| 摘要 |
Double skeleton catalyst electrodes as described in Specification 806,644 and comprising a supporting skeleton of iron, nickel, or silver and, embedded therein, a skeleton of porous Raney metal comprising iron, cobalt, nickel or silver are regenerated, when exhausted, by a process involving three steps. In the first step the electrode is treated with a boiling alkaline solution, e.g. 6N potassium hydroxide, to remove silica and aluminium hydroxide, or alternatively the solution may be forced through the electrode pores. In the second step, oxides and hydroxides of iron, nickel, cobalt and copper are removed by treatment in alkaline solution, e.g. potassium hydroxide of pH9-12, at a temperature between 50 DEG C. and the boiling point of the solution, which may contain 5%-40% of citric or tartaric or their salts, e.g. potassium sodium tartrate, or ethylene diamine tetracetic acid or its salts, or nitrilotriacetic acid or its salts. An alternating current of 200 ma. may be passed through the electrode during this step. In the third step the electrode is made a cathode in a solution as in the first step, whereby silver chloride and oxides and sulphides of iron, nickel, copper and silver are reduced, a nickel or platinum plate serving as anode. The regenerated electrode is kept in a reducing atmosphere. |
