Lightweight Concrete Block and Panel Making Production Line

Basic Introduction:

Autoclaved Aerated Concrete (AAC) is a siliceous material (sand, fly ash and silicon tailings such as waste porcelain clay, stone processing waste materials, blast furnace slag, etc.) and calcareous materials (lime, cement) as the main raw material, mixing fat gas agent (aluminum powder), by ingredients, mixing, casting, pre-raising, cutting, autoclave, curing process made of light porous silicate products, because by the hair contains a lot of gas even after the small pores, hence the name of aerated concrete.

Autoclaved Aerated Concrete Panel:

Autoclaved aerated concrete panel is a new type environment-friendly and lightweight building material which is made from silica sand, cement, lime, gypsum and aluminum powder, and added anticorrosive steel mesh according to structure requirement. The autoclaved aerated concrete panel with porous structure is formed through high temperature, high pressure and steaming, it also has excellent performance like fire resistance, anti-earthquake and insulation.

Autoclaved aerated concrete panel is one kind of aerated concrete products, it can take different processes according to the raw material category, quality, characteristic of main equipments, and it is a good structural performance building component which is made according to certain requirements in the process. But in general, the main technological process includes raw materials preparing, steel processing, steel mesh assembling, material batching, pouring, curing, cutting, steaming, out from autoclave and other processes. Autoclaved aerated concrete panel not only has various properties of autoclaved aerated concrete block, but also has high added value of production, which can greatly improve the constructing efficiency, reduce the building comprehensive cost, and has other advantages, so it is highly promoted.



AAC Production Process

Advantage of AAC:
Lightweight: Porosity achieve 70% to 85%, volume density is generally 500 ~ 900kg/m3, as 1/5 of general concrete the 1/4of clay, the 1/3 of hollow brick, and similar with wood can float in water. It can reduce building weight, reduction in the cost of integrated building.
Fireproof: Most of the major raw materials is inorganic materials, so it has good fire resistance, and do not emit harmful gases when meet fire. Fire 650 degrees, as a refractory material, the thick up of 90mm walls can reach to 245 minutes fire resistance, 300mm thick up wall can reach to 520 minutes fire resistance.
Sound insulation: Due to a unique porous structure, so it has a sound absorption capacity. The sound absorption capacity can reach of 10mm thick wall up to 41 db.
Insulation: As the material inside has a large numbers of the pores and porous, which has a good thermal insulation properties. The Thermal conductivity is 0.11-0.16W/MK, as 1/4-1/5 of brick. Typically, the insulation effect of 20cm thick aerated concrete wall is equivalent to 49cm thick solid brick walls ordinary.
Permeability: Result of material by the composition of many independent small pores, the moisture absorption is slow, in the volume of absorbent is 5 times of clay saturation do. When used in the bathroom, the wall can be treated to interface directly paste tiles.
Anti-seismic: The same building structure, improve the two seismic than the brick level.
Green: Manufacturing, transportation, all use the process of pollution, to protect arable land, saving energy, is one kind of a green building material.
Durability: material strength is stability, in the specimens tested after one year of atmospheric exposure; the intensity increased by 25%, and remained stable after ten years.
Shortcut: it has good machinability, can be sawed, planed, drilled, nailed, and available appropriate as bonding of adhesive material, so create favorable conditions for building construction.
Economies: An integrated lower cost than using more than 5% of solid clay bricks, and can increase the usable area, greatly enhance the utilization of floor space.
Requirements for Raw Materials:

1
Sand
JC/T622-1996
Excellent goods
First-class goods
Qualified goods
SiO2
silicon dioxide
≥
85%
75%
65%
K2O+Na2O
kalia+sodium oxide
≤
1.50%
3.00%
5.00%
SO3
sulfur trioxide
≤
1.00%
2.00%
clay
≤
3.00%
5.00%
8.00%
water ratio
≤
8.00%
calcium carbonate
(coral, sehll, etc.)
≤
10.00%
impurity (bark, grass roots)
N/A
2
Flyash
JC409-91
Excellent goods
First-class goods
Qualified goods
Finess(0.045mm square screen left)
≤
30%
45%
55%
Water requirement of normal consistency
≤
50%
58%
60%
loss on ignition
≤
7%
12%
15%
SiO2
≥
40%
40%
40%
SO3
≥
2%
2%
2%
3
Lime
JC/T621-1996
Excellent goods
First-class goods
Qualified goods
A(CaO+MgO)
Available calcium
≥
90%
75%
0.65
MgO
magnesia
≤
2%
5%
8%
SiO2
silicon dioxide
≤
CO2
carbon dioxide
≤
0.07
degesting speed  min
≤
5--15
degesting temperature ºC
≥
60--90
undigested residue
≤
5%
10%
0.15
Fineness of finished product (remainder above 0.08mm hole screen)
≤
10%
15%
0.2
4
Cement
GB175-1999
Chemical composition
SiO2
silicon dioxide
21-23  %
Al2O3
aluminium sesquioxide
5-7    %
Fe2O3
iron sesquioxide
3-5    %
CaO
calcium oxide
64-48  %
MgO
magnesia
4-5    %
5
Aluminium powder
JC407-2000
Type
Code
Solids content
activated aluminium
in solids
Foaming rate (%)
≥  
≥  
4min
16min
30min
Oil-based formulation
GLY-75
75%
90%
50-80%
90%
99%
GLY-65
65%
Water-based formulation
GLS-70
70%
85%
40-60%
GLS-65
65%

Main Equipments in AAC Production Line:

Material-milling Equipments:
          a. Crusher: Lime, gypsum, and such kind of bulk material need to be crushed as the first step in AAC Plant.  

          b. Ball Mill: The AAC material must be fully grinded in order to make better reaction. Ball Mill is used widely, it has two types: dry and wet, can be chosen upon requirement.

Material Metering Equipments: Computer Control Automatic Metering System is commonly used as measurement of raw material such as lime powder, cement powder, aluminum powder and material slurry.
Material mixing and casting equipments: Mixer, it's the slurry mixing machine, also is slurry casting machine.
Cutting Machine: the AAC blank is formed after casting and pre-curing, as the size is too large, it must be cut to achieve the required product size.
Autoclave: Autoclave is a device for silicate hydration products to get physical and mechanical properties.
Boiler: the boiler supports for the autoclave and pre-heat furnace and other facilities with heat.
Auxiliary Equipments:
          a. Mould Frame, Mould Bottom and Mould Car, they composed together to form the Casting Mould, which is the main forming equipments in AAC Production Line.

          b. Hardening Car, Ferry Cart and Hangers, they must be equipped as auxiliary equipments in autoclave curing system.

          c. Block Separator. The separator is a special machine whose function is to separator the plaste block into piece,in order to be transfered and used.

          d. Finshed product clamp.

          e. Block packing machine.