Table of Contents
Extrusion granulator application:
Extrusion granulator production of compound fertilizer raw material route is extensive has been successfully used for extrusion granulation of more than 20 kinds of materials: nitrogen ammonium nitrate, urea, ammonium chloride, calcium nitrate, and so on, among nitrogen fertilizers, and phosphate fertilizers. There are ammonium phosphate, common calcium, heavy calcium, phosphate rock powder, etc. Potassium fertilizers include potassium chloride, potassium sulfate, etc., and trace elements such as boron, iron, copper, zinc, manganese, etc. can be added. Extrusion granulation affects the particle size of raw materials No special requirements, 1-4mm granular materials and fine powdery materials are available, unqualified powdery materials and powdery products are easy to use, and the use of powdery materials can reduce costs.
Processing technology of compound fertilizer produced by extrusion granulator:
The material is added from the hopper, after the roller extrusion molding, demoloming ball, and through the sub-chain, transferred to the crushing sieve studio, under the screen and separation of the finished product (ball) grain, and then return to the material and the new material mixed, and then granulation. With the continuous rotation of the motor and the continuous entry of materials, batch production can be realized.
The first stage: storage, measurement, and mixing of fertilizer raw materials
When compound fertilizer is produced, the batch mixing operation is generally used. The raw materials of each component in the formula are weighed in the weighing bin. After reaching the formula requirements, all are added to the batch mixer for mixing. A balance bin and balance bin are installed in the system. The other equipment after that is operated continuously. Trace elements can also be added to the mixer. In order to ensure the uniform distribution of trace elements, a high-strength mixer is used. After being lifted by the bucket elevator, the mixed material and the returned material are mixed with the returned material in the Double shaft mixer. The returned material is the unqualified particles after crushing and screening. The ratio of the recycled material to the new material is about 35:65 (production 1-4mm products).
The second stage: extrusion-granulation:
The mixed fertilizer mixture is extruded by a roller type extruder. The principle is to shape the material by extrusion. The mixture material is fed into the gap between the two counter-rotating rollers through a vertical screw feeder. During the extrusion process, the pressure on the material gradually increases. When the gap between the two shafts is very small, The pressure of the material is relatively large, and then gradually decreases until it reaches zero. In the extrusion process, the apparent density of the mixture can increase by 1.5-3 times due to the reduction of the empty volume of the material. The extruded product is generally a flat plate (large block) with a thickness of 5-20 mm. The structure and size of the roller extruder are determined by many parameters, which are generally determined according to the nature of the material and experiments.
The third stage: crushing, classification:
There is a specially designed plate crusher under the roll shaft extrusion granulator. The plates are pre-broken into several small fragments (flakes). The crushed raw materials are divided into large particles, product particles and fine particles on a multi-stage sieve. The fine particles will be recycled into the mixer, and then squeezed and pelletized again. The large particles retained in the upper layer of the multi-stage sieve need to be further crushed, sieved, and manufactured.
The fourth stage: polishing and finishing:
Under normal circumstances, the product needs to be polished and trimmed in one or two steps. Irregularly shaped particles are rounded at the edges and corners by a rounding roller. The fine powder produced in the polishing process passes through the sieving (a layer of screen) and then circulates. When trimming, generally add anti-caking agent. The product of the device is granular fertilizer (1-4mm) in the particle size range.