1. Raw Material Preparation
The foundation of any great product lies in the quality of its raw materials. For AAC blocks, the essential ingredients are:
- Cement: Acts as a binder and gives the blocks their structural integrity.
- Lime: Works as a major constituent that reacts with the aluminum powder to create the desired aeration.
- Sand or Fly Ash: Provides the siliceous component, contributing to the strength of the blocks.
- Gypsum: Enhances the properties of the mixture and helps in the setting process.
- Aluminum Powder: This is the key to creating the aeration process, forming tiny bubbles within the mix.
All raw materials are thoroughly inspected for quality before they enter the manufacturing process.
2. Mixing and Dosing
The carefully measured raw materials are then fed into a large mixer. Water is added to the dry mix to create a slurry. This slurry is mixed at a high speed to ensure a uniform consistency. The aluminum powder is added at this stage, triggering a chemical reaction that releases hydrogen gas. This gas forms tiny bubbles within the slurry, giving the AAC blocks their characteristic lightweight and porous structure.
3. Pouring and Rising
Once the mixing is complete, the slurry is poured into large molds. The molds are designed to accommodate the expansion of the slurry as it rises. Over the next few hours, the hydrogen gas continues to be released, causing the slurry to expand to about twice its original volume. This rising process forms millions of tiny air pockets within the material, which are crucial for the AAC block’s insulation properties.
4. Pre-Curing
After the slurry has risen and solidified, the resulting mass, known as a “green cake,” is ready for pre-curing. The molds are transferred to a pre-curing chamber where they are allowed to set for a few hours. During this stage, the green cake gains enough strength to be cut into blocks without losing its shape.
5. Cutting
Once the pre-curing process is complete, the green cake is demolded and transferred to a cutting machine. This machine precisely cuts the cake into blocks of the desired dimensions. The blocks can be customized to different sizes depending on the construction requirements. Essarcon’s cutting-edge technology ensures minimal waste and maximum precision during this stage.
6. Autoclaving
The most critical phase in the AAC block manufacturing process is autoclaving. The freshly cut blocks are placed in an autoclave, a large pressure chamber, where they are subjected to high temperature and pressure. The blocks are steamed at approximately 180°C (356°F) under a pressure of around 12 bars. This autoclaving process takes about 10 to 12 hours.
During autoclaving, the lime reacts with the silica in the sand or fly ash to form calcium silicate hydrates. This reaction gives the AAC blocks their strength and durability. The process also locks in the tiny air bubbles within the blocks, ensuring their lightweight and insulating properties.
7. Quality Control and Packaging
Once the autoclaving process is complete, the blocks are left to cool. They undergo a rigorous quality control process to ensure they meet the required standards for strength, density, and dimensions. Any blocks that do not meet these standards are recycled back into the production process.
Finally, the blocks are packaged and prepared for shipment to construction sites. At Essarcon, we ensure that our AAC blocks are carefully handled to prevent damage during transportation, guaranteeing that they arrive at your site in perfect condition.
8. Environmental Benefits
In addition to their construction benefits, AAC blocks are also environmentally friendly. The manufacturing process uses fly ash, a byproduct of thermal power plants, which helps in reducing industrial waste. The lightweight nature of AAC blocks reduces the overall structural load, leading to savings in steel and concrete usage. Moreover, the superior insulation properties of AAC blocks contribute to energy savings in buildings.