Mercury cell

In this technology the separation of chlorine from the cathode products is possible because of the high overvoltage of hydrogen at the mercury electrode.




High Performance

Hydrogen and sodium hydroxide are not produced at the cathode; where, sodium is dissolves in the mercury as an amalgam.
The technology has been banned in Europe (2018) and substantially abandoned US but is still present in other countries. De Nora efforts on this technology have been devoted in keeping the mercury process compatible with the increasing EH&S standards and reducing the overall process power consumption.
In this way customers running mercury plants could remain competitive against more modern technologies and able to better plant the future retrofit of their installations.

Products dedicated to this process are:

  • Project Mercury Zero
  • Energy Saving Program (ESP)

Project Mercury Zero

This program aims to reduce the process environmental impact due to mercury cell room emissions and improve the overall cell room safety.

It is performed designing long-life components with minimum mercury pick-up and based on technologies and procedures that limit the number of times a cell must be opened for maintenance.

This solution includes:

  • New components design and materials to minimize cell opening for cleaning and ordinary maintenance: inlet and outlet end boxes, sidewall, caustic vessel, …
  • Process effluents mercury removal treatments: solid (sludges, waste graphite and carbon), liquid (waste water, caustic), gas (hydrogen and vent air);


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Energy Saving Program (ESP)

This program is useful to optimize the cell / electrodes performance and reduce the overall process power consumption.

The ESP foresee the adoption of the following De Nora proprietary solutions:
SLM™ anodes
Anodes able to increase the electrode active surface (lower current density), reducing cell voltage and increasing current efficiency;
Saving could reach 150 kWh/ton Chlorine – ΔKf = 0.02;

Anode Control Protection Device (ACPD)
A system able to monitor / control the distance between anodes and the mercury cathode;
Additional ΔKf = 0.03

New design and material for inlet and outlet cell boxes
Different design and use of TELENE® resin for inlet outlet boxes allow a substantial reduction of maintenance costs;