I. Raw Material Suitability

Q1: Which organic fertilizer raw materials are suitable for disc granulator machine?

A: Livestock and poultry manures (composted chicken, cattle, sheep, and pig manure); fermented straw, mushroom residue, traditional Chinese medicine residue, oilseed cake/meal, humic acid, and peat soil. It can also be combined with inorganic powders like monoammonium phosphate (MAP) and potassium sulfate to produce organic-inorganic compound fertilizers. Provided the raw materials are pulverized to the required fineness and moisture levels are adjusted, they can all be granulated into smooth, round pellets.

Q2: What are the moisture requirements for the raw materials?

A: The optimal moisture content is between 25% and 35%. A small amount of water or binder is used to facilitate the agglomeration of powder into pellets. If moisture is too low, pellet formation is difficult; if too high, the material tends to stick to the disc or form large mud clumps.

Q3: Can pure straw or sawdust be granulated directly in the disc granulator?

A: Using them alone is not recommended. Materials consisting purely of coarse fibers have very low adhesiveness and are difficult to agglomerate; they should be mixed with adhesive additives—such as livestock manure, humic acid, or bentonite—before granulation.

Q4: Can disc granulation be used to produce bio-organic fertilizers with high viable bacteria counts?

A: Granulation is possible, but the disc method is a wet process requiring subsequent drying equipment. High-temperature drying can kill a large number of beneficial bacteria; therefore, if the product's main selling point is high viable bacteria content, dry-method roller extrusion granulation is recommended.

II. Additives and Binders

Q5: Is a binder required for disc granulation? What additives are commonly used?

A: For materials with poor adhesiveness, it is recommended to add bentonite, humic acid, or kaolin as binding carriers to improve the pelletization rate and granule strength. Composted manure is naturally adhesive and can form pellets with just a light water spray, so little to no binder is needed.

Q6: Can NPK powders be added to the mix for granulation?

A: Yes, absolutely. Thoroughly mix decomposed organic matter with urea, monoammonium phosphate (MAP), potash fertilizer, and medium/trace elements; add water and process using a disc granulator to produce spherical organic-inorganic compound granules.

III. Restricted or Unsuitable Raw Materials

Q7: Which raw materials are unsuitable for disc granulators?

A: 1. Dry powders with a moisture content below 20% cannot agglomerate into spheres; 2. Pure urea powder with high salt content and extreme hygroscopicity tends to stick to the disc and form clumps; 3. Large, uncrushed chunks of raw manure or hard, caked materials result in uneven granule sizes; 4. High-oil, highly viscous fermentation residues stick persistently to the disc and are difficult to clean.

Q8: Can wet, slurry-like manure with a moisture content exceeding 38% be processed via disc granulation?

A: No. Materials with excessive moisture stick to the bottom and sides of the disc and fail to roll into uniform granules; they must first be air-dried or mixed with dry materials to reduce moisture content before processing.

IV. Raw Material Pre-treatment

Q9: What pre-treatment is required for raw materials before granulation?

A: First, ensure full decomposition; then, crush the material using a semi-wet material crusher and screen out large impurities. Mix in adhesive additives according to the required ratio, adjust the moisture content to the standard range, and finally feed the mixture into the disc granulator.

Q10: Are there requirements for the fineness of raw materials?

A: Ideally, raw materials should be crushed into a fine powder of 0.3–0.8 mm. The finer the powder, the smoother the spheres and the higher the formation rate; coarse particles result in uneven, fragile granules.

V. Finished Product Quality Based on Raw Materials

Q11: How effective is granulation using only humic acid?

A: Humic acid is naturally adhesive, resulting in excellent granulation performance—rapid sphere formation and high granule strength. It is a high-quality additive for disc granulation and is frequently used in combination with manure.

Q12: Is fermented sludge suitable for disc granulation?

A: Stabilized sludge can be granulated; however, sludge viscosity varies significantly. If viscosity is insufficient, additional bentonite is required. At the same time, moisture content must be strictly controlled to prevent persistent sticking to the granulator pan.