Development and introduction of anodes (OIRTA-Pd) based
on palladium oxide for the production of sodium hypochlorite

Summary

The results of collaborative work of PAO GMK Norill’skii Nikel’and EKOFES SPE LLC on the development of new titanium anodes (MMO electrodes) with an electrochemically active metal oxide coating based on palladium oxide (OIRTA-Pd) are presented. Titanium anodes are designed for the production of sodium hypochlorite, which is in high demand in water treatment technologies as a disinfectant replacing environmentally hazardous liquid chlorine. The results of studying the properties of electrodes with coatings of different oxide compositions and percentage ratios of platinum group metals in them, as well as the results of the production tests of prototypes of the developed electrodes are presented. It is established that palladium oxide in the coating composition improves the selectivity of active chlorine formation and increases the corrosion resistance of the electrodes contributing to an increase in the service life of the anode. The OIRTA-Pd composition is likely to become viable for manufacturing application owing to the improved characteristics relative to the composition of the reference coatings ORTA and OIRTA; whereas, in terms of the specific energy consumption indicator, it has characteristics superior to analogs – 3.72 kW·h/kg. In addition to the above, the voltage of the industrial electrolyzer is 5.6% lower compared to OIRTA. The developed OIRTA-Pd electrodes have a manufacturing cost comparable to OIRTA and a lower life cycle cost.

Key words

sodium hypochlorite , electrolysis , water disinfection , electrolyzer , titanium anode with electrochemically active metal oxide coating , MMO electrodes , OIRTA-Pd , palladium