GB154635A - Improvements relating to electrolysis - Google Patents

Abstract

154,635. Adam, M. A., Stevenson, J., Mabbitt, A. T., and Fieldhouse, J. Feb. 27, 1919. Electrodes; connexions; electrodes, moving; treating after electrolysis; electrolytes, circulating, -In a call for the deposition of metals in non- adherent form, electrolyte flows uniformly between anodes and a rotary cathode. The cathode, of drum form, may rotate near anodes of circular trough form, electrolyte being circulated transversely to the axis of the drum. The cell is suitable for depositing tin from solutions containing ferric chloride, for instance the detinning-solution described in Specification 154,242. In one arrangement, two anode bars a, b, preferably of graphite impregnated with paraffin wax, together form a trough. Electrolyte is admitted to the trough from spaces m between the anodes and the cell wall, preferably by way of holes f near the top edges of the trough, the flow being controlled by weirs o. Outlet ports e at the bottom of the trough lead to a well p, whence passages q conduct the liquid to a compartment r provided with an adjustable outlet weir s. Grooves in the upper edges of the anodes receive conducting-bars h connected to the cell bottom by bolts i which are arranged to avoid the passages q. The ends of the cell are secured by bolts or by nuts on the ends of the conducting-bars h. Sheets of rubber l are placed between the anodes and the bottom and ends of the cell. The removable cathode may also be of carbon impregnated with paraffin wax; it extends beyond the ends of the anodes. Deposited metal is removed from the cathode by a scraper v and a shoot w. A current density of 2.5 amp. per sq. in. of cathode surface may be used. In a modification, the trough is formed by a single anode, in which the conducting-bars are embedded, the electrolyte then flowing over the top edge into the trough; or connexion may be made by drilling holes through the cell ends into the cathode and plugging them with finely powdered carbon impregnated with paraffin wax. In another modification, two troughs are formed by two outer bars shaped as shown in Fig. 1 and a single central bar of the form which would be obtained by placing two such bars back to back. Electrolyte flows into the troughs through holes near the top edges of the outer bars, and escapes through horizontal and downward passages in the central bar, the rotation of the cathodes preferably being in the same direction as the flow of liquid'. Draining passages only are provided at the bottoms of the troughs. Removal of the metal may be aided by shafts each carrying four rubber wipers. The effective cathode area may be regulated by rubber pads fitting against the cathodes; one of the anode bars shown in Fig. 1 may then be omitted.