Specifications and operating data are presented for the EDU-series electrodialysis plants used in various industries . Design of two multi-unit plants is presented and their operation discussed . Various electrodialysis processes are compared .
In recent years, the EDU-series multi-unit electrodialysis plants, simultaneously developed by the Institute of Chemical Sciences of the Kazakh SSR . Academy of Sciences and the Alma-Ata Electromechanical Works, have been regularly produced and are applied in different branches of the national economy [1,2] .
Up to 50 plants of type EDU-I-400X 2(4,6) are produced annually according to PCT KazSSR 384-79 specifications using 26,000 m 2 of MK-40 and MA-40 ion-exchange membranes (Stchekinsky Chemical Plant) . Table I presents operation data and economic evaluation of the two-unit electrodialysis EDU-1-series plant in different industries . The prime cost of demineralization is from 0 .2 to 1 .0 roubles/m' which is much lower than that by other methods. It has high current efficiency and is simple and convenient to regulate and control .
Unlike the widely used production methods, such as rectification, extraction and evaporation, the separation of mixtures is accomplished under normal conditions with considerable simplification of equipment and low power expenditures [3][4][5] . For example, the use of electrodialysis plants for stabilization of wines and grape juices to eliminate crystal turbidity, releases production space occupied by refrigeration units and shortens the time needed for cold treatment . As a result, higher quality wine products are obtained and there is prospect for utilization of organic substances .
Regeneration of mineral acids from pickling and aqueous organic solutions *EDU -electrodialysis plants .