Hongfa has 80 AAC(Autoclaved aerated concrete)plants for domestic and abroad market. Main raw materials of AAC are siliceous material (sand, fly ash and Silicon tailings) and Calcium materials (lime and cement) mixed with foaming agent (aluminum powder). It is the product of light porous silicate through the following processes: batching, mixing, pouring, hardening, cutting, autoclaving and curing etc. Because of large amount of well-distributed tiny pores after foaming, it is named autoclaved aerated concrete.

Project Proposal of AAC block plant, the annual output ranges from 50,000 to 300,000m³.

AAC block history and features

  • Autoclaved Aerated Concrete block is one kind of environmental Block.
  • In fact AAC was perfected in the mid-1920s by the Swedish architect and inventor Dr. Johan Axel Eriksson, working with Professor Henrik Kreuger at the Royal Institute of Technology.
  • Since it went into production in Sweden in 1929 in a factory in Hallabrottet and quickly became very popular.
  • In the 1940s, the trademark Ytong was introduced, and was also often referred to as "blue concrete" in Sweden due to its blueish tinge.
  • It used siliceous (fly ash, sand, slag) and calcareous (lime & cement) as the main raw materials, which through the process of batching, pouring, pre-curing, cutting, autoclaving, separating and packing to make into the final products.
  • AAC block can be made into many kinds of bricks(for example:600×200×100,80×80×180,240×115×53,600×200×125),they could be used industry building and common building. AAC Block is the most mature technology of production and application in the worldwide nowadays.
  • The product has light weight, high compressive strength, excellent thermal insulation, great acoustic insulation and high fire resistance.
  • AAC has a large variety of sizes, and it is easy for nailing and milling like wood. So it is perfectly workable product.
  • Raw materials include cement, lime, fly ash, gangue, river sand and aluminium powder etc. Production through batching, mixing, casting, cutting and autoclaving.

AAC Classification

In general, it can be classified according to the types of raw materials, manufacture process and functions.
Based on the shape of AAC products, it can be divided into AAC block and AAC panel. It is a revolutionary material offering anunique combination of high durability and strength, low weight, excellent heat insulation, fire resistant, noise absorption, unprecedented build ability and superior ecological green features. In China, AAC is one of the light wall materials which was popularized and applied at the earliest and the most widely.

Main Technical Specifications of AAC block

Annual Capacity (300 days) Power Daily Capacity Cycle Time No. of Autoclaves
50,000m3/year 400 KW 166 m3/day 10 hours 2
100,000m3/year 500 KW 333 m3/day 10 hours 4
150,000m3/year 630 KW 500 m3/day 10 hours 6
200,000m3/year 720 KW 666 m3/day 10 hours 8

Main Technical Specifications of AAC block

Volume density level
B06
B05
B04
desiccated density(kg/m³)
≤625
≤525
≤425
Strength level
A5.0
A3.5
A2.0
Drying shrinkage date
0.5
0.4
0.4
Freezing resistance
quality loss %
≤5.0
≤4.0
≤3.0
Strength after freezing(Mpa)
≥4.0
≥2.8
≥0.6
Dry coefficient of thermal conductivity [W/(m•k)]
≤0.16
≤0.14
≤0.12

Working process

Raw material dealing

Put the fly ash or sand into the ball mill to mill via the conveyor belt, after milling, put the slurry into the slurry storage tank by slurry pump.

Curing process

After slurry pouring into the mould, put the mould box into the curing room with 50~70℃. After 2-3 hours curing, the blocks become soft solid and ready for cutting.

Aerated autoclaved process

Finished cutting using semi-product crane carry to the front of autoclave grouped,hoisting machine or dragger will drag steam trolley into autoclave to steam,it need 6-10 hours.

Batching, mixing and pouring process

Lime, cement will convey by conveyor to the dry powder measure scale to scale separately. Then power and slurry go to mixer and pour into mould.

Cutting process

Using reversal crane carry the mould and block to demould on cutting cart. The cutting cart will take the block to level cutting machine,vertical cutting ,two sides cutting,and remove the top waste material.

Finished block dealing process

After 6-10 hours, finished products come out of autoclave, with separting machine to separate blocks layer by layer. Rate of finised product can be controlled more than 98%.

Packing process

Using finished block carry hanger clamp the finished product to package line on wooden pallets,after package, then by forklift transport the finished products to piled yard according to specifications to stack.

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