Pilkington is one of the world’s largest manufactures of glass and glazing products.They are renowned for high quality products supplying major organisations such as car manufacturers. To guarantee high product quality Pilkington have a laboratory facility to perform sample tests on raw materials. For more than 40 years Pilkington have been using a Magnetic Disc Separator manufactured by Boxmag Rapid Ltd to test 25 kg samples of Limestone and Sand on a daily basis. The Boxmag separator was getting dated, and it was decided to upgrade it to a high performance disc separator of a modern design.

The exact requirements of Pilkington engineers and technicians were evaluated after a series of site visits. The machine design was then finalised taking into account these requirements, Master Magnets working closely with Pilkington throughout the design stage.

The Mastermag disc separator is designed for continuous use with all separating parameters such as conveyor belt speed, feed rate, operating gap, working current being variable. Magnet strength, Disc speed and belt speed are controlled by electricity. This allows the operators to fine tune the equipment for many separating requirements.

The magnet yokes and discs are constructed from high permeability mild steel, the coils being wound from best quality aluminium winding material suitably insulated and impregnated.The discs of the machine incorporate a tooth formation at the working zone of the Separator which ensures a magnetic intensity of 1.8 - 2 Tesla is attainable at the minimum gap with careful control of the separating parameters ensures that even the most feebly magnetic minerals can be extracted. This type of Separator extracts minerals on a selective basis in order of magnetic susceptibility, which is achieved by setting the operating gaps at differing heights from the belt.The tilt mechanism aids in the setting of the gaps for the same disc at differing heights. The trailing edge being different from the leading edge enabling two different products to be obtained from the same disc. Six magnetic products can be obtained on a 3 Disc Separator. The diagram to the right shows this, whereby discharge No. 1 discharges the strongest magnetic material, and No. 6 discharges the weakest magnetic material.

The non-magnetic product is then discharged at the end of the conveyor belt. The control panel supplied with the machine gives variable control of all magnet currents, and incorporates motor stop/start push button controls. The material is fed to the machine via a variable controlled Vibratory Feeder complete with feed hopper.

After the design was finalised and manufacture was completed, Pilkington visited the Master Magnet site in Worcestershire UK, to perform sample tests on Limestone and Sand, the results were very promising with 97% Limestone and 99% Sand recovery.

The disc separator will now allow Pilkington to perform more accurate tests, therefore increasing their product quality.