Production Technology of Aerated Concrete
1.Aerated concrete can be produced by different processes according to the
types of raw materials, quality and technological characteristics of equipment.
Generally, fly ash or silica sand, slag are ground into slurry by water, and
powder lime, appropriate cement, gypsum, foaming agent and foaming stabilizer
are mixed into the mould frame. After static curing, foaming and solidification,
various specifications of blocks or plates are cut and cured by autoclave, then
porous lightweight concrete products are formed by high temperature and high
pressure steam curing.
2. Brief description of production process
1. Storage and disposal of raw materials
(1) Fly ash, gypsum, waste
The process of mixing lime and gypsum for pulping is adopted. In production, sand and gypsum are mixed into slurry according to a certain proportion. When water is added to pulp, the pulp with appropriate concentration is preliminarily prepared by adding water quantitatively. The slurry with suitable concentration for production is pumped into the slurry storage tank of the proportioning building by the slurry pump for reserve.
Blocky quicklime is transported to the factory by dump truck and dumped into the stacking shed of lime raw materials for stacking. The block lime is crushed by a compound pendulum jaw crusher and sent into the lime storehouse by a bucket hoist. Before grinding, lime is fed into the closed conveyor by the bottom feeder to grind in the mill. The fined lime powder is sent from the outlet of the mill to the bucket elevator through the screw conveyor, and from the bucket elevator to the lime powder silo of the batching building for reserve.
Bulk cement is used. Bulk cement is transported into the factory by bulk cement truck and pumped directly into the cement powder bin of the batching building for reserve.
(4) aluminum powder.
Bucketed aluminium powder is purchased from abroad and stored in the aluminium powder storehouse at the bottom of the batching building. When in use, the electric hoist is suspended to the third floor of the batching building, and then put into the aluminium powder mixer to mix into 5% suspension for reserve.
(5) Side scrap and waste pulp
The corner material cut by WEDM falls into the bottom inclined groove and is washed by water into the waste slurry tank at the bottom of the cutting machine. After continuously mixing, the waste slurry reaches a certain concentration, it is pumped into the waste slurry storage tank of the proportioning section by the slurry pump in the waste slurry tank for reserve.
2. Ingredients, mixing and pouring
Lime and cement are fed into the electronic powder metering scale by the single solenoid feeder at the bottom of the silo. After accumulative metering, the unloading device of the metering scale is discharged into the pouring mixer
Mortar or waste slurry is opened by the valve under the respective slurry tank and put into the beating tank. Then the slurry pump is pumped into the electronic measurement scale of slurry in the batching building for cumulative measurement. When the slurry weight meets the batching requirements, the automatic control system closes the storage tank discharge valve and stops discharging. The measured slurry is put into the pouring mixer according to the instructions.
The aluminium powder is measured by the aluminium powder measuring scale, and then added to the aluminium powder mixer. The stirred suspension is directly put into the pouring mixer.
The slurry temperature should meet the technological requirements before pouring. If the temperature is not enough, it can not be heated by steam. When pouring, the mould is transported to the lower position of the pouring mixer by ferry, and the pouring mixer is poured.
3. Cutting and marshalling
When the cutting strength is reached after the initial maintenance, the overturning hanger on the cutting line overturning truss (10t) is lifted and overturned to the fixed support of the cutting machine, and the blank body is inverted by demoulding. Cutting device walking for vertical and cross cutting, complete the cutting.
The cut green body and side plate are hoisted from the semi-finished lifting gear on the truck (5t) in front of the kettle to the steaming car in front of the kettle. Each car is stacked with two moulds. The stacked steaming car is pulled by a slow-moving hoist on the track in front of the kettle for formation. Seven steaming cars are arranged on each track in front of the kettle.
4. Autoclaving and finished products
The marshalled green body is pulled into the kettle by a slow-moving hoist for autoclave maintenance. The autoclave curing time is about 7.5 hours, the steam pressure is 1.3 MPa, and the temperature is about 190 C.
After autoclaved maintenance, the products are pulled out of the kettle by a slow-moving hoist, and then lifted from the kettle hanger to the truck for direct delivery or storage in the yard.
5. Return of side (bottom) plate and oiling of die set
After the finished product is lifted, the side (bottom) plate of the steaming trolley and the trolley are lifted to the return line of the trolley through the finished product hoist. The trolley is returned to the side of the cutting machine through the return line. The side (bottom) plate is lifted by the hoist. At the same time, the mould and the side (bottom) plate are lifted and put back on the return track of the mould for cleaning and painting, and then circular pouring is carried out.