clay brick raw materials clay brick making machiery china
clay brick raw materials clay brick making machiery china
If the proportion of ultra-fine particles in the raw material is high, its plasticity index will be higher. In general, the drying sensitivity coefficient of this raw material is also relatively high, and the internal moisture is not easily discharged during the drying process, which is prone to the formation of mesh cracks.
The outer surface has shrunk, while the internal moisture has not been discharged. The internal shrinkage cannot be achieved, only the surface has shrunk, causing a network of cracks. In addition to increasing the temperature of the green body entering the drying room, efforts should also be made to increase the micro porosity of the green body by adding infertile materials to the raw materials. Adding coal gangue, shale, slag and other aggregates can be an economic choice. In fact, the mineral composition contained in such raw materials with high drying sensitivity determines their drying performance. For example, if the content of montmorillonite is too high, even shale cannot be used alone to make bricks.
The raw materials in certain regions contain high levels of montmorillonite, such as red clay soil in Northeast China, Inner Mongolia, Ningxia, Xinjiang, Beijing, and the Loess Plateau region. For this highly plastic raw material, the vacuum degree of the extruder should not be too high. High vacuum can increase the density of the billet, but if the density is too high, it may cause the density of the billet made from this raw material to be too high, affecting the discharge of water inside the billet, causing network cracks, and even bursting in the pre heating zone of the roasting.
