Technology for manufacturing of the calcium silicate bricks
Calcium silicate brick is an artificial unburned material for walls construction manufactured by the press-moulding method from humidified mixture of silica materials and lime followed by hardening under the conditions of saturated steam in an autoclave.
Production of calcium silicate bricks at the plant is carried out using silage technique.
Production process includes the extraction and feeding of sand and limestone (chalk), lime production, preparation of silica-lime cementing material, preparation of silicate mixture, press-moulding of bricks and steam treatment of them in autoclave.
The organization structure of the plant shall include main production workshops:
- Mining workshop; Area of hydraulic and mechanical equipment for sand-wash, limestone or chalk pit, warehouse for sand and limestone (or chalk);
- Workshop for lime burning;
- Mixture preparation workshop;
- Bricks workshop; Silage, mixing, press-moulding and autoclave rooms;
- Area for bricks painting;
- Finished products storage area.
Extraction and feeding of sand into production process.
For the production of calcium silicate bricks natural aggradational sand is used. Sand-wash is carried out by self-propelled floating dredger according to the aggradational map, where it is dried, averaged, and then using dumping wagons by railway it's delivered to the sand storage area of the plant. Sieved sand is stored in the hopper and then fed into mixture preparation workshop for preparation of silica-lime cementing material. (See also drum mixer)
Quality control of the sand used is performed in accordance with the requirements of GOST 8736-93 and OST 21-1-80.
As raw material for lime production carbonaceous rock can be used — limestone from a limestone pit or chalk, which can be extracted from chalk pit.
Here we are going to discuss lime production technology with using chalk (production of lime from limestone is performed through the same technological processes using the same equipment as those for production of lime from chalk, but under slightly different conditions). Chalk from the chalk pit is delivered by road vehicles to the workshop for lime burning, and then it is fed into in the mash (a special device for slurry preparation) using a bulldozer. Slurry is supplied into pyroprocessing complex.
Burning of lime is carried out in lime kiln (Rotary kilns for production of lime from chalk and limestone are included into the product range of Samara plant Strommashina); freshly prepared lime is sorted and stored in lime hopper.
The lump quick-lime obtained meets the requirements of GOST 9179-77.
Preparation of silica-lime cementing material
Preparation of silica-lime cementing material carried out in mixture preparation workshop in the process of joint grinding of sand and lime taken in proportion in two-compartment ball-and-tube mills (two-compartment ball-and-tube mills for grinding of sand and lime within the present technology are included into the product range of Samara plant Strommashina).
Fineness of grinding is characterized by the residue left on sieve with mesh No. 008 (8 microns) — not exceeding 15%. Quality control and inspection of process parameters with proper frequency is carried out in accordance with approved process regulations accepted at the plant. It is a mandatory requirement that the workshop shall be equipped with gas-cleaning and dust-collecting units with the function of return of the collected material back into production according to waste-free technology (gas-cleaning and dust-collecting equipment, usually — cyclones and filters – is included into the product range of Samara plant Strommashina).
Production of calcium silicate brick in brick workshop.
Silage room is designed for storage of silica-lime cementing material; it also accommodates the process of mixture slacking. From silage silica mixture is fed to mixing room.
In mixing room occurs additional moistening (post-humidification) and stirring of silica mixture, followed by further transferring of the finished mixture along the hoppers of brick-molding machine.
Press-moulding room accommodates the process of pressing of raw bricks in brick-molding machines under relatively high specific pressure. Then, empty cars are delivered to brick-molding machine, and raw bricks are automatically stacked with stacking machine into the cars. After that loaded cars are delivered in autoclave room.
Press-moulding of the standard bricks is carried out using brick-molding machines of predetermined production capacity, such as СМС-294, and production of facing brick — with such machines as M125 and M150, or it can be performed using imported equipment, such as German brick-molding machine NDR-500. Facing bricks shall meet higher requirements on appearance and quality of this products (additional information about application of a particular type of equipment you can request from our managers contacting them by phones shown in "Contacts" section of our web-site).
Autoclave room accommodates the process of steam treatment of bricks according to the specified processing conditions in order to accelerate physical and chemical processes during hardening of silica bricks. From autoclave room brick are delivered to the storage area for finished products.
Finished products storage area
In storage area for finished products the bricks are stored, and quality control and sorting according to grade are performed. Step-by-step operation quality control of finished products is introduced at the plant at all stages of production. At the storage area for finished bricks are used loading cranes equipped with gripping devices for package loading of bricks into transport vehicle. Transportation of bricks is performed by road transport and railway.
Area for bricks painting
Finished products, sorted and accepted by Quality Control Department, from brick-molding machine NDR-500 are delivered to area for bricks painting. Painting of bricks can be performed using polymer as well as organosilicate compositions followed by curing and drying.
At customer's request multiple facing surfaces can be painted (stretcher, header and bed) both separately and in conjunction.
Calcium silicate bricks painted using modern technologies have a number of advantages over the brick painted in bulk and other similar construction materials.
For production of calcium silicate bricks Samara plant Strommashina can supply separate machines and units of own manufacture mentioned in this topic, as well as ready-to-use production lines including the equipment of our partners and manufacturing plants cooperating with us.