Bunting Magnets Removing Steel from Old Landfill
A single Cross Belt Overband Magnet and five Magnetic Separation Pulleys supplied by Bunting Magnetics have been installed by Wheatway of Gloucester on mobile screens owned and used by Cotswold Recycling Company Limited, based near Bristol. The screens are being used as part of a process to rework an old landfill site.
Cotswold Recycling has a two-year project for re-processing landfill on an old site near Reading, Berkshire. The landfill originated from industrial and commercial waste and is being reworked and the area cleansed to enable the building of houses. They are using a range of Powerscreen mobile screens to size and segregate the material. Cotswold Recycling was established in 2001 and offer up-to-date crushing and screening equipment to hire or on contract. Their equipment enables effective recycling, reducing costs and producing a re-useable product.
The landfill site had approximately 400,000 tonnes of material that required processing. Originally closed in the mid 1990’s, the site had been used for industrial and commercial tipping for over 15 years.
One issue facing Cotswold Recycling was efficiently removing any steel and ferrous metals from the material. The company was already working closely with Wheatway, who specialises in providing engineered solutions and spares to the crushing, screening and recycling industry. Wheatway was tasked with assessing the application and contacted Bunting Magnetics Europe Ltd. Wheatway had previously worked with another magnetic separation manufacturer and decided to work with Bunting due to their excellent sales support and service. Bunting proved to be flexible when working with Wheatway, something that was essential due to the nature of the project.
Initially, Wheatway designed a tower structure incorporating a Cross Belt Overband Magnet. This was positioned between two screens and separated ferrous metals by lifting them off a 800mm wide connecting conveyor belt inclined at 30º. The Bunting Cross Belt Overband Magnet was a twin-pole design, rather than mono-pole, resulting in a far superior level of separation. Although there was an excellent level of separation, Wheatway then considered how to make a more flexible and mobile solution as the mobile screens were constantly being repositioned. Wheatway contacted Bunting and then purchased five Magnetic Pulleys, one for each of the mobile screens.
The Magnetic Pulleys replaced the head pulleys of the conveyors on the output of the screens. Bunting manufactured the Magnetic Pulley by mounting strong permanent ferrite magnets onto a steel carrier that is then encased by a tightly fitting stainless steel shell. The magnets produce an axial magnetic field that rotates with the normal motion of the pulley. This enables entrapped material to be freed and reduces the carryover of non-magnetic material into the reclaimed ferrous metals. The Magnetic Pulley is a simple and very effective way to separate ferrous metals, especially when the particle sizes are below 50mm and can be designed to be retrofitted on most conveyors.
For the installation, Wheatway designed a stainless steel splitter plate, which was then bolted onto the existing framework without any need for any additional holes or modification of the screen frame. All the screened material would then pass up the belt and any ferrous metals would be attracted to the pulley and discarded under the pulley, whilst all non-magnetic materials continued to cascade under a normal trajectory out and away into a separate pile.
Wheatway designed the retrofit to ensure that there was no reworking of the framework and utilised existing holes and fittings. This meant that a team of three people, including Colin Smith of Wheatway and Richard Cooper of Cotswold Recycling, was able to install all the magnetic pulleys and the chutes in one day.
Each Magnetic Pulley is fitted underneath a 900mm wide conveyor belt carrying approximately 50 tonnes per hour of minus 40mm material and, depending on the area of the landfill being processed, removes up to 5% magnetics. The magnetics are then passed on for further processing to recover, clean and reuse the steel and other ferrous metals.
Richard Cooper of Cotswold Recycling commented on the Bunting equipment, stating, “The magnetic pulleys are very good and are working remarkably well, especially considering what’s going over them.”
Bunting Magnetics design and manufacture a wide range of Metal Separators for the recycling industry and will be at the RWM exhibition at the NEC in Birmingham in September.
For further details on the Bunting range of Eddy Current Separators, Magnetic Separators and Metal Detectors please contact Carlton Hicks (email@example.com) or our technical sales team on: