Yuri L. Mikhlin

Date and place of birth: July 9, 1958, Miory, Vitebsk region, Belorussia ICCT SB RAS 42, K.Marx Street, Krasnoyarsk 660049, Russia Phone: +7 (391) 249-48-85 Fax: +7 (391) 212-47-20 E-mail: yumikh@icct.ru Russian page 1975-1981: Moscow Institute of Fine Chemical Technology named M.V. Lomonosov, Department of Chemical Technology of Rare Elements and Electronic Materials, Russia. Diploma with honours in chemistry. 1983-1986: post-graduate courses, Institute of Chemistry and Chemical Technology of Siberian Branch of Russian Academy of Sciences, Krasnoyarsk, Russia. 1987: Candidat of sciences in physical chemistry, Institute of Solid State Chemistry and Mineral Processing of SB RAS, Novosibirsk. Thesis title: "Study of the kinetics and mechanism of dissolution and the state of surfaces of galena and sphalerite in acidic media". The research has been carried out at Institute of Chemistry and Chemical Technology of Siberian Branch of Russian Academy of Sciences, Krasnoyarsk. 2003: Doctor of sciences in physical chemistry, Institute of Chemistry and Chemical Technology of Siberian Branch of Russian Academy of Sciences, Krasnoyarsk. Thesis title: “Characteristics of real surfaces and kinetics and mechanism of the dissolution and oxidation of metal sulphides upon interaction with acid solutions” Current position: chief scientist, Laboratory of hydrometallurgical processes Professor (part time) of the department of physical and inorganic chemistry of Institute of Non-Ferrous Metals and Materials Science of Siberian Federal University The major research interests are surface chemistry of solids, mechanisms of reactions at sold – aqueous solution in relation mainly to mineral systems, leaching processes in hydrometallurgy of non-ferrous sand precious metals, formation and reactivity of nanoscale particles of gold, other metals and metal sulphides. Most interesting results obtained in last years are as follows. Electronic structures of the reacted non-stoichiometric surface layers formed at mineral sulphides (pyrrhotite, chalcopyrite, bornitte, galena, sphalerite) in the course of their oxidation and leaching were studied applying X-ray photoelectron spectroscopy, X-ray absorption and emission spectroscopies, scanning probe microscopy and other techniques. The modification of surface morphology in nano- and submicrometer scales and local semiconducting properties of the reacted minerals were examined using AFM, STM/STS. It has been found that the amount of gold nanoparticles spontaneously depositing onto minerals varies in the order CuFeS2 > ZnS > PbS > FeAsS > FeS2 > Fe7S8, which is close to that of their electrode potentials and contents of Fe(II). We arrived at conclusion that the rate of gold deposition is determined by decreasing the open-circuit (mixed) potential. This suggests, in particular, that the accumulation of ‘‘invisible’’ gold in arsenian pyrites and arsenopyrite under hydrothermal conditions may be explained by the low electrochemical potentials but not structural relationships between As and Au in solids. A decrease in the tunneling current magnitudes along with the increase in the XPS Au 4f binding energies with decreasing the Au nanoparticle size have been revealed. The effects were tentatively ascribed to retarding the electron transitions by emerging electrostatic charge on gold nanoparticles (Coulomb blockade). Possible mechanisms for the effects, and their potential role in the deposition and hydrometallurgy of ‘‘invisible’’ gold were considered. The list of most important publications Mikhlin Yu., Varnek V., Asanov I., Tomashevich Ye., Okotrub A., Livshits A., Selyutin G. and Pashkov G. Reactivity of pyrrhotite (Fe9S10) surfaces: Spectroscopic studies// Phys. Chem. Chem. Phys. 2000. V.2, No.19. P.4393-4398; Mikhlin Yu. Reactivity of pyrrhotite surfaces: An electrochemical study// Ibid. P.5672-5677. Mikhlin Yu. L., Kuklinskiy A. V., Pavlenko N. I., Varnek V. A., Asanov I. P., Okotrub A. V., Selyutin G. E., and Solovyev L. A. Spectroscopic and XRD studies of the air degradation of acid-reacted pyrrhotites// Geochim. Cosmochim. Acta. 2002. V.66, No.23. P.4077-4087. Mikhlin Yu.L., Kuklinskiy A.V., Pavlenko N.I., Varnek V.A., Asanov I.P., Okotrub A.V., Selyutin G.E., and Solovyev L.A. Spectroscopic and XRD studies of the air degradation of acid-reacted pyrrhotites// Geochim. Cosmochim. Acta. 2002. V.66, No.23. P.4077-4087. Mikhlin Yu.L., Tomashevich Ye.V., Asanov I.P., Okotrub A.V., Varnek V.A., Vyalikh D.V. Spectroscopic and electrochemical characterization of the surface layers of chalcopyrite (CuFeS2) reacted in acidic solutions// Appl. Surf. Sci. 2004. V.225, No.1-4. P.395-409. Mikhlin Yu., Tomashevich Ye., Tauson V., Vyalikh D., Molodtsov S., Szargan R. A comparative X-ray absorption near-edge structure study of bornite, Cu5FeS4, and chalcopyrite, CuFeS2 // J. Electron Spectrosc. Rel. Phen. 2005. V.142, No.1. P.85-90. Mikhlin Yu., Tomashevich Ye. Pristine and reacted surfaces of pyrrhotite and arsenopyrite as studied by X-ray absorption near-edge structure spectroscopy// Physics and Chemistry of Minerals. 2005. V.32. P.19-27 Mikhlin Yu., Romanchenko A., Shagaev A. Scanning probe microscopy studies of PbS surfaces oxidized in air and etched in aqueous acid solutions// Appl. Surf. Sci. 2006. V.252, No.16. P.5245-5258. Mikhlin Yu.L., Romanchenko A.S. Gold deposition on pyrite and the common sulfide minerals: An STM/STS and SR-XPS study of surface reactions and Au nanoparticles// Geochim. Cosmochim. Acta. 2007. 71. P.5985–6001. Mikhlin Yu., Likhatski M., Karacharov A., Zaikovski V. and Krylov A. Formation of gold and gold sulfide nanoparticles and mesoscale intermediate structures in the reactions of aqueous HAuCl4 with sulfide and citrate ions // Phys. Chem. Chem. Phys. 2009. V.11, No.26. P.5445–5454 Mikhlin Yu., Likhatski M., Tomashevich Ye., Romanchenko A., Erenburg S., Trubina S. XAS and XPS examination of the Au-S nanostructures produced via the reduction of aqueous gold (III) by sulfide ions // J. Electron Spectroscopy. 2010. V.177. P.24-29.