Rare earth metal salts as potential alternatives to Cr(VI) in the chlorate process
2010 (English)In: Journal of Applied Electrochemistry, ISSN 0021-891X, E-ISSN 1572-8838, Vol. 40, no 8, 1529-1536 p.Article in journal (Refereed) Published
Chromate is today added to industrial chlorate electrolyte, where it forms a thin cathode film of chromium hydroxide that hinders unwanted reduction of hypochlorite and chlorate. The aim of this study was to investigate rare earth metal (REM) ions as an environmentally friendly alternative to the toxic chromate addition. Potential sweeps and iR-corrected polarisation curves were recorded using rotating disc electrodes of iron and gold. Addition of Y(III), La(III) or Sm(III) to 5 M NaCl at 70 A degrees C suppressed hypochlorite reduction. Activation of hydrogen evolution by REM ion addition to 0.5 M NaCl was more significant at 25 A degrees C than at 50 and 70 A degrees C. Increasing the chloride concentration to 5 M had a detrimental effect on this activation. The major problem in replacing chromate with REM salts is the poor solubility of REM ions at normal chlorate process conditions, and therefore REM salts are not a realistic alternative to chromate addition.
Place, publisher, year, edition, pages
2010. Vol. 40, no 8, 1529-1536 p.
Rare earth metals, Chlorate production, Yttrium, Hydrogen evolution, Hypochlorite, In situ electrodeposition
IdentifiersURN: urn:nbn:se:kth:diva-27266DOI: 10.1007/s10800-010-0136-4ISI: 000279033200010ScopusID: 2-s2.0-77956907518OAI: oai:DiVA.org:kth-27266DiVA: diva2:378742
QC 201012162010-12-162010-12-092013-07-02Bibliographically approved