ADSORPTION OF CYANIDE-CONTAINING SPECIES FROM POTASSIUM CYANIDE SOLUTIONS ON GOLD ELECTRODEPOSITS

The adsorption of cyanide-containing species on gold electrodeposits f rom alkaline solutions of potassium cyanide was studied by the radioac tive labelling (C-14) method. In the potential E region in which gold does not dissolve or the dissolution rate is comparatively low (approx imately up to -0.2 V(SHE)), the adsorption Gamma shows little variatio n with the nature of the supporting electrolyte (0.1 M KOH, 0.1 M K3PO 4 and 0.1 M K2HPO4) and the concentration of KOH (from 0.001 to 0.1 M) . In this potential region the plots of Gamma vs. logarithm of cyanide concentration are essentially linear and significant hysteresis is ob served on the positive and negative going Gamma vs. E plot. A peak of the surface concentration of the cyanide-containing species is observe d on the positive going branch of the Gamma vs. E plot in the potentia l region where the formation of Au(III) compounds takes place. In the original Kazarinov electrode lowering method, the background radiation was reduced to about 95% of the original signal.