The raw material route of extrusion granulation to produce compound fertilizer is relatively wide, which can be used in npk compound fertilizer production line and npk production line. At present, there are more than 20 kinds of materials that have been successfully used in extrusion granulation: nitrate in nitrogen fertilizer Ammonium, urea, ammonium chloride, calcium nitrate, etc. Phosphate fertilizers include ammonium phosphate, common calcium, heavy calcium, phosphate rock powder, etc. Potash fertilizers include potassium chloride, potassium sulfate, etc., and trace elements such as boron, iron, copper, etc. can be added. Zinc, manganese, etc. Extrusion granulation has no special requirements on the particle size of raw materials. Both 1-4mm granular materials and fine powder materials can be used. Powder materials and powder products with unqualified particle size are better to use. Can reduce costs.
The main equipment included in the double roller granulator production line: automatic batching system, roll extrusion granulator, disc mixer, trommel screening machine, belt conveyor, packaging scale, etc.
Extrusion granulation production process:
1. storage, metering
Mixed fertilizer raw materials such as urea, ammonium phosphate, potassium chloride, etc. are transported to the storage silo by bucket elevator and belt. The number of storage bins, the complexity of metering and mixing techniques, is related to the number of components in the product formulation.
2. extrusion
The mixed fertilizer mixture is extruded by a roller extruder, the principle of which is to shape the material by extrusion. The mixed material is fed into the gap between the two oppositely rotating roller shafts through a vertical screw feeder. During the extrusion process, the pressure of the material gradually increases. When the gap between the two shafts is small, The material is relatively compressed, and then gradually decreases until it reaches 0.
3. Crushing and grading
The slabs formed in the double roller granulator are further broken up and classified to the desired particle size.
4. Polishing and finishing
Typically, the final product undergoes one or two steps of polishing.