Ring die granulator
The ring die granulator is a widely used pelletizing machine. It utilizes a mechanical extrusion granulation process and holds a significant position in the pellet production market due to its high efficiency and stable performance. Its core operating principle is to feed pre-treated material between a ring die and a pressure roller. The pressure roller rotates under power, exerting a force on the material, forcing it through the die holes in the ring die to form columnar pellets. This is then cut into pellets of a predetermined length by a cutting device.
This granulation method eliminates the need for complex drying processes and effectively preserves the nutrients and active ingredients in the material while ensuring pellet quality. Compared to other granulation equipment, the ring die granulator offers high production efficiency, with a single machine output of several to tens of tons. The pellets produced are dense and strong, making them suitable for large-scale industrial production.

Where are ring die granulators commonly used?
Ring die granulator is widely used in many industries due to its excellent performance and wide adaptability. The specific application scenarios are as follows:
Fertilizer field
It can produce various organic fertilizers, inorganic compound fertilizers, bio-organic fertilizers, etc. It can ferment organic waste such as livestock and poultry manure and crop straw into granular fertilizers, solving the problems of inconvenient transportation and easy agglomeration of organic fertilizers.
It can also be used to produce special fertilizers such as slow-release fertilizers and controlled-release fertilizers. By adjusting the raw material formula and granulation process parameters, the precise release of fertilizer nutrients can be achieved to meet the nutrient needs of different crops at different growth stages.
Other industrial fields
Feed industry: It is a key equipment for producing pellet feed for livestock, poultry, aquatic products, etc. It can mix corn, soybean meal, bran and other raw materials according to the formula and then granulate them, thereby improving the digestibility and absorption rate of feed, reducing feed waste, and pellet feed is easy to store and transport.
Biomass energy industry: Biomass raw materials such as wood chips, straw, and rice husks can be made into high-density pellet fuel. This fuel has high combustion efficiency and low pollution, and can replace traditional coal in industrial boilers, home heating and other fields.
Chemical industry: Suitable for granulation of chemical raw materials such as catalysts, pigments, detergents, etc. Granulation can make these chemical products have better fluidity, stability and performance.
Forestry industry: Wood processing waste can be made into wood pellets for the production of artificial boards, activated carbon and other products, thus realizing the recycling of resources.

How is the ring die granulator designed according to the pelletizing process?
The structural design of the ring die granulator is closely integrated with the pelletizing process. Each component works together to achieve efficient pelletizing. Its main components and functions are as follows:
Feeding device
It consists of a hopper, a screw conveyor and a conditioner. The hopper is used to temporarily store the material to be granulated. Its capacity depends on the production scale and is generally 1-10 cubic meters.
A screw conveyor transports the material from the hopper to the conditioner. The conveying speed is adjustable by a variable frequency motor to ensure uniform and stable feeding. The conditioner conditions the material by introducing steam or adding moisture or binders, bringing it to an appropriate humidity and temperature, improving its plasticity and cohesiveness for subsequent granulation.
Ring die
It is the core component of the ring die granulator. It is forged with high-strength alloy steel. After heat treatment, the surface hardness can reach HRC55-65, and it has extremely high wear resistance and pressure resistance.
The ring die is cylindrical in shape, with numerous holes evenly distributed along its inner wall. The hole diameter typically ranges from 2 to 20 mm, and can be selected based on the desired pellet size. The hole arrangement and aperture ratio are optimized to ensure uniform force distribution across the material, improving pelletizing efficiency and pellet quality.
pressure roller
There are usually 2-3 rollers evenly distributed inside the ring die, made of wear-resistant cast iron or alloy steel. The surface of the roller is usually processed with special patterns or grooves to increase friction with the material, prevent the material from slipping, and ensure that the material can be smoothly brought into the space between the ring die and the roller for extrusion.
The gap between the pressing roller and the ring die can be precisely adjusted through the adjusting device to meet the granulation requirements of different materials.
Cutting device
It consists of blades and a drive mechanism and is installed on the outside of the ring die. The blades are made of high-speed steel or alloy tool steel, which is sharp and wear-resistant.
By adjusting the position and rotation speed of the blade, the length of the particles can be precisely controlled to meet the specification requirements of different products.
Drivetrain
It consists of a motor, a reducer, a coupling, etc. The motor provides power, and the power depends on the equipment model and production capacity, generally 15-160kW.
The reducer converts the high-speed rotation of the motor into low-speed rotation of the ring die or roller. This power is then transferred to the working parts through the coupling, ensuring coordinated operation of all parts of the equipment. Some equipment uses a variable frequency speed control system, which allows for flexible adjustment of the ring die speed to suit the pelletizing characteristics of different materials.

How does the ring die granulator make fertilizer?
The process of making fertilizers with ring die granulator is rigorous and orderly. Each link has an important impact on the quality of the final product. The specific steps are as follows:
Raw material pretreatment
For organic fertilizer raw materials, they must first be fermented and decomposed. The fermented materials are crushed and sieved to make the particle size reach 60-100 mesh to ensure the granulation effect.
For compound fertilizers, basic fertilizers such as nitrogen, phosphorus, and potassium should be accurately measured according to the formula ratio and then mixed. The mixing uniformity should reach more than 90%, and the moisture content of the mixed materials should be controlled between 8% and 15%.
Quenching and tempering treatment
The pretreated material enters the conditioner, where an appropriate amount of steam (or water or binder) is introduced according to the material characteristics to raise the material temperature to 60-80°C and adjust the moisture content to 12%-18%. The conditioning makes the material soft and sticky, making it easier to extrusion and granulation.
Extrusion granulation
The quenched and tempered material enters between the ring die and the pressure roller. The pressure roller rotates under the drive of the transmission system, exerting a strong extrusion force (generally 20-50MPa) on the material, so that the material overcomes the resistance of the ring die hole and is squeezed into columnar particles and squeezed out of the die hole.
Cutting and cooling
The cylindrical particles extruded from the die hole are cut into particles of a set length (usually 2-10 mm) by the cutting device outside the ring die.
The temperature of the pellets after cutting is high and they need to enter cooling equipment (such as cooling fans, cooling cylinders) for cooling to reduce the pellet temperature to room temperature to prevent the pellets from agglomerating and deteriorating.
Screening and packaging
The cooled particles are screened by screening equipment to separate unqualified particles (too large, too small or broken particles), and the unqualified particles are returned for re-granulation.
Qualified granular fertilizers are packaged after being measured. The packaging materials can be woven bags, plastic bags, etc., which are convenient for storage and transportation.

What are the characteristics and advantages of ring die granulator in fertilizer production?
Compared with other granulation equipment, the ring die granulator has the following advantages when producing fertilizers:
High production efficiency
The ring die granulator adopts a continuous production method with high output per machine, ranging from a few tons to dozens of tons, which can meet the needs of large-scale industrial production and greatly improve production efficiency.
Excellent particle quality
The fertilizer particles produced have high density and strength, generally reaching 25-60N. The particles have regular shape, smooth surface and high uniformity. They are not easy to break or clump during storage, transportation and use, and have good fluidity.
Wide adaptability of raw materials
It can process various fertilizer raw materials, whether organic, inorganic or a mixture of the two, and can achieve good granulation results. It also has strong adaptability to raw materials containing a certain amount of fiber and moisture.
High degree of automation
Equipped with a complete automatic control system, it can accurately control the feed rate, tempering parameters, ring die speed, cutting length, etc., to achieve automated production, reduce manual intervention, and improve production stability and product quality consistency.
Easy operation and maintenance
The equipment has a rational structure design and a simple and easy-to-understand operation interface, allowing operators to take up their posts after simple training. Wearing parts are easy to replace, and daily maintenance workload is minimal, effectively reducing production management costs.

What are the benefits of using a ring die granulator to make fertilizer?
Using a ring die granulator to make fertilizer has many significant benefits, as follows:
Improve fertilizer utilization efficiency
The granular fertilizer produced has uniform nutrient distribution and can slowly release nutrients in the soil, avoiding the problem of rapid nutrient loss in traditional powdered fertilizers. It increases fertilizer utilization rate by 20%-30%, which is beneficial for crops to continuously absorb nutrients and promote crop growth.
Easy to scale production and application
Ring die granulators have high production efficiency and are suitable for large-scale fertilizer production, meeting the large demand for fertilizer in agricultural production. At the same time, granular fertilizers facilitate mechanized fertilization, which can improve fertilization efficiency, reduce labor intensity, and meet the requirements of large-scale development of modern agriculture.
Improved fertilizer storage and transportation performance
Granular fertilizers have high density and small size, requiring minimal storage space. They are also less prone to moisture absorption and agglomeration, offering excellent storage stability and can be stored for 10-18 months in dry, ventilated conditions. They also experience minimal loss during transportation, reducing transportation costs by 30%-40% compared to powdered fertilizers.
Promoting sustainable agricultural development
The ring die granulator converts agricultural organic waste into organic granular fertilizer, realizing the resource utilization of waste and reducing environmental pollution. The produced organic fertilizer can improve soil structure and soil fertility, which is conducive to the development of ecological agriculture and sustainable agriculture.
Meet diverse fertilization needs
Fertilizer formulas and particle specifications can be flexibly adjusted according to different soil types, crop varieties and planting patterns to produce a variety of special fertilizers, such as special fertilizers for field crops and special fertilizers for cash crops, to meet the fertilization needs of different agricultural production scenarios.

How to properly perform regular maintenance on the ring die granulator?
In order to ensure the normal operation of the ring die granulator and extend the service life of the equipment, the following regular maintenance work must be done:
Regular inspection of components
Before starting the machine every day, check whether the feeding device is unobstructed and whether there is any material blockage; check whether the gap between the ring die and the pressure roller is appropriate (generally 0.1-0.3 mm); check whether the transmission system, cutting device, etc. are normal and whether there is any abnormal noise.
Check the ring die holes for blockage, wear or deformation every week. If the die holes are severely blocked, use special tools to clean them. Check the surface wear of the pressure wheel and repair or replace it in time if obvious wear is found. Check the sharpness of the blade and grind or replace it if necessary.
Check the bolts at each connection every month to see if they are loose, and tighten them in time if found loose; check the operating temperature (normal temperature does not exceed 75℃) and vibration of the motor and reducer to ensure stable operation of the equipment.
Conduct a comprehensive inspection of the equipment every quarter, including the tightness of the drive belt or chain, the meshing condition of the gears, the lubrication condition of the bearings, etc., and replace severely worn parts in a timely manner.
Keep your equipment clean
After each production run, promptly clean any remaining material inside the equipment, especially in the ring die, rollers, and feed channel, to prevent it from agglomerating and hardening, which could affect the next run. This can be done by blowing with compressed air or flushing with a high-pressure water jet (for parts that can be washed with water).
Regularly clean the dust, oil, etc. on the external surface of the equipment to keep the equipment clean and tidy, so as to facilitate observation of the equipment's operating status and timely detection of potential faults.
Lubrication maintenance
Regularly add lubricating oil or grease to each transmission component according to the equipment manual. Replace the gear oil of the reducer every 1000-1500 hours of operation; add grease to bearings, chains, and other parts every 500-800 hours of operation.
When adding lubricating oil (grease), choose the appropriate model and specification to ensure the appropriate amount of filling to avoid increased wear of components due to poor lubrication.

Maintenance of ring die and pressure roller
After a period of use, if the die hole is severely worn or cracked, the ring die should be replaced in time. During use, avoid metal foreign matter from entering between the ring die and the pressure roller to prevent damage to the ring die.
When the roller surface is worn, it can be repaired or replaced to ensure the extrusion effect on the material. Regularly check the operating condition of the roller bearings. If abnormal noise or excessive temperature is found, replace the bearings in time.
Transmission system maintenance
Regularly check the tension of the transmission belt. Too loose or too tight will affect the transmission efficiency and equipment life, and should be adjusted in time. For chain transmission, regularly clean the oil and debris on the chain, and add chain oil to ensure smooth chain transmission.
Check the meshing clearance and wear of the gears. If the wear is severe or the meshing is poor, the gears should be adjusted or replaced in time to prevent unstable operation of the equipment.