초록 ▼

An apparatus for de-silvering silver-containing solutions comprises an electrolytic cell (10) having an anode (20), a cathode (30) and a reference electrode (45) positioned adjacent the cathode (30), and electrical power supply control means (41) for controlling the supply of electrical power to the

An apparatus for de-silvering silver-containing solutions comprises an electrolytic cell (10) having an anode (20), a cathode (30) and a reference electrode (45) positioned adjacent the cathode (30), and electrical power supply control means (41) for controlling the supply of electrical power to the anode (20) and the cathode (30). Operation of the cell (10) is controlled potentiostatically while the current exceeds a certain threshold value and the current is controlled galvanostatically at that threshold (minimum) value in circumstances in which the potentiostatic control would result in a current below the threshold value. To this end, the power supply control means (41) includes means (60) for adjusting the cathode potential and control means (70) linked to said adjustment means (60) for controlling operation of the cell potentiostatically at a selected cathode potential, means for monitoring the current drawn through the cell during such potentiostatic control and for comparing such current with a threshold current, and means for controlling the cell galvanostatically at such threshold current value, means for switching from potentiostatic to galvanostatic control in response to cell current dropping below said threshold value, means for periodically re-establishing said selected cathode potential, and means for reverting from galvanostatic to said potentiostatic control in response to a cell current above said threshold value when said selected cathode potential is re-established.

대표청구항 ▼

[ We claim:] [1.] A process for de-silvering a silver-containing solution by use of an electrolytic cell having an anode,a cathode and a reference electrode, the process comprising:(i) supplying silver-containing solution to the electrolytic cell to immerse the anode, cathode and reference electrode

[ We claim:] [1.] A process for de-silvering a silver-containing solution by use of an electrolytic cell having an anode,a cathode and a reference electrode, the process comprising:(i) supplying silver-containing solution to the electrolytic cell to immerse the anode, cathode and reference electrode therein; and(ii) applying electrical power to the anode and the cathode such that a voltage potential of the cathode relative to the reference electrode lies within a de-silvering range to cause silver to be deposited on the cathode; wherein the operation of the cell is controlled potentiostatically while the current exceeds a certain threshold value and the current is controlled galvanostatically at the threshold value in circumstances in which the potentiostatic control would result in a current below the threshold value.