In agricultural production, organic fertilizers and chemical fertilizers are two core types of fertilizers. They differ significantly in nutrient composition, fertilizer efficiency, and impact on soil. Understanding their characteristics is crucial for their scientific and effective use.
In terms of nutrient composition, organic fertilizers originate from the decomposed remains of plants and animals. After processing through organic fertilizer production lines and shaping by organic fertilizer granulators, they retain the advantage of comprehensive and balanced nutrients, containing macronutrients such as nitrogen, phosphorus, and potassium, as well as micronutrients such as calcium, magnesium, and iron, and are also rich in organic matter. Chemical fertilizers are mostly industrially synthesized, with compound fertilizers produced by NPK fertilizer production lines being a typical example. Chemical fertilizers generally have a single, concentrated nutrient composition, usually focusing on one or a few elements, such as nitrogen fertilizers, phosphorus fertilizers, and NPK compound fertilizers, with high nutrient purity.
Regarding fertilizer efficiency, organic fertilizers have a mild and long-lasting effect, with nutrients released slowly after microbial decomposition and absorption by crops, providing long-term nutrition. Chemical fertilizers have a fast and strong effect, with nutrients easily absorbed directly by crops, quickly alleviating nutrient deficiency symptoms. However, their effect is short-lived, and excessive application can lead to nutrient loss.
In terms of application scenarios, organic fertilizers are suitable as base fertilizers, applicable to various crops such as fruits, vegetables, and grains, and are especially suitable for green and organic agricultural product cultivation. Chemical fertilizers are suitable as topdressing fertilizers, used to quickly supplement nutrients during critical growth stages to increase yield. In actual production, a reasonable combination of the two can quickly meet the nutrient needs of crops while also protecting the soil and achieving sustainable farming.
In modern organic fertilizer production, a complete production line not only needs to complete basic processing but also achieves significant value enhancement through refined processing.
After the materials have completed fermentation and mixing, the fertilizer compaction machine initiates the refined processing journey. It shapes loose powdery materials into uniformly sized granules using physical pressure. This process not only improves the physical properties of the product, making it easier to store and transport, but more importantly, it lays the morphological foundation for subsequent processing.
The extruded granules then enter the screening stage. The fertilizer screener machine, through a precise screening mechanism, strictly grades the finished product according to particle size specifications. Particles that meet the standards proceed to the next process, while products with unqualified particle sizes are returned to the previous process for reprocessing.
At the end of the entire organic fertilizer production line, the fertilizer coating machine plays a crucial role. This equipment effectively reduces clumping during storage by coating the granules with a special film material, while also enabling the slow release of nutrients. Products treated with coating not only have a brighter appearance but also significantly enhanced functionality and added value.
The coordinated operation of these specialized organic fertilizer production equipment demonstrates the high level of precision in modern fertilizer production. From the shaping process of the fertilizer compaction machine to the fine selection by the fertilizer screener machine, and then to the value-added processing by the fertilizer coating machine, each step contributes to the quality of the final product.
The superior properties of water-soluble fertilizers stem from meticulous processing, with the core focus on ensuring nutrient purity, solubility, and uniformity. Compared to traditional fertilizers, their processing demands higher standards for raw materials, formulation, and manufacturing processes. The rational use of key equipment such as fertilizer screener machines, fertilizer mixers, and fertilizer packing machines is crucial for efficient processing and quality assurance.
Raw material selection is the first line of defense. High-purity, easily soluble raw materials must be selected to prevent impurities from affecting quality. Fertilizer screener machines are used to remove impurities and large particles, while simultaneous drying and impurity removal processes reduce moisture content, preventing moisture absorption and caking, thus laying the foundation for subsequent processing.
Precise formulation and uniform mixing are core aspects. After accurately weighing the raw materials according to crop needs, they are fed into a fertilizer mixer for thorough mixing to prevent uneven nutrient distribution; powdered water-soluble fertilizers can be further refined using a fertilizer screening machine to improve dissolution speed; liquid water-soluble fertilizers require controlled mixing parameters to ensure complete nutrient dissolution.
Finished product testing and packaging are the final stages. After passing quality control, the product is packaged using a fertilizer packaging machine. Moisture-proof and sealed packaging materials are used to protect quality and prevent moisture absorption and deterioration during transportation and storage. Key information such as nutrient ratios and usage instructions are also included to provide guidance for subsequent use.
NPK fertilizers are prone to caking during storage and transportation, which not only affects ease of application and leads to uneven nutrient distribution, but also interferes with subsequent operations on the NPK fertilizer production line, increasing the burden of secondary processing on core equipment such as NPK fertilizer granulators and fertilizer mixer machines. The core causes are moisture absorption and deliquescence on the particle surface, crystal bridging, and inter-particle pressure. Anti-caking agents can block the caking pathway through scientific mechanisms, ensuring the loose state and stable quality of the fertilizer.
Anti-caking agents mainly work through three mechanisms: firstly, physical isolation, where inert powders or hydrophobic substances uniformly coat the particle surface to form a protective film, isolating water and oxygen and preventing particle adhesion; secondly, moisture control, where some anti-caking agents preferentially adsorb environmental moisture, reducing the water content of the particles and inhibiting crystal bridge formation at the source; and thirdly, improving particle characteristics, increasing surface smoothness, reducing inter-particle friction and adhesion, and alleviating extrusion and adhesion under stacking pressure.
The application of anti-caking agents needs to be integrated into the core process of the NPK fertilizer production line, considering both compatibility and dosage. It is recommended to add them simultaneously during the mixing and conditioning stage in the fertilizer mixer to ensure uniform blending with the particles; at the same time, the parameters of the NPK fertilizer granulator machine should be considered, and the type should be selected according to the characteristics of the granulated particles, such as hydrophobic types for monoammonium phosphate-based fertilizers, and composite types for high-nitrogen fertilizers.
In large-scale organic fertilizer production, rotary drum granulators, as the core type of organic fertilizer granulator, have become the “central equipment” of rotary drum granulation production lines due to their excellent adaptability and production capacity advantages.
The core advantages of rotary drum granulators are “wide adaptability and high production capacity.” Compared with other organic fertilizer granulators, they have a higher tolerance for raw material moisture and viscosity, and can process diverse materials such as composted livestock and poultry manure and straw fermentation materials with a moisture content of 20%-30%, without the need for excessive fine pre-treatment. The equipment’s molding rate is stably above 90%, and the hourly production capacity of a single unit can reach several tons to tens of tons, perfectly meeting the needs of large-scale production.
The efficient operation of the rotary drum granulation production line relies on the precise coordination of the rotary drum granulator with other equipment. The pre-treated raw materials are uniformly mixed by the batching and mixing system and then directly fed into the rotary drum granulator, while water or binders are precisely added through a spraying device; after granulation, the granular materials directly enter subsequent equipment such as dryers, coolers, and screening machines, forming a complete closed-loop process of “batching – granulation – post-processing.”
Whether producing pure organic fertilizer or organic-inorganic compound fertilizer, the rotary drum granulation production line can achieve diversified output with the flexible adaptability of the rotary drum granulator. It not only lowers the operational threshold for large-scale organic fertilizer production but also ensures the stability of finished product quality.
“A crop’s growth depends entirely on fertilizer,” goes the saying. Fertilizer is the “nutritional meal” for crops, and fertilizer machinery is the “precise dispenser” and “efficient deliveryman” of this meal. From traditional manual fertilization to today’s intelligent fertilizer blending and precision fertilization, the iterative upgrades of fertilizer machinery have not only solved the long-standing problems of “difficult and uneven fertilization,” but also propelled agricultural production towards cost-effectiveness, efficiency, and green sustainability. Today, we’ll unveil the mystery of fertilizer machinery and see how these “agricultural marvels” are changing our planting methods.
To understand fertilizer machinery, we must first understand its core mission: to ensure fertilizer is used effectively. In traditional planting, farmers often rely on experience to fertilize, either “over-fertilizing for high yields,” leading to fertilizer waste and soil compaction, or “under-fertilizing for fear of reduced yields,” impacting crop growth. Fertilizer machinery, through standardized and precise operations, perfectly solves this problem. Its family of models comprises many members, each with its own specific “job responsibilities.” In the fertilizer production stage, these “transformation masters” are responsible for converting various raw materials into qualified fertilizers. Taking organic fertilizer production as an example, the compost turner is an indispensable core piece of equipment. Through rotating blades or spiral blades, it continuously turns and tosses the fermenting materials, reducing moisture, promoting the growth of beneficial microorganisms, and ensuring more uniform decomposition, transforming polluting livestock manure and crop straw into loose, fertile organic fertilizer. The granulator, like a “shaping artist,” processes powdered fertilizer into granules through rotating discs and extrusion, facilitating storage and transportation, controlling nutrient release rates, and improving fertilizer efficiency.
In the field application stage, the “distribution experts” showcase their skills. The most common fertilizer spreader has long since moved beyond the extensive “spread as you go” approach. Modern solid fertilizer spreaders, through precise transmission systems and spreading mechanisms, can evenly distribute granular fertilizer in the field, with uniformity errors controlled within ±5%. For complex terrains such as mountains and hills, tracked mobile fertigation machines are particularly adept at maneuvering. They can easily navigate steep orchards and scattered plots, integrating irrigation and fertilization. The work time for 10 acres has been reduced from the traditional 3 people per day to just 2 hours, significantly lowering labor costs.
In recent years, with the development of smart agriculture, fertilizer machinery has also undergone an “intelligent upgrade,” giving rise to the “smart brain”—the intelligent fertilizer blender—that can “tailor-make” a nutritional meal for the land. At the intelligent fertilizer blending station in Hangjin Banner, Inner Mongolia, farmers only need to input the plot coordinates on the terminal to check the nitrogen, phosphorus, and potassium content of the soil. After selecting the crop variety and target yield, the system automatically generates a personalized fertilizer blending plan. The blender then precisely mixes the raw materials to produce a “custom-made” fertilizer. This model completely changes the traditional practice of “using the same fertilizer for everything.” Calculations show that using customized fertilizer can save 60-70 yuan per acre in fertilizer costs, reduce fertilizer application by 20 kg, and increase yield by about 30 kg per acre, truly achieving “supplementing what is lacking.” Beyond precision fertilizer application, variable-rate fertilization technology takes “precision” to the extreme. Intelligent fertilizer applicators equipped with BeiDou navigation and soil sensors can monitor real-time differences in soil nutrients and automatically adjust the amount of fertilizer applied while moving, ensuring every inch of the field receives the appropriate fertilizer supply. Data shows that the number of intelligent fertilizer applicators in my country has exceeded 42,000 units. In major grain-producing areas such as Heilongjiang and Henan, the coverage rate of intelligent fertilization equipment has exceeded 40%, and fertilizer utilization is 2%-3% higher than traditional fertilization.
The advancement of fertilizer machinery not only benefits farmers but also contributes to environmental protection. Problems such as groundwater pollution and soil degradation caused by excessive fertilization in the past have been effectively alleviated with the widespread adoption of precision fertilization machinery. For example, mobile fertigation machines, by precisely controlling the water-fertilizer ratio, can increase water resource utilization by 30%-60% and fertilizer utilization by 25%-40%, reducing waste and preventing soil compaction and salinization. Meanwhile, organic fertilizer production machinery promotes the resource utilization of livestock and poultry breeding waste, turning “waste” into “fertilizer” and forming an agricultural ecological cycle.
From simple mechanized operations to intelligent and precise control, the development of fertilizer machinery is a microcosm of the transformation and upgrading of modern agriculture. These “agricultural marvels” not only liberate farmers from heavy physical labor but also achieve the goals of “reducing fertilizer use and increasing efficiency, and promoting green development” through technological advancements. In the future, with continuous technological innovation, fertilizer machinery will develop towards greater intelligence, efficiency, and environmental friendliness, injecting continuous momentum into ensuring food security and promoting high-quality agricultural development.
Manufacturing Precision: From Factory to Field
The “agricultural marvels” that enable precision farming in the field—like intelligent spreaders and variable-rate applicators—are supplied by a sophisticated industrial manufacturing sector. The efficiency and precision of field application are entirely dependent on the quality and consistency of the fertilizer products themselves, which are produced in dedicated facilities using advanced professional fertilizer manufacturing equipment.
An organic fertilizer factory relies on a complete organic fertilizer production line, which begins with processing raw compost using a windrow composting machine and proceeds through granulation. Similarly, a comprehensive npk fertilizer production line encompasses the entire npk fertilizer production process. This process starts with precise formulation using an npk blending machine or npk bulk blending machine, followed by shaping the mixture using a fertilizer granulator. Granulation technology options include a disc granulation production line with a disc granulator for shaping, or a roller press granulator production line for dry compaction. The collective cost of this fertilizer manufacturing plant equipment directly influences both the organic fertilizer machinery price and the final NPK fertilizer production price. These integrated systems are what allow modern agriculture to have access to the diverse, high-quality fertilizers needed for both broad-acre and precision application.Therefore, the revolution in field application is underpinned by an equally significant revolution in manufacturing, where advanced production lines ensure a reliable supply of the tailored nutrients that smart farming equipment depends on.
In the oil palm industry’s production chain, oil palm empty fruit bunches (OPEFB), once considered a waste product requiring disposal, have now become a valuable resource in sustainable agriculture due to their rich nutritional advantages. As an organic waste rich in nitrogen, phosphorus, potassium, calcium, magnesium, and other nutrients, oil palm empty fruit bunches, through various methods such as composting and biochar conversion, demonstrate unique value in improving soil quality and promoting crop growth, providing an effective path for the green transformation of agriculture.
The utilization of oil palm empty fruit bunches as fertilizer has diverse applications, adapting to different agricultural production needs. Composting is the most common method, where empty fruit bunches are mixed with manure or palm oil mill effluent and fermented to produce a nutritionally balanced organic fertilizer, fully activating its nutrient potential. Pyrolysis technology can convert empty fruit bunches into porous biochar. This special material not only significantly improves soil fertility, with particularly outstanding effects on peat soils, but also promotes nutrient absorption by crops. Furthermore, potassium carbonate extracted from the ash of empty fruit bunches is a key ingredient in liquid fertilizers, enabling precise nutrient recovery; untreated empty fruit bunches can also be directly applied as mulch or mixed into the soil, continuously improving soil properties through natural decomposition.
The benefits of this organic waste to soil and plants are multifaceted. At the soil level, it effectively increases the nutrient content and organic carbon content of the soil, fundamentally improving soil structure, reducing compaction, and enhancing soil water and nutrient retention capacity. More importantly, it provides a favorable living environment for soil microorganisms and beneficial animals, activating the vitality of the soil microbial community and improving the stability of the soil ecosystem. For crops, these improvements ultimately translate into growth momentum, especially at higher application rates or in combination with other treatments, significantly promoting the growth of oil palm and other crops, improving yield and quality, while reducing reliance on synthetic fertilizers and lowering the risk of agricultural non-point source pollution.
Of course, some precautions should be considered when using oil palm empty fruit bunches as fertilizer. Its most significant characteristic is the slow release of nutrients. While it provides long-term nutrient supply, it may not meet the rapid nutrient needs of crops at specific growth stages. At the same time, single-component empty fruit bunch fertilizer often fails to provide balanced nutrition and usually requires supplementation with inorganic fertilizers to fully meet the nutritional needs of crops. Furthermore, due to its high lignin and wax content, unprocessed empty fruit bunches are difficult to handle and require pretreatment methods such as composting and pyrolysis to improve utilization efficiency.
Overall, oil palm empty fruit bunches, with their diverse utilization methods and significant improvement effects, have become a sustainable soil amendment with both ecological and economic value. The rational development and utilization of this valuable resource can not only solve the problem of disposing of by-products from the oil palm industry but also promote the transformation of agricultural production towards a low-carbon, environmentally friendly, and efficient direction, injecting new vitality into ensuring food security and ecological balance.
Integrating OPEFB into Modern Manufacturing Systems
The uses of oil palm empty fruit bunch (OPEFB) as a sustainable fertilizer resource are maximized through systematic industrial processing. To transform this raw organic waste into a consistent, market-ready product, it must be integrated into a complete organic fertilizer manufacturing system.
The process begins with efficient decomposition, often accelerated by advanced fermentation composting turning technology to produce stable compost. This processed OPEFB compost then becomes the primary feedstock for a professional organic fertilizer production line. The core stage of organic fertilizer production granulation shapes the material into uniform pellets. Manufacturers can choose specialized equipment like an organic fertilizer disc granulation machine within a dedicated disc granulation line, or opt for versatile solutions such as a new type two in one organic fertilizer granulator or a comprehensive organic fertilizer combined granulation production line. These systems are designed to handle the fibrous nature of OPEFB, efficiently converting it into a high-value, easy-to-apply fertilizer that fulfills its potential in sustainable agriculture.Therefore, the true value of OPEFB is unlocked not just at the field level but through its seamless incorporation into sophisticated production lines that ensure quality, consistency, and scalability for the global organic fertilizer market.
In the era of emphasizing circular economy and sustainable waste management,trough-type compost turners have emerged as indispensable mechanized equipment in large-scale organic waste treatment systems. These specialized machines operate by traversing along fixed rails positioned above elongated fermentation troughs, leveraging rotating drums equipped with robust teeth or paddles to perform a suite of critical functions—lifting, breaking, mixing, and aerating diverse organic materials such as livestock manure, municipal sludge, crop residues, and even agricultural by-products like oil palm empty fruit bunches. By optimizing aerobic decomposition conditions, they enable the rapid and consistent conversion of organic wastes into stable, nutrient-rich compost, making them a cornerstone in organic fertilizer production, environmental waste treatment, and sustainable agriculture sectors.
The working principle of trough-type compost turners is a sophisticated integration of mechanical motion and biological decomposition, with each functional step meticulously designed to enhance composting efficiency. Aeration, the fundamental prerequisite for successful aerobic composting, is achieved through the machine’s rotating drum. Equipped with sharp, wear-resistant teeth or curved paddles, the drum penetrates deep into the compost pile—often reaching 1 to 1.8 meters in depth—lifting and turning over bottom-layer materials that are prone to oxygen depletion. This process fully exposes the organic matter to atmospheric oxygen, which is essential for fueling the metabolic activities of aerobic microbes (such as bacteria and fungi). By maintaining sufficient oxygen levels (typically 15-20% within the pile), the turners effectively prevent the formation of anaerobic environments that produce foul-smelling gases like hydrogen sulfide and methane, ensuring a odor-controlled composting process.
Mixing and breaking are equally crucial functions that guarantee uniform compost quality. During operation, the high-speed rotation of the drum (usually 25-40 revolutions per minute) shatters dense clumps and hard lumps in the compost pile, which are common in materials like fresh manure or dewatered sludge. Simultaneously, the turning action thoroughly blends different sections of the pile, eliminating uneven distribution of moisture (wet and dry spots) and temperature (hot and cool zones). This uniform mixing ensures that all organic particles are exposed to the optimal composting environment, avoiding incomplete decomposition caused by local deficiencies in oxygen, moisture, or nutrients. For instance, when processing a mixture of high-carbon crop straw and high-nitrogen poultry droppings, the turner ensures the carbon-to-nitrogen ratio (C/N) is evenly maintained at the ideal range of 25:1 to 30:1, a key factor in accelerating microbial decomposition.
Material movement and process control further enhance the continuity and efficiency of the composting process. As the trough-type turner travels along the rails at an adjustable speed (0.5-1.5 meters per minute), the rotating drum pushes the compost material backward slightly, ensuring that every particle in the long trough is sequentially turned and mixed. This continuous material circulation, combined with aeration and mixing, creates a stable composting environment where temperature is regulated between 55-65°C—a range that effectively kills pathogens, weed seeds, and insect eggs while promoting the decomposition of organic matter into humus. Moreover, many advanced models are equipped with intelligent monitoring systems that track real-time temperature and moisture levels in the pile. When moisture content deviates from the optimal 55-60%, the integrated sprinkler system automatically supplements water, further refining process control. Thanks to these optimized mechanisms, trough-type turners can shorten the composting cycle significantly, reducing the traditional 45-60 day process to just 7-10 days for mature compost production.
The applications of trough-type compost turners are diverse and far-reaching, addressing critical needs across multiple industries. In organic fertilizer production plants, they are widely used to convert livestock manure (cow dung, pig manure), poultry droppings, and crop residues (wheat straw, corn stover) into high-quality organic fertilizers, which enhance soil fertility and reduce reliance on chemical fertilizers. In environmental protection, they play a vital role in treating municipal sludge and food waste—processing these potentially polluting wastes into usable compost, thereby reducing landfill pressure and mitigating environmental pollution. In horticulture and landscaping, the compost produced with their assistance is used to improve soil structure in gardens, green belts, and horticultural fields, promoting healthy plant growth. Additionally, they find applications in biomass energy production, where they prepare organic materials for subsequent energy conversion processes, and in mushroom cultivation, facilitating the fermentation of substrate for agaricus growth.
With their efficient performance, odor control capabilities, and versatile applications, trough-type compost turners have become an essential tool in advancing sustainable waste management practices. By bridging the gap between organic waste and valuable compost, they not only contribute to environmental protection but also support the development of a circular economy, making them indispensable in the global pursuit of green and sustainable development.
The Critical First Step in a Value-Adding Chain
The trough-type compost turner is a foundational piece of equipment that embodies advanced fermentation composting turning technology. It is specifically designed to execute trough-type aerobic fermentation composting technology, providing the controlled environment necessary for rapid and uniform decomposition. As a highly efficient agriculture waste compost fermentation machine, it accelerates the organic fertilizer fermentation process, transforming raw waste into stable, mature compost.
This machine is a core component within the broader suite of equipments required for biofertilizer production. While a hydraulic trough compost turner excels in this controlled trench system, other site layouts may utilize a self propelled compost production machine or a windrow compost turning machine for open windrows. The high-quality compost produced by these systems serves as the primary organic feedstock. To create a market-ready product, this compost is often further processed—it can be blended with other nutrients and shaped into uniform granules using equipment like a rotary drum granulator in subsequent processing stages. Thus, the turner’s role is to create the essential raw material that feeds the entire organic fertilizer manufacturing value chain.Ultimately, by ensuring efficient and hygienic decomposition, trough-type turners are not just waste processors; they are the vital first-stage enablers of a sustainable industry that converts organic waste into valuable soil amendments and biofertilizers.
The sulfur-coated urea production line focuses on the slow-release modification needs of conventional urea. Through a closed-loop process of “urea pretreatment – melt sulfur coating – cooling and solidification – finished product grading,” it achieves large-scale production of 15 tons/hour of sulfur-coated urea. The finished granules use urea as the core and sulfur as the slow-release coating layer, combining the advantages of long-term nutrient release and environmental protection and energy saving. It is suitable for large-scale planting scenarios such as grain crops and cash crops, significantly improving fertilizer utilization.
Production Line Configuration and Core Details
I. Urea Pretreatment Unit: Laying the Foundation for Sulfur Coating
(I) Raw Material Storage and Quantitative Feeding
Urea Raw Material Silo: Equipped with two 50m³ conical raw material silos (total volume 100m³), made of carbon steel with an anti-corrosion coating. The silo cone angle is 65°, and a vibrator and star-shaped unloader are installed at the bottom to prevent urea granule bridging and blockage. The raw material silo is equipped with a pulse dust collector at the top to collect feed dust. The dust emission concentration is ≤10mg/m³, meeting environmental protection standards.
Precision Feeding System: Two frequency-controlled belt feeders (model DTⅡ-500) are used, each with a feeding capacity of 7.5-8 tons/hour. Combined operation meets the production capacity requirement of 15 tons/hour. The feeders are equipped with weight sensors to provide real-time feedback on the feed amount. The speed is adjusted via a PLC system, with a batching error ≤±0.5%.
(II) Urea Screening and Preheating
Grading and Screening Machine: One Φ1.8×6.0 meter drum screen is used, employing a single-layer screen (pore size 2.5-4.5mm) to screen out uniformly sized urea particles (removing <2.5mm fragments and >4.5mm large pieces), ensuring uniform sulfur coating. Non-conforming particles are conveyed to a crusher via a return conveyor belt for crushing and recirculation, achieving a material utilization rate of 99% and a screening efficiency of 18 tons/hour.
Low-temperature preheater: A Φ1.5×12 meter drum preheater is used, employing indirect steam heating to raise the temperature of urea particles from room temperature to 40-50℃. Preheating reduces the surface tension of the urea particles, facilitating the adhesion of the sulfur coating layer, while preventing rapid solidification of sulfur due to low-temperature urea, which would affect the continuity of the coating. The preheater is equipped with a temperature sensor, ensuring precise temperature control with an error ≤±2℃.
II. Core Sulfur Coating Unit: Key to Slow-Release Layer Formation
(I) Sulfur Melting System
Melting Tanks: Three 10m³ stainless steel melting tanks are configured (2 in use, 1 as standby), using electric heating + circulating heat transfer oil to heat solid sulfur (particle size ≤5mm) to 125-135℃, melting it into liquid sulfur (viscosity ≤0.02Pa・s). The melting tank is equipped with a level sensor and an automatic replenishment device to maintain a stable liquid level. A single tank has a melting capacity of 6 tons/hour, meeting coating requirements.
Sulfur transfer pumps: Three gear-type insulated transfer pumps (temperature resistance ≥150℃) are used to pressurize and transfer liquid sulfur to the coating machine. The transfer pressure is controlled at 0.3-0.5MPa, and the flow rate is adjustable from 300-500kg/hour (sulfur addition accounts for 8%-12% of the total urea content, adapting to different slow-release cycle requirements). The transfer pipeline adopts a double-layer insulation design, with the outer layer wrapped in rock wool to prevent sulfur from cooling, solidifying, and clogging the pipeline.
(II) High-efficiency coating machine
Core equipment selection: Two Φ2.2×8.0 meter roller-type coating machines (7.5 tons/hour per machine) operate in parallel, with a total capacity of 15 tons/hour. The inner wall of the coating machine’s drum is lined with high-temperature and wear-resistant plates, and a spiral layout with lifting plates drives the material in a “tumbling-spraying-rolling” motion, ensuring that each urea granule is evenly contacted with liquid sulfur.
Coating process details: Liquid sulfur is evenly sprayed onto the surface of the urea granules inside the drum through atomizing nozzles (0.8mm orifice diameter), with an atomization pressure of 0.4MPa, forming a uniform sulfur film layer with a thickness of 0.1-0.3mm. The coating machine is equipped with a variable frequency speed control system, allowing the drum speed to be adjusted within the range of 8-15 r/min, controlling the material residence time to 3-5 minutes to ensure a dense, gap-free coating layer.
Auxiliary coating optimization: Depending on requirements, 0.5%-1% paraffin wax or asphalt can be added as a sealant, sprayed synchronously with the sulfur through an independent atomization system to fill the pores in the sulfur film layer, further enhancing the slow-release effect and extending the nutrient release period to 3-6 months.
III. Post-processing and Curing Unit: Ensuring Finished Product Quality
(I) Cooling and Curing
Counter-flow Cooler: Equipped with two Φ1.8×15 meter drum coolers (each with a processing capacity of 8 tons/hour), using counter-flow cooling with ambient temperature air to rapidly reduce the temperature of the coated particles from 100-110℃ to below 30℃. The cooler has a built-in air guide device to enhance heat exchange efficiency. The cooling time is controlled within 10 minutes to ensure complete curing of the sulfur coating layer, achieving a hardness of over 2.0MPa and preventing damage.
Cooling Air Treatment: A small amount of sulfur dust carried by the cooling air is collected by a pulse dust collector with a collection efficiency of 99.5%, avoiding environmental pollution. The collected sulfur dust can be recycled back to the melting tank for reuse.
(II) Grading and Anti-caking Treatment
Finished Product Screening: Two Φ1.5×4.0 meter vibrating screens are used, employing a double-layer screen design. The upper screen (5.0mm aperture) separates oversized agglomerated particles, while the lower screen (2.0mm aperture) screens qualified finished products, achieving a qualified particle pass rate of 98%. Unqualified particles are crushed and returned to the pretreatment stage, resulting in a material utilization rate of 99%.
Anti-caking Spraying: A small spraying device is added after screening to spray 0.1%-0.2% of an anti-caking agent (such as talc suspension) onto the surface of the finished particles. Through natural mixing during the belt conveyor process, the agent adheres evenly to the particle surface, preventing agglomeration during storage.
IV. Finished Product Storage and Packaging Unit: High-Efficiency Output
Finished Product Warehouse: Equipped with 3 x 100m³ finished product warehouses (total volume 300m³), featuring a sealed design and equipped with dehumidification and ventilation devices to maintain relative humidity ≤60% and prevent finished products from absorbing moisture. A quantitative unloading device is installed at the bottom of the warehouse for continuous and stable discharge.
Automated Packaging: Utilizes 4 dual-station automatic packaging scales (120 bags/hour per scale), supporting rapid switching between 25kg and 50kg specifications, with a measurement error ≤±0.2kg. The packaging machine is equipped with a dust cover and automatic sewing device to reduce dust emissions. Packaged finished products are transferred to the finished product stacking area via belt conveyor. The entire process is automated, minimizing manual intervention.
V. Environmental Protection and Intelligent Control Unit: Stable and Environmentally Friendly Operation
(I) Environmental Treatment System
Waste Gas Treatment: The small amount of sulfur vapor generated by the melting tank and coating machine is recovered by a condensation recovery device. Uncondensed waste gas is purified by an activated carbon adsorption tower before being discharged. The waste gas emission concentration complies with the “Integrated Emission Standard for Air Pollutants”. Wastewater Treatment: Wastewater from the production line cleaning process is treated in an oil separator and sedimentation tank before being recycled for equipment cleaning, achieving zero wastewater discharge.
(II) Intelligent Control System: An integrated PLC central control system with a touchscreen interface monitors the operating parameters of each piece of equipment in real time (sulfur melting temperature, coating machine speed, cooling temperature, feed rate, etc.), supporting automatic fault alarms and data recording (storage period ≥ 90 days). The system supports remote monitoring and operation, facilitating real-time monitoring of production status by management personnel.
Key equipment (melting tank, coating machine, cooler) is equipped with safety interlock devices, such as automatic power-off for overheating of the melting tank and automatic shutdown for overload of the coating machine, ensuring production safety.
Core Advantages and Application Value of the Production Line: High and Stable Production Capacity: The dual-machine parallel configuration achieves an hourly output of 15 tons and an annual capacity of 120,000 tons (calculated based on 300 days of operation per year and 8 hours per day), meeting the needs of large-scale production. Excellent slow-release effect: The dense and uniform sulfur coating allows for flexible adjustment of the nutrient release cycle (3-6 months), increasing fertilizer utilization by 30%-40% compared to conventional urea, while reducing nutrient loss and environmental pollution.
Environmentally friendly and energy-saving: A fully sealed design and dust recovery system result in low pollutant emissions; the preheater and melting tank utilize energy-saving heating technology, reducing energy consumption by 10% compared to conventional production lines.
Enabling Enhanced-Efficiency Fertilizers Through Specialized Production
This sulfur-coated urea production line represents a highly specialized segment within the broader fertilizer manufacturing industry. It focuses on creating a value-added, controlled-release product from a single nutrient source, demonstrating the sophistication possible with modern npk fertilizer production technology.
While this line produces a specialized single-nutrient product, it shares its industrial ecosystem with the equipment used for the manufacturing of npk fertilizer. The production of traditional compound fertilizers often relies on a complete npk fertilizer manufacturing process that begins with precise blending using an npk blending machine or a bulk blending fertilizer machine. The blended mixture is then shaped using an npk fertilizer granulator machine employing advanced npk granulation machine technology as part of a suite of npk fertilizer granulator machine equipment. The scale and efficiency of such integrated systems determine a plant’s overall NPK compound fertilizer production capacity. Therefore, a sulfur-coating line is a complementary technology, adding a specific functionality that works alongside, rather than replaces, conventional bulk blending and granulation systems.Ultimately, the ability to offer both conventional NPK blends and advanced coated products allows manufacturers to serve a wider market, from basic nutrient supplementation to precision, efficiency-focused agriculture.
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A dedicated extrusion granulation production line has been successfully put into operation in Colombia, enabling high-efficiency granulation through steel structures!
In May 2025, Zhengzhou Huaqiang Heavy Industry Technology Co., Ltd. completed the installation and commissioning of a steel-structured extrusion granulation production line tailored for a Colombian client, officially entering the stage of large-scale production. This production line, with its steel structure plant layout as its core adaptation, integrates the entire chain of processes including mixing, lifting, feeding, granulation, screening, and packaging. With its robust configuration of two 3.0-type extrusion granulators, compact and efficient space utilization, and stable and reliable operation, it has become another benchmark project for Chinese granulation equipment in the South American market, providing local fertilizer producers with a highly adaptable and cost-effective mass production solution.
Production Line Configuration and Core Equipment Analysis
The entire steel-structured extrusion granulation production line is built around a closed-loop logic of “precise pretreatment – efficient granulation – quality control – finished product output.” Equipment selection is closely matched to the load-bearing capacity and spatial layout of the steel-structured plant, with each unit seamlessly integrated. This ensures production efficiency while maximizing plant space utilization, fully meeting the large-scale production needs of Columbia’s clients.
Raw Material Pretreatment and Conveying Unit: Laying a Solid Foundation for Uniform Granulation
Efficient Mixing Process: The production line uses a 2000-type disc mixer as the core of raw material pretreatment. This equipment features a large-diameter disc design with a mixing diameter of 2.0 meters, providing ample volume for batch mixing of multi-component raw materials. The mixing blades adopt a spiral layout, coupled with a variable frequency speed control system (speed range 10-25 r/min), which can flexibly adjust the mixing intensity according to the raw material moisture and ratio, ensuring sufficient convection and shearing of nitrogen, phosphorus, and potassium main raw materials and trace elements. The mixing uniformity error is ≤2%, providing a uniform raw material foundation for subsequent granulation. The equipment features wear-resistant lining plates to extend its service life and is equipped with an automatic unloading device to ensure continuous production.
Stable Lifting and Feeding: The mixed raw materials are vertically conveyed to subsequent stages via a 315-type bucket elevator (10 meters). This elevator is optimized for the vertical space of steel structure plants, with a small footprint and high load-bearing capacity. It uses a plate chain drive structure, ensuring smooth and noiseless operation, with a conveying efficiency of 6 tons/hour. Its excellent sealing effectively prevents the raw materials from becoming damp, contaminated, or generating dust during lifting. The lifted raw materials then enter a 2000-type disc feeder. The feeder uses frequency conversion control and automatic material level monitoring technology to precisely regulate the feed rate, ensuring uniform feeding to the two extrusion granulators. This avoids fluctuations in granulation quality or equipment overload caused by uneven feeding, achieving precise matching between raw material supply and granulation rhythm.
The core equipment of the production line consists of two 3.0-type extrusion granulators. This model is a mature product developed by Huaqiang Heavy Industry for medium to large-scale production capacity needs. It is specifically optimized for the load-bearing standards of steel-structured plants, featuring a compact structure and reasonable weight distribution, perfectly adapting to the load-bearing limitations of the plant. The granulator adopts a high-strength double-roller extrusion design with a roll diameter of 300mm and a roll width of 250mm. The extrusion pressure (6-18MPa) is precisely controlled through a hydraulic pressurization system, adapting to the granulation needs of organic fertilizer and compound fertilizer raw materials with different moisture content (28%-35%) and different compositions.
The granulator rollers are made of high-chromium alloy, with a hardness exceeding HRC62 after quenching. This results in three times the wear resistance compared to ordinary materials, extending the service life to over 10,000 hours. The roller surface features a customized anti-slip texture design, enhancing material gripping force and effectively preventing slippage. The granulation rate remains consistently above 93%, with uniform particle size controlled at 3-5mm and a compressive strength of 2.7MPa. The granules are not prone to pulverization, fully meeting the needs of Colombian agriculture for fertilization and long-distance transportation. Two granulators can operate in parallel, each with a capacity of 2.5 tons per hour. Combined operation achieves a total capacity of 5 tons per hour and a daily capacity of 120 tons, significantly improving customer production efficiency.
Grading and Finished Product Output Unit: Strict Quality Control and Efficient Delivery
Precise Screening and Recycled Material Utilization: Granulated particles are transported via a conveyor system to a 1.2×4.0 meter drum screen. This equipment is optimized for the lateral space of steel structure plants, maximizing floor space and screening efficiency. The screen uses a single-layer high-precision screen design, with screen apertures customizable to customer needs. Grading and screening are achieved through uniform drum rotation (18 r/min). Qualified particles (3-5 mm diameter) achieve a 98% pass rate, while substandard particles (too coarse or too fine) are returned to the raw material mixing front end via a 5-meter return conveyor belt, re-entering the granulation process. Material utilization reaches 99%, effectively reducing production costs. The screen is equipped with an automatic screen cleaning device, which cleans material adhering to the screen surface in real time, preventing screen blockage and ensuring stable screening efficiency. The equipment features a sealed enclosure design, reducing dust pollution and meeting local environmental protection requirements.
Finished Product Storage and Automated Packaging: Qualified granules are conveyed to the finished product warehouse via a 7-meter belt conveyor for temporary storage. The warehouse is a custom-designed steel-structure plant with a sealed structure and a dehumidification and ventilation system to effectively prevent fertilizer from absorbing moisture and clumping, ensuring product storage stability. The warehouse capacity can meet the storage needs of 5 consecutive hours of full-load production. Material level sensors are installed inside the warehouse to provide real-time inventory feedback, facilitating customers to rationally plan their shipments. The packaging process utilizes an automatic packaging scale that supports rapid switching between various packaging sizes such as 25kg and 50kg. Employing gravity-based metering principles and high-precision sensors, the metering error is ≤±0.2kg, with a packaging speed of up to 80 bags/hour. This enables rapid, quantitative packaging of finished products, and, in conjunction with the subsequent transfer system, efficiently completes finished product warehousing and shipping.
Core Advantages of the Production Line and its Compatibility with Steel Structures
Exclusive Optimized Design for Steel Structures: All equipment in the production line is customized and optimized for the spatial dimensions, load-bearing standards, and ventilation conditions of steel structure workshops. The equipment layout is compact and rational, requiring only 450 square meters of space, saving 25% compared to traditional production lines. Simultaneously, optimized equipment maintenance access adapts to the maintenance needs of steel structure workshops, ensuring convenient and efficient operation and maintenance.
Stable, Reliable, and Highly Adaptable: Core equipment uses high-temperature, wear-resistant, and corrosion-resistant materials, adapting to the tropical climate of Colombia and effectively resisting the impact of high temperature and humidity. The 3.0-type extrusion granulator can flexibly adapt to various materials such as organic fertilizer, compound fertilizer, and bio-organic fertilizer, supporting rapid switching between different formulations to meet the diverse agricultural fertilization needs of the region.
High Efficiency, Energy Saving, and Cost-Effectiveness: The entire production line uses energy-saving motors and optimized process design, reducing energy consumption by 13% compared to conventional production lines with the same capacity. The equipment has a high degree of modularity, short installation cycle, and standardized design for key components. Wear parts are highly interchangeable. The company provides comprehensive spare parts supply and overseas technical guidance services, significantly reducing customers’ subsequent operation and maintenance costs. The successful commissioning of the Colombian steel extrusion pelletizing production line not only demonstrates Huaqiang Heavy Industry’s comprehensive strength in high-end pelletizing equipment R&D, customized steel structure design, and overseas project implementation, but also provides efficient and stable equipment support for the modernization of agriculture in South America. In the future, Huaqiang Heavy Industry will continue to focus on the production conditions and needs of different regions, optimize product performance and service solutions, and provide global customers with more competitive customized solutions, allowing “Made in China” to shine even brighter in the international market.
Expert Application of Dry Granulation Technology
This successful Colombian project showcases the practical application of a specialized extrusion granulation line, expertly engineered for a steel structure environment. It is a prime example of a specific fertilizer granulation technology being deployed to meet localized production needs efficiently.
The core of this line is the fertilizer compactor performing fertilizer granules compaction, which falls under the category of dry granulation processes. This method is one of several fertilizer granulation processes available to manufacturers. In the broader context of the npk manufacturing process, producers can choose between different types of fertilizer processing machine technologies. For dry compaction, a roller press granulator production line is typically used. For wet granulation, a rotary drum granulator would be the appropriate choice. Each technology represents a different pathway within the overall suite of fertilizer granulation technology, allowing producers to select the optimal method based on raw material properties and final product requirements. this project underscores the importance of matching the right granulation technology to the specific physical, chemical, and economic constraints of the production site, ensuring both operational efficiency and product quality.
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