Optimizing acid-free dissolution process for e-wastes

Image of some parts of shredded hard disk drives after acid-free dissolution reaction
Image of some parts of shredded hard disk drives after  acid-free dissolution reaction

This CMI-funded research was conducted at Ames Laboratory 

Achievement:
Best acid-free chemical solution (CuSO4) for preferential HDD-magnet dissolution at room temperature and varying solution concentrations has been selected

Significance and Impact:
Chemicals with highest hydrolytic stability and REE leaching selectivity for magnet dissolution from e-wastes (<4% of REE) are required for efficient recycling

Details and Next Steps:

  • Other parts of HDDs (e.g. PCBs, ceramic or Al bases, etc.) are non-reactive with copper sulfate solution at recycling conditions
  • Different Cu-based based solutions were tested, leading to CuSO4 being selected
  • Next step is to determine the efficiency of the process including as a function of temperature
     
Images of: iron(III) hydroxide (as hydrolysis product, left) and resulted unreacted HDD parts (right) after reaction with copper(II) chloride
Images of: iron(III) hydroxide (as hydrolysis product, left) and resulted unreacted HDD parts (right) after reaction with copper(II) chloride