AQUATECH MEMBRANE TECHNOLOGY FOR RECOVERY OF ACID-BASE VALUES FROM SALT STREAMS

Bipolar membrane water-splitting technology, which is presently being commercialized by the Aquatech Systems unit of Allied-Signal, is a cost effective route to recovery and recycling of salt streams. In the Aquatech process, the salt stream is directly converted to its constituent acid and base using a direct current driving force. The process, which is electrodialytic, uses a two- or three-compartment cell incorporating bipolar and monopolar membranes. The first commercial application of this technology is on the recovery and recycling of mixed acids used in stainless steel pickling. The Aquatech technology is applicable to sodium sulfate recovery on an even larger scale. Such streams are generated during neutralization, ion-exchange and rayon manufacturing operations.