JAMES HOLMES, HAYS CHEMICALS / SCIENCE PHOTO LIBRARY JAMES HOLMES, HAYS CHEMICALS / SCIENCE PHOTO LIBRARY
MODEL REEASED. Pipes & worker at a plant producing chlorine by the electrolysis of brine (aqueous sodium chloride). The pipes are colour-coded for safety: yellow = chlorine, red = hydrogen, green = water. In the electrolytic process, chlorine gas is liberated at a graphite anode (positive electrode) & sodium at a mercury cathode (negative electrode). Sodium dissolves in mercury to form an amalgam, which is allowed to flow into a second cell to react with water to form hydrogen & sodium hydroxide (caustic soda). The mercury is subsequently recovered & recycled. The plant shown is at Hays Chemicals in Cheshire, UK.
Model release not required. Property release not required.