Physical Separation

Suntech has acquired vast experience in running physical separation test work for recovery and upgrading of metallic minerals and non-metallics through use of appropriate equipment and/or techniques. The laboratory is able to run gravity concentration tests, DMS/HLS, Tabling, screening, jigging, magnetic separation etc. Details of each test and the levels of complexity of testing are presented in the following sections;

Gravity Separation

Gravity separation techniques are used to separate minerals of different relative densities; the dominant competing force in gravity separation is usually a fluid drag force while Van Der Waals and electrostatic forces have a tendency to stick particles together preventing separation. Equipped with this knowledge, Suntech has over the years developed methods and techniques to counteract the effect of these forces and hence developed sustainable methods to achieve clean separations. The beneficiation of chromite and iron ore using gravity and magnetic separation and vermiculite upgrading by dry separation techniques, have become important activities.

DMS/HLS (Heavy Liquid Separation)

HLS or DMS utilises the differences in particle density to concentrate material into various density classes. Separation is facilitated by a heavy liquid medium with an unstable suspension of TetraBromoEthane (TBE) and atomised ferrosilicon used as the medium for densities greater than 2.96g/cm³; this method is time-dependant hence only particles coarser than 1mm can be treated. For densities less than 2.96g/cm³, a mixture of TBE and acetone is used. Density classes with intervals of 0.05g/cm3 can be fractionated with the data being used to construct washability grade-recovery curves. Typical ores treated by HLS include chromite and base metal ores, kimberlites, PGM ores & hematite.

Shaking Tables

Suntech carries out Gravity separation tests using Shaking tables; these utilise mostly particle density and to a lesser extent particle size to fractionate fine ore samples (<1mm) into concentrates, middlings and tailings. The grade-recovery profile obtained on the shaking table is used as a benchmark for modelling performance of a spiral circuit. Ores that we typically characterise using shaking tables include gold, chromite, tantalite, heavy minerals, ferrous and non-ferrous ores as well as PGM-bearing (to a lesser extent and only when it’s UG2 ores).

Enhanced Gravity Separation

Falcon automated batch concentrators are typically applied for the recovery of free gold where low mass pull (<1%) is targeted. The falcon concentrator is essentially a spinning fluidised bed concentrator. The feed of 100%-2mm material flows up the sides of a cone-shaped bowl, where it stratifies according to particle density before passing over a concentrate bed fluidised from behind by back pressure water. The concentrate bed retains dense particles and lighter gangue particles are washed over the top lip of the bowl. For low mass samples, the concentrate produced from the Falcon concentrator is usually further upgraded by panning or shaking table.

Magnetic & Electrostatic Separation

Magnetic separators utilise the differences in magnetic susceptibility to separate either valuable minerals from gangue or vice versa. In general, minerals can be classified as diamagnetic, paramagnetic or ferromagnetic. Different types of separator are used depending on wet/dry applications, particle size and magnetic susceptibility.

Low Intensity Magnetic Separators (LIMS)

LIMS separators are used to recover ferromagnetic minerals such as magnetite or pyrrhotite from paramagnetic and non-magnetic minerals. This method utilises a drum with permanent magnets which generate a magnetic field of ~700 to ~3000 Gauss. Recovery of ferromagnetic is usually very efficient down to <5micron sizes as long as operating conditions are varied to ensure selective magnetic agglomeration can take place.

Wet High Intensity Magnetic Separator (WHIMS)

The WHIMS is suited for particles less than -1mm, and is capable of separating material with paramagnetic properties from non-magnetic material. At Suntech WHIMS is done at laboratory scale using an Eriez magnetic separator. The main application fields of WHIMS are recovery of ilmenite, hematite, rutile and manganese products as well as removal of Fe contaminates from fluorspar and other industrial minerals.

Processing Techniques

  • Gravity Separation
  • DMS Heavy Liquid Separation (HLS)
  • Shaking Tables
  • Enhanced Gravity Separation
  • Falcon Centrifugal Concentrator
  • Magnetic & Electrostatic Separation
  • Low Intensity Magnetic Separators (LIMS)
  • Wet High Intensity Magnetic Separator (WHIMS)

Contact For Services

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+27 (0)11 433 4234

+27 (0)76 102 4182

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