Table salt production, electrodialysis application

Several other potential applications of electrodialysis in wastewater treatment systems which have been studied on a laboratory scale are reported in the literature. In most of these applications the average plant capacity, however, is considerably lower than that in brackish water desalination or table salt production. 

As discussed by Pletcher 24, electrodialysis is an electrically driven membrane separation process. The main use of electrodialysis is in the production of drinking water by the desalination of sea-water or brackish water. Another large-scale application is in the production of sodium chloride for table salt, the principal method in Japan, with production exceeding 106 tonne per annum. 

The second major application of electrodialysis is the production of table salt by concentration of seawater [8], This process is only practiced in Japan, which has no other domestic salt supply. The process is heavily subsidized by the... 

Electrodialysis was developed first for the desalination of saline solutions, particularly brackish water. The production of potable water is still currently the most important industrial application of electrodialysis. But other applications, such as the treatment of industrial effluents [45], the production of boiler feed water, demineralization of whey [46], de-acidification of fruit juices [47], etc. are gaining increasing importance with large-scale industrial installations. An application of electrodialysis which is limited regionally to Japan has gained considerable commercial importance. This is the production of table salt from sea water. Diffusion dialysis and the use of bipolar membranes have significantly expanded the application of electrodialysis in recent years [48]. 

Electrodialysis 1. Desalination of brackish water 2. Production of table salt 3. Waste water treatment 4. Concentration of RO brines 5. Applications in the chemical, food, and drug industries... 

Electrodialysis has a number of other large-scale applications and these would include the manufacture of pure sodium chloride for table salt (in Japan, electrodialysis is the principal method, production exceeding 10 ton yr ), the demineralization of cows milk (for baby food), cheese whey and sugar solutions, the removal of excess acid from fruit juice and the isolation of organic acids from reaction streams. 

Seawater can also be concentrated by electrodialysis. An expenditure of about 150kWhrton of NaCl can bring the NaCl concentration up to 200gpl [20], This process has not found commercial application as an intermediate step in the production of large quantities of industrial salt. Where there is more value added on a smaller scale and not much competition from large producers, as in the production of table salt in Japan, it can operate successfully. 

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