Automatic Silver Recovery Control
In using the system for electrolytically regenerating fixing baths described elsewhere in this issue of the Journal, it is evident that a very exact relation must subsist between the quantity of film fixed and the current supplied for electrolysis. If the current decreases the solution will become overburdened; if the current is too great decomposition will occur owing to lack of silver for plating. A monitoring system has been developed in which the solution is analyzed periodically by an optical titrating device. Measured quantities of the fixing solution and sodium sulfide are mixed, forming a brown suspension which is inspected by a standard lamp and a nickel wire bolometer. The indication is interpreted by a master relay which actuates a motor-operated field control on the plating dynamo. While the monitor works efficiently, it has been found that the lag in increase or diminution of silver in large processing plants is so great that hand adjustments, made after casual inspection two or three times a day secure sufficiently accurate plating. The automatic shows its greatest utility in shutting down the apparatus at night when there is no personal attention available.
- Print ISSN
- 0097-5834
- Published
- 1931-10
- Content type
- Original Research
- DOI
- 10.5594/J05573