A new Bunting ElectroStatic Separator has been launched in response to enhanced material separation requirements in the recycling, plastics and minerals industries. It uses tungsten electrode wire to generate electrostatic charges to separate dry liberated particles.

The new technology significantly broadens separation capabilities, opening up new opportunities for recovering materials from waste and optimising mineral reserves.

Bunting (www.bunting-redditch.com) is one of the world’s leading designers and manufacturers of magnetic separators, metal detectors, magnets, magnetic assemblies and magnetising equipment. Its European manufacturing facilities are in Redditch and Berkhamsted.

ElectroStatic Separation exploits the difference in electrical conductivity between various materials in a feed material to produce a separation and it depends on a number of key material characteristics including conductivity, moisture content and size range.

In many applications, often due to the fine particle size, the ElectroStatic Separator is the only technology that enables a separation (-2mm granulated cable scrap). The technology also replaces less environmentally friendly separation processes such as froth flotation in mineral processing applications, including the separation of rutile from silica sand.

In operation, the technology uses the difference in conductivity between insulators (plastics) and conductors (copper and aluminium) to obtain a separation on an earthed roll. A vibratory feeder evenly feeds a material mix onto the top of a rotating earthed metal roll.

The rotating roll transfers the material under an electrode bar inducing an electrostatic charge. Non-conductive materials (insulators) adhere to the earthed roll via an image force, while the conductors lose their charge quickly and, under centrifugal force, are discharged — this results in a separation.

ElectroStatic Separators enable material segregation in plants processing minerals, producing plastics, and recycling secondary metals. Differences in conductivity found in recycled materials and minerals are sufficient to enable excellent levels of separation. Indeed, this includes the separation of metals with different conductivity.

When recycling wires, the technology enables the separation of plastics (insulators) from conductors (copper and aluminium), followed by segregation of the two metals. The same principle is used to separate aluminium from plastic when recycling shredded window frames and electric waste (WEEE).

The mineral processing industry commonly uses ElectroStatic Separators in conjunction with high-intensity magnetic separators such as the Rare Earth Roll Magnetic Separator and Induced Magnetic Roll Separator. This combined separation process is used when processing beach sands.

The Bunting ElectroStatic Separator is available as a single- or double-staged system in feed widths of 500, 1,000 or 1,500mm to suit specific applications. The Bunting Centre of Excellence in the UK includes a laboratory-scale model of the new ElectroStatic Separator and potential customers are invited to arrange for controlled tests to confirm the separation capabilities on a specific sample of material.