General concepts of brine electrolysis

High current densities to minimize capital investment in plant. 

Cell components which are reliable, readily available and have a long lifetime, so as to minimize downtime, 

A Good current efficiency and material yields for both the anode and cathode reactions. Parasitic reactions not only lower the energy consumption and increase the use of materials but also lead to impurities in the products. 

Low power consumption (kWh ton ). This is determined by the current efficiency and the cell voltage. The latter was discussed in Chapter 2 and it was shown that the cell voltage is made up of a number of terms, i.e.  

Even so, the data do not correspond to the exact conditions of industrial cells, since activity coefficients have been assumed to be I and the values are presented for room temperature and pressure, fn fact, slightly elevated temperatures and pressureSt 60-95 C and 1-10 atm. respectively would be more normal. But the equOibrium potentials in Table 3.2 form a sensible basis for discussing the cell chemistry. 

Chloride ion is usually oxidized in a slightly acid solution to prevent hydrolysis of the chlorine to hypochlorite and also to minimize the oxygen evolved in competing water oxidation at the anode. The pH at the cathode in a diaphragm and membrane cell will be about 14 as the electrode reaction generates hydroxide. Two factors emerge immediately  

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