The core factors affecting the granulation effect of doubel roller press granulator can be divided into three categories: raw material characteristics, equipment parameters, and operating process.  Specifically:

1. Raw Material Characteristics

◦ Moisture Content: This is a key factor. The moisture content of organic fertilizer raw materials should be controlled at 20%-25%, and that of inorganic fertilizer raw materials at 2%-5%.  Excessive moisture can easily cause the material to stick to the rollers and deform the granules, while insufficient moisture results in a low molding rate and easily broken granules.

◦ Binding Properties: If the raw material itself lacks sufficient binding properties, an appropriate amount of binders such as bentonite and humic acid should be added to improve the stability of the granules after molding.

2. Equipment Parameters

◦ Roller Pressure: Too little pressure results in insufficient compaction of the raw material and easily loose granules; too much pressure increases energy consumption and may lead to excessively hard material sheets and uneven particle size after crushing.  The pressure usually needs to be adjusted to 8-15 MPa depending on the raw material.

◦ Roller Speed: Too fast a speed shortens the raw material extrusion time and reduces the molding quality; too slow a speed reduces production capacity.  It is generally controlled at 10-30 r/min and needs to be matched with the feeding speed.

◦ Roller Gap: Too large a gap prevents effective extrusion of the raw material, while too small a gap can easily cause wear and tear on the fertilizer making machine.  It needs to be adjusted to 0.5-2 mm according to the raw material particle size and the desired finished product particle size.

3. Operating Process

◦ Feeding Uniformity: Quantitative and uniform feeding ensures stable force on the rollers, avoiding fluctuations in particle size caused by uneven feeding.

◦ Crushing and Screening Accuracy: The speed of the crushing equipment and the mesh size of the screen need to match the requirements of the finished product. Incomplete screening will lead to a higher proportion of unqualified granules.