Triboelectric Belt Separator for Beneficiation of Fine Minerals

Separation Technologies, LLC (ST) has developed a processing system based on triboelectric charging and electrostatic separation that provides the mineral processing industry a means to beneficiate fine materials with an entirely dry technology. The environmentally friendly technology can eliminate wet processing and required drying of the final material. The process requires little if any pre-treatment of the material other than grinding and operates at high capacity – up to 40 tonnes per hour by a compact machine. Energy consumption is low, approximately 1 kWh/tonnes of material processed. Since the only potential emission of the process is dust, permitting is typically relatively easy. In contrast to the other available electrostatic separation processes that are typically limited to particles greater than 75 μm in size, the ST belt separator is ideally suited for separation of very fine (<1 μm) to moderately coarse (300 μm) materials with very high throughputs. The triboelectric particle charging is effective for a wide range of materials and only requires particle – particle contact. The small gap, high electric field, counter current flow, vigorous particle-particle agitation and self-cleaning action of the belt on the electrodes are the critical features of the ST separator. The high efficiency multi-stage separation through charging / recharging and internal recycle results in far superior separations and is effective on fine materials that cannot be separated at all by conventional electrostatic techniques. Since 1995, this triboelectric technology has been extensively used for the beneficiation of coal fly ash with eighteen separators in place and over 130 machine-years of operation at locations in North America and Europe. The technology has been also successfully applied to the beneficiation of a variety of minerals including calcium carbonates, talc, and potash. Recently, dry electrostatic separation has been successfully demonstrated for beneficiation of phosphate ores.