A sand mill is a piece of industrial equipment designed to grind a given material into very small particles of roughly equal size. Sand mills are used for processing a wide variety of products, and can also be used as mixers and dispersants, creating a uniform mixture of several components during the grinding process. A number of companies produce sand mills for various applications, including different designs and sizes to meet the needs of various applications.
In a sand mill, a central bar agitates the sand, causing it to have a grinding action. Many sand mills produce very small particles on the first pass, with the particles passing through a mesh screen. Others have recapture systems, allowing people to pass the mixture through the sand mill again to make it finer and more even. The design works by agitating the sand, rather than creating pressure, ensuring that the grinding medium does not break apart in the device when it is used properly.
As the name implies, sands can be used as grinding media, but other materials may be used as well. The choice of medium depends on the material being ground. Some companies maintain several mills dedicated for specific uses, while others may change media as needed in a single sand mill. Sand mills are used in cosmetics manufacturing, the production of paints and pigments, and similar activities.
In the case of mixtures, sand mills can be used to run a mixture of components through for processing into a uniform paste or powder. This is widely applied in the production of paints, where pigments need to be ground with stabilizers and other components before being blended with a base. As the ingredients pass through the sand mill, they become thoroughly mixed. The very fine grind offered by this device allows for highly stable mixes without patches and chunks of various materials.
Companies with need for a sand mill may be able to rent or lease equipment for their needs, offering an opportunity to test different kinds of equipment before making a decision to purchase. It is also sometimes possible to buy used and refurbished equipment from a manufacturer or third party. Brand new sand mills can be very expensive. Grinding media are available from sand mill manufacturers, as well as other suppliers. The operator must select the best medium for a given application, weighing a number of considerations, including concerns about contamination and discoloration.