Specifications

Anode coarse gold, gold or titanium as the cathode, to the direct current through the electrolysis of an aqueous solution containing gold crude anodic dissolution of gold, the gold is deposited on the cathode more process one of the methods for refining gold. Is a method of 19th century German Walter Weir (Wohlwill) invention still in use.
Principle to the electrolyte through DC, coarse gold in the gold loses electrons anode reaction occurs:
             Au + 3Cl- + HCl-3e ====== HAuCl4
Gold occurs in the cathode electron reduction reaction precipitate obtained:
          HAuCl4 + 3H ++ 3e ======== Au + 4HCl
Electrolysis, coarse gold anode electrode potential more negative than gold metallic impurities of copper, lead, platinum and palladium galvanic stay dissolved in the electrolyte. But when the electrolyte gold, copper, lead, platinum, palladium were 90g / L ,, 10g / L ,, 1g / L ,, 10g / L, 1g / L, the need for purification, to avoid metal impurities pollution cathode gold. Coarse gold anode in rhodium, ruthenium, iridium and PdCl2, which do not dissolve in the electrolysis process, enter the anode mud. Silver is gold electrolytic refining of the most harmful impurities, it generates insoluble AgCl, adhered to the surface of coarse gold anode, the anode passivation accumulation will cause a certain amount of time to make electrolysis difficult. For this reason, the input DC to DC input is also required 1.1 to 1.5 times the AC ripple current form non-symmetry, so AgCI become loose and fall into the porous anode mud.
Gold electrolyzer using acid ceramic, glass or plastic production, the structure is shown in a small tank, cover with thick gold anode bag hanging vertically into the slot and turn white sheets hanging into the cathode. Tank with extreme parallel grooves and slots in series. Electrolysis of the electrolyte with air circulation or stirring. The crude gold gold anode generally above 90%, from 0.1% to 0.5% silver, 0.5% copper, (Pt + Pd) of 0.5%. Or electrolytic cathode using rolling Preparation of gold pieces.