Core Principle: Dry Extrusion Granulation
Scale Types: Small, Medium, Large
Daily Production Capacity: 5-10 tons, 10-50 tons, 50-100 tons
Floor Area: 500-800㎡, 1000-2000㎡, 2500+㎡
Applications: Family farms, small cooperatives, large-scale livestock operations, large-scale fertilizer production bases, environmentally friendly sludge treatment, etc.
1. Vibrating Screen: Removes impurities from raw materials and screens particle size
2. Raw Material Pulverizer: Breaks up aggregated raw materials and refines particle size
3. Twin-Shaft Mixer: Mixes raw materials and auxiliary materials and adjusts humidity
4. Double-Roller Extrusion Granulator: Core granulation equipment, extrusion molding
5. Pellet Crusher: Breaks extruded flakes into granules
6. Grading Screen: Separates qualified granules, large granules, and fine powder
7. Finished Product Packaging Machine: Automatically measures and packages granules
The double-roll extrusion granulation line follows a process of "raw material pretreatment → mixing and homogenization → extrusion molding → crushing and screening → finished product packaging." The core granulation principle relies on the mechanical pressure of the double-roll extruder. The specific steps are as follows:
1. Raw material pretreatment: The dry powdered raw material is first screened to remove impurities. A pulverizer then crushes the raw material to 80-120 mesh to ensure uniform particle size and prevent interference with extrusion molding.
2. Mixing and homogenization: The pretreated raw material enters a twin-shaft mixer, where it is mixed with a small amount of auxiliary materials or a trace amount of binder to maintain a moisture content of 8%-12% and a mixing uniformity of ≥95%.
3. Extrusion molding: The homogenized raw material enters the double-roll extrusion granulator. Two counter-rotating rollers within the machine apply pressure through a hydraulic system to extrude the raw material into a granule with a thickness of 2-5mm. For flaky materials, the roller surface can be engraved with grooves of varying shapes to determine the final shape of the pellets.
4. Crushing and Screening: Flaky materials are first crushed into irregular particles by a crusher, then passed through a grading and screening machine to separate qualified particles. Large particles on the sieve are returned to the crusher for secondary crushing, while fine particles below the sieve are returned to the mixing stage, achieving a raw material utilization rate of ≥98%.
5. Finished Product Processing: Qualified pellets that require further stability can be dried in a low-temperature dryer (40-60°C) to remove trace moisture. Finally, they are packaged in a finished product packaging machine (25-50kg/bag).
Advantages of the double-roller granulation line:
1. No drying required, energy-saving and cost-saving:
No water is added during the granulation process, resulting in a low moisture content in the finished product. This eliminates the need for drying, significantly reducing energy consumption and equipment investment costs.
2. Wide range of raw material compatibility:
It can process organic, inorganic, and compound fertilizers, and is particularly suitable for high-fiber, high-nitrogen, phosphorus, and potassium raw materials, with minimal clogging.
3. High pellet strength:
The roller-forming principle ensures high pellet density, making it resistant to breakage and durable in storage and transportation, reducing transport losses.
4. Environmentally friendly and pollution-free:
No dust or wastewater discharge, ensuring a clean production environment that meets environmental requirements and is suitable for a variety of compliant production scenarios.
Model | Power (KW) | Granule Diameter (mm) | Roller Sheet Size (mm) | Dimensions (mm) |
ASLDG - 1T | 15 | 3-10 | 150*220 | 1450*800*1450 |
ASLDG - 1.5T | 18.5 | 3-10 | 150*300 | 1450*850*1500 |
ASLDG - 2T | 22 | 3-10 | 185*300 | 1630*850*1650 |
What raw materials are suitable for processing on a double-roller granulation line? What is the required moisture content?
Double-roller granulation lines primarily offer dry granulation and are compatible with a wide range of raw materials, covering three core categories:
① Fertilizers: compound fertilizers, organic fertilizer powders, biofertilizers, and slow-release fertilizers;
② Chemicals: chemical powders such as ammonium chloride, potassium chloride, potassium sulfate, soda ash, and baking soda;
③ Minerals: mineral powders such as limestone powder, dolomite powder, and fluorite powder.
The moisture content of the raw materials must be strictly controlled between 8% and 15%. Too high a moisture content can easily cause sticking to the rollers and agglomeration, while too low a moisture content can increase fines and reduce the pelletizing rate.
What pelletizing rate can the line achieve? Does pellet strength meet industry standards?
With uniform raw material particle size and optimal extrusion parameters, the pelletizing rate of a double-roller granulation line can reach 92%-98%. The pellet strength is typically 15-30N, far exceeding national standards:
① Compound fertilizer: Pellet compressive strength ≥ 15N;
② Organic fertilizer: Pellet compressive strength ≥ 10N;
Even during long-distance transportation or stacked storage, the pellet breakage rate is kept below 3%.
Is it necessary to add a binder during production? What is the appropriate addition ratio?
Most raw materials do not require a binder; a small amount is only required in special cases:
① No binder required: Raw materials with a certain degree of viscosity, such as compound fertilizer, potassium chloride, and limestone powder, can be formed by extrusion pressure.
② No binder required: Organic dry powder and light mineral powder require a 0.5%-2% binder, primarily to prevent sticking to the rollers and improve pellet stability, thereby avoiding excessive costs.
Can the pellet size and shape of the production line be adjusted? What custom specifications are available?
Particle size and shape can be flexibly adjusted:
① Size Adjustment: This is achieved by replacing the screen mesh of the grading and screening machine. Conventional granules can be produced in the 2-8mm range (e.g., 2-4mm is common for compound fertilizers, and 3-5mm is common for organic fertilizers). Custom sizes of 1-2mm (for trace fertilizers) or 8-12mm (for slow-release fertilizers) can be customized for specific needs.
② Shape Adjustment: This is achieved by replacing the rollers of the double-roll extruder. The roller surface can be engraved with circular, square, strip, or oval grooves, with circular shapes being the most common (accounting for over 80%), facilitating subsequent packaging and fertilization.
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