Proceedings of the NTUU “Igor Sikorsky KPI”. Series: Chemical engineering, ecology and resource saving最新文献

{"title":"Increasing the efficiency of transfer processes when using inhomogeneous fluidization","authors":"Yaroslav M. Kornienko, S. Haidai, Oleksandr Sameliuk","doi":"10.20535/2617-9741.1.2023.276443","DOIUrl":"https://doi.org/10.20535/2617-9741.1.2023.276443","url":null,"abstract":"The processes of dehydration and granulation are associated with the heat transfer to the solid particles from the gas coolant, which acts as a fluidizing agent and causes the stochastic movement of the granular material in the apparatus. To implement the layered structure mechanism of granulation of organic-mineral fertilizers it is necessary to ensure intensive circulation of granular material with intensive gradual passage through the appropriate technological zones of the apparatus. The main problem is the low efficiency of interphase exchange in the gas-liquid-solid system and the formation of agglomerates during granulation with the injection of a liquid heterogeneous solution into the bed of solid granular material. \u0000In this work the conditions for increasing the efficiency of the transfer processes when using an inhomogeneous jet-pulsating mode of fluidization were determined. \u0000Analysis of the intensity of renewal of the contact surface of the phases when using inhomogeneous jet-pulsating fluidization in the self-oscillating mode was carried out. It was established that the use of this mode of fluidization allows getting a significant intensification of heat and mass transfer processes due to the activation of diffusion-controlled processes and an increase in the dynamics of interphase contact exchange by 1.9÷2.9 m2/s, which is 27÷41% of the total surface of the material in device.","PeriodicalId":20682,"journal":{"name":"Proceedings of the NTUU “Igor Sikorsky KPI”. Series: Chemical engineering, ecology and resource saving","volume":"42 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77644956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Disposal of short-lived low- and intermediate-level waste: analysis of foreign experience","authors":"B. Shabalin, O. Lavrynenko, N. Mitsiuk","doi":"10.20535/2617-9741.1.2023.276449","DOIUrl":"https://doi.org/10.20535/2617-9741.1.2023.276449","url":null,"abstract":"The article summarizes and analyzes the main approaches and practical experience of foreign countries regarding the disposal of short-lived low- and medium-level waste. Their place in the category of low-level waste according to the recommended classification of the IAEA, for which disposal in near-surface storage facilities is provided, is shown. Currently, in countries that operate nuclear facilities and develop nuclear technologies, there is no one approach to the disposal of such waste. The type of repository and its structural and technological solutions are determined by the specifics of the waste itself, the nature of the site, the state strategy in the nuclear industry, as well as social and economic factors. To date, several types of storage facilities have been developed for the disposal of short-lived low- and medium-level waste: relatively simple trench-type near-surface storage facilities; modular-type near-surface storage facilities with a complicated system of engineering barriers and criteria for selecting containing rocks (natural barriers) compared to the trench type; geological storages, which are mainly built in mining operations with a complex system of tunnels and barrier protection. Bentonite clays are widely used as components of engineering barriers. In the simplest case of near-surface repositories, the bentonite layer serves as the base material of the repositories and helps to reduce filtration and increase the sorption of radionuclides and other components. In the organization of geological repositories, the bentonite layer contributes to the reduction of water filtration into the repositories, increases the sorption of radionuclides, prevents the destruction of concrete structures during a shift by containing rocks, and, in the event of the destruction of cement-concrete structures of engineering barriers, leads to a decrease in the removal of radionuclides from the repositories into the environment. The work gives examples of different types of storage facilities in countries around the world.","PeriodicalId":20682,"journal":{"name":"Proceedings of the NTUU “Igor Sikorsky KPI”. Series: Chemical engineering, ecology and resource saving","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80823572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical analysis of the thermal-elastic-plastic state of electrical contact gasket made from dispersion-reinforced composite materials using the fusioned deposition modeling method","authors":"V. Soloveǐ","doi":"10.20535/2617-9741.4.2022.269748","DOIUrl":"https://doi.org/10.20535/2617-9741.4.2022.269748","url":null,"abstract":"The article presents the results of a theoretical study on determining the suitability of using electrical contact gaskets (ECG) in industrial conditions (Castner direct graphitization furnaces), made of coke-pitch composite using additive technologies based on the Fused Deposition Modeling (FDM) method. \u0000Numerical analysis of the physical state of ECG under the conditions of industrial application was performed on the basis of the mathematical statement of the thermo-elastic-plasticity problem and the algorithm of implicit inverse mapping of its solution based on the finite element method in the Mathcad programming environment. To construct the geometry and tetraid mesh of the ECG model, a freely open program code was used - the Gmsh CAD system for grid generation, and for the visualization of the results of physical field calculations, the free open program code ParaView was used. \u0000The study of the thermo-elastic-plastic state of ECG under the conditions of the graphitization process in Castner furnaces was carried out in the temperature range up to 900 °С, at which the thermoplastic properties of the material are manifested. At the same time, such physical fields of ECG were analyzed as temperature distribution, resulting displacements, equivalent elastic stresses according to Mises, equivalent total, elastic and plastic deformations according to Mises, and the volume fraction of ECG material in a plastic state, depending on the temperature level and radial gradient temperatures (radial temperature difference) of electrical contact gaskets. \u0000Numerical simulation of the thermo-elastic-plastic state of the ECG was carried out under the conditions of force loading by external pressure on the lateral surface of the gasket of 2.5 MPa and different values ​​of the radial temperature difference in the range of 15–90 °C in the temperature range up to 900 °C. It was established that: at the stages of formation of semi-coke and coke in the material of the coke-pitch composite ECG under the thermomechanical conditions of operation of the Kastner furnace, a margin of strength of not less than unity was obtained; with the subsequent increase in the temperature level in the Castner furnace to 3000 °C and above, the raw material of ECG, as a result of thermal destruction, has already turned into coke and, therefore, its mechanical properties have become close to the mechanical properties of electrode blanks in columns that are subjected to graphitization. This gives reason to assert that the ECGs will not be mechanically destroyed during the entire graphitization campaign of the Castner furnace. \u0000On the basis of the analysis of the results of numerical simulation, the possibility of using ECGs made from dispersion-reinforced composite materials (coke-pitch mixtures) by the FDM method in the technology of graphitizing electrode products according to the Сastner method is substantiated.","PeriodicalId":20682,"journal":{"name":"Proceedings of the NTUU “Igor Sikorsky KPI”. Series: Chemical engineering, ecology and resource saving","volume":"32 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74176659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Method for PID-tuning via feedback control system pole placement","authors":"A. Zhuchenko, Redrikh Putiatin","doi":"10.20535/2617-9741.4.2022.269779","DOIUrl":"https://doi.org/10.20535/2617-9741.4.2022.269779","url":null,"abstract":"Pole placement is the only PID-tuning technic that allows one to obtain a control system with desired, and, moreover, highly predictable performance and control quality. Number of controller tuning parameters is equal to number of poles closed-loop poles it can precicely place, so that PID-controller can place exactly three poles, and PI- can place only two. For this reason PI-controller is best used with first-order processes (second-order closed loop system), and PID-controller with second-orded ones (third-order closed loop system). However, many processes have higher order than two, and still are controlled with PID-controllers. To tune it using pole placement techniques, it is necessary to consider only dominant poles, which affect performance of the system to the greatest extent. First, it is necessary to study a PI-controller with a second-order process, which is the most basic case. Tuning is performed using global optimization methods to fit dominant poles of a tuned system to dominant poles of a reference system.","PeriodicalId":20682,"journal":{"name":"Proceedings of the NTUU “Igor Sikorsky KPI”. Series: Chemical engineering, ecology and resource saving","volume":"13 3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77572514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The dependence of the efficiency of the ion exchange of manganese ions from water on the type and form of the ionite and its hardness","authors":"M. Gomelya, I. Trus, M. Tverdokhlib, Viktor Kamaiev","doi":"10.20535/2617-9741.4.2022.269788","DOIUrl":"https://doi.org/10.20535/2617-9741.4.2022.269788","url":null,"abstract":"Drinking water must comply physical, chemical, bacteriological and radiochemical guidelines therefore its quality should be continuously monitored before being introduced into the distribution system. Water used for human consumption may come from various sources: groundwater, spring water; water from rivers, streams, lakes, among other. A large part of the population of Ukraine uses drinking water that does not meet hygienic requirements according to various indicators. Manganese compounds are quite often present in natural waters. Their quantitative content can vary in a wide range, depending on the region, it can be 0,5-10 mg/dm3. It is worth noting that with a high content of manganese compounds in water, their removal is a rather difficult task. Removal of manganese compounds from water can be implemented using the ion exchange method, which consists of filtering water through loading in salt or acidic form. At the same time, softening and desalination of water can occur simultaneously. Therefore, the ion exchange method should be used for comprehensive water purification, softening, and removal of manganese compounds. \u0000The article presents the results of obtained during the extraction of manganese ions from distilled and tap water using the strongly acidic cationite KU-2-8 and the weakly acidic cationite Dowex MAC-3. Cationites were used in Na+ and Ca2+ form. The concentration of manganese ions (Mn2+) was varied from 5 to 500 mg/dm3. It was shown that the sorption capacity of the cationite KU-2-8 depended on the concentration of manganese ions, the form of the ionite, the presence of hardness ions in water and was little dependent on the pH of the medium. The sorption capacity of the weakly acidic cationite increased with the increase in the concentration of manganese ions and with the increase in the pH of the medium, which changed with the change in the concentration of magnesium sulfate in distilled water. Sorption of manganese ions from tap water decreases for strongly acidic and weakly acidic cations, compared to solutions in distilled water, which is associated with competitive sorption of hardness ions. This is especially noticeable when using ionites in Ca2+ form in solutions in tap water. The use of ionites in Ca2+ form reduces their sorption capacity for Mn2+ and in distilled water to a certain extent. But this effect is smaller compared to tap water. The Thomas model was used in the work to estimate the full exchange capacity of weakly acidic cationite at low concentrations of MnSO4 solution in distilled water.","PeriodicalId":20682,"journal":{"name":"Proceedings of the NTUU “Igor Sikorsky KPI”. Series: Chemical engineering, ecology and resource saving","volume":"2006 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82552596","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characteristics of nano-sized composites based on rare earth orthoferrites and hematite","authors":"O. Lavrynenko, O. Pavlenko, O. Olifan","doi":"10.20535/2617-9741.4.2022.269813","DOIUrl":"https://doi.org/10.20535/2617-9741.4.2022.269813","url":null,"abstract":"Photocatalysts based on orthoferrites of rare earth elements are used to neutralize a number of harmful substances and organic dyes under the influence of visible light, which makes them to promise the introduction of resource-saving water purification technologies. The thermal-gravimetric analysis, X-ray phase analysis, scanning electron microscopy, and energy-dispersive spectroscopy was used to study nanoscale samples of orthoferrites of rare earth elements and hematite obtained by the chemical precipitation of aqueous solutions of inorganic salts of ferrum with lanthanides (La, Er, Sm, Dy, Nd, Yb ) and Y in a weakly alkaline environment and subsequent heat treatment of sediments at 800 and 1100 °C. It was found that during the simultaneous precipitation of hydroxide phases of ferrum and REE, their transformation under the influence of temperature is spatially separated due to the differences in the temperatures of phase transformations and the hydrogen index of the precipitation of precursor phases. It is shown that, depending on the chemical composition of the initial solutions, goethite is formed in the temperature range of 190-250 °C, and the formation of hematite takes place at 425-450 °C. Dehydroxylation of lanthanum hydroxide is observed at 300-330 °С, and the formation of lanthanum oxides continues in the range from 390 to 900 °С. The perovskite phase crystallizes at 960 °C. Using the X-ray phase analysis method, it was established that hematite and a mixture of REE oxygen phases are present in the sediments heat-treated at 800 °C. At 1100 °C, the structure of perovskite and hematite with particle sizes from 25 to 40 nm was identified in the composition of the powders. It was determined that the removal of auxiliary substances takes place at temperatures of 650-770 °C and no impurities of K, Na, S, Cl, or C in the powders fired at 1100 °C. Hematite and perovskite particles are well crystallized and form fragile aggregates, the specific surface area of the samples is several m2/h.","PeriodicalId":20682,"journal":{"name":"Proceedings of the NTUU “Igor Sikorsky KPI”. Series: Chemical engineering, ecology and resource saving","volume":"72 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88128907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Efficiency of magnesium ions removal from water in processes of its mitigation","authors":"Yaroslav Radovenchyk, Kateryna Hordiienko, T. Krysenko, V. Radovenchyk","doi":"10.20535/2617-9741.4.2022.269815","DOIUrl":"https://doi.org/10.20535/2617-9741.4.2022.269815","url":null,"abstract":"Significant concentrations of calcium and magnesium ions in natural waters force the majority of domestic drinking and energy waters to undergo preliminary softening. Therefore, mitigation technologies are becoming particularly acute today, and research in this field is increasing every year. Since water hardness is determined by the total content of calcium and magnesium ions, these elements are the focus of such research. \u0000Traditionally, it is believed that calcium ions are the first to be removed, and magnesium ions are less likely to form a solid phase. However, the effectiveness of softening technology depends equally on both cations. Therefore, sufficient attention should also be paid to magnesium ions. Sodium phosphate is considered a promising reagent in this direction. Its use in the processes of removing calcium ions allows to ensure the residual hardness of water at the level of 0.1 - 0.2 mg-eq/dm3 in a wide range of temperatures and hydrogen index. Detailed studies of the use of sodium phosphate in the processes of removing magnesium ions showed its insufficient efficiency. \u0000The effectiveness of soda-sodium softening allows to ensure at pH 11.0 - 11.5 the residual hardness of water at the level of 0.4 - 0.6 mg-eq/dm3. But the need to adjust the hydrogen index and the high consumption of reagents make this technology unsuitable for widespread use. The determining factor in water softening processes using phosphate ions is the ratio between the concentrations of phosphate ions and magnesium ions K = [PO43-, mg-eq] / [Mg2+, mg-eq]. Taking into account the strict requirements of current regulatory documents for the content of phosphates in treated waters, it is desirable to carry out the treatment with stoichiometric ratios of reagents for a more complete reaction between the components. The advantage of sodium phosphate as a reagent for removing magnesium ions can be considered the fact that in the pH range of 3.16 - 10.07 at K = 1, the residual hardness ranges from 1.8 to 3.4 mg-eq/dm3. At the same time, the minimum value of the residual stiffness was recorded at the level of 0.75 mg-eq/dm3 at pH 10.07 and K = 2. As the pH decreases, a stable decrease in efficiency is observed, although it is not very significant. Thus, during the transition from an alkaline to an acidic medium, the residual concentration of magnesium ions increases by a factor of 2, regardless of the value of the coefficient K. Similar trends persist in the case of a change in the initial hardness of water. The biggest difference is observed at values ​​of K ≤ 1, which is explained by the deficiency of phosphate anions and the impossibility of forming a solid phase of stoichiometric composition. However, even with a stoichiometric ratio of reactants (K = 1), the residual hardness of treated water is quite significant and ranges from 2.5 to 3 mg-eq/dm3. A further increase in the dose of sodium phosphate allows to slightly reduce the residual hardness of the treated wate","PeriodicalId":20682,"journal":{"name":"Proceedings of the NTUU “Igor Sikorsky KPI”. Series: Chemical engineering, ecology and resource saving","volume":"50 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81630952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Algorithm of coordinated control of an open-type headbox","authors":"A. Zhuchenko, Mykola Pirhach, Y. Zhurakovskyi, Roman Sadovnychyi","doi":"10.20535/2617-9741.4.2022.269773","DOIUrl":"https://doi.org/10.20535/2617-9741.4.2022.269773","url":null,"abstract":"The control system of an open-type headbox has a high complexity, which is associated with the need not only to stabilize the parameters of the object, but also to carry out coordinated control of it in the case of automatic transfer of a paper machine from one type of product to another for a minimum time. \u0000A mathematical model of an open-type headbox as an object of mass level control has been developed. In the model, the output variable of the control object is the level of mass in the injection chamber, and the control action is the mass flow rate supplied to the injection chamber. The model takes into account the disturbing action - the area of the discharge slot. On the basis of the developed model, two options for constructing an algorithm for controlling the pressure box during its transfer from one mode to another are considered. The structure of the algorithm for coordinated control of the pressure box is developed. An illustrative example of application of the developed algorithm is given. The calculations of the optimal transient process in the object confirm the effectiveness of the developed control algorithm. The algorithm of coordinated control is applied to the standard pressure box YANO-180. The development of the algorithm for transferring the pressure box from the working (0.485 m) to the maximum (0.575 m) height of the mass level in the pressure box for 180 seconds is demonstrated. The calculation results show that the coordinated control algorithm provides the transfer of the mass level to the maximum height for a given time. \u0000The algorithm developed on the basis of the obtained mathematical model allows to control the level of mass in such a complex object as an open-type headbox when transferring a paper machine from one mode of operation to another for the time specified by the coordinated control system.","PeriodicalId":20682,"journal":{"name":"Proceedings of the NTUU “Igor Sikorsky KPI”. Series: Chemical engineering, ecology and resource saving","volume":"31 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88608508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Parameters of crack resistance of nanoreinforced polymeric engineering products","authors":"Oleksandr Gondlyakh, Oleksandr Mamchur","doi":"10.20535/2617-9741.4.2022.269740","DOIUrl":"https://doi.org/10.20535/2617-9741.4.2022.269740","url":null,"abstract":"Currently, structural elements made of polymer and rubber materials are widely used in various branches of mechanical engineering. One of the leading directions for improving the properties of such elements is the procedure of strengthening them by nanomodification with carbon nanotubes. The analysis of literary sources allows us to state that the process of nanomodification is a reliable tool for increasing the parameters of strength and crack resistance of polymer products. \u0000The purpose of this work is to build and numerically implement a model for physical prediction of the properties of nanomodified materials in order to determine the strength parameters of nanomodified objects. To analyze the mechanisms of formation and propagation of defects at the nano-, micro- and macro-levels, the method of discrete-virtual crack propagation was used, which allows for effective investigation of the strength of spatial systems of polymer nanocomposites. \u0000As a result of the conducted numerical experiments, it was established that the process of pulling out a carbon nanotube, which is under the action of an asymmetric load, is accompanied by a complex process of accumulation of defects, which depends on the change in conditions load and significantly affects the evolutionary scheme of the destruction of the nanocomposite. \u0000The developed methods make it possible to reliably assess the strength of nanomodified polymer materials and can be used in the development and implementation of information support systems for their life cycle elements of machine-building equipment.","PeriodicalId":20682,"journal":{"name":"Proceedings of the NTUU “Igor Sikorsky KPI”. Series: Chemical engineering, ecology and resource saving","volume":"15 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77143051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Potential impact of dispersion products of magnetite quartzites on the environment","authors":"O. Lavrynenko, V. Yatsenko, B. Shabalin, I. Yatsenko","doi":"10.20535/2617-9741.3.2022.265364","DOIUrl":"https://doi.org/10.20535/2617-9741.3.2022.265364","url":null,"abstract":"Using XRF, TG-DTA, chemical and sedimentation analysis of the products of processing of magnetite quartzites from the N Ore Processing Plant of Krivorozhye, changes in the phase and chemical composition of samples of four stages of magnetic separation and tailings were traced compared to a sample of the raw ore, and the potential impact of the dispersion process on the environment was revealed. Thermogravimetric studies indicate phase transformations of magnetite to maghemite (250-340 ° C), polymorphic transformations of iron oxides and destruction of rock-forming minerals (430-480 ° C), conversion of alpha quartz to beta-form (564-568 ° C), dehydroxylation of iron and magnesium oxyhydroxides (385 ° C), conversion of beta-quartz to beta-cristobalite (970 ° C). In the process of enrichment, there is an increase in the loss of mass of the samples, which is %: 0.06 (I); 1.46 (II); 1.9 (III), and 2.6 (IV). According to X-ray diffraction, the main ore mineral is magnetite, the rock-forming mineral is quartz. Among the secondary minerals are sulfides, cummingtonite, actinolite, and others. It is shown that at the first stage of enrichment all primary and secondary minerals are present in the samples, at the 2nd stage sulfides disappear from the sample, at the 3rd stage secondary minerals disappear, and at the 4th stage quartz remains in the sample and it forms aggregates with magnetite. The parameter of the crystal lattice of magnetite varies between 8.397-8.403 nm, its coherent scattering region (CSR) is 31.4-35.6 nm. It is found that in the course of ore grinding the destruction of secondary minerals takes place with the removal of destruction products, as evidenced by the occurrence of disperse quartz in the tailings. According to sedimentation analysis data, in the first 20 seconds, more than half of the particles with a size of 24-28 μm were deposited from the pulp, after 3 minutes, particles with a size of 8-9 μm settled, after 6 minutes - particles with a size of 6-7 μm. Within 30 minutes, almost complete precipitation of particles with sizes of 4.5-2.7 μm was observed. Hydraulic classification of the tailings showed the deposition of mainly quartz particles in the first and second chambers of the separator, actinolite and muscovite particles were separated in the third chamber, and cummingtonite, biotite and chlorite in the fourth chamber. Analysis of the chemical composition of the dispersion products indicates that Si, Ca, and Na accumulate in the tailings, whereas Ti is removed, and could potentially enter the environment. It is shown that the tailings and separation products increase the content of Zn, and the tailings accumulate environmentally hazardous As, and Nb. At the same time, the concentrations of other elements remain stable at all stages of processing.","PeriodicalId":20682,"journal":{"name":"Proceedings of the NTUU “Igor Sikorsky KPI”. Series: Chemical engineering, ecology and resource saving","volume":"78 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77674071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}