Organic fertilizer materials (such as animal manure, straw, humic acid, kitchen waste, etc.) are rich in organic matter and fiber, and have large fluctuations in humidity and viscosity. The granulation process is prone to problems such as "clumping, low balling rate, fragile particles, and adhesion to the cylinder wall". Targeted control is required from four key aspects: material pretreatment, equipment adaptation, process control, and post-treatment. The following are specific precautions:

1、 Material pretreatment: laying the foundation for granulation (core prerequisite)

The pain points of organic fertilizer granulation are mainly due to inadequate pre-treatment, and priority needs to be given to solving the problems of "humidity, particle size, impurities, and maturity" of the materials:

Strictly control the initial humidity to avoid being too wet or too dry

The optimal granulation humidity for organic fertilizer is 15% -20% (when held in the hand and dispersed on the ground):

If the humidity is greater than 25% (such as fresh chicken manure or newly fermented materials): it needs to be first reduced to below 20% through "extrusion dewatering machine" or "drying", otherwise it is easy to adhere to the cylinder wall during granulation, forming "large clumps" that block the discharge port, and the subsequent drying load will increase dramatically;

If the humidity is less than 12% (such as dried straw powder or aged organic fertilizer), it is necessary to use "atomized water+a small amount of decomposed liquid" to adjust the humidity (to avoid direct spraying of water causing local over wetting), and at the same time add 1% -2% starch or molasses (to enhance viscosity) to prevent loose and fragile particles.

Attention: Different raw materials have different humidity requirements - straw organic fertilizers (with more fiber) require slightly higher humidity (18% -20%), while livestock manure (with high viscosity) requires slightly lower humidity (15% -17%).

Grind to a reasonable particle size to avoid excessive fiber length or impurities

If the fibers (such as straw and rice husk) in organic fertilizer are too long (>5mm), they will wrap around the plate or discharge port of the granulator, causing poor material flow. A combination of "hammer crusher+screening machine" is needed to ensure that the particle size<2mm accounts for ≥ 80% and the fiber length is ≤ 3mm;

It is necessary to remove hard impurities (such as stones, metal blocks, and plastic sheets) from the material: a "magnetic separator (for metal removal)+vibrating screen (for stone/plastic removal)" can be installed after crushing to avoid impurities wearing down the cylinder wall and supporting wheels, or causing hard spots to mix into the particles, which affects product quality.

Ensure that the materials are fully decomposed and avoid secondary fermentation after granulation

Untreated organic fertilizers (such as fresh cow manure and raw kitchen waste) contain a large amount of easily decomposable organic matter. After granulation, they undergo "secondary fermentation" inside the particles, releasing gas that causes the particles to crack, pulverize, and even produce odors.

During pre-treatment, it is necessary to confirm the maturity: materials that have passed the maturity test should be dark brown, odorless, and have passed the "germination test" (watering seeds with material extract, germination rate ≥ 85%) to avoid rework after granulation due to incomplete maturity.