Raw materials are the most crucial part of making quality bricks. Consistent, high quality raw materials combined with sound processes normally result in good quality fired ware. Unfortunately, in the real world, raw materials vary in quality and consistency. Variations in raw materials such as particle size, fired color, carbon content, and shrinkage are routinely measured during exploration, mining, stockpiling, and production. Another characteristic of raw materials that is critical and should be measured and monitored is the level of soluble sulfates present in the raw materials used to make brick.
For many years, bentonite has been introduced in ceramic bodies to enhance plasticity in an economic way. However, its use in ceramics is not only bringing advantages but also some inconveniences related to its ability to increase plasticity. Its layer structure is responsible for these properties.
The raw materials used to make bricks are the most important part of the process. The quality of the brick and the success or failure of the brick plant can often be traced to the raw materials. The planning and implementation of a raw materials program is the backbone of a well-run brick plant. Brick plants are often built in close proximity to the primary raw materials to be used for decades. The quality and consistency of these raw materials normally vary throughout the mine property. When the characteristics of some mined materials are too far out of specifications it may be necessary to avoid these raw materials thus reducing the raw material reserves. Some of the characteristics and some of the ways to optimize the usage of raw materials are described below.