Kiln Burnt Bricks; manufacturing procedureArticles > Kiln Burnt Bricks; manufacturing procedure
Phases of the Brick Production:
There are many types of materials used in masonry work of construction. Among which the bricks are most important and widely used in the construction of buildings, bridges, and other infrastructures. Bricks are also classified into several types. But the most sought-after bricks are "Kiln Burnt Bricks". In this article, we will discuss in detail the "kiln bricks", with special reference to their production process.
(1). Mining and Storage of Bricks Raw Materials:
Bricks are made of clay, shale, and fire ash. These items are first mined by equipment or laborer, depending on the cost of the method. The excavated material is transported to a brick plant and then placed near the plant as raw materials. Keeping in mind the weather challenges, a sufficient amount of the raw material is stored near the plant, so that future needs can be meet without any obstacle caused by adverse weather conditions.
(2). Cleaning and Mixing the Raw Materials:
The second stage of brick making is the preparation of raw materials. At this stage, the raw material is mixed with water, and equally mixed with the help of workers. Before mixing raw materials with water, they are passed through a size reducing plant, which grinds the larger particles into fine particles. The raw material is also transferred to an inclined filtering screen, which filters away the pebbles and large rocks.
(4). Brick Molding and Forming:
When the clay is mixed evenly with water, it is poured into a form-mold. Construction work can be done by workers, as well as machinery. The mud poured into the mold is well pressed to fill the gaps with the object. This category is time-consuming, more expensive than other categories. The texture and finish of the bricks depend on this phase. There are three ways to build bricks.
(a). In the case of mud with very low plasticity, the clay is mixed with a small amount of water and mixed evenly. The well-mixed mud is transferred to a metal mold with a high-power compressor. The pressure in the mud on the skin presses it well, thus giving it a better blend. Blended bricks will dry in the sun and then passed through the firing process.
(b). In the event that automatic mechanical technology is used, solid mud is used to build the bricks. This process is also known as the extrusion process. In this process, about 12 to 16 percent of the water is added to the clay to form a plastic compound. The mixture is processed and thoroughly mixed for a few hours. Molded clay is placed in an air-drying room to remove air from the clay. Air removal increases the performance and performance of the plastic of the object, which creates greater strength. In the next step, the clay mixture is extracted by die to produce a clay column. Since the clay column leaves the die, the formation or cover of the earth can be used. The automatic cutter then cuts the clay column to create each brick. Cutting spacing and size of the die should be carefully calculated to compensate for the normal shrinkage that occurs during drying and shooting (see ASSETS, Variations in size). About 90 percent of the bricks in the United States are produced by the extraction process.
(c). Another way to create it is the "Soft Mud Molding Process". A soft or molded mud process is especially suitable for clay with a high water content that can be extracted by a solid mortar process. Clay is mixed with 20 to 30 percent water and is then molded into bricks for molding. To prevent the clay from sticking, the mold is moistened with sand or water to produce a "sand-blown" or "water-beaten" brick. Brick can be made this way by machine or by hand.
(5). Sun Drying of the Bricks:
The bricks from molds contain a large amount of moisture and water. To remove the mixed water from the wet bricks, and to prepare them for heating and fire burning, these are placed in the open air in sunlight. The bricks are sun-dried. This procedure may take several days, depending on the weather conditions. In hot and sunny weather, the bricks dry soon, while in the colder region and season, the drying process may take weeks. The sun-dried brick can also be used directly as unpaved constructions. These are known as sun-dried bricks.
(6). Firing Phase:
The sun-dried bricks are then placed in the firing chamber/ kiln in such a way, that spaces are left among these brick, to allow fire contact with each and every brick. This process is more technical than the rest of the processes. Skilled labor is needed to carry out this job. Deviation from the guided rules may impact the quality of the bricks. The spaces of the bricks are filled with fuel material, like wood, coal, straws, and gases, etc. The fuel is fired evenly. Overheating the bricks are also harmful to bricks. Overheated bricks may melt and deform. The molten bricks are unable to bind with the cement during masonry. The bricks kiln are specially designed in order to even supplement fire/ heat and to expel the carbon dioxide gas by means of a chimney. The firing process continues from 10 to 40 hours. The time of firing is dependent on the quality of fuel. The good quality of fuel like coal, gas, and wood, require less time for burning the bricks, while the inferior quality fuel like straw may require much time for finishing the job.
(7). Cooling Phase:
The well heated and compacted bricks are left for cooling. Some bricks are burnt well, thus giving better compaction, while some are not properly heated. The bricks, which are not properly heated and burnt, are processed again. The burnt bricks are left for cooling. The cooling procedure may take a week or more, depending on the volume of the kiln. The cooled bricks are then evacuated from the kiln chambers.
(8). Evacuation Phase:
The cooled bricks are then evacuated and tested the quality. The bricks of good quality are segregated from those of inferior quality.
(9). Storing Phase:
The last phase of the bricks is the storing phase. Bricks do not need any special storehouse, but rather, they are dumped in an open-air. Weather conditions do not influence the performance of the bricks during their storage phase.
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