With the ever-increasing demand for lightweight and energy-efficient building materials, autoclaved aerated concrete (AAC) is experiencing rapid development. The core of AAC's performance lies in a key raw material—aluminum powder. Its purity, reactivity, and stability determine whether AAC blocks can expand uniformly, form uniform porosity, and maintain structural strength.

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What Is Aluminum Powder for AAC?

Aluminum Powder for AAC is a finely milled metal powder that reacts with alkaline slurry (commonly Ca(OH)₂) to release hydrogen gas.
This gas forms billions of micro-bubbles, creating the porous structure AAC blocks are known for.

The reaction follows:

2Al + 2NaOH + 6H₂O → 2NaAl(OH)₄ + 3H₂↑

According to industry data from the China Building Materials Federation, over 85% of AAC pore formation quality issues are linked to aluminum powder reactivity stability—showing why reliable powder is essential.

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Key Performance Indexes of Aluminum Powder for AAC

1. Reactivity (Gas Generation Rate)

A stable reaction rate is critical for:

• uniform foaming

• consistent density

• predictable final block height

Typical gas generation target:
90–120 mL/min per gram (varies by formula and climate).

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2. Particle Size Distribution

Finer particles react faster; coarser particles supply sustained hydrogen release.
The ideal AAC aluminum powder contains a balanced distribution to avoid:

• too fast reaction → cracking, collapse

• too slow reaction → insufficient rise

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3. Coating Type (Coated vs. Uncoated Powder)

AAC typically uses coated aluminum powder, especially in humid climates.

Coatings may include:

• stearic acid

• resin coatings

• inorganic silicate coatings

Benefits:

• improved shelf stability

• controlled reaction rate

• reduced moisture-triggered premature hydrogen release

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Why Aluminum Powder Quality Determines AAC Block Stability

H2: Typical Problems Caused by Poor Aluminum Powder

1. Block Cracking or Collapse

Possible causes:

• excessively high reactivity

• uneven particle distribution

• moisture-contaminated powder

2. Density Instability

Possible causes:

• inconsistent gas release

• impurity contamination (Fe, Si)

• humidity-affected powder storage

3. Uneven Pore Structure

Possible causes:

• insufficient gas generation

• too coarse particle fraction

• reaction inhibition due to slurry additives

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How to Select Quality Aluminum Powder for AAC (Expert Guide)

1. Check Reactivity Index

Choose powders with a certified gas evolution curve to prevent over-foaming or under-foaming.

2. Inspect Moisture Control

Moisture >0.5% can trigger hydrogen release before mixing.

Recommended from industry standards:
Moisture ≤ 0.3% for best stability.

3. Prefer Resin-Coated Aluminum Powder

Especially important for humid regions such as Southeast Asia and the Middle East.

Benefits:

• longer shelf life

• slower and predictable reaction

• safer storage

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Applications & Comparison

Application of Aluminum Powder for AAC

• AAC blocks

• AAC panels

• Lightweight concrete

• Heat insulation materials

Coated vs. Uncoated Aluminum Powder for AAC

Conclusion: Coated powders provide far more predictable AAC block performance.

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Frequently Asked Questions

1. Why does AAC sometimes rise unevenly?

Usually due to inconsistent reactivity or moisture-affected aluminum powder.

2. Can aluminum powder cause gas expansion before mixing?

Yes. Exposure to moisture triggers hydrogen generation. Always use sealed packaging.

3. How much Aluminum Powder for AAC is normally added?

Typical addition is 0.05–0.12% of dry materials, depending on density targets.

4. Does climate affect AAC aluminum powder performance?

Yes—humidity accelerates oxidation and premature reaction. Coated powder is strongly recommended.

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Conclusion — Partner with a Trusted AAC Aluminum Powder Supplier

AAC manufacturers depend on consistent, controlled, and stable Aluminum Powder for AAC. Poor powder leads to costly defects: cracking, low rise, density deviation, and scrap rates that can exceed 15–20%.

At ZHANGQIU METALLIC PIGMENT CO., LTD, we supply high-stability, low-moisture, and coating-enhanced aluminum powders engineered specifically for AAC plants across Asia, the Middle East, and Europe.