Recovered Carbon Black (RCB) is obtained from the pyrolysis of waste tires and is widely used in rubber, plastics, masterbatch, and pigment applications. To make it suitable for end-use, RCB requires ultra-fine grinding with tight particle size distribution (PSD) and removal of agglomerates.
Due to its high bulk density, dusty nature, and tendency to form agglomerates, conventional grinding systems often face challenges such as inconsistent fineness, poor dispersion, and handling issues.
The Air Classifying Mill (ACM) system provides a high-efficiency solution for producing ultra-fine carbon black powder. Its integrated grinding and classification design ensures precise micron-level control, high recovery, and closed-loop dust-free operation.
This application note outlines the process flow, system design, technical performance, and advantages of an ACM plant optimized for Recovered Carbon Black grinding.
Design and Working Principle
The grinding system operates on a continuous, automated principle comprising the following stages:
Step 1: Material Feeding
Recovered Carbon Black is fed into the system through a feed hopper.
A Rotary Airlock Valve (RAL) ensures:
- Uniform and controlled feeding
- Air sealing to maintain system pressure balance
- Prevention of backflow
Step 2: Fine Grinding in ACM Rotor
Material enters the ACM grinding chamber where it is subjected to high-speed rotor action.
Grinding occurs due to:
- Impact forces
- Shearing forces
- Particle-to-particle collision
- Air turbulence
The rotor creates strong airflow, keeping particles suspended and ensuring efficient micronisation.
Step 3: Air Classification
The ground material enters the dynamic classifier zone.
- Classifier wheel rotates at controlled speed (VFD driven)
- Fine particles pass through and exit with airflow
- Coarse particles are rejected and returned for regrinding
This ensures :
- Ultra-fine grinding (~8 micron)
- Narrow PSD
- High dispersion quality
Step 4: Pneumatic Conveying
The centrifugal fan generates airflow that:
- Conveys material to downstream system
- Maintains system pressure balance
- Enhances classification efficiency
Step 5: Bag Filter & Product Collection
The air-material mixture enters the bag filter where:
- Powder is separated from air
- Fine particles are collected efficiently (>99%)
- Clean air is exhausted
Pulse-jet cleaning ensures continuous operation without choking.
Step 6: Product Discharge
Collected powder is discharged via Rotary Airlock Valve into:
- Storage silos
- Jumbo bag filling systems
- Downstream processing
Model Variants
| Variant | Model | Capacity (Approx.) | Target Fineness |
|---|---|---|---|
| RCB-150 | ACM 150 | 450 – 500 kg/hr | 90% < 8 microns |
| RCB-250 | ACM 250 | 650 – 750 kg/hr | 90% < 8 microns |
⚠️ Capacity may vary depending on feed characteristics and fineness requirement.
Key Components
| Component | Function | Key Technical Feature |
|---|---|---|
| ACM Mill | Grinding & classification | High-capacity mill, ultra-fine grinding (~8 micron) |
| Feed Hopper + RAL | Controlled material feeding | Uniform feed, airlock sealing |
| Bag Filter (TRL Type) | Powder separation & dust control | >99% recovery, pulse-jet cleaning |
| Rotary Airlock Valve | Product discharge | Maintains pressure balance |
| Centrifugal Fan with Silencer | Airflow generation | Cooling, conveying, noise reduction |
| Ducting System | Equipment interconnection | Optimized airflow, low pressure drop |
| Control Panel (MCC/PLC) | System control & monitoring | VFD control, interlocks, automation ready |
Key Features & Benefits
- Ultra-Fine Grinding Capability
- Consistent Product Quality
- High Product Recovery (>99%)
- Dust-Free Operation
- Suitable for High Bulk Density Material
- Energy Efficient System
- Continuous Operation
- Automation & Easy Control
Achieves ~8 micron particle size suitable for high-end applications.
Dynamic classifier ensures narrow PSD.
Efficient bag filter minimizes material loss.
Fully enclosed system ensures clean and safe working conditions.
Designed for handling dense powders (1100–2200 kg/m³).
Optimized airflow reduces power consumption.
Designed for industrial 24/7 operation.
PLC/MCC system with VFD enables process control.
Applications
- Rubber Compounding
- Plastic Masterbatch
- Pigments & Coatings
- Carbon Black Replacement
Model Variants
| Variant | Model | Capacity (Approx.) | Target Fineness |
|---|---|---|---|
| RCB-150 | ACM 150 | 450 – 500 kg/hr | 90% < 8 microns |
| RCB-250 | ACM 250 | 650 – 750 kg/hr | 90% < 8 microns |
Performance Parameters
| Characteristic | Specification |
|---|---|
| Feed Size | ~100 micron |
| Final Fineness | 90% < 8 microns |
| Bulk Density | 1100 – 2200 kg/m³ |
| Product Recovery | > 99% |
| Operating Temperature | Ambient |
| Noise Level | ~110 dB (without acoustic enclosure) |