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A review of systematic studies of unbranched radical-chain reactions by the example of pyrolysis of hydrocarbons and dichloroethane with the participation of heterogeneous catalysts is presented. It is shown that the determining role in catalytic pyrolysis is played not by the concentration of surface or gas-phase active centres but by the total concentration of free radicals per unit reaction volume, which determines the heterogeneous-homogeneous nature of the process. Four types of surface impact on the process have been identified: inhibitory, neutral, accelerating the heterogeneous or homogeneous components of the process. A phenomenological model of these reactions and experimental evidence of its validity are proposed. For catalysts that accelerate the homogeneous component, the effect of “ignition” of the catalyst activity is detected, and its nature is explained. The concept of catalysis spheres is introduced - the areas above the catalyst with an increased concentration of radicals. Its dimensions and conditions of existence are determined. Experimental criteria for the emergence of the sphere are determined. Techniques of purposeful selection and synthesis of catalysts, selection of methods of technological arrangement of radical-chain heterogeneous-homogeneous processes are shown.

A method for producing biocomposite fertilizers with increased water resistance, based on the sequential impregnation of supports from pine bark with the solutions of urea and potassium dihydrophosphate is proposed. The structure of supports prepared from pine bark and fertilizers based on them was studied by means of scanning electron microscopy. The ability of biocomposite fertilizers based on pine bark supports to provide slow outwashing of mineral components with water for a long time was established. The treatment of fertilizers with water at room temperature for 15 days results in the removal of nitrogen, phosphorus and potassium by not more than 34.4, 74.3 and 58.4 wt. %, respectively (of the initial content), which evidences in favour of the prolonged action of biocomposite fertilizers based on pine bark. It is shown that the use of support obtained through extraction treatment of pine bark with organic solvents allows making a fertilizer with higher stability against nitrogen removal with water in comparison with the fertilizer based on the support prepared by treating pine bark with 1 % NaOH solution. Vegetation experiments on germination of Megion oat seeds revealed the same growth-promoting effect of biocomposite fertilizers based on supports obtained using different methods: the length of sprouts and roots increased by a factor of 1.5 in comparison with the reference experiment (water). The studies demonstrated the high potential of the developed fertilizers as an alternative to traditional water-soluble fertilizers and provided evidence of the possibility to obtain them using either original pine bark or wastes from its extraction processing.

Electron microscopy and X-ray fluorescence spectroscopy were used to study the effect of the cooling parameters of the melt obtained by reductive melting of the Chuktukon rare metal ore on the composition of the silicate and metal phases formed. The conditions for ore reduction and melt cooling are established, ensuring the predominant transition of iron, manganese, niobium and titanium into the metallic phase, and rare earth elements concentrating in the silicate phase, which is important for subsequent stages of ore processing. With relatively rapid cooling of the melt, the slag and metal parts of the system are homogeneous. In contrast, with a slow decrease in temperature, the formation of several phases with different chemical compositions is observed in both parts of the system.

Thermodynamic modeling of hypergene processes in copper-nickel ore tailings was performed with the variations of temperature (3 and 20 ^oC) and water evaporation processes in the upper layers of tailings during summer months at low filtration coefficients. It is established that the major cations of pore solutions are magnesium, calcium, nickel and copper ions, while predominant anions are sulphate and hydrocarbonate ions. The main newly formed phases in the system are the minerals of smectite group, as well as goethite, carbonates, silica, chlorite and gypsum.

The efficiency of the dissolution of bituminous coal at moderate temperature to produce quinoline-soluble substances was studied using commercially available coal tar (CT), its anthracene fraction (AFCT), heavy coal semicoking tar (HCST), heavy gas oil from catalytic cracking of petroleum (HGOCC), their binary blends, as well as tetralin (for comparison) as solvents. The chemical and molecular compositions of the coal, solvents, and the extracts obtained were characterized in detail by chemical and group analyses, FTIR spectroscopy, liquid chromatography, analysis by means of gas chromatography-mass spectrometry. The highly aromatic CT, AFCT, low aromatic HGOCC solvents, binary blends of these solvents and hydrogen donor tetralin showed high performance for coal dissolution at 380 °C in the quinoline-soluble substances, the yields of gases being no more than 0.6 %. The extracts obtained with CT and AFCT solvents represented highly aromatic pitch-like matter with rarely substituted aromatic rings. The extract obtained with the HGOCC solvent was characterized by lower aromaticity, the aromatic nuclei being highly substituted with fairly large alkyl fragments. The blended solvents yielded more extracts whose structural parameters were intermediate between those obtained with each solvent separately. Heavy semi-coking HCST tar showed no dissolving ability because of the high content of phenolic hydroxyls. The concentration of benzo(a)pyrene (BaP) in the toluene-soluble fractions of the extracts obtained was much lower than that in the solvents used, and decreased as the coal dissolution time increased, thus indicating BaP conversion.

The possibility of hydrothermal synthesis of Cs and Sr bearing framework aluminosilicates in the CsNO₃-NaOH-H₂O-(SiO₂-Al₂O₃)_glass and Sr(NO₃)₂-NaOH-H₂O-(SiO₂-Al₂O₃)_glass systems using coal fly ash cenospheres was studied as a low-temperature method to include the water-soluble forms of radionuclides ¹³⁷Cs и ⁹⁰Sr in a mineral-like form. The syntheses were carried out at temperatures in the range of 80-200 °С and autogenous pressure. Narrow fractions of cenospheres with the glass phase content of 90-95 mass % were used as aluminosilicate glass, and compounds of stable isotopes of Cs and Sr were used as imitators of radionuclides ¹³⁷Cs и ⁹⁰Sr. Based on the data obtained in the studies of solid products and post-synthetic solutions by means of X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray microanalysis (SEM-EDX) and atomic absorption spectroscopy (AAS), it was established that the Cs bearing analcime-pollucite solid solutions (Na _n Cs_{1- n} )AlSi₂O₆∙ n H₂O are crystallized in the Cs-containing system at 120-150 °C with 98 % Cs⁺ removal from solution to the solid product. The Sr bearing phases of tobermorite and plagioclase structural types are formed in the Sr(NO₃)₂-NaOH-H₂O-(SiO₂-Al₂O₃)_glass system. In this case, the effectiveness of Sr²⁺ extraction from solution is not less than 99.99 %.

An overview of the research carried out at the Boreskov Institute of Catalysis SB RAS on the application of catalytic technologies to develop energy-efficient designs of high-temperature fuel cell (FC) batteries is provided. The catalysts for high-temperature combustion of methane and catalytic burners for efficient fuel combustion in the reformers of installations operating on fuel cells were developed. Internal reformers with active and durable catalytic coatings have been developed, allowing the formation of synthesis gas directly inside the battery of high-temperature molten carbonate and solid oxide FC, providing a compact and energy-efficient design of power plants.

One of the most complicated tasks in spent nuclear fuel reprocessing is the separation of rare earth elements (REE) from transplutonium elements (TPE). This is due to the proximity of the extraction and sorption properties of REE and TPE. One of the most efficient and industrially tested methods of separating REE from TPE is extraction with tributyl phosphate in the presence of complexones. The difficulty in developing an effective technology for REE separation from TPE is that these elements are capable to form many complex compounds both in the aqueous phase and in the extractant. Moreover, almost any change in the extraction system (pH, type of salting-out agent, concentration of the target component, etc .) leads to a change of the dominant reactions and significantly changes the distribution coefficients. These features of the behaviour of the elements under consideration have led to the fact that the effective development of the technology of REE and TPE separation is practically impossible without designing a multifactor computer model of the process The formal system of equations of chemical thermodynamics (CTD) is a convenient element for presenting and processing data during modeling such systems. Relying on this postulate, we have developed a new specialized numerical method for calculating the composition of equilibrium chemical systems through the iterative solution of the formal system of CTD equations. The developed program based on this numerical method was used to optimize the technology of extraction separation of REE and americium.

The effect of electron-beam treatment with doses up to 450 kGy on the properties of triaminotrinitrobenzene (TATB) was studied. A linear dependence of the number of paramagnetic centres on the treatment dose and their stability upon heating have been revealed. It is shown that electron beam treatment leads to an increase in the interlayer distance in the crystal structure of TATB, causes a significant increase in its volatility and a decrease in the temperature of the onset of intense decomposition by 20 ^oС.

Procedures for the control of iron content at all stages of the mechanochemical synthesis of lithium aluminates were developed. The procedures were proposed to determine iron content using two independent methods: molecular and atomic spectroscopy. Atomic absorption spectrometry should be used for iron content lower than 10^-3 mass %, as well as for aluminium-containing samples. It was found that lithium content in the sample up to 1 g/L does not affect the analytical signal of iron in the sample with iron concentration 2-5 µg/mL of iron when analyzing lithium carbonate by means of atomic absorption.