AAC blocks introduction
AAC (Autoclaved aerated concrete) block Main raw materials of AAC are siliceous material (sand) 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 block 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.
AAC blocks production processing
-Material dealing process
Put the sand into the ball mill to mill via the conveyor belt, after milling, put the slurry into the slurry storage tank by slurry pump. IF the lime is block, it also should be crushed and milled to be powder then storage by silos.
-Batching, mixing and puring process
The lime, cement will convey by spiral conveyor to the dry powder measure scale to scale separately. The slurry convey by slurry pump then to the automatic scale;the power and slurry put into the mixer,pouring into the mould.
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 solid.
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 10-12 hours.
-Finished block dealing
Finished product out of autoclave,with separting machine to separate layer by layer.
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.
Raw material of AAC block
Sand is the core raw material of AAC product; It is the main resource of silica-aluminum components; the clay should less than 4%.
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. -Cement (8-10%)
This Project aims to utilize OPC cement as main binder material. It will give faster strength to the bricks, besides giving improved consistent quality. It also ensures a better cost effectiveness for the same. Using OPC will be a standardized practice. The other prime advantages of using OPC (compared to other binders) is it's easy availability locally through nationwide Retail Network of Cement Companies..
Gypsum is the foaming regulator in AAC which dispels quicklime and postpones slurry's densification.CaSO4 should be more than 70%.
It is the forming agent type and recommendation for supply depend on raw materials and mix formula.