This is the first rotary kiln in South Africa, after 6 month construction, now this automatic clay brick production line runs successfully.
The whole brick production line includes raw material processing, VP120 vacuum extruder extruding, auto robot brick stacking,
Rotary kiln drying and burning, also with brick loading and packing machine. This plant is the largest brick plant in Cape Town.
Why do bricks have wind cracks during the drying process:
Brick air cracking refers to the irregular small cracks that appear on the smooth surface of the brick after extruding the mud strip or forming the brick. Because the crack appears in a very short time after extrusion (within ten minutes to several hours), referred to as Wind crack, which means "cracks that appear in the wind after the mud strip (brick) is extruded".
The causes and solutions of wind cracks are:
(1) To strengthen the weathering and humidification of raw materials, the mixing of various raw materials and internal fuels should be uniform, and the impurities in the raw materials should be removed in time to ensure uniform drying and shrinkage of the green body.
(2) Overhaul the raw material preparation equipment in time to make it meet the technical requirements to ensure the crushing and stirring quality of the raw materials. Prevent the green body from cracking due to equipment reasons, resulting in uneven raw material crushing, stirring, extrusion and other processes.
(3) Repair and replace the extruder reamer in time to prevent cracks caused by excessive wear of the reamer, unbalanced extrusion speed of raw materials, inconsistent compactness of the green body, and inconsistent drying shrinkage.
(4) Keep the slitting machine flat, repair or replace the mouth of the extruder to prevent the slime from being bent when passing through due to the unevenness of the slitting machine, causing the blank to crack; prevent the mouth of the extruder from being broken. Cracks caused by uneven water (oil) paths at the four corners.
When the water is discharged from the green body, a large capillary force will be generated, and its value can reach 70kg/m3. Dry cracks can only be avoided by providing a homogeneous and healthy body.