Author: organic fertilizer production line

In the agricultural input market, “Formula Fertilizer No. 7” is a frequently chosen option by farmers when purchasing fertilizers for the fruit enlargement period. However, it is not a nationally standardized number, but rather a custom-designed formula code used within the industry. As a specialized fertilizer designed specifically for the reproductive growth stage of crops, Formula Fertilizer No. 7 features “high potassium, low nitrogen, and medium phosphorus” as its core characteristics, precisely matching the nutrient requirements for fruit enlargement, coloring, and sweetening. It has become a key fertilizer for improving the yield and quality of fruits and cash crops, and is also a standard “fruit enlargement fertilizer” commonly used in the agricultural input industry.

The core advantage of Formula Fertilizer No. 7 lies in its scientific nutrient ratio. The classic formula ratios for mainstream Formula Fertilizer No. 7 in the industry are mostly 15-5-20, 16-6-22, etc., with the core characteristics of potassium content not less than 20%, nitrogen content moderate to low, and phosphorus content moderate. Potassium, known as a “quality element,” promotes the transport of photosynthetic products to fruits and seeds, effectively improving fruit sweetness, color, and firmness, and reducing fruit cracking and deformities. A low-nitrogen design prevents excessive vegetative growth, avoids nutrient competition, and ensures nutrient supply for reproductive growth. Appropriate phosphorus levels maintain root vitality, ensuring successful pollination and preventing empty seeds and fruit drop. Some manufacturers also add micronutrients such as calcium, magnesium, boron, and zinc to further enhance fertilizer efficiency.

Compared to other numbered fertilizer formulas, Formula 7 is highly targeted in its application. In the agricultural input industry, fertilizer formulations are typically categorized by crop growth stage and nutrient emphasis: Fertilizer No. 1 is high in nitrogen, low in phosphorus, and low in potassium, suitable for promoting seedling growth and leaf development; Fertilizer No. 2 has a balanced nitrogen, phosphorus, and potassium content, suitable for general supplemental fertilization throughout the crop’s growth period; Fertilizer No. 3 is high in phosphorus, medium in nitrogen, and low in potassium, primarily promoting root and flower development; while Fertilizer No. 7, with its “low nitrogen, medium phosphorus, and high potassium” formulation, is specifically targeted at critical reproductive stages such as fruit expansion, grain filling, and coloring, making it a dedicated fertilizer for the crop’s yield and quality formation stages. This clear positioning allows farmers to quickly and accurately select the right fertilizer.

Fertilizer No. 7 has a wide range of applications, especially suitable for crops with high potassium requirements. In fruits and vegetables such as watermelon, strawberries, tomatoes, grapes, and citrus, application significantly improves fruit expansion speed and fruit quality; in cash crops such as peanuts and soybeans during the pod-setting stage, and sweet potatoes and potatoes during the tuber enlargement stage, application increases yield and marketability; even in field crops such as rice and corn, application during the grain-filling stage and the late trumpet stage can improve grain plumpness. The optimal application time is during the fruit enlargement stage after flowering, typically 2-3 times consecutively, with an interval of 10-15 days, to maximize its effectiveness.

When applying Formula 7 fertilizer, attention must be paid to its suitability and scientific formulation. For chlorine-sensitive crops such as grapes, citrus, and sweet potatoes, potassium sulfate-based Formula 7 fertilizer should be chosen; for field crops, potassium chloride-based formula can be used to reduce planting costs. It is mainly used as a top dressing or fertigation fertilizer and cannot replace base fertilizer; it should be used in combination with organic fertilizer or balanced fertilizer as a base fertilizer. Foliar spraying with potassium dihydrogen phosphate and boron fertilizer during the fruit enlargement stage can further enhance the quality improvement effect. In addition, some manufacturers adjust the formula according to regional soil characteristics; for example, Formula 7 fertilizer for acidic soils in the south adds calcium and magnesium to adjust the acidity, while Formula 7 fertilizer for greenhouses uses a fully water-soluble formula suitable for drip irrigation. Farmers can choose according to their needs.

Manufacturing Precision: From Formula No. 7 to Professional Production

The widespread use of specialized formulas like Fertilizer No. 7 is enabled by sophisticated, flexible production systems. This precise formulation of “high potassium, low nitrogen, medium phosphorus” requires a manufacturing process that can accurately blend and shape specific nutrient ratios to meet exacting market demands.

The creation of such products is the domain of modern professional fertilizer manufacturing equipment. A typical npk fertilizer production line for this purpose would begin with a precise npk blending machine to mix raw materials to the exact No. 7 specification. This mixture is then formed into granules using specialized fertilizer granulator technology. Manufacturers might choose a disc granulation production line featuring a disc granulator (or disc granulator for shaping) for rounded particles, or a roller press granulator production line with a double roller press granulator for high-density granules. This entire sequence forms the core of the npk fertilizer production process. For producers also offering organic options, this specialized NPK line could be complemented by a separate organic fertilizer production line that begins with raw material processing using a windrow composting machine.

Ultimately, the availability of targeted fertilizers like Formula No. 7 is a direct result of advanced, adaptable manufacturing technology that can efficiently translate agronomic science into precise, high-quality products for farmers.

In summary, Formula 7 fertilizer is a high-potassium fertilizer specifically designed for the reproductive growth stage of crops. Its scientific nutrient ratio precisely addresses the nutrient requirements during the fruit enlargement stage. For farmers pursuing high and high yields, choosing the right No. 7 compound fertilizer and applying it scientifically can safeguard crop quality and yield, becoming an important aid to precision fertilization in modern agriculture.

The sodium carbonate (soda ash) extrusion granulation production line focuses on the solidification and molding needs of powdered sodium carbonate. With “precise pretreatment – high-pressure extrusion – grading and screening – finished product output” as its core process, it achieves a stable production capacity of 4m³/hour (approximately 6.8 tons, based on a sodium carbonate density of 1.7g/cm³) through customized equipment configuration and process optimization. The finished granules are characterized by high strength, good flowability, and low moisture absorption, making them suitable for applications in chemical, building materials, and environmental protection industries.

Production Line Configuration and Core Details

I. Raw Material Pretreatment Unit: Ensuring Basic Granulation Quality

(I) Raw Material Storage and Feeding System

Raw Material Silo: Equipped with one 10m³ conical raw material silo, made of 304 stainless steel (resistant to slight corrosion from sodium carbonate). The silo has a 60° cone angle and is equipped with a vibrator and a star-shaped unloader at the bottom to prevent powder bridging and blockage. The raw material silo is equipped with a pulse dust collector at the top to collect dust generated during the feeding process. The dust emission concentration is ≤10mg/m³, meeting environmental protection standards.

Quantitative feeding device: A variable frequency controlled screw feeder (model LS300) is used, with the feeding rate precisely adjustable within the range of 2-5m³/h, suitable for a production capacity of 4m³/h. The feeder shell adopts a sealed design, and the internal spiral blades are treated with a wear-resistant coating to reduce wear on the equipment caused by sodium carbonate powder and prevent moisture absorption and agglomeration.

(II) Raw material drying and crushing pretreatment

Low-temperature dryer: Because sodium carbonate is prone to moisture absorption and agglomeration, one Φ1.2×6.0 meter drum dryer is configured. Hot air circulation heating is used, and the drying temperature is controlled at 80-100℃, reducing the raw material moisture content from ≤5% to ≤0.5%, avoiding agglomeration that affects extrusion molding. The dryer has a built-in lifting plate spiral layout, ensuring uniform heating of the material, with a drying uniformity error of ≤2%. Fine Pulverizer: A 400-type vertical pulverizer is selected, with a cutter disc made of high-chromium wear-resistant alloy. It pulverizes any lumps (particle size ≤20mm) that may exist after drying into uniform powder ≤1mm, ensuring consistent raw material fineness and improving extrusion granulation rate. The pulverizer is equipped with a grading screen, allowing flexible adjustment of the discharge particle size. The pulverizing efficiency reaches 6m³/h, meeting the continuous operation requirements of the production line.

II. Core Extrusion Granulation Unit: Key Link in High-Pressure Molding

(I) Precise Feeding and Pre-compression

Twin-Screw Pre-compressor: The pulverized sodium carbonate powder is conveyed to the twin-screw pre-compressor via a 1.5-meter belt conveyor. Through spiral extrusion, the loose powder is pre-compressed into a dense column with a density of 1.2g/cm³, avoiding problems such as uneven pressure and low granulation rate caused by direct entry into the granulator. The pre-compressor is equipped with a material level sensor, automatically linking with the front-end feeder to adjust the feed rate, ensuring stable material supply.

(II) High-Pressure Extrusion Granulation Main Unit

Core Equipment Selection: Two 2.5-type double-roller press granulators, each with a capacity of 2 m³/h, operate in parallel, achieving a total capacity of 4 m³/h. The granulator rollers are made of wear-resistant alloy steel, hardened to a hardness of HRC62 or higher, and feature customized anti-slip textures (0.8 mm depth) to enhance powder penetration.

Key Parameter Design: The extrusion pressure is precisely controlled at 12-18 MPa via a hydraulic system, ensuring that sodium carbonate powder is fully extruded and shaped within the die, resulting in granules with a compressive strength exceeding 3.0 MPa and minimal pulverization. The roller diameter is 400 mm, the roller width is 250 mm, and the die diameter can be customized (3-8 mm). A single unit achieves a stable hourly output of 2 ± 0.2 m³/h. Auxiliary Function Configuration: The granulator is equipped with an automatic roller cleaning device and a die hole unblocker to remove material adhering to the roller surface in real time, preventing die hole blockage and extending continuous operating time (≥8 hours per continuous run). Equipment operating noise is controlled below 75dB, meeting industrial production noise standards.

III. Post-processing and Finished Product Output Unit: Optimizing Quality and Efficiency

(I) Particle Crushing and Grading Screening

Roller Crusher: The extruded flaky granules are conveyed to a double-roller crusher via a 4-meter belt conveyor, crushing the flaky granules into irregular particles (3-8mm in diameter). The crusher roller gap is adjustable (1-5mm) to ensure uniform particle size after crushing.

Grading and Screening Machine: Equipped with one Φ1.5×4.0 meter drum screen, featuring a double-layer screen design. The upper screen (8mm aperture) separates oversized particles, while the lower screen (3mm aperture) screens for qualified particles. Unqualified particles (too coarse or too fine) are returned to the crusher for reprocessing via a return conveyor belt, achieving a material utilization rate of 98%. The screen is equipped with a vibration cleaning device to prevent screen clogging, achieving a screening efficiency of 5 m³/h.

(II) Finished Product Cooling and Moisture Prevention Treatment

Cooler: Qualified particles enter a Φ1.0×8.0 meter counter-current cooler, using ambient air to rapidly reduce the particle temperature from 60-80℃ to room temperature (±5℃), preventing high-temperature particles from absorbing moisture and clumping. The cooler is equipped with an induced draft device to enhance heat exchange efficiency, with cooling time controlled within 15 minutes. After cooling, the particle moisture content stabilizes at ≤0.5%. Moisture-resistant coating (optional): One Φ1.0×3.0 meter coating machine can be added according to customer needs. Using atomized spraying technology, a small amount of anti-moisture agent (such as calcium stearate, ≤0.3%) is evenly adhered to the granule surface, forming a dense protective film to further enhance the finished product’s moisture resistance and extend its shelf life.

(III) Finished Product Storage and Packaging

Finished Product Warehouse: Two 10m³ finished product warehouses (total volume 20m³) are configured. They feature a sealed design and are equipped with dehumidification and ventilation devices to maintain a relative humidity of ≤50% to prevent moisture absorption by the finished product. A star-shaped unloader is installed at the bottom of the warehouse for quantitative discharge.

Automated Packaging: A dual-station automatic packaging scale is used, supporting rapid switching between 25kg and 50kg specifications. The metering error is ≤±0.2kg, and the packaging speed reaches 120 bags/hour. The packaging machine is equipped with a dust cover and bag sealing device to reduce powder flying. Packaged finished products are transferred to the finished product stacking area via belt conveyor.

IV. Environmental Protection and Auxiliary Systems: Ensuring Stable and Environmentally Friendly Production

(I) Dust Control System Each dust-generating stage of the production line (raw material silo feeding, crusher, screening machine, packaging machine) is equipped with a pulse dust collector. A total of 3 MC-96 pulse dust collectors are installed, with a total air volume handling capacity of 15,000 m³/h and a dust collection efficiency of 99.5%, ensuring that the dust concentration in the workshop is ≤8 mg/m³, meeting national environmental protection standards.

The dust collected by the dust collectors is returned to the raw material pretreatment stage via a screw conveyor and reused in production, avoiding material waste.

(II) Intelligent Control System An integrated PLC central control system is provided, equipped with a touch screen operating interface. It can monitor the operating parameters of each piece of equipment in real time (feed rate, extrusion pressure, drying temperature, particle temperature, etc.), and supports automatic fault alarms and data recording (recording cycle ≥30 days). The system supports manual and automatic mode switching, facilitating operator management and maintenance.

(III) Equipment Protection and Adaptation Design

All equipment in contact with sodium carbonate (raw material silos, feeders, granulators, etc.) is made of mildly corrosive materials or treated with anti-corrosion coatings to prevent sodium carbonate from corroding the equipment.

The production line has a compact overall layout, occupying an area of ​​approximately 600 square meters. Maintenance access channels (≥1.2 meters wide) are reserved between each piece of equipment for easy future maintenance. The equipment foundations are designed to withstand vibrations, reducing the impact of vibrations during the extrusion granulator operation.

Core Advantages and Application Value of the Production Line

Stable and Efficient Production Capacity: The dual-machine parallel extrusion granulation design achieves a precise hourly output of 4 m³, with an annual capacity of up to 30,000 tons (based on 300 days of operation per year and 8 hours per day), meeting the needs of large-scale production.

Excellent Finished Product Quality: The high-pressure extrusion molding process ensures high particle strength, resistance to pulverization, low moisture content, and strong moisture resistance, making it suitable for long-distance transportation and long-term storage. Environmentally friendly and energy-saving: The fully sealed design and pulse dust removal system result in minimal dust pollution; the dryer uses hot air circulation, which reduces energy consumption by 15% compared to conventional drying equipment, and keeps operating costs under control.

From Industrial Chemicals to Agricultural Inputs: A Shared Technology Base

The successful application of this sodium carbonate extrusion granulation line underscores the versatility of modern dry compaction technology. While designed for industrial chemicals, its core principles are directly transferable to the agricultural sector, highlighting a shared foundation in precision npk granulation machine technology.

The high-pressure extrusion process used here is essentially the same technology employed in a roller press granulator within a dedicated roller press granulation production line for fertilizer. This demonstrates how equipment like a npk fertilizer granulator machine operates on similar mechanical principles. For agricultural applications, a complete npk fertilizer production line integrates this granulation step into a broader npk fertilizer manufacturing process. This process begins with precise formulation using an npk blending machine or npk bulk blending machine, followed by granulation via the npk fertilizer granulator, and concludes with coating and packaging. The entire npk fertilizer production technology is an integrated system where each machine, from blender to granulator, plays a specific role in the npk fertilizer production process.

Thus, expertise in granulating sodium carbonate translates directly into the capability to produce high-density, low-dust NPK fertilizers, showcasing the interdisciplinary nature of advanced granulation engineering.

This innovative carbon-based fertilizer disc + drum granulation production line integrates two processes: “disc pre-granulation + drum finishing.” Specifically designed for the granulation needs of carbon-based raw materials (straw charcoal, bamboo charcoal, biochar, etc.), it solves the granulation pain points of lightweight and poor binding properties of carbon-based raw materials through a closed-loop process of “pre-forming + densification.” This enables large-scale, high-quality production of carbon-based fertilizer, suitable for green development scenarios such as ecological agriculture and organic farming.

Production Line Configuration and Core Details

Raw Material Pre-treatment Unit: Laying the Foundation for Granulation

(I) Raw Material Storage and Precision Batching

Multi-Compartment Storage System: Equipped with 5 raw material compartments (total volume 120m³), storing biochar, organic fertilizer fermentation material, nitrogen, phosphorus, and potassium inorganic fertilizer, binders (such as bentonite and starch), and trace elements respectively. The compartments are made of carbon steel with an anti-corrosion coating, and vibrators and star-shaped unloaders are installed at the bottom to prevent bridging and clogging of carbon-based raw materials.

Precision Batching Device: Employs a frequency-controlled screw feeder, with 5 batching systems operating synchronously, achieving a batching error of ≤±1%. The proportion of biochar can be flexibly adjusted (30%-60%), the ratio of inorganic to organic fertilizer is customized according to crop needs, and the binder addition is controlled at 3%-8% to ensure pellet formation rate.

(II) Raw Material Mixing and Moisture Adjustment

Twin-Shaft Mixer: A 50-type twin-shaft mixer is used. The impellers employ an anti-rotation design, driving strong convection and shearing of the materials to thoroughly mix the charcoal-based raw materials with other components, achieving a mixing uniformity error of ≤2%. The mixer is equipped with a spray humidification device to precisely adjust the raw material moisture content to 28%-35% (suitable humidity for the charcoal-based raw materials), preventing clumping due to excessive moisture or insufficient adhesion due to insufficient moisture.

Pulverization Pretreatment: If large lumps (particle size > 10mm) of biochar exist, they are first crushed to ≤3mm using a 400-type vertical pulverizer to ensure uniform raw material fineness and improve subsequent granulation results. The pulverizer is equipped with a cyclone dust collector to collect and reuse the crushed dust, achieving a material utilization rate of 99%. II. Core Dual Granulation Unit: Carbon-Based Particle Densification Forming

(I) Disc Pre-granulation: Key to Lightweight Material Pre-forming

Core Equipment Selection: Two Φ3.2×1.2 meter disc granulators (3-5 tons per hour per unit), with an adjustable inclination angle of 45°-55° and a rotation speed controlled at 20-30 r/min. The discs are lined with wear-resistant rubber plates to prevent wear from the carbon-based raw materials and enhance material adhesion.

Pre-granulation Process Details: The mixed raw materials are fed into the disc granulator. Through the centrifugal force and friction generated by the rotating disc, spherical wet particles with a diameter of 5-8 mm are formed (granulation rate ≥85%). A scraper is installed at the edge of the disc to promptly clean material adhering to the wall, and a spray device replenishes moisture in real time to ensure that the pre-formed particles are round and uniform, laying the foundation for drum finishing.

(II) Rotary Drum Granulation: Particle Densification Upgrade

Core Equipment Configuration: One Φ2.2×10 meter rotary drum granulator (6-10 tons per hour) is used, precisely matched with the capacity of the disc granulator. The inner wall of the drum is lined with wear-resistant ceramic plates, combined with a spiral layout of lifting plates, driving the material through a “tumbling-rolling-collision” motion to achieve particle densification.

Refinement Process Highlights: A spray device is installed inside the drum to replenish a small amount of binder solution, further rolling the pre-formed granules into dense granules of 3-6mm, increasing the particle strength from 1.2MPa to over 2.5MPa, solving the problem of easy pulverization of carbon-based granules. The drum speed is adjustable from 10-18 r/min, and the material residence time is 8-12 minutes to ensure dense and uniform particles.

III. Post-processing Unit: Quality Optimization and High-Efficiency Output

(I) Drying and Cooling Curing

Low-Temperature Dryer: Equipped with a Φ1.8×18 m drum dryer, using hot air circulation heating, the drying temperature is controlled at 70-90℃ (to avoid high temperature damage to carbon-based nutrients), reducing the particle moisture content from 30% to below 12%. The dryer has a built-in staggered lifting plate layout, ensuring uniform heating of the carbon-based particles, with a drying uniformity error ≤2%.

Dual-Stage Cooler: Employing a “first-stage counter-current cooling + second-stage co-current cooling” process, the particle temperature is first reduced from 70-80℃ to below 40℃ by a Φ1.6×15 m counter-current cooler, and then cooled to room temperature ±3℃ by a Φ1.2×12 m co-current cooler, further improving particle strength and moisture resistance. The cooler is equipped with a pulse dust collector to collect dust for recycling.

(II) Grading and Finished Product Processing

Grading and Screening Machine: A Φ1.5×6.0 meter drum screen with a double-layer screen design (upper layer aperture 6mm, lower layer aperture 3mm) is used to screen out qualified particles (3-6mm). Unqualified particles are returned to the disc granulator for reprocessing via a return conveyor belt, achieving a material utilization rate of 98%.

Anti-caking Treatment: When the screened finished particles are conveyed via conveyor belt, 0.1%-0.2% of an anti-caking agent (such as talc powder) is sprayed on them to ensure even mixing and prevent clumping during storage.

(III) Finished Product Storage and Packaging

Finished Product Silos: Two 100m³ sealed finished product silos are provided, equipped with dehumidification and ventilation devices to maintain a relative humidity of ≤60% to prevent the carbon-based fertilizer from absorbing moisture. A quantitative discharge device is installed at the bottom of the silo to achieve continuous and stable discharge.

Automated Packaging: Utilizing a dual-station automatic packaging scale, supporting rapid switching between 25kg and 50kg specifications, with a measurement error ≤ ±0.2kg and a packaging speed of 100 bags/hour. The packaging machine is equipped with a dust cover to reduce dust emissions, and the fully automated operation minimizes manual intervention.

Environmental Protection and Intelligent Control Unit: Stable Green Production

(I) Environmental Treatment System

Dust Treatment: Each dust-generating stage of the production line (crushing, screening, packaging) is equipped with a pulse dust collector, with a total processing air volume of 18000m³/h. Dust emission concentration ≤10mg/m³, meeting national environmental protection standards.

Wastewater Treatment: A small amount of cleaning wastewater during production is treated in a sedimentation tank and then recycled for raw material humidification, achieving zero wastewater discharge.

(II) Intelligent Control System

Integrated PLC central control system, real-time monitoring of key parameters such as ingredient ratio, moisture content, granulation speed, and drying temperature, supporting automatic fault alarms and data recording (storage period ≥90 days). The system supports manual and automatic mode switching and can dynamically adjust process parameters according to raw material characteristics to ensure stable production.

Core Advantages and Application Value of the Production Line

Breakthrough in Granulation Pain Points: The combined disc and drum granulation processes solve the problems of poor adhesion and low granulation rate of carbon-based raw materials. Granulation formation rate is consistently above 90%, with a strength exceeding 2.5 MPa, making it resistant to storage and transportation and less prone to pulverization.

Flexible Capacity: Hourly capacity covers 6-10 tons, with an annual capacity of 50,000-80,000 tons (based on 300 days of operation per year and 8 hours per day), adapting to the production needs of enterprises of different sizes.

Superior Product Quality: Carbon-based raw materials and nutrients are uniformly integrated, resulting in rounded granules with good flowability, facilitating mechanized fertilization. The slow-release characteristics of carbon-based components can improve fertilizer utilization by more than 30% and reduce nutrient loss.

Green, Environmentally Friendly, and Energy-Saving: High dust recovery and utilization rate; energy consumption is reduced by 12% compared to conventional single-process granulation production lines, meeting the requirements of green agricultural production.

A Specialized Link in a Broader Manufacturing Ecosystem

This carbon-based fertilizer granulation line represents a significant advancement in processing challenging, lightweight organic materials into high-quality, market-ready fertilizers. Its innovative dual-granulation approach sets a new standard for product quality and production efficiency in the niche of carbon-enriched soil amendments.

This specialized line is a prime example of professional fertilizer manufacturing equipment designed for a specific purpose. It exists within a larger ecosystem of fertilizer production technologies. For instance, the disc granulator used here is a key component in a disc granulation production line and can also serve as a disc granulator for shaping in other contexts. While this line produces organic-carbon blends, its principles complement other systems. A complete organic fertilizer production line might begin with a windrow composting machine to produce the base compost. For mineral-based production, an npk fertilizer production line would utilize an npk blending machine and different granulation technologies like a roller press granulator production line or a double roller press granulator as part of the npk fertilizer production process. Each type of fertilizer granulator serves a unique role in the diverse portfolio of modern fertilizer manufacturing.

Thus, this carbon-based line is not an isolated solution but an integral part of a comprehensive toolkit that allows manufacturers to meet the growing global demand for both specialized organic inputs and conventional high-analysis fertilizers.