Utilizing Sulfur Containing Material Patents (Class 205/613)
  • Patent number: 6641712
    Abstract: A method for selective dissolution of tin and/or lead- or tin-containing alloys from printed circuit boards is provided comprising contacting a printed circuit board with a solution comprising Ti(IV) and an acid which forms stable and soluble salt of Ti(III), Ti(IV), Sn(II) and Pb(II), under conditions to effect dissolution of substantially all of the Sn and/or Pb- or Sn-containing alloy therefrom, as Sn(II) and/or Pb(II) and recovering from the solution by electrolytic reduction substantially all of the Sn(II) and/or PB(II) species as Sn and/or Pb. After the electrolytic reduction step, the oxidant metal species is regenerated by oxidation and recycled to the first stage of the process.
    Type: Grant
    Filed: October 10, 2001
    Date of Patent: November 4, 2003
    Assignee: Alpha Fry Limited
    Inventors: Robert William Gibson, Paul David Goodman, Lyn Holt, Ian McCrady Dalrymple, Derek John Fray