Calcined Clay is widely used in ceramics, paints, coatings, rubber, paper, and construction industries. It requires controlled fine grinding with narrow particle size distribution (PSD) to achieve improved dispersion, brightness, and functional performance.
Due to its abrasive nature and tendency to generate fine dust, conventional grinding systems may face challenges such as high wear, inconsistent fineness, and dust handling issues.
The Air Classifying Mill (ACM) system offers a high-efficiency solution for producing uniform fine powder. Its integrated grinding and dynamic classification design ensures precise fineness control, high product recovery, minimal heat generation, and dust-free operation.
This application note outlines the process flow, system design, technical performance, and advantages of an ACM plant optimized for Calcined Clay grinding.
Design and Working Principle
The grinding system operates on a continuous, automated principle comprising the following stages:
Step 1: Material Feeding
Raw material is fed into the system through a feed hopper equipped with a magnetic grill to remove tramp metal.
A Rotary Airlock Valve (RAL) ensures:
- Uniform and controlled feeding
- Air sealing to maintain system pressure balance
- Prevention of backflow
Step 2: Impact Grinding in ACM Rotor
Material enters the grinding chamber where it is subjected to high-speed rotor action.
Grinding occurs due to:
- Impact of hammers/pins
- Shearing forces
- Particle-to-particle collision
- Air turbulence
The rotor creates strong airflow, keeping particles suspended and ensuring efficient size reduction.
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:
- Narrow particle size distribution
- Minimal oversize
- Consistent product quality
Step 4: Pneumatic Conveying & Cooling
The centrifugal fan generates airflow that:
- Conveys material to downstream system
- Maintains system temperature near ambient
- Enhances classification efficiency
For calcined clay, this helps:
- Prevent overheating
- Maintain powder quality
- Improve dispersion properties
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 or recirculated
Pulse-jet cleaning ensures continuous operation without choking.
Step 6: Product Discharge
Collected powder is discharged via Rotary Airlock Valve into:
- Storage bins
- Packing systems
- Downstream processing
Model Variants
(Based on standard material properties and references)
| Variant | Model | Capacity (Approx.) | Target Fineness |
|---|---|---|---|
| CC-60 | ACM 60 | 600 – 650 kg/hr | 80% < 10-15 microns |
| CC-100 | ACM 100 | 1000 – 1800 kg/hr | 80% < 10-15 microns |
⚠️ Capacity may vary depending on material characteristics and fineness requirement.
Key Components
| Component | Function | Key Technical Feature |
|---|---|---|
| ACM Mill (Air Classifying Mill) | Performs grinding and classification | Integrated rotor + classifier, adjustable fineness (10–25 microns) |
| Feed Hopper + RAL | Controlled material feeding | Uniform feed, airlock sealing, magnetic protection |
| Bag Filter System | Powder separation & dust control | >99% recovery, pulse-jet cleaning |
| Centrifugal Fan (C-Fan) | Airflow generation | Maintains system pressure, cooling, conveying |
| Control Panel (MCC/PLC) | System control & monitoring | VFD control, interlocks, automation ready |
| Ducting System | Interconnection of equipment | Optimized airflow, low pressure drop |
Key Features & Benefits
- Precise Fineness Control
- Consistent Product Quality
- High Product Recovery (>99%)
- Dust-Free Operation
- Energy Efficient System
- Reliable Continuous Operation
- Automation & Easy Control
- Wear-Resistant Design
- Scalable Design
Dynamic classifier with VFD enables accurate control of particle size.
Closed-loop grinding and classification ensure stable PSD.
Efficient bag filter minimizes material loss.
Fully enclosed system ensures clean and safe working environment.
Optimized airflow and mill design reduce power consumption.
Designed for 24/7 industrial usage.
PLC/MCC system enables real-time monitoring and control.
Suitable for abrasive materials like calcined clay.
Multiple ACM models available to match capacity requirements.
Applications
- Ceramics industry
- Paints & Coatings
- Rubber and plastics
- Paper industry
- Construction materials
Model Variant
| Variant | Model | Capacity (Approx.) | Target Fineness |
|---|---|---|---|
| CC-60 | ACM 60 | 600 – 650 kg/hr | 80% < 10-15 microns |
| CC-100 | ACM 100 | 1000 – 1800 kg/hr | 80% < 10-15 microns |
⚠️ Capacity may vary depending on material characteristics and fineness requirement.
Performance Parameters
| Characteristic | Specification |
|---|---|
| Feed Size | < 5 mm |
| Final Fineness | 10 – 45 microns (adjustable) |
| Bulk Density | 500 – 700 kg/m³ |
| Moisture | < 1% |
| Product Recovery | > 99% |
| Operating Temperature | Ambient |
| Noise Level | ~110 dB (without acoustic enclosure) |
Frequently Asked Questions (FAQ)
Q1: Can fineness be controlled for different applications?
A: Yes, fineness can be adjusted using classifier speed and airflow control.
Q2: Is calcined clay abrasive?
A: Yes, it is abrasive; hence wear-resistant materials are recommended for long life.
Q3: How is dust handled in the system?
A: Through a high-efficiency bag filter ensuring >99% recovery and dust-free operation.
Q4: Can the system operate continuously?
A: Yes, it is designed for continuous industrial operation.
Q5: What ensures consistent product quality?
A: Closed-loop control of airflow and classifier ensures stable PSD.
Q6: Is the system energy efficient?
A: Yes, optimized airflow and mill design reduce overall energy consumption.