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The electrical conductivity of solid solutions with tetragonal syngony formed in 0.86(xKF - (1-x)PbF2) - 1.14SnF2 systems has been studied by 19F NMR and impedance spectroscopy. It was found that the Pb0.86Sn1.14F4 phase is characterized by better values of fluoride-ion conductivity than the ?-PbSnF4 compound. It was found that the substitution of Pb2+ ions by K+ up to ? = 0.07 in the structure of Pb0.86Sn1.14F4 contributes to increase in electrical conductivity by an order of magnitude relative to the original Pb0.86Sn1.14F4. The sample of the composition K0.03Pb0.83Sn1.14F3.97 has the highest electrical conductivity (?600 = 0.38 S cm-1, ?330 = 0.01 S cm-1). The fluoride anions in the synthesized samples of KxPb0.86-xSn1.14F4-x solid solutions occupy three structurally nonequivalent positions. It is shown that with increasing temperature, there is a redistribution of fluorine anions between positions in the anion lattice, which results in an increase in the concentration of highly mobile fluoride ions, which determine the electrical conductivity of samples.

Based on studies of the decomposition of pe­ta­lite ore, the hydrothermal method for the extraction of lithium and aluminum compounds from lithium aluminosilicate Li[AlSi4O10] (petalite) has been developed. The studied sample of ore contains, wt. %: Li2O – 0.75 and Al2O3 – 14.65. For unenriched petalite ore with low lithium content, it is proposed to use the hydrochemical method of aluminosilicate processing – Ponomarev – Sazhin method. According to this method, the decomposition of ore is carried out directly in autoclaves by chemical interaction of ore components with NaOH solution in the presence of calcium oxide. The conditions (high temperature and pressure) for the destruction of petalite and the transition of lithium into the liquid phase are created exactly in the hydrothermal process. In this case, lithium and aluminum compounds pass into the solution, and calcium and silicon form a partially soluble compound in the solid phase – sodium-calcium hydrosilicateNa2O·2CaO·2SiO2·2H2O. The degree of extraction of lithium reaches 89–94 %, aluminum reaches 77–95 % within 1 hour at a tempe­rature of 240–280 °C, given caustic modulus 14–18, the concentration of the initial solution of 400–450 g/dm3 of Na2O and the ratio of CaO : SiO2 = 1 : 1 in the reaction mixture. Aluminate or lithium carbonate and other compounds can be obtained from an aluminate solution containing 1.5–2.5 g/dm3 of Li2O and 32–44 g/dm3 of Al2O3. The solid phase formed as a result of decomposition, with a high degree of extraction of lithium from the ore contains a small amount of Li2O in its composition and therefore can be used in the cement industry. Depending on the quality of the decomposed raw material, the course of the hydrothermal process is influenced by a set of factors. With a small content of lithium and aluminum in the ore, the caustic modulus of aluminate solutions (αк = 1,645*Na2O/Al2O3) formed after decomposition is important. Its calculation is required in order to determine the amount of alkaline solution of the required concentration to ensure almost complete decomposition of the ore. This value should be higher the lower the decomposition temperature and the concentration of the initial solution to achieve the same degree of recovery of useful components in the liquid phase. With the same caustic modulus, the efficiency of ore decomposition increases significantly with increasing process temperature and increasing the concentration of the initial solution. This can be seen in the values of the degree of extraction of aluminum, which increases by 12 % with increasing temperature from 240 to 280 °C, while the extraction of lithium remains practically unchanged.

Cobalt and manganese oxides and their complex oxide compositions were obtained by the sol-gel method using various precipitators(ammonia solution and HMTA). It was determined by X-ray diffraction method that both individual and co-precipitated hydroxo compounds after calcination at 400 °С form oxide phases of Co3O4 and Mn3O4 composition. Samples obtained by sedimentation with ammonia solution have a larger specific surface area than synthesized in HMTA solution. When calcined at 400 °C, the specific surface area for cobalt-containing samples sedimentated with ammonia solution decreases, and for samples sedimentated from HMTA solution - increases. The pore volume depends on the precipitator and changes little during calcination. For co-sedimentated and calcined at 400 °C samples, the specific surface area plays a significant role: the higher it is, the greater the catalytic ability of the sample to decompose hydrogen peroxide. On the SEM image of samples driedat 100 °C, sedimentated with ammonia solution, agglomeration of flat particles of gitrated oxides of cobalt and/or manganese of globular form is observed. For samples deposited in HMTA solution, SEM images are represented by agglomeration of particles in the form of planar layers. Calcination at 400 °C partially destroys the structure. Kinetic studies of the decomposition of hydrogen peroxide with theparticipation of the obtained samples indicate the first order of the reaction. Samples of cobalt hydroxide and co-sedimentated cobalt and manganese hydroxy compounds synthesized in HMTA solution showed the best ability to catalyze. The highest productivity (dm3 H2O2 of decomposed 1 g of catalyst) is inherent in samples of cobalt hydroxy compounds and its composition with manganese compounds synthesized by HMTA, after heat treatment at 100 °C. The ability of such samples to catalytic decomposition of hydrogen peroxide is estimated to be not less than 2.4 dm3 H2O2 (14 days). Compared to compounds synthesizedwith ammonia solution, they retain their activity for a longer time.

The results of studies of the interaction of titanium dioxide with the eutectic melt of (0.48) NaCl–(0.52) CaCl2 (mol.) in the temperature range of 823–1073 K are shown. It is established that the interaction of titanium dioxide with the melt of sodium chlorides and calcium is accompanied by the formation in the salt phase of titanium compounds soluble in 1.0% solution of hydrochloric acid, and in the solid residue is recorded calcium titanate, and the number of products formed in both phases substantially. At temperatures above 923 K is formed calcium titanate, the relative amount of which increases with increasing temperature by reducing the equilibrium content of titanium compounds in the salt phase. At temperatures below 923 K, calcium titanate was not detected in the interaction products, and the content of titanium compounds in the salt phase was higher than at higher temperatures. The absence of calcium titanate in the solid residue after prolonged isothermal contact of TiO2 with the NaCl-CaCl2 melt in the temperature range 823–923 K may be due to the fact that at such temperatures, the dissolution of titanium dioxide occurs by physical mechanism or by a mixed physicochemical mechanism. The results of the calculations by the Schroe­der-Le Chatelier equation support this. In the specified temperature range, the concentration of titanium compounds increases with tempe­rature.  Starting   from 923 K the nature of the interaction between titanium dioxide and the melt changes. Apparently at such temperatures (923–1073 K), the contribution of the chemical interaction between the components accompanied by the formation of calcium metatanate and volatile titanium compounds is dominant. The quantitative content of the phase, which in composition in the solid residue is identified as CaTiO3, increases, and the number of titanium compounds in the salt phase (based on TiO2) decreases. The change of isobaric isothermal potential (∆G) in the temperature range of 300–1300 K of the exchange reactions between sodium chloride and calcium and titanium oxide is positive, so self-directed course is unlikely. The lowest Gibbs free energy values correspond to the reaction of the interaction of calcium chloride with titanium dioxide to form titanate or calcium oxide and tetrachloride or titanium oxochloride.