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Magnetic Phase Separation for Solvent Extraction

Patent-pending simple technique where phase separation is significantly enhanced using a magnetic field from inexpensive magnets

The Invention

Patent-pending simple technique where phase separation is significantly enhanced using a magnetic field from inexpensive magnets, relying on the paramagnetic nature of the extracted metal ions and without adding any extra magnetic particles into the system. The technique significantly accelerates phase disengagements and improves phase clarity.

  • Solvent extraction processes in the field of hydrometallurgy used to produce many metals such as rare earths. Solvent extraction involves contacting an organic phase bearing an extractant with an aqueous phase bearing the metal ions. The metal ions are extracted into the organic phase selectively. Then the organic phase is contacted with a clean aqueous phase to recover the metal ions from the organic (a process called stripping’).
  • Key to this process is how quickly and completely the phases separate, determining flow rates and process performance. This is dependent on two factors. (1) The speed at which the phases disengage. (2) The completeness of separation to minimize entrainment. Entrainment is when one phase is retained in the other giving it a cloudy appearance.
  • Often extreme measures are taken to deal with phase disengagement and entrainment. Centrifugal contactors for example are expensive and costly to run, but quicken phase disengagement. To deal with entrainment, chemicals are often added to the phase to promote coalescence, but this can be costly and create more downstream problems.

Benefits

  • Easy to adapt, clean, inexpensive, and effective phase separation
  • Non-intrusive: externally induced forces
  • Increases flowrates and efficiency of solvent extraction in metal refining
  • Inexpensive: Permanent NdFeB magnets are cheap.
  • Effective under stripping and loading conditions
  • Applicable to any SX system with paramagnetic metals (vast majority)
  • Easy to adapt technology for a variety of systems
  • Demonstrated using two repelling magnets. The field gradients could be further enhanced by employing 4 magnets in quadrupole arrangement around a vessel or tube.
  • The emulsified phases could be pumped through a pipe lined with inexpensive magnets in quadrupole arrangement to enhance phase separation. This would significantly accelerate phase separation and reduce entrainment, leading enhanced process performance and efficiency in hydrometallurgical solvent extraction.
  • Application in recycling and refining of various metals including rare earths, precious and base metals.’

Applications and Industries

  • Recycling and refining of various metals including rare earths, precious and base metals

Development Stage

Patent pending