AAC Brick Production Line

Full Production Process Flow

An AAC brick production line is governed by a strict, sequential process chain where each stage directly influences the next. From raw material preparation to final autoclaving, the process must be synchronized in terms of timing, temperature, and material consistency. Any deviation—especially in early stages—will propagate and amplify downstream.

Below is the standard industrial process flow, with practical control points and operational guidance.

1. Raw Material Preparation (Foundation Stage)

Objective: Ensure all incoming materials meet particle size and consistency requirements before batching.

Process:

• Sand or fly ash → Ball milling → Slurry (controlled fineness, typically 200–300 mesh)
• Lime → Crushing + grinding
• Cement and gypsum → Stored in silos (ready for dosing)

Key Control Points:

• Slurry density (typically 1.55–1.65 g/cm³)
• Particle fineness (affects reaction rate and final strength)
• Impurity control (especially in fly ash)

Action Insight:
If slurry fineness is inconsistent, you will see unstable expansion and uneven pore structure later in the process.

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2. Batching & Mixing (Critical Accuracy Stage)

Objective: Achieve precise proportioning and uniform mixing of all materials.

Process:

• Automated weighing system doses:
  • Slurry
  • Cement
  • Kapur
  • Gypsum
  • Aluminum powder (aerating agent)
• Materials enter high-efficiency mixer

Key Control Points:

• Aluminum powder dosage (typically 0.05%–0.08%)
• Mixing time (short → uneven pores, long → premature reaction)
• Temperature of slurry (ideal: 35–40°C)

Action Insight:
Overdosing aluminum leads to over-expansion and cracks; underdosing leads to high density and poor insulation.

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3. Casting & Pre-Curing (Expansion Stage)

Objective: Allow the slurry to expand and form a stable porous structure before cutting.

Process:

• Mixed slurry poured into molds
• Chemical reaction begins (aluminum + alkaline environment → hydrogen gas formation)
• Material expands to 2–3 times original volume
• Pre-curing in chamber (typically 2–3 hours)

Key Control Points:

• Pre-curing temperature: 35–45°C
• Expansion time synchronization
• Mold filling level (must match expansion ratio)

Action Insight:
Cutting too early → collapse
Cutting too late → hardening → wire breakage

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4. Cutting Process (Dimensional Precision Stage)

Objective: Shape the semi-hardened “green cake” into final block dimensions.

Process:

• Demolding (tilting or lifting system)
• Horizontal cutting → defines block height
• Vertical cutting → defines length and width
• Optional profiling (tongue & groove)

Key Control Points:

• Cutting timing (must match cake hardness)
• Wire tension and alignment
• Dimensional tolerance (±1–2 mm)

Action Insight:
This stage determines final product geometry and surface quality—errors here cannot be corrected later.

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5. Autoclave Curing (Core Transformation Stage)

Objective: Convert raw materials into a stable crystalline structure (tobermorite) using high-pressure steam.

Process:

• Cut blocks loaded into autoclave
• Steam curing cycle:
  • Heating phase
  • Constant pressure phase
  • Cooling phase
• Total cycle: 8–12 hours

Typical Parameters:

• Pressure: 1.2–1.3 MPa
• Temperature: 180–200°C

Key Control Points:

• Steam pressure curve (must be gradual, not abrupt)
• Holding time consistency
• Condensate drainage

Action Insight:
Poor steam curve design results in:

• Low compressive strength
• Micro-cracks
• High breakage rate

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6. Finished Product Handling (Output Stage)

Objective: Prepare finished AAC blocks for storage, transport, and sale.

Process:

• Block separation
• Quality inspection
• Automatic stacking and packing
• Waste recycling (cutting scrap returned to slurry system)

Key Control Points:

• Breakage rate (<2–3% is considered good)
• Moisture content before packaging
• Palletizing stability

Action Insight:
An efficient handling system directly reduces labor cost and improves plant throughput.

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7. Process Synchronization (What Actually Determines Performance)

In real production, the biggest challenge is not individual machines—it is process synchronization:

• Mixing cycle must match mold turnover
• Cutting speed must match pre-curing rhythm
• Autoclave capacity must match daily casting volume

If one section is mismatched, it creates:

• Bottlenecks
• Idle equipment
• Increased energy consumption