Abstract: A sodium chlorate plant comprising a plurality of cell units linked in parallel flow relationship is described. The plant utilizes a single acidification, brine make up and heat exchange for liquor circulating therein. Each cell unit includes a plurality of individual chlorate cells linked in parallel-flow manner with a single reaction tank. The individual chlorate cells have a box-like body structure with lower inlet and upper outlet mild steel manifolds welded thereto. The cell box is cathodic on three sides and constructed of mild steel, the fourth side being an anode plate bolted to and insulated from the remainder of the cell box. Spaced interleaved vertical thin anode and cathode plates are located within the cell box and are welded into vertical slots formed in the respective backing plates to provide a plurality of parallel vertical electrolysis paths between the lower inlet and the upper outlet manifolds.