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Mining & Mineral Processing

HF “Mortsell” Rotary Drum Separator

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Permanent Low Intensity [Ceramic Ferrite]
Application Summary
Dry of concentration of magnetite ores
Materials / Commodities

This unique forty pole low intensity rotary drum separator is used for the dry concentration of magnetite ores. The drum shell rotates at a high peripheral speed around the stationary alternating pole low intensity ferrite magnet with a uniform magnetic field. Sufficiently liberated magnetite particles are transported through the series of alternating magnetic poles releasing any entrained gangue particles thereby increasing product grade and yield of magnetite ore.

A drum rotates around a static magnet array comprising of a series of alternate north-south magnet poles in an arc slightly greater than half the drum circumference. The magnet array is designed to parameters laid down by the inventors LAURILLA and MORTSELL. In “US patent 2 711 249 Laurilla for magnetite concentration” claims the best results are obtained when the magnetic field produces an attractive force directed against the drum cover and acting upon the magnetic particles, which is distributed as uniformly as possible over the entire operating surface.

US patent 3 327 852 MORTSELL is specific with both the pole spacing 45 mm and the magnetic field flux density being 1000 gauss on the drum surface.

Ore particles are fed to a hopper located above the top of the drum by means of a feeder of the belt or vibrator type. The particles are dragged from the hopper and settle on the drum where they are acted on by three forces: magnetic radially and inwards; centrifugal; radially and outwards; gravity downwards.
Depending on the ore particle size and the magnetite content, particles may travel individually or form clusters. Clusters will tumble as they travel around the drum allowing release of entrained gangue particles which are thrown from the drum by centrifugal force and slightly augmented by gravity as they pass the drum horizontal centre line. The magnetic force opposes the other forces and retains the magnetic particles on the drum until they reach the end of the magnet array and fall from the drum.

A particle will leave the drum when the magnitude of the centrifugal force exceeds that of the magnetic attraction force.

The MAGQUIP Mortsell Dry Drum separator will upgrade ferromagnetic magnetite ores to desired magnetite percentage.

The separator is usually used as a two-stage separator with either the tailings being scavenged for higher concentrate recovery or the concentrate being cleaned for higher grade.

The product chutes can be configured for a middlings product. Three products can be produced. The middlings can be ground and processed on a low intensity wet magnetic separator LIMS.

The advantages of the MAGQUIP Mortsell Dry Drum Separator include:

  • Proven 40 pole magnet element with unique flux “smoothing” configuration and required 1000 gauss flux density.
  • Suitable enclosure for prevention and containment of dust ingress.
  • Robust high quality drum components for operational longevity in arid environments.
  • Uniquely engineered drum drive arrangement to overcome “eddy current braking” overheating issues due to fast moving steel drum in magnetic field.
  • Available with diverging type vibrating feeders to cover wider drum widths.
  • Custom drum dimensions and separator configurations are available as required.
  • Various product/chute configurations available.

The MAGQUIP Mortsell High Frequency separator employs a standard 900mm diameter drum with standard drum widths from 600–3000 mm

Drum speed variable from 3m/s to 8m/s

Permanent magnets Ferrite grade ceramic 8A

Drum shell AISI 304 stainless steel.

Drum Ends and bearing hubs machined carbon steel.

Drum bearings spherical roller type.

Bearing seals grease purged taconite labyrinth type.

Drum assembly contained in fabricated carbon steel housing with chutes for concentrate and tailings.

Fabricated carbon steel support framework.

Drum drive direct to end plate from in type gear motor with flexible coupling oversized motor allows for eddy current braking effect on the drum shell.