High-temperature electric conductivity of magnetite ore (magnetite) in connection with genetic properties of the deposit

Abstract

995 By its degree of perfection, the crystalline structure of natural minerals differs from that of ideal crystals by the occurrence of many distortions and defects. These features of real crystals are variable for the same min� eral species from different deposits and belong to typo� morphic mineral properties [1, 2]. Moreover, “differ� ent generations of the same mineral, which are formed at successive formation phases and stages of the same deposit, always differ from each other in the composi� tions, shapes, and sizes of aggregates, structural parameters, and physical properties” [2, p. 17]. In the crystalline structure of real minerals that contain sev� eral cation species, their distribution through different positions in the lattice differs depending on the min� eral formation conditions and the subsequent thermal history. Most magnetite varieties exhibit a complex chemi� cal composition and contain various isomorphic admixtures. Being characterized by a defect spinel tex� ture, magnetite is very sensitive to changes in the min� eral formation conditions, which is reflected in its tex� ture and physical properties. The magnetite heteroge� neity is reflected in isomorphic replacements of Fe 2+ and Fe 3+ by several accessory elements. It is known that during the concentrating procedure, magnetite from ores of different genetic types behaves in different manners. This is to a large extent determined by differ� ences in its composition and texture [3]. When crystal� lizing in different thermodynamic and physicochemi� cal conditions, magnetite records genetic information on these conditions in its chemical composition and crystal structure. The physical properties of magnetite, which contain such information, are diverse and stim� ulate undying interest in the latter. New, previously unused properties are becoming known. Of impor� tance among typomorphic features are its electrical properties, features appearing at high temperatures and bearing information on crystallochemical pecu� liarities in the phase and structural state of matter