Log Washers can be used to remove tough clay from aggregate or mineral feeds through material-on-material attrition. Intermeshing paddles on two screw shafts provide additional scrubbing.
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.
Attrition Cells/Scrubbers employ particle-on-particle action to liberate deleterious clay and other materials. They can be used in a variety of sand industries and are especially ideal for breaking apart clusters of frac sand material.
Blade Mills break down deleterious material by means of alternating paddles and flights along a screw shaft. These machines are ideal for removing crusher dust and water soluble clays from coarse rock and sand feeds.
Screw Washers use a combination of paddles and screw flights to remove light clays, dirt, dust and other deleterious material. These materials are then separated from the feed material by a rising current of water and discharged via overflow weirs.