Is chlorine production related to mercury (Hg) emissions? Isn’t this a reason to stop producing chlorine?
Chlorine is produced by passing electricity through a solution of common salt (NaCl) via a positive electrode (named anode) and a negative electrode (named cathode). Today a majority of Western European plants still have a process based on the use of metallic mercury as cathode, but change to new membrane technology using no mercury is speeding up and will substitute more and more mercury units. Mercury has the property to keep separated the highly reactive chlorine and sodium ions produced, which is essential for a safe and efficient plant operation. As mercury is a toxic metal, the industry has improved the performance of its mercury based electrolysis plants and reduced their emissions to a level below the most stringent regulations ensuring the absence of environmental impact. . Mercury emissions were reduced by over 85% in the past decade, to reach 10 tonnes (1997) and even less today. This should be compared with estimated global total man-made and natural emissions of 20,000 ton
