Preparation of ultra-high-purity copper by anion exchange

Equilibrium studies of anion-exchange distribution pointed out the feasibility of eliminating virtually all the impurities from a copper chloride solution containing copper initially in the monovalent state. Elution tests proved that the proposed anion-exchange separation can offer extremely high degrees of purification by utilizing both the mono- and divalent states of copper and by properly controlling the HC1 concentration during the procedure. Initially, the Cu(I) chlorocomplexes are fixed and most of the impurities are eliminated, followed by an in situ oxidation for eluting copper in the Cu(II) state while retaining the rest of the elements in the column. Copper was extracted from the purified and oxidized CuCl₂-HCl solution by evaporation to dryness and hydrogen reduction. The produced copper sponge was melted in Ar-H2 plasma, followed by cold rolling, cutting, and wire drawing to obtain samples for glow discharge mass spectrometry (GDMS) analysis.