​How Triboelectrostatic Separation is Beneficial to Mineral Processing

Mineral processing isolates valuable minerals from ore through beneficiation, which is the treatment of raw material (such as iron ore) to improve its physical or chemical properties. There are many different approaches to this process. The most common are wet and dry methods, all of which use separation technology equipment.

One of the most promising developments in dry processing is triboelectric separation. This technology has a wider fine particle size range than conventional electrostatic separation technologies, making beneficiation possible in instances where flotation (a wet method) had been successful in the past.

ST Equipment & Technology, LLC (STET) has developed a Tribo electrostatic belt separator that has given the mineral processing industry a way to beneficiate fine materials with an entirely dry technology. There are many advantages to this process, but let’s begin with some terminology.

What’s the Difference Between Wet and Dry Beneficiation?
Wet grinding, in combination with froth flotation, is the most commonly used method for reducing particle size and liberating minerals from ore. The minerals are soaked in a solution, causing the materials to separate based upon whether they are water-repelling (hydrophobic) or water-attracting (hydrophilic).

Because of the amount of water required, and the inclusion of chemical agents, froth flotation isn’t environmentally friendly. In addition, it’s impossible to recycle all the water used, since portions of the process water are likely to contain trace amounts of chemical reagents.

Dry beneficiation separates mineral matter based on differences in its physical properties such as size, shape, density, luster, and magnetic susceptibilities. As the name implies, it uses less, if any water in processing, eliminating many of the drawbacks of wet grinding.

What is an Electrostatic Separator?
Electrostatic separation is a dry processing technique that separates minerals according to their electrical conductivity or electrical charging properties. It consumes less energy than conventional wet separation, and eliminates both the need to dry out the beneficiated material and disposal issues.

What Is Triboelectricity?
Triboelectricity is a centuries-old science that dates back to experiments conducted by the ancient Greek philosopher Thales of Miletus. He discovered that rubbing amber against wool led to electrostatic charging. As a result, triboelectric in Greek means “electricity resulting from rubbing.”

How Do Triboelectric Charges Work?
Every electric charge is either positive or negative. An object with a positive charge pushes away other positively charged objects, separating them into distinct groups. Conversely, a positive charge always attracts a negative charge, causing the two to draw together. Most everyday static electricity is triboelectric.

The triboelectric effect (or triboelectric charging) is a kind of contact electrification in which certain materials become charged after separating from a different material with which they’ve made contact. Put simply, rubbing two materials together creates friction between their surfaces and creates electricity.

For example, if you rub a plastic pen cartridge across your sleeve, it will become electrified and able to attract and pick up pieces of paper while repelling any other pens that may also have been electrified. The polarity and strength depend on the materials, surface roughness, temperature, strain, and other mineral properties.

As a kind of electrostatic separation, triboelectric separation is useful in ore processing because it can detect finer mineral sands than other methods. The STET tribo-electrostatic belt separator has been proven to effectively beneficiate many both insulating and conductive materials. Because it’s able to process materials with particle sizes from about 300 µm to less than 1 µm, this technology greatly extends the range of applicable material beyond that of conventional electrostatic separators.

Why Choose ST Equipment & Technology For Your Dry Minerals Separation Equipment?
If you’re in search of the best dry minerals separation equipment in the industry, ST Equipment & Technology LLC (STET) is a leader in the minerals separation industry located in Needham, Massachusetts. Our tribo-electrostatic belt separator provides a host of benefits over traditional wet processes.

Our Triboelectrostatic Separators beneficiate micron-size particles in a completely dry way. It requires no additional materials, eliminates the need for drying, and because it runs without water or chemicals, produces no wastewater or air pollutants Contact us today for more information.