A Nigerian mineral processor is installing two magnetic disc separators (MDS) to extract individual minerals in a Coltan processing plant supplied by UK-based Bunting Magnetics.

This latest export project reflects th UK company’s position as a recognised global leader for the design, manufacture, and supply of high-intensity magnetic separators for mineral processing. The Bunting European manufacturing facility are in Redditch, just outside Birmingham.

The Bunting design is widely regarded as one of the best in the world and its origins date back to the early 1900s, with subsequent enhancements following advances in material and manufacturing technology.

Since the mid-1980s, Bunting’s skilled engineers have further improved the design, providing greater magnetic strength and unrivalled flexibility for improved levels of mineral separation. The Nigerian mineral processor first contacted Bunting after viewing previously supplied magnetic disc separators operating successfully in other local Coltan processing plants.

Following a review of the project specification and subsequent recommendations by Bunting’s mineral application engineers, the Nigerian processor ordered two model MDS 3-375 Magnetic Disc Separators.

Coltan (columbite-tantalites) is a dull black metallic ore that includes the minerals columbite and tantalite. Tantalum is extracted from tantalite for capacitors used in mobile phones, personal computers, and electronics. Columbite is a source of Niobium, which is used in superconducting materials as well as in the nuclear, electronics, optics, and electronics sectors.

In operation, an even layer of approximately 500 kg/hr of Coltan raw mineral feeds via a vibratory feeder onto the magnetic disc separator's 375mm wide belt. The monolayer of material initially passes under a permanent ferrite Plate Magnet, suspended at 75mm above the belt, which captures strongly magnetic particles.

The Coltan then feeds under a series of three (3) individual spinning high-intensity electromagnetic discs, each generating different magnetic field intensities and positioned at an increasingly lower suspension height above the conveyor. The magnetic intensity of each electromagnetic disc increases along the length of the conveyor, starting at approximately 10,000 Gauss (1 Tesla) and ending with 23,000 Gauss (2.3 Tesla).

As the Coltan mineral mix passes under the rotating magnetic disc, magnetically susceptible particles lift and deposit into a discharge chute to the side of the conveyor. Each magnetic disc stage focuses on a particular magnetic mineral including tantalite, tin, and columbite.

Adrian Coleman, general manager of Bunting-Redditch, said: “Our superior magnetic disc separator design is exceptionally popular with Coltan processors due to the ability to vary the magnetic field and the manufacturing quality.”

“This latest project is particularly important, resulting from seeing our equipment successfully working in another Coltan installation — the perfect recommendation.”