Sohd electrolyzers

The reaction mixture is filtered. The soHds containing K MnO are leached, filtered, and the filtrate composition adjusted for electrolysis. The soHds are gangue. The Cams Chemical Co. electrolyzes a solution containing 120—150 g/L KOH and 50—60 g/L K MnO. The cells are bipolar (68). The anode side is monel and the cathode mild steel. The cathode consists of small protmsions from the bipolar unit. The base of the cathode is coated with a corrosion-resistant plastic such that the ratio of active cathode area to anode area is about 1 to 140. Cells operate at 1.2—1.4 kA. Anode and cathode current densities are about 85—100 A/m and 13—15 kA/m, respectively. The small cathode areas and large anode areas are used to minimize the reduction of permanganate at the cathode (69). Potassium permanganate is continuously crystallized from cell Hquors. The caustic mother Hquors are evaporated and returned to the cell feed preparation system. 

A (a) Sohds such as potassium bromide, KBr, and sodium nitrate, NaNOs, do not conduct electric current even though they are ionic. Why Can these substances be electrolyzed as sohds (b) Support or refiite the statement that the Gibbs If ee energy change, AG, is positive for any electrolysis reaction. 

The materials and stmcture of an RFC depend on the operating temperature (polymer electrolyte type or sohd oxide type), cell design (unitized or separate fuel ceU/electrolyzer units), and reactants (H2/O2, H2/CI2, etc.). 

The electrolytic permeabiHty is a property of any sohd electrolyte, since a local equilibrium involving ions and electrons is required by - thermodynamics for any conditions close to steady-state or global equilibrium. However, it is possible to optimize the level of permeability, depending on particular applications. In many cases, the permeability is a parasitic phenomenon leading to power losses in - fuel cells and - batteries, lower efficiency of solid-state - electrolyzers and electrochemi-... 

Sodium metal is mainly produced by the electrolysis of molten sodium chloride. Because solid NaCl has a rather high melting point (800°C), it is usually mixed with sohd CaCl2 to lower the melting point to about (600°C). The mixture is then electrolyzed in a Downs cell, as illustrated in Fig. 17.25, where the reactions are... 

---