Double-Stack Firing Process 

I. Process Description
Double-stack firing represents a modern, two-stage production process in which drying and firing are conducted separately.
This method follows European brick plant standards, ensuring stable quality and product diversification.

1. Typical process flow:
Clay preparation → Extrusion forming → Cutting → Automatic stacking onto drying car → Tunnel dryer → Secondary stacking onto kiln car → Tunnel kiln firing → Cooling → Packaging

2. Equipment Configuration
This process requires:
• Forming system: Vacuum extruder + automatic cutting and stacking line
• Drying system: Single-layer tunnel dryer (through-type or circulation-type)
• Firing system: Dedicated tunnel kiln
• Handling system: Robotic manipulators or automatic stacking machines
• Control system: Centralized PLC automation and temperature-pressure regulation

3. Product Range
Double-stack firing enables production of:
• High-strength hollow blocks
• Thin-wall facing bricks
• Thermal-insulating perforated blocks
• Decorative sintered bricks with color control
The product quality meets or exceeds EN and ISO standards.

4. Process Advantages
• Wide product range and high precision.
• Energy-efficient operation: optimized drying and firing balance reduces overall fuel consumption by 10–15%.
• Stable quality: independent drying ensures consistent moisture control.
• High automation level: less labor required.
• Suitable for export-grade or high-end construction products.

5. Limitations
(1) Higher initial investment (about 1.5× to 2× that of single-stack).
(2) Longer construction and equipment commissioning period.
(3) Requires higher management and technical capability.

II. Economic and Technical Comparison

III. Summary and Recommendations
1. Single-Stack Firing is suitable for regions where:
(1) Local clay quality is stable;
(2) Market demand focuses on common construction bricks;
(3) Investors aim for low investment and quick returns.
2. Double-Stack Firing is recommended for:
(1) Enterprises pursuing premium brick quality, product variety, and export capability;
(2) Projects seeking long-term, sustainable development aligned with European energy-saving standards.
Both systems have their merits — Single-stack firing emphasizes cost-efficiency and simplicity, while double-stack firing focuses on technological advancement and product excellence.