Small pellets, big impact: The evolution of organic fertilizer through granulation

In organic fertilizer production, granulation is more than just a cosmetic enhancement. Its primary purpose lies in practicality. Powdered organic fertilizers have a low density and are bulky, taking up a lot of space during storage and transportation. They are also prone to generating dust, leading to nutrient loss and environmental pollution. Granulation compacts the material, significantly reducing its volume, making long-distance transportation and economical storage possible.

More importantly, granulation profoundly impacts the ease and efficiency of fertilization. Uniform granules facilitate mechanized spreading, adapting to the operational needs of modern large-scale farms. Furthermore, their compact structure regulates the release rate of nutrients into the soil, preventing rapid decomposition and providing a more stable and long-lasting nutritional supply for crops.

So, how are various agricultural and forestry wastes transformed into uniform granules? Currently, mainstream granulation processes, such as disc granulators and double roller press granulators, each have their own advantages.

The advancement of granulation technology, from dusty powder fertilizer to uniform, uniform granules, is a significant step toward the modernization and standardization of traditional organic fertilizers. It has transformed organic fertilizer from a traditional “homegrown” method into a standardized commodity that can be integrated into modern agricultural production systems. These tiny granules embody the industry’s unwavering pursuit of efficiency, environmental protection, and practicality.

Rotary drum granulator: The core “Shaping” equipment in fertilizer production

In fertilizer processing, the rotary drum granulator is a key piece of equipment for converting powder into granules. Its stable performance makes it a common choice for most fertilizer production scenarios.

Structurally, the core of a rotary drum granulator consists of an inclined drum, a drive system, a spray device, and a heating and insulation layer. The drum’s tilt angle can be adjusted based on the characteristics of the raw material, typically controlled at 3°-5°. This ensures adequate tumbling of the raw material while preventing the granules from clumping due to prolonged dwell time. The drive system drives the drum at a constant speed of 10-20 rpm via gears or belts, ensuring a stable and controllable granulation process.

During operation, mixed fertilizer raw materials enter the drum through the feed inlet. As the drum rotates, the raw materials continuously tumble and collide within the drum. Simultaneously, a spray device applies an appropriate amount of binder to the raw materials, gradually agglomerating them into small granules. The heating and insulation layer maintains the temperature inside the drum within an optimal range, helping the granules quickly solidify and form. Finally, the formed fertilizer granules are discharged from the discharge port and enter the subsequent screening and cooling stages.

This rotary drum granulator’s advantage lies in its wide adaptability. Whether it’s nitrogen-phosphorus-potassium compound fertilizer, organic fertilizer, or biological fertilizer, efficient granulation can be achieved by adjusting parameters. The highly uniform granulation and moderate granule strength facilitate subsequent storage and transportation, providing equipment support for the large-scale advancement of fertilizer production.

BB fertilizer mixers: Key equipment for ensuring uniform nutrient distribution in blended fertilizers

In BB fertilizer (blended fertilizer) production, the BB fertilizer mixer is a key piece of equipment that determines product quality. Its core function is to evenly blend multiple raw materials of varying density and particle size into a nutrient-consistent fertilizer, directly impacting subsequent fertilization effectiveness.

In terms of equipment structure, mainstream BB fertilizer mixers mostly adopt a closed-cylinder design with an internal mixing assembly. The cylinder is typically positioned horizontally, with the mixing assembly driven by a motor. Some BB fertilizer mixers also feature forward and reverse rotation to reduce residual material in the cylinder. The feed inlet is typically located at the top of the cylinder, and the discharge outlet at the bottom. Some models feature an observation window for easily monitoring the mixing status.

During operation, raw materials such as urea, monoammonium phosphate, and potassium chloride are introduced into the mixing cylinder according to the formulated ratio. The rotating mixing assembly propels the raw materials: the screw conveys the raw materials from both ends toward the center, the paddles shear and stir the raw materials, and the guide plates facilitate convection, ensuring full contact between raw materials with density differences of 30%-50%. The entire process does not require the addition of adhesives, and mechanical force is used to achieve “small particles filling gaps and large particles colliding with each other”, ultimately achieving a uniform mixing effect.

Fertilizer granulators: How to adapt to the special production requirements of functional fertilizers?

As the fertilizer industry upgrades toward “precision and functionalization,” demand for functional fertilizers such as slow-release fertilizers, biofertilizers, and trace element compound fertilizers has surged. The production of these fertilizers places special demands on granulators, balancing functional retention and granule formation.

For slow-release fertilizer production, fertilizer granulators must meet the dual requirements of “granule formation” and subsequent coating. For example, when producing sulfur-coated slow-release fertilizers, the granulation process requires producing base granules with a smooth surface and uniform hardness. The “rolling forming” feature of a rotary drum granulator is perfectly suited for this purpose. By controlling the drum speed (8-12 rpm) and the amount of binder used, the granules are naturally rounded and smooth. Some granulators also feature a “pre-cooling section” at the discharge port to reduce the granule temperature to below 30°C, paving the way for subsequent coating and preventing the coating material from melting and becoming ineffective due to high temperatures.

For compound fertilizers containing trace elements, fertilizer granulators must address the issue of uneven trace element distribution. These fertilizers contain low concentrations of trace elements such as zinc, boron, and iron. Inhomogeneous mixing can lead to nutrient deficiencies in some granules. In this case, the low-speed extrusion design of a flat die granulator is optimal. After thoroughly mixing the trace elements with the base raw materials in a twin-shaft premixer, the low-speed rollers slowly extrude the granules into shape, minimizing material separation and ensuring a trace element content variation of ≤0.1% per granule, thus preventing functional deficiencies.

For biofertilizers, the granulator’s low-temperature performance is crucial. Flat die and disc granulators utilize a low-friction, no-high-temperature extrusion design to maintain a temperature within the granulation chamber below 40°C, ensuring the survival rate of the microbial inoculant.

Fertilizer granulators contribute to efficient agricultural development

With the agriculture and fertilizer industries deeply intertwined, fertilizer form directly impacts fertilization effectiveness and industry efficiency. As the core equipment connecting fertilizer raw materials and finished products, fertilizer granulators are becoming a key driver of industry upgrades.

Fertilizer granulators transform powdered raw materials into uniform fertilizer granules through processes such as physical extrusion and conditioning. These granulated fertilizers are not only highly stable, making them suitable for long-term storage and long-distance transportation, but also enable a slow release of nutrients, extending the fertilizer’s effective lifespan and enabling more efficient crop absorption, thereby boosting agricultural production returns from the source.

Furthermore, the adaptability of fertilizer granulators meets the diverse needs of the industry. Whether producing organic fertilizers, compound fertilizers, or customized fertilizers for specific crops, the equipment can adapt to different raw material ratios by adjusting parameters. More importantly, modern fertilizer granulators continuously optimize energy efficiency, improving production efficiency while reducing energy consumption.

For fertilizer companies, fertilizer granulators are a powerful tool for enhancing product competitiveness. Against the backdrop of growing demand for high-efficiency fertilizers in agriculture, fertilizer granulators will undoubtedly drive fertilizer production towards greater efficiency, higher quality, and greater environmental protection.

Rotary drum granulators optimize the nutrient content and application experience of organic fertilizer granules

The core value of organic fertilizer lies in nutrient supply and convenient application, and granule shape directly impacts these two properties. Insufficient nutrient retention reduces fertilizer efficiency, while uneven granules increase the difficulty of field application. By optimizing process details, rotary drum granulators can reduce nutrient loss during the granulation process while creating granule shapes that meet field needs.

In terms of nutrient retention, the rotary drum granulator’s low-temperature granulation is particularly advantageous. Relying on physical tumbling to form granules, the granulator eliminates the need for high pressure and maintains an internal temperature below 35°C, maximizing the retention of active ingredients in the raw materials. Its nutrient retention rate is 5%-8% higher than that of traditional equipment.

In terms of granule application experience, granules produced by rotary drum granulators better meet field needs. On the one hand, the equipment can produce uniform granules with a diameter of 2-5mm by adjusting the drum speed and die aperture, making it easier for farmers to apply fertilizers using seed drills and reducing the unevenness of manual spreading. On the other hand, the moderate hardness of the granules (compressive strength of 10-15N) prevents them from breaking down during transportation and slowly disintegrates in the soil, achieving “slow-release fertilizer supply” and avoiding the root burn caused by concentrated nutrient release.

For organic fertilizer companies pursuing “high quality and low price,” the high-nutrient, easy-to-apply granules produced by the rotary drum granulator can significantly enhance their product’s market competitiveness.

Bio-organic fertilizer equipment: A key link to unlocking green fertilizer production

With the growing adoption of green agricultural development, market demand for bio-organic fertilizer continues to rise due to its ability to improve soil quality and crop quality. Bio-organic fertilizer equipment has become the core link between raw materials and qualified products, directly determining production efficiency and quality.

In the bio-organic fertilizer production process, equipment plays a crucial role throughout. During the raw material pretreatment stage, crushing and mixing equipment refines and evenly distributes raw materials like livestock manure and straw, laying the foundation for subsequent fermentation. The fermentation stage is crucial. Specialized fermentation equipment can maintain a stable fermentation temperature within a range suitable for microbial activity through temperature, humidity, and ventilation control. This not only shortens the fermentation cycle but also effectively eliminates insect eggs and pathogens in the raw materials, reducing the risk of farmland diseases.

Subsequent granulation, drying, and screening equipment determine the product’s form and purity. Granulation equipment can convert loose fermentation materials into granules, facilitating storage and transportation while minimizing nutrient loss. Drying equipment can control the product’s moisture content to below 15%, preventing clumping and mold. Screening equipment can remove impurities and ensure uniformity of organic fertilizer particles.

In addition, high-quality bio-organic fertilizer equipment incorporates environmentally friendly features, such as deodorization and dust removal devices, to reduce exhaust and dust emissions during production, helping companies achieve green production.

Why are double screws compost turning machines the preferred choice for large-scale organic fertilizer production?

The fermentation process of large-scale organic fertilizer production (processing over 500 tons of raw materials daily) faces the challenges of high processing volume, tight fermentation cycles, and high labor costs. The double screws compost turning machine’s design features perfectly meet these requirements, making it a core piece of equipment for large-scale production.

1.Efficient and Continuous Operation

The double screws compost turning machine continuously moves along the fermentation tank, turning the compost without frequent downtime and adjustments. A single unit can process up to 100-200 tons per hour, meeting the continuous fermentation needs of large-scale production lines and ensuring timely composting.

2.Stable and Uniform Compost Turning Quality

Large-scale production requires high consistency in fertilizer quality. The double screws compost turning machine’s two spirals work in tandem, ensuring uniform mixing of the material, both vertically and horizontally, and ensuring even oxygen exposure. Fertilization temperature fluctuations are controlled within ±3°C, preventing uneven fermentation and causing uneven fertilizer quality.

3.Significantly Reduced Labor Costs

Traditional manual compost turning can only process 5-10 tons of material per person per day. A single double screws compost turning machine can replace 20-30 workers. The machine operates without human intervention (it supports automatic movement and compost turning), eliminating the efficiency fluctuations associated with manual operation.

Drum fertilizer dryers: Why can they adapt to the different drying requirements of organic and compound fertilizers?

In the fertilizer industry, the drying requirements of organic and compound fertilizers differ significantly. Organic fertilizers require rapid dehydration and fiber clumping prevention, while compound fertilizers require gentle drying to prevent particle breakage.

For drying organic fertilizers, drum fertilizer dryers offer two key design advantages: First, they utilize a “high-speed + multiple lifter” combination. High speed combined with dense lifters effectively lifts fibrous materials, preventing entanglement and clumping. Hot air also directly penetrates the material layer, quickly removing moisture. Second, an anti-stick coating on the inner wall of the drum reduces wet organic fertilizer from sticking to the wall, reducing cleaning frequency and ensuring continuous production.

For drying compound fertilizers, the drum fertilizer dryer emphasizes “gentle temperature control + low speed”: steam heating is used, keeping the temperature between 120-150°C to avoid direct contact with high temperatures that could cause cracking on the particle surface. Furthermore, a reduced drum speed reduces particle friction within the drum, keeping the particle breakage rate below 3%.

Even when processing temperature-sensitive biofertilizers, the drum fertilizer dryer can adapt to these needs through a “low-temperature hot air modification.” This reduces the hot air temperature to 60-80°C, prolonging the material’s residence time. This allows for slow dehydration while maintaining a microbial survival rate above 85%, truly achieving “one device, multiple fertilizers.”

Flat die granulator: Proper raw material pretreatment increases granulation efficiency by 30%

For small and medium-sized fertilizer companies using flat die granulators, poor granulation results and frequent malfunctions are often not due to equipment issues, but rather to inadequate raw material pretreatment. Flat die granulators are more sensitive to raw material conditions than other granulation equipment. Proper pretreatment not only improves pellet formation efficiency but also reduces equipment wear and tear.

  1. Precise Control of Particle Size

The die holes of flat dies typically have a diameter of 2-5mm. If there are still lumps larger than 1mm in the raw material, they can easily become stuck in the die holes, causing blockage and interrupting discharge. It is recommended to add a “fine screening” step before feeding to ensure uniform raw material particle size. This not only reduces the risk of die blockage, but also ensures more complete compression of the raw material within the die holes, resulting in more stable pellet hardness.

  1. Dynamic Control of Moisture Content

The flat die granulator is optimally suited for raw material moisture contents of 18%-22%. However, in actual production, the moisture content of fermented organic fertilizers often fluctuates seasonally. If the moisture content is too high, the raw material will easily stick to the flat die surface, requiring frequent machine stops for cleaning. If the moisture content is too low, the pellets will be loose and fragile. During the pretreatment stage, the moisture content can be monitored in real time. If it is high, hot air drying can be used; if it is low, a small amount of spraying can be used to replenish moisture to ensure the stability of the raw material.

  1. Targeted Optimization of the Conditioning Stage

Adding conditioning agents tailored to the specific characteristics of the raw material can significantly improve pelletizing results. For example, when processing pure straw fiber raw material, adding 3%-5% bentonite as a binder can enhance the raw material’s viscosity. When producing organic-inorganic compound fertilizers, adding 1%-2% humic acid can improve moldability and increase the added value of the fertilizer.