Developments in the electrolysis of alkali chloride solutions since 1970

The rapid increase in chlorine production over recent decades actually gave way in the latter months of 1974 to a decline; despite this, the chlorine capacities in many countries were extended. In the course of this expansion, the proportion of mercury cells decreased in favour of diaphragm cells. To counter the numerous developments in diaphragm cells, chlorine producers who use mercury cells have been constantly improving their techniques towards environmental protection. Developments with membrane cells have been started in many places throughout the world. In addition, various large plants are under construction. In order to be able to make a final judgement, we must wait for the experiences gained from these large-scale plants. The latest developments and the differences between the three processes will be described and their chances of further development discussed.