The horizontal mixer is responsible for the uniform mixing of base raw materials. The equipment features a U-shaped horizontal vessel equipped with an internal rotor consisting of dual-layer (inner and outer) spiral ribbons or mixing paddles. Upon entering the vessel, materials undergo axial and radial circulation driven by the rotating rotor: the inner ribbon pushes material from the center toward the ends, while the outer ribbon pushes it back from the ends to the center, creating a large-scale convective circulation pattern. Horizontal mixers are highly adaptable to powdered, granular, and even high-viscosity materials, offering rapid mixing speeds, high uniformity, and minimal residue. For organic materials with high fiber content and high viscosity, a twin-shaft organic fertilizer mixer provides a more robust solution; two parallel mixing shafts rotate synchronously in opposite directions, subjecting the material to simultaneous shearing, compression, and convection, resulting in mixing performance significantly superior to that of single-shaft equipment.

In the context of bulk blend (BB) fertilizer production, NPK blenders and BB fertilizer blending lines execute precise formula preparation. BB fertilizer production is essentially a purely physical process: pre-granulated single-nutrient fertilizers—such as large-granule urea, monoammonium phosphate (MAP), and potassium sulfate—are blended directly according to soil-test-based formulations. The complete BB fertilizer blending line comprises a raw material storage and conveying system, a high-precision batching system, an NPK blender, and an automatic packaging system. The NPK blender utilizes a twin-shaft paddle or "zero-gravity" mixing structure, specifically optimized to mitigate the stratification and segregation issues that can occur when blending granules of varying densities and sizes. The equipment features a gentle mixing process, achieving uniform blending within 3 to 5 minutes without damaging the original shape of the granules. The entire line utilizes centralized PLC control, ensuring high dosing precision and flexible recipe switching; a single production line can manufacture dozens of different product formulations in a single day.

The core equipment in the granulation stage is the fertilizer roller press granulator. It employs a dry extrusion process, utilizing a pair of counter-rotating, high-strength pressure rollers as its primary working components. Powdered materials are fed into the gap between the rollers by a metering feeder and compressed into dense, sheet-like cakes under high pressure. A key advantage of the roller press granulator is its ambient-temperature, dry process; it requires no water or heat, eliminating the drying and cooling stages found in traditional wet granulation and significantly reducing energy consumption. The roller extrusion granulation line comprises a crusher, feeder, mixer, roller press granulator, screening machine, and packaging machine. The production process consists mainly of three stages—extrusion, crushing, and screening—offering a high degree of automation and zero discharge of waste gas, wastewater, or solid waste. The equipment has strict requirements regarding raw material moisture content, typically necessitating levels below 5%; the resulting granules possess high strength and high bulk density, making them resistant to pulverization during storage and transport.

Post-granulation processing is equally critical, with the fertilizer coating machine playing a pivotal role in functional coating. Using a spraying system within a rotating drum, the machine applies anti-caking agents, slow-release materials, or protective agents for functional bacteria evenly onto the granule surfaces. The core technology lies in precisely balancing the spray volume with the drum's rotational speed; insufficient spraying leads to uneven coverage, while excessive spraying causes the granules to stick together. Designed with atomizing nozzles and a variable-speed drum, the coating machine ensures a uniform and controllable coating thickness, effectively preventing caking caused by moisture absorption during storage. In the production of slow- and controlled-release fertilizers, the machine also applies materials such as sulfur or resin, allowing for precise control of nutrient release rates by adjusting the coating thickness. This four-stage equipment assembly covers the entire fertilizer production chain—from raw material processing to final product modification—encompassing basic mixing in horizontal mixers, precise blending in BB fertilizer lines, dry granulation via roller presses, and functional coating in fertilizer coaters. Whether producing organic, compound, or functional fertilizers, this system offers flexible configurations tailored to specific process requirements, ensuring both high quality and operational efficiency for manufacturers.