Chlorine industry

Treatment of mercury residues from former chlor-alkali electrolysis plants

Mercury cell process


Unterhalb der Zellen

The mercury cell process is a formerly widely-used production technique for the production of chlorine and caustic soda. The liquid metal, mercury, acts as cathode (negative pole) in this process. In the past, the loss of mercury during the process (to air, soil and water) led to serious health and environmental problems. Therefore, most European chlorine producers have decided to phase out the mercury cell process by 2020. Nevertheless, even today, almost 6000 tons of mercury is used per year for chlorine production in Europe alone. As a result of this, yearly waste outputs contain around 1200 tons of mercury, which are stored on-site or sent off for disposal. The bulk of these wastes are pure mercury (former cathode), mercury contaminated graphite balls (from decomposer), activated carbon, caustic sludge, sediments, waste water treatment sludge, contaminated soil and building rubble. Mercury can be recovered safely from all these waste streams by utilizing the VacuDry® process.

EU regulations require that excess mercury originating from the chlorine industry is removed from the material cycle and stabilized before safe disposal. econ industries offers a stabilisation solution, the so called VaCure process; where mercury is transformed to the non-leachable and chemically-stable compound red cinnabar (HgS). The red cinnabar is suitable for safe disposal fulfilling even the strictest regulations.

Here’s where you can read more about our complete solution for all kinds of mercury contaminated wastes.

Key Facts


VacuDry® vacuum distillation & VaCure Hg Stabilization

Throughput capacity:

0.5 – 5 t/h

Input material:

Mercury contaminated adsorbents, graphite balls, caustic sludge, filter cakes, sediments, soils and building rubble, other mercury waste
Pure mercury (for stabilization)

Cleaning capacity:

Hg from 10,000 ppm to 10-50 ppm
Hg from 1000 ppm to < 5 ppm (0.5 ppm possible)

Heating system fired by:

Fuel oil, diesel, electricity, natural gas, biofuels

We provide:

  • Complete turn-key solutions from one source for any type of mercury containing wastes
  • Only the highest standards in regards to work safety, environmental protection, legal requirements and traceability (liabilities)
  • Individual mobile and stationary solutions (on-site; off-site)
  • Extensive experience and a 20-year proven track record in the treatment of various forms of mercury wastes
  • Full consultation for waste handling and support for the approval process