Chloralkali Process

The chloralkali process is the chemical engineering method of producing chlorine gas and sodium hydroxide by passing an electric current through a concentrated solution of sodium chloride, a form of electrolysis that splits the salt solution into its constituent products at the cell's electrodes. Industrial versions of the process, including the mercury-cell, diaphragm-cell and, increasingly, membrane-cell designs, are used to supply the two chemicals in the roughly fixed ratio the reaction produces them, and they underpin large sectors of the chemical industry, since chlorine and caustic soda are basic feedstocks for products ranging from PVC plastic and paper bleaching to water treatment and soap manufacture.