This demonstration project documents the practicality of a new evaporative approach for recovering chromic acid from metal finishing rinse waste waters, as well as the economics of the system under actual operating conditions. The six-month study of chrome plating operations was conducted by Advance Plating Company in Cleveland, Ohio. The design of the recovery system centered around a Corning PCR-60 climbing-film evaporative recovery unit manufactured by Corning Glass Works, a cation exchange column and monitoring equipment. The test design established a preliminary data base from information collection prior to system operation. Histories of chemical use were also compiled to aid in the cost analysis. The active study program involved collecting and evaluating data to determine the economics of the recovery approach as well as investigating the effects of varying rinse flow rates economics and rinsing quality. Results of the study showed that the system can be accommodated with little impact on the existing operation. The recovered chromic acid can be recycled back into the bath without affecting product quality. The recovery system can decrease chromic acid consumption significantly and is economically viable.

Prepared under grant no. S-803781. Microfiche.