What are the npk compound fertilizer additives used during the production process?
When the raw materials for compound fertilizer granulation are not viscous enough, or the ingredients of the compound fertilizer lack some trace elements, or when the compound fertilizer needs to achieve specific functions, then additives, binders, pesticides, etc. are needed in the compound fertilizer. In this article we will introduce the ingredients, functions and types of these additives and some operating specifications that need attention.
What is the binder of compound fertilizer additive for manufacturing?
- The granulation method of compound fertilizer must have a binder. When there is a sufficiently viscous “plastic raw material” in the ingredients (such as ammonium phosphate, ordinary calcium phosphate, etc.), the “plastic raw material” is the binder during granulation, but it must be carried out with water or steam. Spray, so that the “plastic raw material” contacts the water mist to form a viscous solution, and other dry powders are pelletized. Or use a slurry of a certain raw material and then spray it to dissolve the “plastic raw material” in the water of the mist, and aggregate other dry powders into granules;
- When the ingredients are all composed of non-viscous or weakly viscous substances, the binder used for granulation can be divided into two situations:
- One is the case where the required amount of filler for granulation can be added after the ingredients are calculated. The filler should be a non-toxic and highly viscous “plastic substance” containing effective nutrients as both a filler and a binder. Agents (such as attapulgite powder, bentonite, etc.
- Another situation is that when it is not possible to add a “plastic substance” with strong viscosity as a filler, a solution with a strong viscosity is generally used for materialization (such as caprolactam or ammonium sulfate mother liquor, a by-product in sulfuric acid production, or ammonium sulfate mother liquor discharged from the paper industry Solution after sewage treatment, etc.), or acids and alkalis that can undergo rapid chemical reactions (such as urea-calcium magnesium phosphate fertilizer-potassium chloride series, using 25% to 45% sulfuric acid or 25% to 45% P2O5 wet method Phosphoric acid). In this way, the crushing strength of its products can meet the requirements of GB15063-94 standard.
What is the coating agent of compound fertilizer production additive?
- The absorption of nutrients by crops is a very complex process. It actively absorbs ionic nutrients into the root cell wall, the cell-cell gap, and the wall-membrane space, and enters the cell through the selective permeability of the cell membrane for assimilation and utilization.The amount and proportion of nutrients required by crops at different growth stages are not exactly the same.
- In order to make the amount of effective nutrients dissolved and released in the compound fertilizer basically consistent with the amount absorbed by the crops in each growth period, reduce dissolution, release, and loss, and improve the utilization rate of nutrients, film technology needs to be used.
- Use a coating agent to coat the surface of the compound fertilizer particles with a thin layer to slowly release the nutrients in the compound fertilizer. Adjusting the coating thickness of the compound fertilizer and selecting different coating agents can control its effective nutrient release rate.
- Coating agents generally used as compound fertilizer coatings should be water-insoluble or water-insoluble substances that can be dissociated in alkaline, acidic or soil environments with enzymes secreted by crop roots, and can be absorbed or assimilated by crops. It would be more suitable if it can also contain the nutrients needed by crops.
Commonly used coating materials include sulfur, calcium magnesium phosphate fertilizer, paraffin, asphalt, resin, organic slow-release nitrogen fertilizer and polyolefin coating.
What is the filler of raw materials for compound fertilizer production?
Filling agents such as phosphogypsum, attapulgite powder, zeolite powder, fly ash, pyrite slag ash, yellow phosphorus slag, etc. are often added to the ingredients for compound fertilizer production to achieve a balance of ingredients and prevent excessive quality of effective nutrients in the product.
What are pesticides as raw materials additive for compound fertilizer production?
- During the growth and development of crops, weeds will rob effective nutrients, and pests and diseases will damage the crops. In severe cases, they will cause no harvest. One of the measures to maintain normal crop growth is to use pesticides to kill insects and weeds and make compound fertilizers.
- Any pesticide that can be made into poisonous soil and applied to the soil to kill insects and weeds and maintain normal growth of crops can be made into compound fertilizer and applied to the soil to play a preventive role. The prepared medicinal fertilizer must be tested jointly by the agricultural department and the pesticide research department and passed the identification before it can be promoted.
What are the disadvantages of compound pesticides and why excessive use is not recommended?
- There are still varying degrees of pollution to agricultural products, soil and waters;
- Killed species of pests will gradually become resistant to pesticides
- The natural enemies of the killed pests will also be killed.
Conclusion: why excessive use of pesticides in compound fertilizer is not recommended?
When applying additives, binders, pesticides, etc. in compound fertilizers, we must not only consider whether they are “beneficial and harmless” themselves, but also whether they will react chemically with other substances after being added, and whether they will have a negative or complementary effect. It is necessary to strictly prevent the introduction or production of substances harmful to crops, soil, and the environment, or the “degradation” and loss of original nutrients, as well as the deterioration of compound fertilizer materials and the deterioration of the operating environment.
