Institute of Metallurgy of Ural Branch of Russian Academy of Sciences, Ekaterinburg, Russia:

E. N. Selivanov, Director, e-mail: pcmlab@mail.ru

R. I. Gulyaeva, Senior Researcher

R. Z. Zaripov, Engineer

N. I. Selmenskikh, Researcher

“Ural Mining and Metallurgical Company Holding” LLC:

V. V. Belyaev, Head of Department of Metallurgy of Strategic Planning Section

S. V. Zhidovinova, A. A. Pankratov and L. A. Marshuk (Members of Institute of Metallurgy of Ural Branch of Russian Academy of Sciences) were the participants in this work.

The purpose of this work is estimation of influence of calcium oxide on elemental composition and microhardness of phases, formed during the crystallization of slags of autogenous melting of copper zinc concentrates in Vanyukov furnace. Methods of metallography, X-ray radiography and spectral X-ray microanalysis estimated the influence of calcium oxide on microstructure and elemental composition of the phases, formed during the slags crystallization. Measurement of phases’ microhardness was carried out by Vickers method. The content of the basic elements in researched samples was changed in the following ranges: 36.9–39.4% of Fe, 3.3–10.3% of CaO, 26.7–36.5% of SiO₂, 0.6–0.9% of Cu, 5.1–5.5% of Zn and 2.0% of S. It is shown that growth of CaO content in slags up to 10.3% leads to increasing of dispersity of its structure, formation of calcium-containing pyroxene and replacement of fayalite by iron-calcium olivine. With increased concentrations of CaO, copper is mainly included in slags in the form of sulfides. Zinc was found as a component of oxide and dispersed sulfide (christophite) phases. Zinc content in olivine and pyroxene phases is decreased with growth of calcium oxide concentration up to 3.6 and 1.7%, respectively. When the slag is cooled, the release of (Fe, Zn)S phase, containing up to 50% of Zn, is confirmed. On the basis of the data about microhardness and thermal expansion of phases, there was made an assumption about sulfides treatability during the grinding process as a stage of preparation of slag to flotation regrinding of non-ferrous metals.

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