BB fertilizer (mixed fertilizer) is also divided into several different types, so the raw materials used for BB fertilizer vary according to different types of fertilizers, mainly including the following:

　　Elemental fertilizer:

　　Nitrogen sources: urea, ammonium nitrate, ammonium sulfate, etc. Urea is the most commonly used nitrogen source due to its high nitrogen content, moderate price, and easy solubility in water.

　　Phosphorus sources: monoammonium phosphate (MAP), diammonium phosphate (DAP), superphosphate, etc. Monoammonium phosphate and diammonium phosphate are widely used due to their high phosphorus content and good solubility.

　　Potassium sources: potassium chloride, potassium sulfate, etc. Potassium chloride has become the main source of potassium due to its high potassium content and low price, while potassium sulfate is suitable for crops sensitive to chlorine.

　　Compound fertilizer:

　　Compound fertilizers such as potassium dihydrogen phosphate and potassium nitrate can be used as raw materials for BB fertilizers, providing a variety of nutrients. These fertilizers usually have a fixed nutrient ratio, which can simplify formula design.

　　Trace element particles:

　　Borax, zinc sulfate, manganese sulfate, copper sulfate, etc. are used to supplement the trace elements required by crops and improve the overall nutritional value of fertilizers.

　　Functional additives:

　　Anti caking agent: prevents fertilizer particles from clumping during storage and transportation, maintaining the looseness of the fertilizer.

　　Slow release coating material: such as green bio based biodegradable coating, used to control the release rate of nutrients and extend the fertilizer efficiency period.

　　Enhancers: such as humic acid enhancers, can improve fertilizer utilization and enhance crop stress resistance.

　　Other auxiliary materials:

　　Filler: such as crushed limestone, used to adjust the particle size and specific gravity of fertilizers and improve physical properties.

　　Coloring agent: used to distinguish different formulas or brands of fertilizers for easy identification and use.

　　Key requirements for raw material selection:

　　Particle size similarity: The particle size of the raw materials should be similar (usually 2-4mm) to ensure mixing uniformity and storage stability.

　　High particle strength: Raw material particles should have high hardness to avoid breakage during mixing, transportation, and application.

　　Dry without clumping: The raw materials should be kept dry to prevent clumping from affecting the mixing effect and fertilizer quality.

　　Characteristics of raw materials for BB fertilizer production:

　　Flexible formula: The types and proportions of raw materials can be adjusted according to different crops, soil, and climate conditions to produce specialized fertilizers.

　　Nutrients are comprehensive: By adding various elemental fertilizers, compound fertilizers, and trace elements, crops can meet their needs for multiple nutrients.

　　Simple process: using mechanical mixing technology, no complex chemical reactions are required, high production efficiency, and low cost.