The diaphragm cell process
In the diaphragm cell process the anode area is separated from the cathode area by a permeable diaphragm. The brine is introduced into the anode compartment and flows through the diaphragm into the cathode compartment.
Diluted caustic brine leaves the cell. On various sites, evaporation of caustic is not needed because of a site-specific process integration, technology and management of the energy balance.The caustic soda can also be concentrated to 50% and the salt removed. This is often by using an evaporative process with about three tonnes of steam per tonne of caustic soda.
The salt separated from the caustic brine can be used to saturate diluted brine. The chlorine contains oxygen and must often be purified by liquefaction and evaporation.
In 2015, the diaphragm process accounted for less than 14% of total installed European chlorine production capacity.
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