|Type:||Brick making machine||Brick Raw Material:||sand & lime||Processing:||Brick Molding Machine|
|Method:||Hydraulic Pressure||Automatic:||Yes||Place of Origin:||Kelantan Malaysia|
|Delivery Detail:||3 months|
The manufacturing process of sandlime bricks begins with sand. Different coloured sands effect the final colour of the brick
The manufacturing process of calcium silicate bricks begins with sand. Different coloured sands effect the final colour of the natural brick, with red sand creating a brick with a slight pink finish and a white sand producing a near white brick. Different grades or mixes of grades are used to produce the required result. The sand is normally stored in sand hoppers where the mix of sand is transported to the next stage by conveyor belt.
90% of a calcium silicate brick comprises the sand and it is essential that this sand is of the right type and grade, being rich in silica, clean and granular. Other matter such as clay, loam or any organic matter should not be present in any significant quantity. Mineral pigments are added at the second stage. It is necessary for the pigment to be mixed thoroughly with the sand. After any required mineral pigment has been added the lime is then added. Like the mineral pigment the lime must be thoroughly mixed with the sand. It is essential that the lime is free from any impurities and it must be completely hydrated before the brick goes through the hardening process. It is an essential requirement that sufficient water is present to enable the mixed sand and lime to be moulded under pressure and slightly more water is added than is needed to hydrate the lime, to ensure that this is the case.
Once mixed and, with a properly adjusted moisture content, the sand and lime mix is conveyed to feed the brick presses. Normally the presses are of the rotary table type with an output of up to 3000 bricks per hour. As each brick is produced it is normally automatically stacked to await transfer to the hardening chambers known as autoclaves. These are long steel cylinders, six to seven feet in diameter and each holding upto 20,000 bricks.
Essentially the autoclave is a large pressure cooker into which the uncured bricks are conveyed on trucks running on rails. Once the bricks are in place within the autoclave, the chamber is sealed. Steam is introduced and the pressure steadily raised for about an hour and then maintained at pressures of 8 to 16 bars and the temperature is raised up to approximately 200 °C. After some hours the steam is then shut off and that in the autoclave released through a valve, this allows the bricks to cool steadily. At this point the bricks are cured and have developed their final properties, especially the strength, and are ready for removal from the autoclave and on to packing and dispatch.