2026/08/05
A granulation recycled system refers to a closed-loop recycling system where, during the screening process, oversized particles and overly fine powder are conveyed back to the crusher or granulator for reprocessing. The core value of this process lies in achieving full utilization of production materials, automatically returning unqualified products to the production line for reprocessing, ultimately achieving a raw material utilization rate close to 100%.
I. Operation Flow of the Recycled System After granulation, the granules are dried and cooled before entering a vibrating screen for grading. The screener is typically equipped with multiple layers of screens, separating the material into three levels:
Qualified granules (target size, e.g., 2–5 mm): Enter the coating or packaging process, becoming the final product;
Oversized particles (>5 mm): Sent to the crusher via a recycled conveyor belt, pulverized into fine powder, and returned to the granulator;
Overly fine powder (<2 mm): Directly returned to the granulator via the recycled pipeline, serving as "core seed" for the next round of granulation.
This cycle is not an intermittent "waste recycling," but rather a synchronized, automatic, and continuous operation with the main machine, an indispensable component of the entire granulation production line.
II. Core Advantages of the Recycling System
1. Extremely High Raw Material Utilization Rate, Significantly Reducing Costs
On production lines without a recycling system, undersize and oversize materials are typically piled up as waste or disposed of at low cost, resulting in a raw material waste of 5%–15%. With a recycling system, all defective materials are returned for reprocessing, achieving a comprehensive raw material utilization rate of over 99%, significantly reducing the raw material cost per unit product.
2. Ensuring Consistent Product Particle Size
Through the continuous circulation of the recycling system, the granulator can achieve a stable "recycle ratio" (typically controlled at 20%–30% of the feed rate), which helps maintain the dynamic balance of material quantity and stable particle size control within the granulator, thereby ensuring good uniformity and a high pass rate in the finished product.
3. Achieving Continuous Clean Production
The recycling system enables closed-loop operation of the production line, avoiding the accumulation and transfer of intermediate waste materials. This not only saves labor costs but also reduces workshop dust and material loss, meeting clean production requirements. 4. Improve Production Line Automation Modern recycling systems are equipped with automatic metering devices that monitor the amount of recycled material in real time and provide feedback to the central control system. When the amount of recycled material suddenly increases, the system can automatically issue an early warning or adjust granulation parameters, detecting process deviations in advance.
III. System Design and Selection Considerations Key equipment in a recycling system includes a vibrating screen, a recycling conveyor belt (or bucket elevator), and an intermediate silo. During design, the following should be considered: the recycling conveying route should be as short and straight as possible to reduce secondary crushing and dust generation; the recycling silo capacity should be able to accommodate at least 2-4 hours of recycled material to buffer the rhythm differences between preceding and following processes; an iron removal device should be installed during the conveying process to prevent metal impurities from entering the crusher and damaging the hammers.
When building a new fertilizer production line, the matching of the recycling system is one of the important indicators for evaluating the technical strength of the equipment supplier. A well-designed recycling system can increase the overall production line's operating rate by more than 10%, making it one of the auxiliary systems with the highest return on investment.
The granulation recycling system is not an isolated auxiliary unit — it is the circulatory system that ensures efficiency and sustainability across the entire fertilizer production line. In a typical compound fertilizer production technology process, the recycling loop works hand‑in‑hand with the fertilizer granulator machine (whether a disc, drum, or extrusion type) to maintain a stable material balance, preventing fluctuations that could affect particle size and nutrient uniformity. For NPK production, the npk granulation machine technology relies heavily on a well‑tuned recycling ratio (typically 20‑30%) to achieve consistent granule strength and dissolution rates. After granulation and drying, the screened overs and fines are returned, and the final qualified granules proceed to the npk blending machine or npk bulk blending machine (and the BB fertilizer blender for custom blends) where additional trace elements or coatings are added to meet specific crop needs. The entire loop — from the npk fertilizer granulator machine through screening, recycling, and blending — creates a closed‑loop system that minimises waste, reduces raw material costs, and delivers a uniform, high‑quality product. Moreover, modern recycling systems equipped with automated weight sensors and feedback controls enable real‑time adjustment of granulation parameters, significantly improving line uptime and product consistency. Investing in a properly designed recycling loop, integrated with advanced granulation and blending equipment, is one of the most cost‑effective decisions for any compound fertilizer plant — transforming what would be waste into profit, while meeting stringent quality standards for every batch.