Fertilizer category
Fertilizer types can be broadly divided into two types: inorganic fertilizers and organic fertilizers.
Common chemical fertilizers include elemental nitrogen fertilizers, phosphate fertilizers and potash fertilizers, two-element compound fertilizers, three-element compound fertilizers and multi-element compound fertilizers, as well as organic-inorganic compound fertilizers.
Inorganic fertilizers are chemical fertilizers, such as various nitrogen, phosphorus, potash fertilizers or compound fertilizers. Chemical fertilizers commonly used in the planting industry include: diammonium phosphate, urea, potassium sulfate, potassium chloride, and various compound fertilizers. Long-acting fertilizers such as superphosphate can also be used on fruit tree
(1) Nitrogen fertilizer. That is, chemical fertilizers with nitrogen nutrients as the main component, such as urea, ammonium bicarbonate, etc. (2) Phosphate fertilizer. That is, chemical fertilizers with phosphorus nutrients as the main component, such as superphosphate. (3) Potassium fertilizer. That is, chemical fertilizers with potassium nutrients as the main component. The main varieties include potassium chloride, potassium sulfate, etc. (4) Compound fertilizer. That is, the fertilizer containing two of the three elements of nitrogen, phosphorus and potassium is called binary compound fertilizer, and the compound fertilizer containing the three elements of nitrogen, phosphorus and potassium is called ternary compound fertilizer. (5) Trace element fertilizers and some medium element fertilizers: the former such as fertilizers containing trace elements such as boron, zinc, iron, molybdenum, manganese, copper, etc., and the latter such as calcium, magnesium, sulfur and other fertilizers. (6) Fertilizers that are beneficial to certain crops: such as steel slag silicon fertilizer applied to rice.
Fertilizer granulation method
1. Stirring granulation method
Stirring granulation is to infiltrate a certain liquid or binder into solid fine powder and stir it appropriately so that the liquid and solid fine powder are in close contact with each other to generate cohesive force to form pellets. The most commonly used mixing method is through the turning, rolling and curtain-type falling motion of a disc, conical or cylindrical drum during rotation. According to the molding method, it can be divided into rolling pellets, mixed pellets and powder agglomeration. Typical equipment includes granulating drums, swash plate granulators, cone drum granulators, disc granulators, drum granulators, kneaders, drum mixers, powder blenders ((hammer, vertical shaft) (type, belt type), falling pellet machine, etc. The advantages of the stirring method are that the molding equipment has a simple structure, the single machine has a large output, and the particles formed are easy to dissolve quickly and have strong wettability. The disadvantage is that the uniformity of the particles is poor, and the resulting The particle strength is low. At present, the processing capacity of this type of equipment can reach up to 500 tons/hour, and the particle diameter can reach up to 600 mm. It is mostly suitable for mineral processing, fertilizers, fine chemicals, food and other fields.
2. Boiling granulation method
The boiling granulation method is the most efficient among several methods. The principle is to use the wind blown from the bottom of the equipment to float the powder particles into full contact with the slurry sprayed from the upper spray gun and then collide with each other to combine into particles. The particles produced by this method are relatively loose, with poor true sphericity and surface finish. They are suitable for manufacturing particles with low requirements or for pre-processing of other preparations. This method is to configure a small-diameter core cylinder or isolation cylinder in the center of the lower part of the boiling granulation cylinder, and distribute the ventilation area of the hot air ventilation orifice plate at the bottom to be larger in the center and smaller on the surrounding sides, resulting in a state where the hot air flow rate in the center is greater than the surrounding areas. Under the influence of different wind forces, the particles float up from the middle of the core tube and come into contact with the adhesive sprayed from the spray gun installed in the center of the bottom. They are then bonded with the powder falling from the upper part and then settle from the outside of the core tube to form a particle structure. It circulates up and down to achieve the purpose of making the particles grow evenly.
3. Extrusion granulation method
Extrusion method is currently the main method of pressure forming granulation in my country’s powder industry. Extrusion granulation equipment can be divided into vacuum rod granulators, single (double) screw extrusion granulators, model stamping machines, plunger extruders, roller extruders, and counter mixers according to their working principles and structures. Gear granulator, etc. This type of equipment can be widely used in petrochemical industry, organic chemical industry, fine chemical industry, medicine, food, feed, fertilizer and other fields. This method has the advantages of strong adaptability, large output, uniform particle size, good particle strength, and high granulation rate.