With the continuous development of China's chemical fertilizer industry and agricultural production, compound fertilizer has developed rapidly in recent decades as a fertilizer with relatively complete nutritional content. For countries with developed fertilizer industry, compound fertilizer has accounted for total fertilizer. 70%-80% of the amount, for the country where the fertilizer industry is developing, it will also be an inevitable trend of development. There are many manufacturers of compound fertilizers in China, and the production of compound fertilizers has changed the proportion of agricultural production fertilizers in China to some extent. Today we mainly explain the process of NPK fertilizer production line
using extrusion granulator.
First, a brief introduction to the process of compound fertilizer extrusion granulation process:
(1), the qualified raw materials are added to the mixer according to the ratio of the ratio, and uniformly mixed.
(2) Transfer to the disc feeder to clean the iron in the material during the conveying process.
(3) The material in the disc feeder enters the roller press granulator
uniformly, the material is forced to pass between the two pressure rollers and is extruded into a thin sheet, and the sheet is broken into a coarse crusher under the pressure roller. The chips are sieved and the material on the sieve is continuously broken and sieved.
(4) The semi-finished product is conveyed to the finished sifter, and the fine particles after the screening are directly returned to the disc feeder, and the large particles are pulverized by the crusher machine and then returned to the disc feeder.
(5) The qualified products after screening are transported to the fully automatic packaging machine for weighing, packaging and storage.
Working principle of the roller press granulator:
The belt and the pulley are driven by the motor, transmitted to the drive shaft through the reducer, and rotated in opposite directions by the split gear and the passive shaft. The material enters from the feed inlet, is extruded, and rotates off the roll of the roll granulator, and passes through a chain to transfer the large crushing chamber, breaks up the particles and separates the finished particles through the lower screen. The separated powder is sent to the feed port through a conveyor belt and mixed with the new material to continue granulation.
Understand the production process; let us look at the advantages and disadvantages of using this process:
(1) Extrusion granulation does not require heating and humidification of materials. It can be granulated at room temperature, saving investment and saving energy, and can also be adapted to granulation of ingredients that contain heat sensitive materials such as ammonium bicarbonate and certain organic fertilizers.
(2) There is no waste water or exhaust gas in the production process, which will not pollute the environment.
(3) The extrusion granulation process is short, easy to operate, easy to achieve production automation control, and improve production efficiency.
(4) There is no special requirement for the nature and particle size distribution of raw materials, so the source of raw materials is broad.
(5) The production is more flexible, and the product can be changed at any time, which is beneficial to the production of special fertilizers in small batches.
(6) The product has a uniform particle size distribution and will not cause segregation or agglomeration.
(7) The shape of the extruded granulation product is not as round as that produced by traditional methods such as drum granulator
and slurry granulation; if a chemical reaction occurs between the components of the product granules, the granules may be cracked.