organic fertilizer production line

In numerous industries such as mining, building materials processing, chemical production, food processing, and pharmaceutical manufacturing, material grading and screening are crucial for ensuring production quality and efficiency. As a widely used material screening device, the vibrating screen, with its high screening capacity, precise grading effect, and wide adaptability, has become an indispensable core piece of equipment in the production processes of various industries. It achieves rapid separation of materials of different particle sizes through the vibration energy generated by a specific vibration device, providing qualified materials for subsequent production processes, helping enterprises improve production efficiency and ensure product quality.

The stable operation of the vibrating screen relies on a scientifically sound structural design. Its core structure consists of six key parts working together to form a complete screening system. The screening box is the core load-bearing component of the equipment, and the screen inside is the core element for material separation. Different screen sizes can be replaced according to different screening needs, precisely adapting to the separation requirements of materials of different particle sizes. The vibrating motor or exciter, as the “power heart” of the equipment, provides a stable vibration source for screening operations, driving the material to move on the screen surface through vibration, providing the basic power for screening. The support system utilizes springs or rubber shock absorbers, which not only stably support the screening box but also effectively buffer the impact of vibration on the ground and the main body of the equipment, extending its service life. The inlet and outlet form the material flow channel. After entering the screening box through the inlet, materials of different particle sizes, after screening and separation, are discharged from their respective outlets, ensuring a smooth and orderly screening process. The sealing device effectively prevents dust leakage during screening, maintaining a clean working environment and meeting environmental protection production requirements.

The working principle of the vibrating screen is based on the precise coordination of vibration energy and material movement to achieve efficient screening. Its core logic is to generate vibration through a vibrating motor or exciter, driving the screening box to perform linear or circular motion in three-dimensional space. When the material enters the screening box through the inlet, it undergoes a forward projectile motion along the screen surface under the action of vibration—this special motion mode ensures both uniform distribution of the material on the screen surface and full contact between the material and the screen mesh. During this process, materials smaller than the sieve apertures pass smoothly through the apertures, becoming the undersize product; materials larger than the apertures remain on the sieve surface, continuing to move forward as the oversize product, and are eventually discharged from the corresponding outlet, thus completing the separation of materials of different particle sizes. It is worth noting that the adjustment of parameters such as vibration frequency, amplitude, and sieve surface inclination angle directly affects screening efficiency and accuracy. Enterprises can flexibly adjust relevant parameters according to material characteristics (such as humidity, viscosity, and particle size distribution) and production requirements to achieve optimal screening results.

The unique structural design and working principle endow vibrating screens with many significant features, enabling them to adapt to the complex needs of multiple industries. High-efficiency screening is its core advantage; high-frequency vibration significantly increases material throughput, effectively improving production efficiency and helping enterprises increase capacity. High screening accuracy is achieved through precise matching of sieve aperture and vibration parameters, allowing for strict control of the screened particle size and ensuring the quality of materials in subsequent production. Its wide applicability is particularly outstanding; it can handle both dry and wet materials, and has good adaptability to different types and particle size ranges of materials. Meanwhile, vibrating screens boast a compact structure, small footprint, and ease of installation in various production sites. They are also simple to operate, convenient to maintain, and highly automated, effectively reducing labor costs. Furthermore, their sealed design provides excellent environmental performance, reducing dust pollution and aligning with the modern trend of green industrial production.

From ore grading in mining to raw material purification in the food industry, from precision screening of chemical products to impurity removal in the pharmaceutical field, vibrating screens, with their core advantages of high efficiency, precision, and flexibility, provide strong support for optimizing production processes across various industries. Against the backdrop of industrial production transforming towards higher efficiency, precision, and green practices, vibrating screens, with their irreplaceable screening value, will continue to play a vital role in more industries, becoming a key piece of equipment for improving the quality and efficiency of industrial production.

Critical Screening in Integrated Fertilizer Manufacturing

In the context of fertilizer production, the vibrating screen is an indispensable unit within any professional fertilizer manufacturing equipment line. It performs the critical final quality control by separating oversized and undersized particles from the finished granules, ensuring a uniform product. This is vital in both the npk fertilizer production process and organic fertilizer lines. For example, in an npk fertilizer production line, raw materials might first be blended in a npk bulk blending machine before granulation. The formed granules, whether from a disc granulation production line (using a disc granulator for shaping) or a roller press granulator production line (using a double roller press granulator), must be screened to meet size specifications.

Similarly, in an organic fertilizer production line or a bio organic fertilizer production line, the screening stage is equally crucial. The raw material may originate from a windrow composting machine, and after granulation—potentially via a disc granulator—the pellets are sized by a vibrating screen. The screened “fines” are often recycled back into the process, maximizing material utilization. Thus, whether it’s a dedicated npk fertilizer line or an organic system, the vibrating screen is the final arbiter of product consistency, directly impacting marketability and application performance.

Therefore, the integration of high-efficiency screening technology is non-negotiable in modern fertilizer plant design. It works in concert with granulation and blending equipment to deliver a polished, standardized final product that meets strict quality benchmarks.

Slow-release/controlled-release fertilizers are a type of fertilizer that regulates the nutrient release rate through specific technological means. The core objective is to match the nutrient release rate with the nutrient needs of crops at different growth stages, thereby addressing the shortcomings of traditional fertilizers, such as “rapid nutrient release, low utilization rate, and easy loss and pollution.” While the concepts are similar, there are slight differences; controlled-release fertilizers offer greater control over the release rate and are considered a more precise type of slow-release fertilizer.

I. Core Technological Principles and Classification

The key to slow-release/controlled-release fertilizers lies in the “nutrient release control mechanism,” which mainly involves the following three technological approaches:

Polymer-Coated Type (Mainstream Controlled-Release Technology)

Principle:  Ordinary granular fertilizers (such as urea and compound fertilizers) are coated with one or more layers of high-molecular-weight polymer film (such as polyurethane, polyolefin, resin, etc.). The thickness and porosity of the film determine the nutrient release rate – water penetrates the film to dissolve the nutrients, which then slowly diffuse through the film pores into the soil; as the temperature rises, the permeability of the film increases, and the nutrient release accelerates, and vice versa.

Release Characteristics: This is a temperature-dependent release, matching the pattern of most crops that require more nutrients during high-temperature growth periods. The release cycle can be precisely designed (e.g., 3 months, 6 months, 12 months).

Representative Products: Resin-coated urea, polymer-coated compound fertilizers (NPK).

Chemically Synthesized Slow-Release Type

Principle: Through chemical synthesis reactions, fertilizer nutrients (mainly nitrogen) are combined with organic compounds to form stable, low-water-soluble compounds. These compounds gradually decompose under the action of soil microorganisms or enzymes, releasing effective nutrients.

Release Characteristics: This is a microorganism/enzyme-controlled release, and the rate is affected by soil temperature, pH value, and microbial activity. The release cycle is longer (up to several months to a year).

Representative Products:

Urea-formaldehyde (UF): A condensation product of urea and formaldehyde. During decomposition, formaldehyde is released first, and then gradually converted into ammoniacal nitrogen. The nitrogen utilization rate is more than 30% higher than that of ordinary urea. Ammonium polyphosphate (APP): A slow-release fertilizer containing nitrogen and phosphorus. After hydrolysis, it releases orthophosphate ions for plant absorption. It is suitable as a phosphorus source in compound fertilizers and can also chelate micronutrients in the soil.

Others: Urea-formaldehyde (CDU), isobutylidene diurea (IBDU), etc.

Matrix-based composite type (traditional slow-release technology)

Principle: Fertilizer nutrients are mixed with porous matrices such as bentonite, zeolite, and humic acid. The adsorption and pore structure of the matrix are used to delay nutrient dissolution; or sulfur coating technology is used (a sulfur layer is coated on the outside of urea granules), and nutrients are controlled-released through the slow breakdown of the sulfur membrane and microbial decomposition.

Release characteristics: The release rate is relatively gentle, and the cost is lower than polymer-coated and chemically synthesized types, making it a low-cost slow-release solution.

Representative products: Sulfur-coated urea (SCU), humic acid compound slow-release fertilizer, zeolite-loaded fertilizer.

II. Core Advantages (compared to traditional quick-acting fertilizers)

Significantly improved nutrient utilization: The utilization rate of traditional quick-acting nitrogen fertilizers is only 30%-40%, and a large amount of nitrogen is lost with rainwater or volatilized into the air; the nitrogen utilization rate of slow-release/controlled-release fertilizers can reach over 60%, and some controlled-release fertilizers can even exceed 80%, reducing nutrient waste.

Labor-saving and time-saving, enabling one-time fertilization: Traditional fertilizers require multiple top dressings according to the crop growth period, while slow-release/controlled-release fertilizers can be applied to the soil at once during sowing or transplanting. The nutrients are slowly released to meet the needs of the crop throughout its entire growth period, especially suitable for large-scale planting scenarios such as field crops, fruit trees, and lawns, reducing labor costs.

Reduced environmental pollution: The slow release of nutrients avoids excessively high concentrations of nitrogen and phosphorus in the soil, thereby reducing environmental problems such as soil compaction, water eutrophication (such as agricultural drainage polluting rivers and lakes), and atmospheric ammonia volatilization, meeting the needs of green agricultural development. By synchronizing nutrient supply with crop demand through controlled release cycles, the peak release period of fertilizer nutrients can be precisely matched with the peak nutrient demand period of crops (such as the tillering stage of rice and the large bell stage of corn), avoiding seedling burn in the early stages and nutrient deficiency and premature aging in the later stages, thereby improving crop yield and quality.

III. Product Forms and Applicable Scenarios

Form Characteristics: Mostly granular, with a larger particle size (usually 2-4 mm), high physical strength, and not easily broken, suitable for mechanized sowing and fertilization.

Applicable Crops and Scenarios

Field Crops (corn, wheat, rice): Choose controlled-release compound fertilizers with a release cycle of 3-6 months, applied as a base fertilizer in one application, reducing the need for topdressing.

Fruit Trees, Flowers, and Seedlings: Choose long-acting slow-release fertilizers with a release cycle of 6-12 months (such as urea-formaldehyde, polyammonium phosphate), suitable for the nutrient needs of perennial crops.

Protected Agriculture and Potted Plants: Choose polymer-coated controlled-release fertilizers to precisely control the release rate and avoid excessively high nutrient concentrations in potted plant soil.

IV. Precautions for Use

Not suitable for topdressing: Slow-release/controlled-release fertilizers release nutrients slowly. If crops show acute nutrient deficiency symptoms, fast-acting fertilizers should be used for topdressing.

Appropriate fertilization depth is necessary: ​​It should be applied to the soil near the crop roots (avoid surface application) to allow sufficient water penetration to trigger nutrient release; coated fertilizers should not be crushed during use, otherwise, the coating structure will be damaged, and the controlled-release effect will be lost.

Higher cost than ordinary fertilizers: The price of slow-release/controlled-release fertilizers is 1.5-3 times that of ordinary fertilizers, but considering the benefits of “labor saving + increased efficiency + reduced pollution,” the long-term use is more cost-effective.

Production of Slow-Release Fertilizers: Granulation and Beyond

Manufacturing coated or chemically synthesized slow-release fertilizers involves specialized adaptations of standard npk fertilizer production technology. The core npk fertilizer manufacturing process begins with precise formulation using a npk blending machine or a bulk blending fertilizer machine. For creating the base granules, an npk granulation machine employing specific npk granulation machine technology—such as a rotary drum for agglomeration—forms the uniform particles. This entire suite of fertilizer raw material processing machinery and equipment is the foundation of the npk fertilizer production line, which must be designed to achieve the required NPK compound fertilizer production capacity and granule quality.

Following granulation, the process diverges for slow-release products. The base granules are fed into a coating drum, a critical piece of additional npk fertilizer granulator machine equipment, where polymer or sulfur coatings are applied. For chemically synthesized types like urea-formaldehyde, the reaction occurs earlier in the process, and the resulting material is then granulated. The integrated npk fertilizer production process thus combines standard equipment like the fertilizer mixer machine and npk fertilizer granulator with specialized coating or synthesis units to create a value-added product with controlled nutrient release profiles.

Therefore, producing advanced slow-release fertilizers requires an expansion of the traditional npk fertilizer machine line. It demonstrates how core granulation and blending technologies serve as a platform for innovation, enabling the creation of products that deliver both agronomic efficiency and environmental benefits.

In material conveying scenarios requiring overcoming height differences, such as mining, port loading and unloading, and construction sites, traditional conveying equipment is often limited by the conveying angle, resulting in problems such as large footprint and low conveying efficiency. large-angle belt conveyors, as specialized equipment designed for large-angle inclined conveying, can achieve material conveying at large angles, even close to vertical (90°), effectively solving the industry pain points of high-drop conveying. It can efficiently transfer bulk materials such as coal, ore, sand, and grain, as well as some single items, becoming a core conveying equipment in industrial production for bridging height differences and optimizing site layout.

The stable and efficient operation of large-angle belt conveyors relies on targeted structural design, with each core component working in concert to ensure the stability of large-angle conveying. The inclined-angle conveyor belt is the core component of the equipment, employing a special design with corrugated sidewalls and transverse partitions—the corrugated sidewalls prevent material from slipping off the sides, while the transverse partitions divide the conveyor belt into several “hopper”-like spaces, fundamentally solving the problem of material slippage during large-angle conveying. The drive unit, consisting of a motor, reducer, and drive roller, provides sufficient traction to the conveyor belt, ensuring smooth operation even under large-angle load conditions. The redirecting roller changes the belt’s direction of travel, effectively adjusting belt tension distribution, especially during large-angle conveying operations, thus ensuring equipment stability. Idler rollers and the support frame form a support system; the idlers support the conveyor belt and reduce running resistance, while the support frame provides robust structural support for the entire device, adapting to installation requirements in complex environments. The tensioning device is crucial for large-angle conveying, ensuring the conveyor belt maintains appropriate tension during operation and preventing slippage due to excessive angle. Furthermore, the control system monitors and adjusts parameters such as conveyor speed and belt tension in real time, and, in conjunction with safety devices such as emergency stop switches and belt misalignment alarms, comprehensively ensures the safety of the equipment and operators.

The working principle of the large-angle belt conveyor is based on the synergistic effect of a dedicated conveyor belt and drive system, resulting in a clear, efficient, and reliable process. During operation, materials are first loaded onto a conveyor belt with corrugated sidewalls and transverse partitions from the lower feed inlet. The special structure of the conveyor belt firmly “locks” the material in, preventing it from scattering before inclined transport. Then, the drive unit starts, driving the conveyor belt upwards along a preset large-angle inclined path via the drive rollers. Under the combined constraint of the corrugated sidewalls and transverse partitions, the material is stably lifted with the conveyor belt, preventing slippage due to excessive inclination. When the material reaches the upper part of the conveyor belt, it is unloaded by its own gravity or a dedicated unloading device. The entire conveying process is continuous and smooth, achieving efficient material transfer from low to high.

The unique design gives the large-angle belt conveyor many core advantages, enabling it to adapt to complex high-drop conveying needs. Its large-angle conveying capacity is its most prominent highlight, achieving near-vertical conveying up to 90°, significantly shortening the conveying distance and saving considerable space, making it particularly suitable for space-constrained environments such as mines and ports. High efficiency is equally noteworthy. The specialized conveyor belt’s structural design ensures no material slippage during large-angle conveying, guaranteeing continuous and stable transport and improving overall efficiency. Its adaptability is exceptional, capable of conveying heavy bulk materials like coal and ore, as well as lightweight materials such as grain. It also adapts to complex terrain conditions such as steep mine slopes and high stockpiles in ports. In terms of operation and maintenance, the equipment’s structural design prioritizes ease of maintenance, making daily inspections and upkeep convenient and efficient. Compared to other large-angle material lifting methods, it consumes less energy and generates less noise, exhibiting excellent energy-saving and environmental performance. Comprehensive safety protection devices further enhance the equipment’s reliability, providing strong protection for industrial production safety.

From lifting ore underground in mines to stacking cargo in ports, from transferring sand and gravel at construction sites to vertical transport in grain warehouses, the large-angle belt conveyor, with its unique large-angle conveying capacity, highly efficient and stable performance, and compact structural design, provides the optimal solution for high-drop material transport in various industries. Against the backdrop of industrial production transforming towards higher efficiency and greater intensification, this equipment not only optimizes site layout and improves production efficiency, but also promotes energy-saving upgrades of conveying systems, becoming an indispensable core equipment in scenarios involving conveying across height differences.

Integrating Conveyance with Granulation in Fertilizer Production

The efficient vertical transfer capability of large-angle belt conveyors is a critical component within modern professional fertilizer manufacturing equipment setups. In a fertilizer plant, these conveyors are essential fertilizer raw material processing machinery and equipment, moving bulk powders or granular materials between different process levels. For instance, in an npk fertilizer production process, a conveyor may lift blended material from a npk bulk blending machine to the feed hopper of a granulator. Similarly, in an organic line, it can transfer cured compost from a windrow composting machine to the granulation unit.

This reliable material flow is vital for feeding the core shaping equipment. The conveyed material might be directed to a disc granulator (central to a disc granulation production line), where the disc granulator for shaping forms spherical pellets via a tumbling action. Alternatively, it could feed a double roller press granulator within a roller press granulator production line for dry compaction granulation. The disc granulator machine and other granulators thus rely on seamless, high-angle conveying to maintain a continuous and efficient production line.

Therefore, the integration of robust, space-saving conveying solutions with specialized granulation technology is fundamental to designing compact, multi-level fertilizer plants that optimize both floor space and production workflow.