Aerated concrete (AAC) blocks have become the preferred material for green buildings due to their lightweight, thermally insulating, and environmentally friendly properties. However, building a high-performance AAC block production line requires mastering core technologies and avoiding common pitfalls. Based on industry best practices and over 15 years of experience, this article provides an in-depth analysis of the production process, highlights key technical points, and shares solutions to common challenges, helping investors and manufacturers achieve efficient and cost-effective production.
1. Core Components of an AAC Block Production Line: Equipment Selection Determines Quality
A reliable production line begins with the right equipment configuration and the technological advantages of key system equipment.
Raw Material Preparation: A ball mill + magnetic separator grinds fly ash/sand to a 200-mesh fineness and removes 99% of metallic impurities.
Batching and Mixing: A PLC-controlled weighing machine + twin-shaft mixer measures materials (cement, lime, and aluminum powder) to an accuracy of ±0.3%, achieving 98% uniformity within 90 seconds.
Pouring and Foaming: An automatic pouring machine with temperature sensors maintains a temperature of 40-45°C for optimal foaming, reducing "collapse defects" by 80%.
Cutting: A six-axis CNC wire-cutting machine cuts green blocks into over 100 sizes (with a tolerance of ±1 mm), creating a dust-free and minimal material waste process.
A horizontal autoclave (1.2 MPa) controls the pressure/temperature profile, reducing curing time to 6 hours (compared to 8 hours for conventional models).
Unloading and Packaging: A robotic arm with stretch wrapping can process 200 blocks per hour, preventing edge damage during transportation.
Waste Recovery: A slurry recovery system reuses 95% of cutting waste, reducing raw material costs by 12%.
2. A Step-by-Step Production Process: Technological Breakthroughs at Every Stage
The aerated concrete (AAC) production cycle consists of eight key steps, the hidden technical details of which distinguish high-quality production lines from average ones:
Step 1: Raw Material Pretreatment – The "Fineness Threshold"
Fly ash/sand: Grind to 200-300 mesh (no less than 180 mesh!). Coarse particles will result in uneven foaming. Lime: Calcinate at 900-1000°C to ensure a CaO content of ≥85%. Low-quality lime will result in slow setting and low block strength.
Step 2: Precise Mixing – Aluminum Powder Control is Key
Aluminum powder (the "foaming agent") must be precisely mixed – an excess of 0.1% will result in excessive expansion; a deficiency of 0.1% will result in dense, heavy blocks.
Step 3: Casting and Foaming – Temperature and Humidity Balancing
Maintain the foundry room humidity between 85-90%. Dry air can cause surface crusting, while excess moisture can delay foaming.
Step 4: Autoclave Sterilization - Pressure Profile Optimization
The biggest mistake? Rush to increase the pressure. Our proven profile:
0-1 hour: Gradually increase pressure to 0.5 MPa, 1-3 hours: Increase pressure to 1.2 MPa (hold for 2 hours), 3-6 hours: Slowly decrease pressure (≤0.2 MPa/hour). This prevents "thermal shock cracking."
3. Efficiency and Cost Optimization:
Problem 1: How can we increase production capacity by 30% without expanding the production line?
Implement "bottleneck shifting": When the cutting system is overloaded, use a spare agitator to pre-prepare the next batch of slurry. Optimize autoclave loading: Use an adjustable rack to load 15% more blocks per cycle. With this adjustment, we increased the annual production capacity of our 50,000 cubic meter production line to 65,000 cubic meters.
Question 2: How to reduce energy costs?
Autoclave Energy Saving: Install a heat exchanger to reuse 70% of waste steam for raw material preheating. Reduce natural gas costs by 25%. Power Optimization: Use variable frequency drives (VFDs) to drive agitators and pumps, reducing power consumption by 18% during off-peak production periods.
Question 3: How to address "low compressive strength"?
Three key points to check: Batching Accuracy: Calibrate the scale every two weeks (40% of strength issues are caused by drift). Autoclave Pressure: Ensure pressure is maintained at 1.2 MPa (no less than 1.0 MPa). Aluminum Powder Health: Use powder that is less than six months old (old powder loses its reactivity).
4. Sustainability and Compliance: Meeting Green Building Requirements
With advanced manufacturing taking center stage globally, our production lines incorporate the following environmentally friendly features:
Waste Reduction: 95% of cutting mud is recyclable; fly ash (industrial waste) replaces 70% of natural sand. Emission Control: Low-NOx burners used during lime calcination reduce emissions by 60% and meet EU Stage V emission standards.
Certification: Our blocks meet LEED v4 standards and have passed GB/T 11968-2020 (China) and EN 771-4 (Europe) testing—critical for winning green building projects.
Conclusion
Building a high-performance AAC block production line requires more than just equipment—it requires mastery of materials science, process optimization, and lean management. Our lines leverage proven technology and practical experience to address the most common pain points (low strength, high cost, and low efficiency). Whether you're planning a new line or upgrading an existing one, we offer turnkey solutions from design to commissioning.
Ready to build a profitable and sustainable AAC production line? Contact us for a customized layout and cost analysis—we'll answer all your technical questions.
