Raw Materials Processing for Clay Brick Plant

Aging, one of the most necessary key steps for clay brick plant raw materials processing:

To ensure the stability and physical properties of raw materials, long-time weathering and homogenization is necessary for the raw materials, for better physical properties and well-distributed chemical composition. In the treatment stage, crushing and homogenization are particularly important, which will directly determine the final product quality. By comparing internal tests among some factories, the particle size of raw materials after crushing and out of cage screen, directly affects the shrinkage between brick shaping and firing. During the production according to the new national standard, we found that the most prone to deviation is the shrinkage, variation of cavity size, rib deformation and small cracks. When other processes and raw materials unchanged, smaller is the particle size after cage screen, the less happened this phenomenon is. In addition, by comparative tests, we found the raw materials newly mined and used directly after fineness treatment are prone to the above phenomena. Therefore, we suggest that factories implementing the new national standard must stack raw materials for long time, weathering and homogenizing the raw materials, and control the fineness of the crushed particle sizes. Though reducing the particle size will inevitably increase power consumption and equipment wear, this raised production cost will be rendered by the higher qualification rate after this adjustment.

Aging is a very important process, whose purpose is to allow the water penetrate into the particles inside, realizing maximum uniform and consistent of water distribution, improving the surface brightness, strength, qualification rate of green bricks and reducing the product shrinkage at the same time. Four elements of aging are particle size, moisture, time and temperature. Particle size determine aging time and effect: the finer the particle size, the easier the moisture will penetrate,  the better the aging effect, the time will be shortened accordingly. Via tests, the residue after 0.2mm screen will decrease by 3.51% after 48 hours aging. Relatively speaking, the higher the aging moisture content is, the better the aging effect will be. However, generally the aging moisture control is determined by the mold water rate, and it cannot be higher than the molding water rate, normally less than 16%. Time is also important to the aging effect: the longer the aging time, the more powder there will be.

The aging temperature is relatively easy to be solved in southern China, for instance, the general temperature in Guangxi is 10-25 ℃, which has little impact on the aging. However, as to the cold and frozen northern China, the impact of temperature on aging effect will be reflected quickly and heat sources should be used for aging if necessary. Factories should have an aging warehouse with more than 4 days storage. In case the aging warehouse is small, it has to adopt stricter crushing process, increasing the processes of crushing, rolling and multistage mixing and etc. The purpose is to reduce the particle size, increase specific surface area, make the mud materials fully contact with water, shorten the water soaking path and wet the mud materials evenly and fully.

Post time: Oct-01-2021