Recovered Carbon Black (rCB), produced from pyrolysis chars of waste tires, plastics and biomass, serves as a critical sustainable substitute for virgin carbon black across the rubber, filler and composite sectors. Particle size stands as one of the most decisive quality metrics for rCB, as it directly impacts the material’s dispersion ability, reinforcement performance and compatibility with downstream applications.
For commercial high-grade rCB products, the typical target particle size is defined as D90 < 10μm. This specification indicates that 90% of the finished rCB particles measure less than 10 micrometers in diameter, and it has become the mainstream industry standard for premium rCB production.
Why D90 < 10μm is the typical standard
Raw pyrolysis char naturally forms coarse granules with heavily agglomerated structures, which cannot be directly applied in end products. Effective pulverization is required to break apart these carbon black agglomerates and unlock the material’s inherent functional value.
The D90 < 10μm fineness level is widely accepted as the optimal benchmark for two key reasons:
- It achieves thorough de-agglomeration of pyrolysis char granules, fully releasing the reinforcement properties of carbon black.
- It preserves the native structural integrity of rCB, avoiding performance degradation caused by excessive grinding.
How to consistently achieve this typical particle size
Stable and reliable D90 < 10μm particle size control relies on a complete precision processing workflow covering pre-treatment, grinding, classification and intelligent regulation. As a leading supplier of rCB grinding and classification systems, JACAN Powder Equipment delivers this precise fineness control through four core processes:
1. Raw Material Pre-treatment & Magnetic Separation
Optimized for various pyrolysis char feedstocks, this step removes residual steel wires and solid impurities via high-intensity magnetic separation. Clean feedstock not only protects downstream equipment, but also ensures stable feeding conditions for consistent fineness control.
2. Ultra-fine Grinding & Agglomerate De-clumping
Raw pyrolysis granules undergo micron-level pulverization in specialized grinding systems. With precise parameter regulation, the process effectively breaks down carbon black agglomerates to reach the D90 < 10μm fineness target, while maintaining the material’s structural integrity and reinforcement characteristics.
3. High-Precision Aerodynamic Classification
After grinding, the powder enters dedicated air classifiers for size and density-based separation. This stage screens out oversized particles, narrows the particle size distribution, and achieves an accurate cut-point through refined aerodynamic tuning. It is the critical process to guarantee the final product uniformly meets the D90 < 10μm standard.
4. Multi-Parameter Intelligent Optimization
The system supports real-time adjustment of operating frequency, feed rate and air velocity. This flexible control enables high-yield rCB production adapted to pyrolysis materials from different sources and production processes, ensuring consistent particle size performance even with varying raw material traits.
Industry adoption of the D90 < 10μm standard
The D90 < 10μm particle size has been widely recognized as the typical specification for high-performance rCB in the global recycled carbon industry. It is the standard fineness adopted by most top-tier rCB manufacturers to ensure their products can match the application requirements of virgin carbon black in tires, industrial rubber goods and polymer filling scenarios. As China’s premier provider of rCB and pyrolysis char grinding and classification solutions, JACAN has earned the trust of over 100 industry leaders. Its high-efficiency dry processing systems, which deliver reliable D90 < 10μm particle size control and high product purity, now serve more than 35% of the world’s top-tier recovered carbon black processors.
Conclusion
D90 < 10μm is the established typical particle size for commercial high-quality recovered carbon black. Realizing this index requires systematic precision processing technology, and it is also the core quality benchmark that supports rCB as a competitive sustainable alternative in the carbon black market.
