Chloralkali industry electrode materials

Traditional electrodes have been graphite based but since 1970, RUO2 on Ti02/Ti has been used " " very successfully in the chloralkali industry. This material seems to have optimum electrocatalytic properties and exceptional corrosion resistance. 

Ruthenium nowadays finds many uses in the electronics industry, particularly for making resistor tracks. It is used as an ingredient in various catalysts and, importantly, in electrode materials, e.g. Ru02-coated titanium elements in the chloralkali industry. Osmium tetroxide is a very useful organic oxidant and, classically, is used as a tissue stain. Both elements are employed in making certain platinum alloys. 

Rapp et al. (1991) found that the total concentration of PCDD/Fs in a Swedish graphite electrolytical sludge was 650 ng g-1. The use of graphite electrodes has been banned in developed countries because of the associated high pollution levels. The chloralkali industry is the fundamental raw material industry in China. Among the 500 chloralkali... 

These materials [164-166], consisting of precious metal (e.g., ruthenium) oxides coated on baser metals (e.g., titanium), have already had a major impact on the chloralkali industry as replacements for graphite. Sometimes an inactive oxide (e.g. Ti02) is mixed with the catalyst to improve corrosion resistance [167]. These types of electrodes may in many cases be used where previously only platinum could be employed and may thus make a number of organic electrosyntheses possible that were not considered industrially viable due to the price of platinum. 

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