Bauman Moscow State Technical University, Moscow, Russia:

E. A. Eliseeva, Associate Professor at the Department of Chemistry, Candidate of Chemical Sciences
S. L. Berezina, Associate Professor at the Department of Chemistry, Candidate of Technical Sciences

Moscow Pedagogical State University, Moscow, Russia:

I. G. Gorichev, Professor at the Department of Chemistry², Doctor of Chemical Sciences

Bauman Moscow State Technical University, Moscow, Russia¹ ; D. Mendeleev University of Chemical Technology of Russia, Moscow, Russia²:
V. S. Boldyrev, Candidate of Technical Sciences, Associate Professor at the Department of Chemistry¹, Head of the Chemical System Engineering Department at the Engineering Centre for Automation and Robotics², Master’s Student of the Faculty of Digital Technology and Chemical Engineering³, e-mail: boldyrev.v.s@bmstu.ru

The processes of metal extraction from ores, in which metals can often be found as part of oxides and sulphides, involve stages of chemical or electrochemical dissolution. Few publications can be found in the literature that describe detailed research studies looking into how the surface phenomena of d-metal oxides are linked to the acid-base properties and the dissolution mechanics. Consequently, it would be of relevance to establish kinetic relationships of the processes related to the extraction of metals from lean ores and secondary raw materials, leaching and beneficiation, surface etching and purification. This paper describes the results of a study that relied on potentiometric titration in an aqueous solution of potassium chloride to understand the dissolution kinetics of zirconium dioxide suspension. Titration curves were produced for different concentrations of the background electrolyte and pH values and a relationship was established between ZrO₂ dissolution kinetics and pH of the medium. Acid-base equilibrium constants were calculated at the metal oxide/electrolyte solution interface. The obtained results were used to analyze the distribution of surface particles that form as a result of hydrogen ions adsorption and desorption. Interpretation of the experimental relationships was based on comparison with theoretical calculations. The authors simulated the dissolution process. The paper demonstrates that metal oxides dissolve in stages, and adsorption complexes form in the process, the composition of which is linked to the surface charge. These findings could be useful when studying the kinetics of d-metal oxides, as well as in practical applications related to the dissolution of transition metal oxides in electrolyte solutions.

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