Mercury Cell

Name:
Mercury Cell
Detailed information:
An electrolytic cell for the production of caustic soda and chlorine from sodium chloride brine. Continuously fed brine is decomposed in one compartment between graphite anodes, where chlorine is liberated, and a mercury cathode, where a sodium amalgam is formed. The amalgam flows continuously or intermittently to a second compartment where it is decomposed with water, forming a caustic solution. The decomposition is usually performed electrolytically by making the amalgam anodic with respect to an iron or graphite cathode. Pure water is supplied to the decomposition compartment at such a rate as to maintain a constant concentration of caustic in the product. With respect to the diaphragm cell, the mercury cathode cell has generally a more concentrated solution (50–70%); it has the disadvantages of higher operating voltage and lower efficiency (52–55%) and a high capital investment in mercury. Examples of mercury-cathode cells are Castner cell and DeNora cell.