Spiral separator

SX7 and MX7 Coal Spiral Concentrators

Multotec has designed and optimised the double stage MX7 coal spiral concentrators to process feed with a size range of 2.0 mm to 0.1 mm for difficult-to-wash coal. The 2-stage spirals, the SX7 and MX7, incorporate two stages of spiralling into a single spiral assembly, reducing plant height and floor space requirements – ultimately reducing capital and operating costs.

These coal spiral concentrators are constructed with materials that ensure a high quality product with a longer life, lower maintenance requirements and reduced costs. To add flexibility when building or replacing the spiral plant, it has a compact modular design.

SX7 and MX7 Coal Spiral Concentrator benefits:

  • Two different basic models and two different combinations to suit the coal quality
  • Assemblies supplied in twin or triple starts, 7 turns high, or low feed ash profiles
  • Compact modular design adds to flexibility
  • Construction material used gives a long product life, low cost and low maintenance
Get in touch with your local Multotec branch about your mineral processing requirements.Learn more

Housing Frame

  • Each module houses 2 spiral assemblies
  • Modular and custom-designed
  • Dismantles entirely for retrofitting
  • Optional features include safety handrails, cat ladder hoops and kick-plates

Feed Box

  • Solid polyurethane casting
  • Impact wall provides longer life
  • Design ensures homogenous pulp mix
  • Replaceable

Auto Reject Channel® (MX7)

  • Improved removal of high density particles without the aid of auxiliary splitters
  • Improved removal of misplaced material
  • High reject capacity
  • Less sensitive to beaching of coarse particles

Distributor and Piping         

  • Robust, galvanised steel shell
  • Cast polyurethane lining
  • Replaceable parallel throat orifice
  • Anti-syphoning off-takes
  • Rigid H.D.P.E. piping
  • Modular polyurethane elbows
  • Top or bottom fed
Enhance your mineral processing operation with our gravity concentration solutions.


  • Solid polyurethane casting
  • Integral auxiliary splitter
  • Forced rejection of discard to reject gully or centre column
  • Homogeneous mixing of middlings and product for reintroduction onto trough
  • Divides spiral into two stages

Spiral Trough

  • Accurately manufactured by reverse lamination
  • Working surface is sprayed with polyurethane to a thickness of (3mm +/-0.5mm) or as requested
  • Improves circumferential strength
  • Prevents spillage
  • Integrally moulded
  • Ribbed for extra strength

Product Box and Splitters

  • Solid polyurethane casting
  • Splitter calibration
  • Box design assures no solids build up
  • Linked steel reinforced splitters

Multotec provides additional services with regards to its coal spiral concentrators, including test work on spiral concentrators at their R&D facility or on coal plant sites, consultation and commissioning of equipment, as well as optimisation of spiral plants.

Multotec’s SX7 and MX7 coal spiral concentrators are designed to suit the coal quality, making the Multotec coal spiral range one of the most extensive in the world.
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