V. A. Krenev

Calculation of the mineral composition of basaltic rocks

A technique for the recalculation of data of the chemical analysis of basaltic rocks in terms of mineral composition by the method of physicochemical calculations is proposed. On the basis of data available in the literature on the chemical composition of a series of samples of these rocks, calculations of their mineral composition are carried out. A good correlation of the calculation and experimental data is obtained. The technique proposed can be applied to estimate the mineral composition of raw materials and evaluate the methods of its modification in the technology for obtaining basaltic fibers and stone-cast materials.

Physicochemical Interaction in the System Si-Al-Ti-Ca-Mg- Fe-Na-K-O with the Consideration of the Formation of Solid Solutions

Based of a physicochemical model of basalt melting processes with the consideration of the solid solution formation, a method for determining the mineral compositions of gabbro-basalt rocks was proposed, which helps estimate the technological properties of melts for mineral fiber production and stone casting.

Extrapolation of thermodynamic functions in calculation of phase equilibria by the Gibbs energy minimization method

A separate description of polymorphs and glassy, liquid, and gaseous states makes it possible, using the isobaric-isothermal potential minimization approach, to describe both the phase transformations of an individual substance and its behavior in complex systems, which is required for the representation of metal and salt systems that have melting points lower than the melting points of the pure components. The suggested methods of extrapolation of the thermodynamic functions of an individual substance, performed assuming that of the phase transition heat is constant and that the heat capacity beyond the equilibrium temperature range is equal to the heat capacity of the preceding or subsequent (by temperature) phase state, enable to avoid thermodynamic paradoxes in all cases and reliably describe the composition of complex systems in a wide P,T range of their existence with allowance for the existence of solid phases, melts, and gases in equilibrium.

Method of approximation of dependence of isobaric heat capacity on temperature

A method of approximating temperature dependence of heat capacity has been developed on the basis of a power polynomial in variables with different exponents in combination with the Nelder-Mead simplex method. For especially complicated dependences, the method makes it possible to match polynomials at junction points with infinitesimal deviation. The method provides high reproducibility and correct interpolation of empirical and semiempirical data.

Evaluation and modification of the initial composition of gabbro-basalt rocks for mineral-fiber fabrication and stone casting

Literature data and calculation results demonstrate that it is appropriate to use the acidity coefficient for the initial evaluation of the properties of gabbro-basalt raw materials for fiber production and stone casting. We examine the capabilities of hydrochloric acid leaching for modifying the composition of raw materials and those of physicochemical calculations for determining the mineralogical compositions of raw materials and modification products.

Interaction of basalt with hydrochloric acid

Physicochemical modeling and experimental investigations are performed to study the interaction of basalt with hydrochloric acid. The equilibrium compositions of the liquid and solid phases of the basalt-hydrogen chloride-water system are calculated. The effects of the hydrochloric acid concentration and solid-to-liquid weight ratio on the phase composition of reaction products are quantified, and the degrees of extraction of iron, aluminum, calcium, sodium, and silicon into liquid are determined. The results of physicochemical modeling are compared with the experimental data. Conditions for selective extraction of the basalt components into solution are estimated.

Effect of iron content on the sintering of ground basalt into ceramics

Ground basalt from the Myandukha occurrence, Arkhangelsk oblast, was divided into magnetically enriched and magnetically deficient components by magnetic separation, and their chemical compositions were determined. We investigated the difference in thermal behavior between the two components using differential scanning calorimetry and thermogravimetry data and the mineralogical composition obtained by thermodynamic modeling of the basalt. The sintering behavior of the magnetic and nonmagnetic components of the ground basalt was examined, and some properties of the resultant ceramic materials were studied.

Specifics of Representation of Thermodynamic Functions in the Method of Thermodynamic Potential Minimization

The type of physicochemical model dictates the choice of a minimized thermodynamic potential that provides the most adequate description of specific features of a natural or technological process. In the developed approach, the Gibbs energy was selected as the basis potential, and other thermodynamic potentials were considered as functions of G(T, P) and thermodynamic parameters with inclusion of independent factors of state. The presented thermodynamic functions of individual substances can be used in minimization of all basic thermodynamic potentials regardless of the conditions of existence of modeled systems.

Basalt leaching with orthophosphoric acid

Basalt leaching with orthophosphoric acid is studied by the method of isothermal dissolution. The total degree of dissolution of basalt and degrees of extraction into solution of separate elements as a function of temperature (20, 100°C), acid concentration (5–40%), and liquid-to-solid ratio are determined. Through the control of leaching conditions, it is possible to vary the coefficient of acidity of the basalt charge, decreasing the content of separate components. The possibility, in principle, of using this process for the optimization of charge composition in the manufacture of basalt-fiber materials and cast stone products is shown.

Effect of the properties of the water sorbent on the heat generation in the Fe-C-NaCl-H2O-O2 system

The water adsorption and retention behaviors of vermiculite, silica gel, activated carbon, and a zeolite are analyzed in relation to their pore structures, and their effects on the dynamics of heat generation in Fe-C-NaCl-H2O-O2-water sorbent systems are investigated.