Magnets That Sort and Lift Ferrochrome From Mechani Mags

Most plant engineers know Mechani Mags, the Boksburg company that makes the African Magnets range, for its suspended belt magnets that lift tramp metal off conveyors at mines and processing plants. This October, Mechani Mags wants buyers to look at the rest of the catalogue. That includes the rare earth Ferrochrome Magnet for recovering ferrochrome from slag, heavy duty lifting magnets for scrap handling and furnace loading, and a line of drum magnets, demagnetising coils and permanent magnet designs. Many South African operations schedule maintenance and upgrades for the year end shutdown, so now is a good time to look at where magnetic equipment could do more on site than guard a conveyor.

Recovering ferrochrome from slag

The Ferrochrome Magnet's full name is the In-Line Style Rare-Earth Permanent Magnetic Agitating Field Separator, which the company shortens to the MAFS machine. It is built for feed material with only small amounts of ferromagnetic particles, such as ferrochrome, banded ironstone and shales.

At its core are neodymium rare earth magnet elements of the highest available strength. In the agitating field section, the magnetic material is moved around so that non-magnetic particles caught between the ferromagnetic ones fall away, which gives a cleaner separation. Weaker magnetic elements sit near the end of the separator so the magnetics release more easily at discharge. Mechani Mags fits its own wear plate design, and the whole unit adjusts vertically, so its height can be set to suit the material on the belt.

The separator suits three main applications. In ferrochrome processing, recovering ferrochrome particles from slag improves the quality of the output. In mining and mineral processing, it can raise the purity of banded ironstone or shales. In recycling, it removes ferromagnetic contaminants from recyclable material.

Magnets that lift scrap, mill balls and furnace charge

For material handling, the company builds circular heavy duty lifting electromagnets for on-off duty. When energised, the magnet picks up steel and carries it. When de-energised, it drops the load and goes back to the loading point. The magnetic field is fairly shallow but highly concentrated, so the lifted steel is held as firmly as possible. Common jobs include scrap handling, mill ball loading and furnace loading. These magnets are not meant to hang over conveyor belts.

Diameters run from 300 mm to 3,000 mm, and rectangular and oval versions are available for specific applications. Every unit is oil free and fully sealed to IP66, so it keeps out dust and water and can even work submerged. The casing is reinforced to handle knocks and drops. The coils are impregnated with high temperature resin and have Class H insulation, and a heavy duty wear plate guards the underside. A warning light or siren can be added to show when the magnet is live, and a heat shield plate is available as an option for high heat work. The magnets handle high duty cycles and run on a wide range of DC supply voltages.

Power supply units, control panels, remote control pendants and DC cable reeling drums are available to go with them.

Choosing the right way to catch tramp metal

There are several types of Magnetic separators, and the right one depends on where in the process the steel has to come out and how the plant is laid out. Besides its suspended overband magnets, Mechani Mags makes drum magnets, also known as magnetic pulleys, which separate material as it leaves the head end of a conveyor belt. Its demagnetising coils demagnetise material as it passes through the middle of the coil. Custom permanent magnet designs are built to order and can be adapted for tight spaces.

Plenty of sites rely on a Conveyor metal detector to stop the belt whenever metal is detected. That protects crushers and downstream equipment, but someone still has to find the steel and remove it by hand. A suspended belt magnet works differently: it pulls ferrous tramp metal out of the moving burden continuously. Mechani Mags' suspended range covers fan cooled and oil cooled electromagnets in self-cleaning and manual-clean versions, plus its newer dry-type design.

That design, the Dry magnetic separator, is the company's most modern suspended overband magnet. It needs no oil or fans and has an energy efficiency rating equivalent to IE4. Mechani Mags says it gives the same magnetic power as standard models on 50% less electrical input. The unit is self-cleaning and comes with a belt slip and tear detection system and a PT100 temperature probe for monitoring. A low headroom model is available for plants with little vertical clearance. The separator can be used underground and can be Ex certified for hazardous areas.

One supplier for auxiliaries and spares

Magnets need dependable power, suspension and belting to do their job, and Mechani Mags supplies these too. The auxiliary range covers power supply units for mains voltages up to 1000 VAC at 50 or 60 Hz, control panels that work with almost any electromagnet system, three phase heavy duty solid state bridge rectifiers and DC cabling. It also includes adjustable suspension chain slings supplied with rating tags and a certificate of compliance, beam crawlers and trolleys, cable reeling drums and festoon systems.

On the spares side, the company keeps replacement belts, pulleys, gearboxes, motors, bearings, shafts, couplings and DC terminal poles in stock. It also supplies Type F flame retardant conveyor belting with test certificates, and reinforced heavier duty belts made specifically for use with magnets.

Using the shutdown for repairs and inspections

Plants often use the slower weeks at the end of the year for maintenance that is not possible at full production. The Mechani Mags workshop in Jet Park, Boksburg repairs and upgrades magnets of any make or brand, up to 20 tons in weight, and a loan unit may be available while a customer's magnet is being repaired. The company also does oil to dry conversions. In most cases, these turn an existing oil cooled electromagnet into a dry-type electromagnet of equal strength while keeping the existing power supply.

A trained site service team is on standby all year and works worldwide. Its on-site work includes gauss testing and reporting, routine inspection reports, certificate of compliance inspections, help with commissioning and installation, fault finding, general repairs and servicing, and site assessments for new magnet applications. Training is available as well. If a magnet has a fault, customers can drop it off at the Jet Park workshop for a free assessment and strip and quote, or have the company collect it.

Half a century of magnetic engineering

Mechani Mags bases its designs on more than 50 years of experience with magnetic equipment. It exports worldwide and supports clients in many countries. Because it focuses on custom engineering, it can design magnets around a plant's specific constraints, such as low headroom or awkward mounting angles.

Engineers, buyers and plant managers who want to talk about ferrochrome separation, lifting magnets or any other magnetic separation need will find the full product range and support services at https://africanmagnets.com/.

About Mechani Mags

Mechani Mags is a South African manufacturer of conveyor magnets, magnetic separators and lifting magnets. It trades as African Magnets from its head office and workshop at 30 Bisset Road, Jet Park, Boksburg. Its products include dry-type, fan cooled and oil cooled suspended belt magnets, the rare earth Ferrochrome Magnet, lifting magnets, drum magnets, demagnetising coils and custom permanent magnet designs, along with a full line of auxiliaries and spares. The company serves mining, processing and recycling customers in South Africa and abroad, and provides repairs, upgrades, training, site inspections, compliance reports and gauss testing.