AAC Block Production Line

AAC Block are made of flyash (lime slag or sand) as main raw material,cement and lime as cementing materials,and aluminum powder as foaming agent.The main forming procedures are Material crushing,measuring,mixing,pouring,curing,cutting and steaming.As a new wall body material with the characteristics of light weight, heat preservation,energy saving,waste recycling, environmental protection and convenience etc,AAC Light-weight block is now emphatically promoted by the world.

Production Procedure

Raw Material Preparation → Cement → Lime → Gypsum → Additive → Sand → Raw Material Batching → Mixing and Casting → Used for adding steel bars into aerated concrete slabs (optional) → Pre-curing → Turning crane turns over the mould and start to demould → Cutting cart gets ready → Cutting machine cuts the formed material horizontally and vertically → remove the bottom part of the formed material → Group the curing cart and send the semi-finished products into the auto claves → Curing → Finished blocks move out from the auto claves → cubering → packed for loading → Finished products transportation 

1、Raw Material Treatment

AAC block production line needs to pulverize the siliceous material such as sand, fly ash, etc. According to raw materials and the process characteristics, the grinding process could be classified into: dry grinding into powder, wet grinding with water into slurry and mixed grinding with lime. Mixed grinding also could be classified into dry mix for preparing plastic material and wet grinding with water. Wet grinding technology with water is to improve the characteristics of fly ash or sand, which is called “hydrothermal ball smashing” Generally, most of limes are lump limes, and should be crushed and grinded. Gypsum ( plaster) generally will not be grinded alone, commonly add with fly ash or lime, and to be grinded with the same miller of lime. Other auxiliary materials and chemicals are often prepared in advance.

Raw material preparation process is the preparatory process of ingredient, which is to meet the technological requirements and processing of raw materials and the store process before completing the ingredients for the entire production can be carried out smoothly, product quality can meet the requirements of the most basic aspects of the process have a direct impact. 

    (1)Jaw Crusher

In order to make the material meets the technological requirements of aerated concrete blocks, generally calcareous and siliceous materials should be grinded. Before entering the mill, some bulk materials should be crushed firstly, in order to achieve feed size required to enter the secondary ball mill grinding.

a. Operating Principle

During running, the motor through the belts driven eccentric shaft rotation, so that the movable jaw periodically closes and leaves the fixed jaw，and thus the materials are squeezed, rubbed, grinded, so that the materials are smaller , gradually falling from discharge port.

b. Features

The crusher has characteristics such as: large crushing ratio, high yield, uniform particle size, simple structure, reliable operation, easy maintenance, economic cost etc.

c. Main Technical Specification

   (2)Bucket Elevator

Bucket elevator is indispensable equipment in AAC production line. It is used to carry lime, gypsum and other materials which have been pulverized by jaw crusher into storage silos, which is the preparation for raw material mixing.

a. Operating Principle

NE bucket elevator consists of operation parts (bucket and traction belt), upper parts with transmission drum, bottom parts with tension roller, middle enclosure, actuating device, and braking device etc. It is used to convey powder with loose density material(ρ < 1.5t/m³), particulate or block such as coal, sand ,breeze, cement and broken ore etc .

b. Main Features

NE Bucket elevator adopts the flow-through feeding way. Material will be conveyed to the top via Plate-Link chain, then discharge under the effect of gravity. Our elevators are Multi-Standard, high production capacity and low energy –consumption. It is designed as totally-enclosed with slow-running chain, which can avoid the material returning, so no power wasted. Meanwhile, there is no noise pollution while it works.

c. Main Technical Specification

   (3)Belt Conveyor

Belt conveyor is very important transportation equipment in AAC production line, used to transport fly ash, sand, lime and other raw materials, is the most efficient continuous conveyor equipment, conveyor belt moves by friction-drive principles. Featured with big capacity, long transmission, smooth transportation, materials and conveyor no relative motion, less noise, simple structure, easy maintenance, less energy consumption and standardized components.

 Main Technical Data for Belt Conveyor

(4)Ball Mill

Raw materials grinding is an important step in the AAC block production. Lime, gypsum, sand, slag and other materials could be fully mixed and interact only after powder grinding, then to make products strength qualified. Ball mill is the key equipment of the material smashing.

a. Working Principle of Ball Mill

Ball mill is a horizontal cylinder rotating device, outer gear, two cabins, lattice-type ball mill. Raw materials are evenly fed into the first cabin through hollow shaft screw. There is ladder liner or corrugated liner inside the first cabin, and different size steel ball. When ball mill is working, the cabin generates centrifugal force and brings the ball to a certain height and falls then pound and grinds the materials. After coarse grinding in first cabin, raw materials will come to the second cabin through the single-compartment plate. There are flat lining and steel ball in the second cabin, and will grind raw materials father. Finally, powder will be discharged through the discharge grate plate to complete the grinding operation.

b. Main Features

The machine consists of feeding part, discharging part, turning part and driving part (reducer, small transmission gear, motors, electrical control) and other major components. This machine uses outer gear, hollow shaft support. Hollow shaft adopted steel casting, and removable liner, turning gearwheel machining adopted casting hobbling, wear liners was embedded in the cylinder (there are two kinds of liners: rubber liner & steel liner, the rubber one is light, low noise, wearable, good sealing, generally preferred. )This machine has good wear resistance as well as smoothly & reliable running.

c. Main Technical Data of Ball Grinder

　(5)Wasted-Slurry Mixing Tank (Ahead the Ball Mill)

       Wasted-Slurry mixing tank consists of fixing platform, ladder, barrier, mixer and tank. Usually the wasted slurry from ferry cart and all other wasted material should be mixed with water in the tank. The mixed material will be recycled used with the original slurry.

    (6)Lime, Cement Silo

      The silo role is used for storage of materials, it’s with air cushion or vibration motor; according to volume, the specifications are: 100m ³, 200m ³, 300m ³. They can be configured according to the demand of select lines.

2、Dosing And Pouring

The dosing are equipments which are weighted finished batching materials and all raw materials ,adjusted temperature ,concentration and added material as well, then according to the requirement of process, feeding material into mixer at one time. Dosing is a key link of aerated concrete process, related to the raw material between the percentage of active ingredients, in relation to the fluidity and viscosity of slurry is appropriate whether aluminum powder suitable for gas and green body hardening normally.

Pouring process is the unique production process of aerated concrete which is different from other kinds of concrete. Pouring process is the batching process after the measurement and the necessary adjustment put into mixer to mix the materials, made to process the stipulated time, temperature, density of slurry, through the pouring hole of mixer poured into a mould. Slurry makes a series of physical and chemical reactions in the mould and produces bubble, and the bubble makes the slurry inflated, thickened and hardened. Pouring process is an important process for affecting pore structure; the dosing process and pouring process constitute a core part of the production process of AAC block.

Pre-Curing process is mainly the process after pouring slurry to continue to be thickened and hardened.   

    (1)Weighing System

The physical states of raw materials for aerated concrete are liquid type, slurry type, powder type, powder aluminum and lump aluminum. Different materials have different weighing scales, such as lime scale, cement weighing hopper, slurry weighing tank etc.Material will be precisely measured by the automatic measuring system.        

       a. Lime & Cement Weighing Hopper

        Used to weigh cement and lime, and then convey them into pouring mixer.

　  b. Slurry Weighing Tank

　　Used to weigh slurry and then put it into pouring mixer.

　　c. Water Measuring Tank

　　Water measuring and Automatic transferring water to the slurry mixer.

（2）Aluminum Powder Mixer

    Consist of the cylinder, a bracket and a pneumatic butterfly valve (double signal output device). It is used to mix aluminum powder.

（3）Pouring Mixer

　A pouring mixer is consist of mixing barrel, mixing shaft, transmission mechanism, diversion device, nozzle device and so on, which is the main equipment of aerated concrete plant. Pouring mixer is used to mix slurry, cement, lime, gypsum and powder aluminum with certain proportion, after mixed uniformly and full reaction, then pour mixed slurry into mould frame in time.

（4）Pouring Ferry Cart

　Pouring ferry cart is the essential equipment of autoclaved section in the AAC block production line which for dragging. It is consists of the cart frame, drive and positioning mechanism. The cart frame is welded by section steel. Drive is consist of reducer, coupling, shaft, the driving wheel and driven wheel. Ferry cart has the characteristics of strong power in dragging and pushing, and stopping. when quickly moving, it could position and connect accurately, and could be frequency slow running when full loading, also could be frequency fast running when empty loading.

（5）Air bubble finishing machine

　The air bubble finishing machine adopts high frequency vibration, which is used to eliminate the large air bubbles existing in the slurry after casting. It consists of frame, vibrating bar and walking system, and is generally divided into fixed type and swinging car type according to the installation method.

（6）Mould Frame, Side Plate

　Moulds of AAC block production line are divided into mould frame and side plate, which is an important equipment of product forming. The mixed raw materials through pouring mixer poured into mould, gasing and pre-curing, after solidify, demoulding, then the green block can be cut. The mould frame and side plate can contain slurry, pre-curing, gasing, solidify after combination. At the same time, side plates take green blocks to cutting machine for cutting, and group into Curing Cart , then move into the autoclave.  

3、Turning &Cutting

Turing crane and Cutting Machine are the two main equipment in AAC Block production plant，which are used for Block Cake cutting and Shape processing. The Turning & Cutting technology has the features of: Bulk Molding, Flexible Shape& Size, and Massive Mechanization production.    

（1）Turning Crane

Turning crane consists of hanger, rings, rotary lock, and rigging shackle etc. It is used for block demoulding and transferring.

Turning crane will overturn the block of 90°in air. Then demoulding will subsequently be done. The seperated side plate will combine with the returned Mould Frame for recycling slurry pouring.

  （2）Cutting Machine

    It is consist of vertical cutting machine and horizontal cutting machine. After the pouring Aerated concrete will become a formed cake after pre-curing. The cake will be cut into the exact size according to user’s requirement.          

         Working Principle

　　   After demoulding, the Side Plate with block cake will be transferred and fixed on Cutting Cart, which will be driven by Motor. Then the cake will move to the cutting machine for Vertical and Horizontal cutting. When cakes arrived at horizontal cutting machine, the Side Plate with Cake will be uplifted by lifting device. Cutting cart will turn back to the start position and prepared for another transportation while Horizontal cutting. After Horizontal cutting, the Lifting device will load the Side Plate with Cake on another Cutting Cart. Then the cake will be moved to Vertical cutting Machine for vertical processing.

 （3）Tilting &Grouping Crane

　After cutting, Tilting &Grouping crane will separate the Bottom and Top waste by tilting block cake. And then will hoist and transfer the cake for grouping,

  （4）Grouping Crane

    Grouping Crane will vertically move the Cake with side plate via the chain. Chain is drived via the Oil Cylinder and the crane will be horizontally moved at the function of Gear motor. This is how the cake moves and groups.

4、Finished Product

The block cake will be cured in the autoclave. It is the last working procedure which will directly affect the quality of finished block.

As the automation improvement, block separating and packing system are also commonly used. After the drying, AAC Blocks move out of autoclaves, though the process of hoisting, separating, and packing, they could be transferred to finish –products area by forklift.

  （1） Curing Cart

    Curing cart consist of fame and wheel. It is used for transferring the block in and out of the Autoclave, which is dedicated transportation cart during production. It sent the cut green block into autoclave for curing, and move out to finish-products area after curing.

  （2）Autoclave 

   Being the core equipment in the production line, Autoclave is used to cure the Block under high pressure and temperature.

（3）Boiler

Boiler is used to provide heat energy and steam for autoclave to guarantee the interior high pressure and temperature, which ensure the block to complete the hydration reaction for qualified AAC block.

5、Finished product out of the kettle

  （1）Finished-block Clamp

    Finished-block clamp are equipped at special crane. The walking and lifting of clamp both rely on the crane. The lifting is oriented by Guiding Frame, which is stable and accurate. It is specially used for moving finished blocks from side plate for final packing.

  （2）Mobile Separator

    Separator is used to separate the finished block from layer to layer. Our separator will automatically do the working and group the finished products.

 （3）Automatic Cuber Crane

    Cuber Crane will cuber the Finished Products after the Separating process. It will divide the finished products stack by stack. Thereafter, the tank-type conveyor will move the stacked block for packing.

 （4）Automatic Pallet Provider

    Equiped with Block Clamping system and Tank-Type conveyor.Efficiently and Stably providing the Pallet for production.  

  （5）Tank-Type Conveying and Packing System

    Finished Block will be packed after the separating and stacking. The Packed Blocks will be transferred to finished products via forklift.