Most rocks contain some form of metals or minerals. Not all of them have a concentration significant enough to justify mining. Those that do contain commercially valuable materials are the ones chosen for mineral processing.
Mineral processing goes by many names. Sometimes it’s referred to as beneficiation, mineral dressing, ore dressing, mineral extraction, mineral beneficiation, or mineral engineering. All of these terms can be used interchangeably but refer to the process of separating usable minerals from the low-value minerals in ore known as gangue.
Beneficiation falls into two categories, wet and dry. Wet beneficiation, or wet grinding, based on mineral density, combines with froth flotation to reduce particle size and separate the minerals. In other words, the minerals are soaked in a solution that separates them based on their water solubility. Dry beneficiation is based on a separate set of physical properties which include mineral size, shape, density, or magnetic susceptibilities. Dry separation technology uses less if any water throughout processing and is a burgeoning field because of its benefits in reducing our carbon footprint.
Since there’s no one size fits all separation method for minerals, there are a wide variety of mineral separation technologies. The separation technology equipment industry continues to develop groundbreaking techniques for mineral separation. Steqtech, a mineral separation company in Needham, MA, is a leader in this industry. We’ve created a triboelectrostatic belt separator using a dry beneficiation technique that’s both effective and eco-friendly.
The first step is to identify the differences within the ore so those attributes can be used to separate the minerals from the rocks that contain them. This is accomplished through crushing and/or grinding (comminution) until the minerals are fully exposed, or “liberated.”
In mineral processing, comminution uses the most energy, though originally it was even more labor-intensive. Centuries ago, small hand-operated pestles and mortars were used for crushing, and millstones, operated by men, horses, or waterpower were used for grinding. Today mechanized crushers and mills have greatly sped up this process.
Because of so many differences between minerals, they can respond differently to comminution. For example, one mineral might be softer or have larger or smaller grains than another, causing it to break apart more easily.
Crushing and grinding often work in conjunction with sizing, which groups the minerals according to size. The simplest sizing method is screening, which passes the particles through a screen.
Dewatering is another important mineral processing stage that removes any water absorbed by the mineral particles. Dewatering processes include screens, filtering, and thermal drying. After extraction, the water is treated, then recirculated to be used in plant operations.
A mineral’s different properties are the basis for efficient separation, which concentrates valuable particles. Processing also separates them from gangue, which is then disposed of. Separation properties include physicochemical (flotation separation), density (gravity separation), and magnetic or electric (magnetic and electrostatic separation).
Electrostatic separation technology (used at ST Equipment & Technology) includes triboelectric separation, which in addition to being better for the environment, can also detect finer mineral sands than other methods. ST Equipment & Technology’s triboelectric separator belt separates minerals based on how particles respond when placed in an electromagnetic field.
Founded in 1989, ST Equipment & Technology LLC (STET) is a major player in the mineral separation industry located in Needham, MA. We develop and sell dry mineral processing equipment used for the beneficiation of fine particle materials. This includes a proprietary, compact triboelectrostatic belt separator that’s easy to permit and can beneficiate materials within several industries.
Micron-size particles are beneficiated through an entirely dry process, with no additional materials or drying time. We’d love to share more about what we offer, so please contact us!