GB817912A - Improvements in or relating to the recovery of silver from solutions of silver compounds - Google Patents

Abstract

817,912. Electrolytic apparatus. ILFORD Ltd. Nov. 6, 1957 [Nov. 7, 1956], No. 33965/56. Class 41. An apparatus for recovering silver from solutions of silver salts comprises a shaft 1, means, e.g. an electric motor 8, for rotating the shaft 1 about its axis, at least one helically wound metal fin 12 mounted axially on the shaft 1 and adapted to be connected to form the cathode of an electrolytic cell, and an electrode element, e.g. a plurality of carbon rods, spaced from the fin 12 and adapted to be connected to form the anode of the cell. Each fin 12, which is of stainless steel, makes one circuit of an element 10 which is suitably grooved at 11, the shaft 1 screwing into the element 10. Electrical connection is by a bushing 3 and a collar 5 to the shaft, all parts of the cathode unit except the fins 12 having an insulating surface. In an example, a bath containing 5 to 10 gms. per litre of silver is electrolysed employing a current of up to 5 amps., e.g. 2 amps. at 1.5 volts, the cathode being rotated at 100 r.p.m. Silver is removed from the fins 12 by flexing them. The electric circuits to the motor 8 and to the cell are preferably interconnected to prevent electrolysis taking place if the motor 8 stops, the stirring action of the cathode preventing sulphiding where a thiosulphate bath is employed. One fin only may be employed, and it may constitute less than a complete turn, and where more than one fin is employed, they may be separated by collars on the shaft. The anode rods may surround the cathode and both anodes and cathode be supported from a common framework.