(BAT) Reference Document for the Production of Chlor-alkali ...

Chapter 2
Source: [ 25, Vinnolit 2011 ] (Source: Uhde) {The figure was
replaced.}
Figure 2.10: View of a membrane cell room equipped with bipolar electrolysers
Source: [ 32, Solvay 2010 ]
Figure 2.11: View of a membrane cell room equipped with monopolar electrolysers
The cathode material used in membrane cells is either stainless steel or nickel. The cathodes
Like the cathodes of diaphragm cells, they are often coated with a catalyst that is more stable
than the substrate and that increases surface area and reduces over-voltage. Coating materials
WORKING DRAFT IN PROGRESS
include Ni-S, Ni-Al, and Ni-NiO mixtures, as well as mixtures of nickel and platinum group
metals. The cathode coatings for membrane cells have to be more chemically resistant than
those of diaphragm cells because of the higher caustic concentration.
The anodes used are metal consist of titanium coated with a mixture of ruthenium dioxide,
titanium dioxide and iridium dioxide. At present, the second-generation coatings for membrane
cells show lifetimes comparable to those of the diaphragm cell technique [ 1, Ullmann's 2006 ],
[ 10, Kirk-Othmer 2002 ].
34 December 2011 TB/EIPPCB/CAK_Draft_1