, adsorption force, crystal bridge and in-line connection. Extrusion granulated particles are mainly the strength of the particles formed by the forces between the molecules.
Extrusion granulation to produce NPK fertilizer mainly has the following process characteristics:
1. Low energy consumption. Extrusion granulation is the granulation of the material at normal temperature. Compared with other methods, it does not require drying measures such as fuel and gas.
2. No additional adhesive is required. The common NPK fertilizer production in China is steam granulation. After the water vapor condenses and crystallizes between the molecules of the material, it acts as a binder during the granulation process. However, in the drying process, the water inside and outside the particle must be driven out, otherwise the fertilizer is easy to stick and agglomerate during storage. Dry granulation does not require additional additives. It only uses the intermolecular forces of the material itself to simplify the process and reduce energy consumption.
3. The investment is low. Since the drying process is omitted, and the return ratio is low (about 35% of the total feed amount of the extruder), the process flow is simple and the investment is low.
4. Flexible composition of raw materials. The raw material route for extrusion granulation to produce compound fertilizer is extensive. At present, there are more than 20 kinds of materials that have been successfully used for extrusion granulation. In addition, the extrusion granulation process can be flexible in a very short time to achieve product formula replacement. Therefore, the compound fertilizer produced by extrusion granulation can be adapted to the needs of small batches and multi-species compound fertilizers.
5. Applicable raw material particle size range is large. Extrusion granulation has no special requirements on the particle size of raw materials. 1-4mm granular materials and fine powder materials can be used. Powdered materials and powdery products with better particle size can be used better. Powdered materials can reduce costs.
6. The only drawback is that the shape of the product is irregular particles, but the irregular particle shape has no effect on the application of the fertilizer.
We are leading fertilizer machine manufacturers in China,besides the fertilizer granulator machine,we also produce other kinds of fertilizer machine for the fertilizer production line,welcome to inquiry.