the drive shaft 14 and so the cathode 16 are connected to a suitably insulated wiper 56 which is engaged with the shaft 14 as shown in fig1 for connection to the negative pole of the dc supply to the cell in use the shaft 14 is rotated to cause the cathode to be rotated within the anode in the tank and gold rich eluate from a carbon in pulp circuit is fed into the tank to fill the cell tank 10 and the settling tank 22 with the electrical supply to the anode and cathode of the cell activated soluble gold in the eluate is liberated from the eluate conventionally according to the following reactions although the reduction of other metallic ions such as ag cn 2 u2212 and cu cn 2 3 u2212 may also be important if they are highly concentrated 2cn u2212 u2192 cn 2 2e catalyzed by copper in solution being the oxidation of water to oxygen gas and the oxidation of cyanide to ammonia and carbon dioxide or to cyanogen the evolution of oxygen is the predominant reaction the gold particles which are liberated from the eluate are electrolytically deposited on the surfaces of the cathode panels 36 to form a gold rich sludge on the panels the.