Apparatus and method for electrolytically treating an ion containing liquid such as chromium plating rinse water

摘要

A method and apparatus are provided especially adapted for electrolytically treating chromium plating rinse water to recover hexavalent chromium in recycled rinse water in an economical and efficient manner. The invention may also be practiced in a wide variety of other treatment systems, such as for the recovery of nickel and other metals from their respective rinses and the like. A plurality of integral electrolytic cell structures (30), including ion transfer membranes (31) with electrodes (33, 36) inside and outside the membranes, and with a chimney (45) extending upwardly from the membranes, are provided in a tank (25) distinct from a plating operation rinse tanks. Rinse water is passed into the tank around the electrolytic cell structures with ions from the liquid passing through the membranes into interior volumes defined by the membranes. Air is introduced into the tank (by spargers 64) to maximize efficient ion transfer at the membranes. The tank (25) is provided above the rinse water tanks (10-13) and the inlet (27) and outlet (28) are arranged to prevent draining of the purifying tank into the rinse water tanks should a malfunction occur. The electrolytic cell assemblies are designed to have a minimum of parts, to facilitate removal of electrolytes without interrupting operation, and to facilitate cool operation.