Product Description

AAC (Autoclave Aerated Concrete) Production Line

1. First,dose and match measured raw materials

2. After distributing,feed raw material into pouring mixer to make slurry

3. Through thoroughly mixing,the slurry is poured to mould

4. After pre-curing under a certain temperture and time,the block would reach a  certain hardness prepare for cutting

5. Tilting hoister would turn over 90 degree of mould

6. Then open the mould and separate it from block,and take the block woth side plate ti cutting cart

7. The blocks then be cut through the cutter firstly of two vertical sides of block

8. Secondly the horizontal cutting

9.  Finally the vertical cutting

10. After cutting,the block is hanged to trolly with side plate by semi-finished product hoister

11. Organizing the cut blocks and put them into autoclave

12. Hardending the blocks under certain temperture and pressure

13. Take finished products out of autoclave

14. The finished product hoister take the finished product to stock shield

15. Packed for loading

16. The side plate return back by side plate roller

17. Side plate would be organized with open mould

18. Clean the mould and preparing for next pouring

19. Steel bars processing line for slab production

Detail Introduction of Autoclaved Aerated Concrete

What is AAC?
AAC (Autoclaved aerated concrete) Concept    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.
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 blocks and AAC panels. It is a revolutionary material offering an unique 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.
1.       Low weight: holes gap: 70%~80%; volume density: 400～700kg/m3,1/4 of common cement ,1/3 of fireclay brick and 1/2 air brick, able to float like wood, and to reduce building weight and low building comprehensive construction cost.
2.       Fire resistant: well fire resistance performance without harmful gas when fired; able to resistant 700°,225mins for 100mm wall and 480mins for 200mm wall.
3.       Noise absorption: absorbing noise with porous structure; 100mm can absorb 41 decibel.
4.       Heat insulation: excellent heat insulation with large amount of holes and micro pores; coefficient of thermal conductivity: 0.11-0.16W/MK, 1/4-1/5 of fireclay brick.
5.       Anti-permeability: low water-uptake for the materials consist independent pores
6.       Anti-seismic: comparing to fireclay brick, AAC can increase 2 seismic levels.
7.       Ecological green: no pollution during manufacture, transportation and application; protect farm land, save energy and reduce consumption.
8.       High durability: stable strength
9.       Easy workability: unprecedented build ability offers advantages to construct
10.   Economic: comparing to fireclay bricks, AAC reduces 5% comprehensive construction cost
AAC Application   Non-load-bearing masonry is the most widely produced and used with the volume density 500 kg/m3 and 600 kg/m3. It is mainly used as filler and partition without bearing load. Load-bearing masonry, with the volume density 700 kg/m3 and 800 kg/m3, was used to undertake load after being specially disposed in construction. Thermal-insulation block, with the volume density 300 kg/m3 and 400 kg/m3, was mainly used for heat insulation in buildings. Roof panel and wall panel is reinforced AAC panel with different reinforced condition for different purpose.
AAC Block Standards    
Standard number: GB 11968-2006   Standard code: AAC blocks

AAC Raw Materials  
Abundant raw materials can be used to produce AAC, especially flyash which is the ideal kind of wall material to take the place of fireclay bricks, not only can it make use of industrial solid waste, curb environmental pollution, protect farm land, but also can create benefits to social effect and economic effect. Over these years, it has been greatly supported by national wall-revolution policy, tax policy and environmental policy.
1.       Fly ash:  the core raw material of AAC product; the main resource of silica-aluminum components; correspond with JC409-91
2.       Cement:  the strength of fly ash AAC product mainly depends on cement which provides calcium materials. The cement suits to the AAC product lying on its type and label. Ordinary Portland Cement 52.5 should be first choice. While considering the cost of production Ordinary Portland Cement could also be a choice.
3.       Lime: one of the main raw materials of fly ash AAC; the main effect is to provide efficient calcium oxide with cooperation of cement making calcium oxide react with SiO2、Al2O3 in hot water then to produce calcium silicate hydrate. Therefore, lime is also the main resource of strength. Effective calcium oxide of lime should not less than 65%, over 80% is perfect and should accord with JC/T621-1996.
4.       Gypsum: Gypsum is the foaming regulator in AAC which dispels quicklime and postpones slurry’s densification.
5.       Foaming Agent: There must be foaming materials working as foaming agent making air holes to form porous structure.
6.       Foam Stability: After foaming, the thin bubbles are easily breakup disturbed by other things affecting AAC quality.
Typical Formula and Consumption of Fly ash AAC
Fly ash: content ratio 70%, consumption 350kg/m3;   Cement: content ratio 13.8%, consumption 25-30kg/m3;   Lime: content ratio 13.8%, consumption 140-150kg/m3;   Phosphogypsum: content ratio 2.96%, consumption 15kg/m3;   Aluminum: micro scale, consumption 0.4kg/m3
Typical Formula and Consumption of Sand AAC
Sand: content ratio 69.2%, consumption 350kg/m3;   Cement: content ratio 13.8%, consumption 70kg/m3;    Lime: content ratio 13.8%, consumption 70kg/m3;   Gypsum: content ratio 2.96%, consumption 15kg/m3;   Aluminum: micro scale, consumption 0.4kg/m3
Main Production Facility of AAC
1.       Prepared Facilities for Raw materials 
          (1) Crusher: block materials like quicklime, gypsum etc which have to be crushed before using;
          (2) Grinding Machine: materials have to be grinded before reacting, mainly use ball mill.
2.       Metering Facilities: wholly automatic system is usually controlled by microcomputer
3.       Mixing and pouring Facilities: mixer is the mixing machine and also the slurry pouring machine
4.       Cutting Machine: Autoclaved aerated concrete shapes blocks after pouring and foaming.
5.       Autoclave: it is the facility for silicate product to do hydration reaction to gain physical mechanical property. The operation is related to workplace safety and energy use.
6.       Boiler: it is used to provide autoclave and hardening room with thermal energy
7.       Auxiliary Facilities:
         (1) Model frame, side plate, trolley, these facilities are used to made up pouring mould.
         (2) Autoclaving cart, ferry cart, hoister, these facilities are necessary to autoclaving and curing system.