Zirconia and high alumina ramming masses stand out as efficacious variants within the domain of unshaped refractories. In the interface between these materials, the utilization of transitional zirconia-alumina ramming mass is recommended. This study delves into the impact of alumina additive on the fundamental properties of ramming mass samples based on calcium oxide-stabilized zirconia, employing a phosphate bond. The investigation encompasses both the characterization of these samples, ranging from cold to heat-treated states across temperatures spanning 200–2100 °C, and an analysis of phase evolution throughout these conditions. The alterations in ZrO2 phases during thermal processing in the presence of Al2O3 and P2O5, along with the ramifications of these transformations on the properties of the ramming mass, are elucidated. Notably, the most comprehensive interaction between P2O5 and cubic ZrO2 materializes within the temperature interval of 1200–1400 °C, resulting in a marked destabilization of the cubic ZrO2 phase accompanied by a marginal reduction in sample strength that remains acceptable. The process of cubic ZrO2 phase destabilization reaches completion at 1700 °C. Elevating the heat treatment temperature of samples from 1700 to 2000 °C engenders the disintegration of aluminium, calcium, and zirconium phosphates, consequently leading to the re-stabilization of ZrO2. This, in turn, fosters densification and fortification of the sample structure. Designed for constituting the functional layer of linings at the interface of combustion and reaction zones within carbon black production reactors, the zirconia-alumina ramming mass with a phosphate bond showcases noteworthy potential. Experimental validation of this developed ramming mass at a carbon black plant has yielded favourable outcomes.

The use of a combined additive consisting of silica-containing additives"F"(thinning)and"S"(accelerating castable hardening)instead of the previously used silica-containing additive"A"and a mixture of dispersing additives based on polyethylene glycol in low-cement silicon carbide castable allows to improve the castable workability by increasing(in 5.4 times)the flowability of a freshly prepared castable,and increase by 1.2 and 1.1 times the cold crushing strength of heat-treated at temperatures of 110 and 1 580℃,respectively,castable samples from low-cement silicon carbide castable with practically equal values of open porosity(15.8％and 16.0％).The petrographic studies of the castable sample microstructure after firing at a temperature of 1 580℃showed that the investigated silica-containing additives"F"and"S"contribute to the denser and more uniform structure formation.As a result of the carried out research,the manufacturing technology of a low-cement silicon carbide castable was improved,of which the production was mastered at JSC"URIR named after A.S.Berezhnoy".

A phenomenological model is developed to take into account the effect of hydration complexes on the properties of electrolytes. The results of validation of the model are demonstrated for experimental pH values of aqueous solutions of sodium metaborate within a molal concentration range of 10−3–4.0 mol kg−1 at the temperatures 20, 25, and 50 °C.

The authors have presented a mathematical model of heat- and mass-transfer processes in a circulating-type reactor implementing the hydrolysis of sodium borohydride in the hydrogen generator. The model was used to analyze two methods of control of the generator output and can be applied to scaling and optimization of structures of generators of this type.

A steady-state jet model is developed to simulate combustion of iron rods in a high-pressure oxygen atmosphere. The suggested jet mode of combustion is characterized by a constant regression rate of melting interface (RRMI) with its value solely controlled by a melting droplet area between the melting front and the maximum temperature region; experimentally observed periodic droplet detachment does not affect RRMI. An analytical solution in an adiabatic approach and a numerical solution with radiative losses are obtained. The developed model comprises two parameters that simulate mass and heat transfer. The analytical solution contains the product of these coefficients. By analyzing the results of experiments with 1-mm diameter rods, the values of these coefficients were obtained by means of an optimization procedure. The simulation predictions are in agreement with experimental data for different rod diameters and oxygen pressures.

Calcium hexaluminate is one from such perspective materials.It is characterized by high refractoriness（ above 1 830 ℃）,as well as properties stability in reducing atmosphere, high alkali- and slag-resistance,low thermal conductivity and wettability by molten metals.In this work influence researches of fused calcium hexaluminate material additive in amount of 5%,15% and 25% on the main properties of alumina refractories were carried out.It is established that,the refractories containing the additive of 25% calcium hexaluminate material are characterized by the highest properties,slightly impregnated with metal melt and the highest metal corrosion resistance.The alumina purging plugs for blowing of metal with calcium hexaluminate material additive are produced and intended to one metallurgical plant of Ukraine for carrying out tests.

Two reactor designs with either passive or active thermal insulation were tested to produce synthesis gas from natural gas using catalytic partial oxidation on a system that exceeded laboratory scale. Preheating the working mixture significantly improves the conversion parameters. Preheating levels are limited by two factors: mixture ignition in the heater and overheating at the catalyst bed inlet area. The use of hot conversion products to provide active thermal insulation significantly improves the quality of the conversion. Because the same amount of identical catalyst was used in both reactors, the observed effect supports the hypothesis that the product composition depends primarily on the heat transfer process.

Because of the service temperatures increasing need in the combustion chamber of carbon black reactor up to 2200 degrees C the ramming mix from Y2O3-stabilized zirconia on the phosphate bond has been developed. Since 2003 year this ramming mix is successfully served in the carbon black reactors lining, ensuring the prolonged service period and high temperature service. After 18 months service in the lining at the temperature of similar to 2000 degrees C and the high-speed gas streams (similar to 400-150 m/sec) in the carbon black reactor the lining samples from ramming mix were selected for studies. The complete chemical, petrographie, XRD and electronic microscope researches made it possible to establish the wear mechanism of lining. It was established that in the service process gradual reduction of monoclinic ZrO2 amount occurs from the coldest part to the hottest part of lining, that leads to lining density increasing. At the same time, the indicated processes do not cause to any significant wear of the zirconia ramming lining and its service period is not less than 2 years.

The inspection of refractory lining, which had been executed from developed and produced by Ukrainian Research Institute of Refractories named after A.S. Berezhnoy chromic oxide (Cr), alumina-zirconia-silica (AZS) and alumina-chromic oxide (ACr) refractories, after 88 months campaign of industrial direct melting furnace for fiberglass production from E-glass has been realized. The most intensive wear of Cr refractory took place at the glass mirror level in the bubbling area. Research of refractories after service showed absence of chemical interaction of Cr refractories with E-glass melt, as well as glass penetration in the refractory in its pores and considerable crystals size increasing. The main factor of wear is the slow erosion of Cr refractory by the stream of glass melt. The wear of AZS and ACr refractories occurs as the result of their interaction with batch components and E-glass melt splashes, which leads to formation of low melted anorthite in the contact area.

A mathematical model of the combustion of a thin iron rod in the atmosphere of oxygen with no forced air flow around it has been constructed. This model includes an adjustment parameter that relates the rate of combustion of the rod with its diameter and the content of oxygen. The problem on the combustion of a thin iron rod in oxygen was solved analytically in the adiabatic approximation. The results of calculations were compared with the corresponding experimental data.

The present article is a part of the research program to study the combustion of steel in oxygen at high pressure. A fundamental understanding of iron and steel combustion in oxygen is important to the selection and specification of safe materials for oxygen production, storage and transport technologies. In the article a standard upward-burning ignition model was considered for cylindrical iron rods in oxygen with non-flowing test conditions. A combustion model with the drops separation to investigate influence of different burning factors on the combustion process was presented. The model results were compared with the NASA experiments to clarify the values that were introduced parametrically. The present model allows to calculate and visualize such combustion parameters as burning velocities, the period of droplet detachment, temperatures and stoichiometric compositions of melt droplets, etc. The Wolfram Mathematica 9.0 program was used for simulation.

In the experimental setup designed for catalysts testing and development of technological modes, experiments on partial oxidation were carried out using four types of catalysts in the range of equivalence ratios from 2.2 to 6. The characteristic residence time of working mixture in the catalyst unit is similar to 0.05 s. The processing of experimental data indicates that the yield compositions may be explained by the radial temperature profile in the catalyst. For all the tested catalysts the measured yield composition is well approximated by averaging the isothermal equilibrium compositions calculated using the suggested temperature profile. (C) 2013 Elsevier B.V. All rights reserved.

Experimental data were used to study the hydrolysis kinetics and construct an approximating expression for calculation of quasistationary hydrolysis constants for sodium borohydride in a wide range of alkali concentrations and temperatures.

Stability of sodium borohydride in the form of concentrated solutions and suspensions and solids corresponding to a crystal hydrate in composition was studied. The effects of temperature, concentrations of sodium borohydride and alkali, and nature of alkali metal cation on the rate of sodium borohydride hydrolysis were studied.

Distinctive features of an experimental procedure for determination of the conversion of sodium borohydride in hydrolysis in an aqueous-alkaline medium are described; the procedure is based on measuring the amount of the released hydrogen. Technical and methodological features of implementation of this procedure and measurement errors are discussed; a technique for calculation of the conversion of sodium borohydride in hydrolysis is presented. Experimental data in the form of the constants of a quasistationary hydrolysis regime are given for different isothermal conditions. The range of experiments covers temperatures from 20 to 95°C and alkali concentrations from 10−2 to 5 M.

Using the analysis of the experimental data on partial oxidation of methane as an example, we have shown that the chemical processes in the inert medium of a reciprocating flow reactor can be modeled with good accuracy by the standard kinetic scheme for homogeneous processes due to the fact that the gas flow in the region of combustion is described by two temperatures — the gas and framework temperatures. Such a modification of the chemical model requires neither changing the recognized mechanism of homogeneous chemistry nor correcting the volume heat transfer coefficient.

It has been shown that the diffusion interaction of growing impurity clusters within catalytic nanodroplets determines the important geometric parameters of a nanofiber. The characteristic time of coalescence of the clusters has been found.

The heat treatment of iron-ore pellets on the modernized OK-124 roasting machine at AO SSGPO is investigated. The temperature is measured over the height and width of the roasting car, along with the parameters of the gas-air flux. Uniform pellet heat treatment is ensured over the width of the car; the harmful emissions through the longitudinal seals are reduced; and the optimal heat-treatment conditions are determined.

Stability of sodium borohydride in the form of concentrated solutions and suspensions and solids corresponding to a crystal hydrate in composition was studied. The effects of temperature, concentrations of sodium borohydride and alkali, and nature of alkali metal cation on the rate of sodium borohydride hydrolysis were studied.