The authors propose a way of using ultrasound to clean cathode material of the aluminum foil of a spent lithium-ion battery. A general diagram of the device’s layout is developed, and the interaction between the main units of the structure is analyzed. The procedure is based on the cavitation effect of the ultrasonic erosion of solids placed in a liquid exposed to ultrasound. An expression is obtained for the depth of the coating layer that is removed from the tape during a single run through all cavitation zones of the device. An analytical and numerical analysis is performed of the dependence of the cleaning rate on the intensity of ultrasound, its frequency, the speed of the tape, and other parameters of the diagram. The possibility of effectively cleaning cathode material off the aluminum foil from an NMC-type lithium-ion battery is demonstrated experimentally.

This paper presents a mathematical model of the granulation process in a fluidized bed of diammonium sulfate solutions. Expressions are derived for calculating granule growth, the density function of granule distribution at the apparatus outlet, and the distribution variance as a function of external recycle characteristics and process parameters. The adequacy of the proposed mathematical description to the actual process is demonstrated.

The authors discuss two types of limitations in today’s means modeling chemical processes at elevated pressures. These limitations are due to the specificity of thermodynamics in the vicinity of the critical point and incorrectly applying the law of mass action at elevated pressures. The first type of limitations singles out the range of thermodynamic parameters near the critical region of the compound, which slow the transfer of mass near the critical region and cause greater density fluctuations at temperatures above and below the critical temperature. These conditions prevent the use of technological processes. An analysis is performed using the molecular theory for non-ideal reaction systems based on the lattice gas model. The second type of limitations specifies the range of thermodynamic parameters in modeling chemical processes at elevated pressures, for which the use of the above molecular theory and the law of mass action for ideal systems differ noticeably.

The article presents the results of research on the effect of intrapore fluid surface tension on the structural and surface properties (specific surface area, pore volume, and pore size distribution) of silica (SiO2) synthesized via the acid decomposition of nepheline mineral raw materials. The synthesized samples were analyzed using chemical and X-ray diffraction (XRD) methods, as well as the Brunauer–Emmett–Teller (BET) method for determining specific surface area and the Barrett–Joyner–Halenda (BJH) method for pore size distribution. Equations were obtained linking the specific surface area, pore volume, and pore diameter of the synthesized SiO2 samples to the surface tension of the intrapore medium. It was shown that replacing the aqueous medium in the pore space with an organic liquid before drying significantly (~2 times) increases the adsorption monolayer capacity and affects the pore volume distribution. Based on the specific surface capacity of SiO2 samples and Gibbs free energy (ΔG°) changes during sorption, it was concluded that the synthesis method does not significantly affect the physicochemical properties of their surfaces (the type and number of sorption sites per unit area) or the nitrogen sorption mechanism.

Relevance: Carbon capture and storage technology involving geological storage of carbon dioxide in deep aquifers is widely used in the world as this technology is aimed at reducing the emission of greenhouse gases into the Earth’s atmosphere and minimizing the influence of these gases on global climate change. Objective: To carry out preliminary investigation of the features of water–rock–carbon-dioxide interactions in application to carbonate reservoirs, which are widespread in hydrogeological basins over the territory of the Russian Federation and are potentially suitable as carbon dioxide storage facilities. These processes are considered on the example of the ancient Siberian Platform, where industrial production of hydrocarbons is currently increasing and a series of large-scale projects in the area of petroleum and gas chemistry are underway. Methods: Mathematical physical and chemical modeling is applied to solve the problem. The calculations are implemented by the HydroGeo software package, in which the achievement of chemical equilibria for the “water–rock” system is implemented on the basis of the method of equilibrium constants. Results: The obtained results allow us to evaluate the directions of geochemical processes in the reservoirs under consideration and to provide qualitative estimation of changes in the pore space under the conditions of its saturation with carbon dioxide, with respect to different saturation degrees. It is established that solution acidification is observed as a result of its saturation with CO2, with the transition of chemical elements to the prevailing forms of complex ions bound with hydrocarbonate and chloride ions (Mn, Na, K). At the same time, saturation with carbon dioxide does not have such a substantial effect on the forms of Ca and Fe migration. Special attention is paid to Al, which is transformed almost completely from complex forms into Al3+ in the presence of carbon dioxide. In the studied reference samples, rather intense transformation of the reservoir rocks with redistribution of elements between the primary and secondary mineral phases is observed (both rock dissolution and precipitation up to several hundred g/dm3) with comparatively small absolute changes in open porosity. In a number of the considered objects, the dissolution of calcite and dolomite proceeds due to a decrease in pH. The directions of the transformations, as well as the trend of changes in the filtration-capacity properties, are determined by the specific mineralogical combination of the reservoir rocks and the brine present in them, as well as by the stage of evolution of the system under consideration (the first part of the considered combinations is initially far from equilibrium and continues interacting, while the second part is close to equilibrium and is transformed into the non-equilibrium state due to saturation with carbon dioxide).

The article is devoted to an analysis of the role of chemical technology in the development of the concept of best available techniques and the features of its practical application in the development and updating of BAT Reference Documents, as well as their use for the purposes of environmental and technological industrial regulation. The evolution of the concept of best available techniques is briefly described, and its basic principles are outlined, in the substantiation of which leading Russian scientists took part. It has been shown that the best avaiulable techniques are aimed at resource and energy efficiency enhancement and negative environmental impact reduction. An analysis of the main trends in the development of mineral fertilizer production technologies is presented. The paper presents BAT-associated emission levels, resource efficeincy parameters, and cardon intensity indicators for the best available and perspective techniques. It is emphasized that chemical technologies play a key role in reducing the negative impact on the environment in various industries; projects for cleaning exhaust gases from sulfur oxides developed for metallurgical enterprises are analyzed. The article presents the views of an international group of authors on the prospects for improving the concept of best available techniques and expanding the practice of its application in the Russian Federation and abroad.

The influence of unsteadiness of the gas flow in the channel of the slot matrix of a rotating heat exchanger on its thermal characteristics is studied. For this purpose, mathematical simulation of conjugate heat transfer during the flow of air along the steel walls forming the analyzed channel is carried out. Due to the features of the rotating heat exchanger’s operation, mathematical simulation is carried out repeatedly using the results obtained as initial conditions for the following calculations to obtain the parameters of conjugate heat transfer in the nominal mode. It is shown that the flow in the studied channel of the matrix of the heat exchanger repeats itself every 60 cycles. The distribution curves of the local values of the Nusselt criterion along the length of the channel at all timesteps of the flow process, as well as the values of the Nusselt criterion averaged over the length of the channel, are calculated. It is shown that the average value of the Nusselt criterion increases gradually over time. The time-averaged value of the Nusselt criterion is determined and is shown to slightly exceed the values obtained in the steady formulation.

In this paper, we propose the construction of a thermal physico-mathematical model of a contour heat pipe with a mechanical pump, based on the results of experimental validation of which a model of a heat pipe with a branched contour is constructed. This model consists of 55 isothermal units and hydraulic resistances varying along the length of the pipe. The models have low sensitivity to errors in setting the heat-transfer coefficients and hydroresistance. With the help of this model, data are calculated by the Runge–Kutta method of the fourth order of accuracy. The correspondence of the experimental and calculated parameters is good. According to this method, calculations of the functioning of a two-phase experimental circuit which has been subject to thorough extensive ground and flight testing are carried out. Propylene is used as a coolant. The temperature difference between the calculated and experimental data is about 1.5°C (at a saturation temperature of 25.5°C); the difference in the pressure drops is about 0.05 atm (with a pressure drop at the pump of 0.7 atm and an absolute pressure in the circuit of 12.2 atm.).

A number of versions of a process flow diagram for the post-treatment of wastewater from the production of protective coatings and printed circuit boards are considered. It is shown that the choice of water treatment flow diagram depends mainly on the quality of the initial wastewater composition and on the requirements for the treated water. In this case, the simplest solution to the problem consists in separating the flows of the least polluted wastewater and in returning them after treatment to the lines of industrial water supply. As an alternative solution, joint reagent treatment of all the types of wastewater followed by post-treatment with the use of ion-exchange methods is proposed. However, staged wastewater treatment, wherein water is prepared in accordance with the technological requirements for the corresponding industries may represent a more flexible and cost-effective system.

A new method for dispersing gas from an open vortex cavity into localized zones with reduced pressure in the liquid behind rotating mixer blades is studied. The optimum distance between the blade mixers on the shaft, which ensures the intensification of mass transfer with lower power consumption for mixing, is established. The conditions allowing for an increase in the mass-transfer coefficient are demonstrated and confirmed through numerical simulation. The experimental values of power, gas content, bubble diameter, and mass-transfer coefficient in the apparatus with the mixer implementing the proposed dispersion method are presented.