More About Scrubbing
Deleterious materials are not as strong as aggregates and minerals. They can degrade quickly, causing a loss of support in the pavement or structure. Therefore, desirable aggregates and minerals should be clean and free of impurities that can cause problems that affect their performance.
For example, lumps of clay present in aggregate that is intended for cement or asphalt can cause bonding issues, creating weaknesses in the structure and affecting durability and wear, as well as other problems. Because clay can absorb water, its presence in rock intended for concrete can increase the amount of water required to mix the materials. Clay can also decrease the permeability of a final product intended for drainage or the release of natural gas, as clay fills in the voids needed for the water to drain or the gas to escape.
Since the value of minerals is dependent on their quality, clay and other deleterious materials need to be removed at the processing plant prior to the downstream process. Sometimes these impurities can be removed by washing, but other times a more aggressive approach is required to work the deleterious material free.
Deleterious materials that can’t be removed with just washing need to be scrubbed in order to be released. Scrubbing is more intense and requires more energy than washing. During the scrubbing process, minerals are freed, or separated, from deleterious materials by agitation with water and then thoroughly flushed away from the desired product to a settling pond or water treatment process.
Most scrubbing action occurs through material-on-material attrition created by the violent agitation of a drum or rotating paddles on a shaft. As the material turns on itself, creating a scrubbing action, the deleterious material is separated and the desirable products are moved to the next part of the wet processing system. Scrubbing is required to produce a high-quality, silt-free aggregate or mineral product that meets the specifications outlined in the contract with the customer. Efficiently removing the clay and other deleterious materials increases the value of the final product.
McLanahan is a leader in producing equipment designed to scrub a large variety of aggregates and minerals for the removal of deleterious materials such as light, loamy clays; silt; soft stone; shale; twigs; roots and other harmful impurities. Offering more equipment choices than any other manufacturer in the industry, McLanahan can provide aggregate and mineral producers with the best solution to fit their application and increase the value of their deposit by cleaning it to conform to project specifications. McLanahan’s cost-effective scrubbing solutions can effectively and efficiently remove deleterious materials and clean your rock while providing the highest return on investment.