Chemical Processes during the Heat Treatment of Basalt Fibers

A. V. Knot’ko^{a, b}, A. V. Garshev^b, I. V. Davydova^b, V. I. Putlyaev^b,
V. K. Ivanov^a, and Yu. D. Tret’yakov^{a, b}

^a Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences,
Leninskii pr. 31, Moscow, 117907 Russia

^b Moscow State University, Department of Chemistry, Vorob’evy gory, Moscow, 119899 Russia

E-mail: knotko@inorg.chem.msu.ru

Received November 21, 2006

Abstract—It has been established that, during the heat treatment of an unsubmixed (unsub-blended) glass
(with the contents of Ca and Mg, corresponding to the natural basalt) at the first stage of the oxidation process,
magnetic nanoparticles (>20 nm according to the transmission electron microscopy data) of (Mg, Fe)₃O₄ are
formed in a nonmagnetic glassy matrix (that is, the oxidation proceeds as internal reaction), followed by the
crystallization of alumosilicate phases. In the glasses enriched in CaO, such a crystallization occurs simulta-
neously with the evolution of the spinel phase. An analysis of the distribution of cations over the fiber cross
section has demonstrated that annealing under oxidative conditions is conducive to an increase at the surface of
fibers in the concentration of Ca in the case of utilizing an unsubmixed material and that of Na in the case of
the glass with a higher content of CaO. The long-term annealing of the nanocomposite at the temperatures of
its production results (according to the measurement data of magnetic properties) in the interaction of a part of
the formed (Mg, Fe)₃O₄ with the alumosilicate matrix.

DOI: 10.1134/S0033173207070132

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