How to make bricks from clay

Bricks - manufacture of bricks

Bricks are made from clay, loam or clay-containing masses with or without aggregates. Aggregates such as sawdust, paper traps or polystyrene balls reduce the bulk density, while adding heavy material increases it. The various raw materials and aggregates are dosed accordingly in the raw material processing via feeders and, if necessary, also crushed and mixed with the addition of water in the pan mill and rolling mill. In the wall tower or swamp house, even moisture penetration and further mixing (homogenization) is achieved.

After the required consistency has been achieved by adding steam, the clay is strongly compressed under high pressure in an extruder with negative pressure and pressed through a mouthpiece via screw shafts. The mouthpiece specifies the shape of the later brick and whether it has to meet certain requirements without perforation or with a specific perforation (hole pattern). Through the composition of the clay and the choice of the structure of the hole pattern, parameters such as compressive strength, thermal and sound insulation of the later product can be predefined.

After the continuous strand has been cut into individual blanks with a single or harp cutter, these are dried in chambers over a period of 1 to 3 days at temperatures of 50 to 100 ° C.

The clay blanks are burned over several temperature zones in the tunnel kiln. Perforated bricks are fired at temperatures of around 950 to 1050 ° C. At temperatures above approx. 1100 ° C one speaks of sintering or melt sintering, in which the surface begins to melt and gives the clinker properties such as particularly high compressive strength, particularly low water absorption, frost resistance, etc.

In the case of flat bricks, which are intended for processing using the thin-bed method, the horizontal joints are ground flat with an accuracy of less than one millimeter after the firing process.

In a further processing step, the properties of plane-ground vertically perforated bricks can be further optimized in terms of heat and sound insulation by filling the air chambers with purely mineral thermal insulation materials such as perlite, mineral fiber insulation panels or loose mineral fiber insulation.

After the quality control, bricks are palletized, wrapped in a weatherproof film, stored and loaded.