Henan Hongke Heavy Machinery Co., Ltd. is pleased to report on the successful deployment of a Φ2.5×60m rotary kiln for quartz sand whitening at a customer site in India. The system is designed for a capacity of 150 tons per day and represents a proven solution for high-purity quartz processing.
Application: Quartz Sand Whitening via Calcination
Quartz sand (SiO₂) is a critical raw material for the glass, ceramics, foundry, and semiconductor industries. However, natural quartz sand often contains iron impurities that negatively affect product quality—particularly whiteness and optical clarity .
Iron is the most common impurity in quartz sand and occurs in three forms: (1) within the quartz crystal lattice as isomorphous substitution, (2) as independent mineral inclusions, and (3) within gas-liquid inclusions . Due to the diversity of occurrence forms, iron removal remains a technical challenge.
How Calcination Enables Whitening
High-temperature roasting triggers a phase transformation in the quartz crystal structure—from α-quartz to β-quartz at approximately 573°C, and further transformations at higher temperatures . This crystal transformation, followed by rapid quenching, creates micro-cracks on particle surfaces. Iron impurities trapped in inclusions and lattice sites are exposed to the new surfaces, making them accessible for subsequent acid leaching removal .
Research demonstrates that roasting at 900°C for 4 hours achieves β-quartz content of 94.7%, with subsequent acid leaching removing 98.7% of iron impurities and 88.2% of total impurities . The industrial process typically involves:
Preheating zone: 200–800°C – moisture removal and organic decomposition
Calcination zone: 800–1,300°C – phase transformation and impurity exposure
Cooling zone: Controlled cooling to prevent re-absorption of impurities
Equipment Specifications
The Φ2.5×60m rotary kiln supplied to the Indian customer features the following specifications:
| Parameter | Value |
|---|---|
| Kiln diameter | 2.5 meters |
| Kiln length | 60 meters |
| Capacity (design) | 150 TPD (tons per day) |
| Operating temperature | Up to 1,200°C (adjustable) |
| Kiln inclination | 3.5–4% |
| Rotation speed | Variable frequency control |
| Sealing system | Labyrinth seals with air purge |
The Φ2.5×60m configuration is a commonly used model in the industry for medium-scale mineral processing applications .
System Configuration
The complete system supplied for this Indian project includes:
Rotary Kiln Body – Φ2.5×60m with refractory lining (high-alumina brick) for thermal efficiency and wear resistance
Feed System – Screw or belt feeder for consistent material entry
Burner System – Multi-fuel capability (gas or pulverized coal) for flexible operation
Cooling System – For controlled product cooling after calcination
Dust Collection – Cyclone + bag filter for emission compliance
Control System – PLC-based with temperature monitoring across heating zones
Key Advantages for Quartz Sand Processing
| Feature | Benefit |
|---|---|
| Precise temperature control | Ensures complete crystal phase transformation for optimal iron exposure |
| Continuous operation | 24/7 production with minimal downtime |
| Uniform heating | Rotary design ensures consistent thermal treatment of all particles |
| Scalable design | φ2.5×60m configuration supports 150 TPD with room for capacity expansion |
| Advanced sealing | Minimizes heat loss and dust emissions |
Customer Benefits
Once fully commissioned, the system will deliver:
Increased product whiteness – iron impurities reduced to meet high-grade silica specifications
Higher market value – whitened quartz commands premium pricing in glass and ceramics markets
Consistent quality – automated temperature control ensures repeatable results
Environmental compliance – integrated dust collection meets regulatory standards
About Henan Hongke Heavy Machinery Co., Ltd.
Henan Hongke Heavy Machinery Co., Ltd. (Henan Hongke Machinery) has been manufacturing industrial processing equipment since 2006. Our product portfolio includes:
Rotary Kilns – for lime, cement, metallurgy, and mineral calcination, including quartz sand whitening
Rotary Dryers – for sand, sludge, and industrial materials
Ball Mills – for ore and mineral grinding
Crushers – for primary and secondary size reduction
We provide custom engineering, full manufacturing, installation guidance, and after-sales support for customers worldwide.
Summary
The Φ2.5×60m quartz sand rotary kiln in India is engineered to deliver 150 TPD of whitened, high-purity quartz—transforming a natural resource into a higher-value product for industrial applications. The system leverages proven calcination principles to expose and remove iron impurities, ensuring consistent product quality and operational reliability.
For quartz sand calcination, mineral processing, or other thermal treatment applications, contact Henan Hongke Heavy Machinery Co., Ltd.
Henan Hongke Heavy Machinery Co., Ltd.
Rotary Kilns | Dryers | Ball Mills | Crushers – Engineering Excellence for Global Industry