Harmful Impurities Research Articles

Metal degassing in vacuum-chamber of circulating vacuum degasser of JSC EVRAZ NTMK

For smelting of high-quality metal for transport purposes, it is necessary to limit the content of harmful impurities in it, including dissolved gases. For example, hydrogen content in the finished product should not exceed more than 2 ppm. In order to obtain low residual hydrogen content in steel in the converter shop of JSC EVRAZ NTMK, the transport metal is processed at circulating vacuuming plants. Circulating vacuum degasser is the last stage of steel processing before casting on continuous casting machine, so it is important to study and improve the technological processes in it. To investigate the physico-chemical processes occurring in this metallurgical unit, a hydrodynamic model of the system circulating vacuum degasser – steel ladle was created. Based on theoretical calculations and experiments conducted on a physical model, the main dependencies between the structural and technological parameters of the metallurgical unit were determined. The resulting equation makes it possible to determine the rate of metal circulation in vacuum chamber depending on gas flow rate supplied to inlet snorkel and its inner diameter at circulating vacuuming plants designed for metal processing in steel ladles with a capacity of 140 – 180 tons. Theoretical calculations were confirmed by practical smelting in a steelmaking unit. It is shown that during the wear of lining of the inlet snorkel vacuum chamber, in order to obtain stable residual hydrogen content, it is necessary to make changes in the technological process of vacuuming. Additionally, rational technological parameters of steel processing at the circulating vacuuming plant were determined on the basis of theoretical calculations.

Natural landscape, historical and town‐planning factors of Khabarovsk development

Aim. A comprehensive analysis of the development of the living environment of the city of Khabarovsk, Russia.Discussion. The article discusses the stages of the formation of the city of Khabarovsk under the conditions of the mutual influence of natural landscape, historical and town planning factors. The territory of Khabarovsk exists under the influence of a number of interacting factors, the combination of which determines the low quality of life of the population. These factors ensure the uniqueness of the territory, which often fulfill a compensatory role, but also determine the ecological vulnerability of the city and limit its development. In the category of natural landscape factors there are 4 principal impacts: Khabarovsk is associated with an intermountain depression, which contributes to atmospheric pollution stagnation and the domination of the Siberian anticyclone during the cold season, which creates unfavourable conditions for the dispersion of harmful impurities in the atmosphere; potential exposure to flooding; and potential fire hazard. The main historical factor in the development of Khabarovsk is the inclusion of the Far East in the space of Russia and the awareness of its geostrategic importance. However, the development of the region has always been accompanied by difficulties due to remoteness and vicinity to China. For all urban systems there are specific general urban development factors. Their influence is unevenly traced at different stages of the formation of Khabarovsk’s territory, at times fixing errors in the layout of the city, and at others reducing the comfort of the environment. Only at the present stage is a balance of factors taking shape that sets the prospects for the comprehensive improvement of the population’s living space.Conclusion. Sustainability of Khabarovsk development is possible under the condition of creating a viable model of advanced economic development of the Far East.

Metal Degassing in Vacuum-Chamber of Circulating Vacuum Degasser of JSC EVRAZ NTMK

For smelting of high-quality metal for the applications in transport vehicles, it is necessary to limit the content of harmful impurities in it, including dissolved gases. For example, hydrogen content in the finished product should not exceed more than 2 ppm. In order to obtain low residual hydrogen content in steel in the converter shop of JSC EVRAZ NTMK, the transport metal is processed at circulating vacuuming plants. Circulating vacuum degasser is the last stage of steel processing before casting on continuous casting machine, so it is important to study and improve the technological processes in it. To investigate the physico-chemical processes occurring in this metallurgical unit, a hydrodynamic model was created for the system that includes the circulating vacuum degasser and the steel ladle. Based on theoretical calculations using physical model and experiments conducted, the main dependencies between the structural and technological parameters of the metallurgical unit were determined. The resulting equation makes it possible to determine the rate of metal circulation in vacuum chamber depending on the gas flow rate supplied to inlet snorkel and its inner diameter at circulating vacuuming plants designed for metal processing in steel ladles with a capacity of 140–180 tons. Theoretical calculations were confirmed by practical smelting in a steelmaking unit. It is shown that in order to obtain stable residual hydrogen content during the wear of lining of the inlet snorkel vacuum chamber, it is necessary to make changes in the technological process of vacuuming. Additionally, rational technological parameters of steel processing at the circulating vacuuming plant were determined on the basis of theoretical calculations.

Micromicelle-mechanical coupling method for high-efficiency phosphorus removal and whiteness improvement of phosphogypsum

Phosphogypsum contained harmful impurities and seriously affected its large-scale utilization. The existing stockpiling and water washing methods gradually fail to meet the requirements of environmental protection and process in the purification effect during the phosphorus chemical production process. Compared with various purification processes, although the application of phosphogypsum could be optimized, most processes had the characteristics of high energy consumption. Therefore, it was urgent to develop a new method for purifying phosphogypsum with low energy consumption, water saving, and high efficiency. In this work, the coupling of mechanical activation and chemical solubilization method successfully realized the efficient and water-saving purification of phosphogypsum. The experimental data showed that the chemical bond breakage in the phosphogypsum crystals after grinding and the promotion of the chemical microenvironment not only achieved the grain refinement of the phosphogypsum but also achieved the removal of soluble phosphorus and the improvement of the whiteness of the phosphogypsum. It provided a new idea for the large-scale utilization of phosphogypsum with improved purification efficiency, which has good industrial value and application prospects.

Ecological and economic assessment of forest ecosystem services on the example of SE "Vovchanske forestry"

Problem. Forests are the most important natural resource that has shaped the history and culture of each region. The economic assessment of forest ecosystem services is essential for improving the environmental situation, and acts as the basis for making informed management decisions. The economic assessment of ecosystem services is a complex scientific and methodological problem and is characterized by certain contradictions. One of these problems is the diversity and specificity of individual ecosystem services, in connection with which it greatly complicates the process of formation of standardized scientific and methodological approaches to the assessment of ecosystem services. Goal. The aim is to analyze methodological approaches to the cost assessment of forest ecosystem services and give an economic assessment of forest ecosystem services on the example of SE "Vovchanske forestry" of Kharkiv region. Methodology. Analytical research methods were used to determine standardized scientific and methodological approaches to the economic evaluation of ecosystem services and to identify forest ecosystem services for which there is sufficient source information for calculating the cost. The calculation method was used for the economic assessment of certain categories of forest ecosystem services and for the consolidated assessment of the cost of providing and regulating forest services of SE "Vovchanske forestry". Results. The result is a number of key principles of best practice for the cost assessment of ecosystem services “The Economics of Ecosystems and Biodiversity” (ТЕЕВ). Analysis of the main approaches to the commodification of ecosystem services made it possible to determine the established practice of their cost assessment on the basis of the Belarusian methodology "The procedure for carrying out a cost assessment of ecosystem services". The paper considers the main ecosystem services of the forest, identifies services for which there is enough initial information to calculate the cost. This is the characteristic of forestry SE "Vovchansky forestry". Of all the ecosystem services, forests are currently involved in market turnover and have an established cost of direct actual use services – providing services, and of the latter – the provision of wood. To calculate the cost of harvested wood, the average price was taken (taking into account the price of wood – firewood) per 1 m3 – 857 UAH/m3. The calculated cost of wood resources with a specific volume of felling 28.9 m3/ha is 24767 UAH/ha. In addition to wood, the forest also supplies the so-called non-wood resources, food resources and medicinal plants. The cost of wood and non-wood-providing forest services is 55297 UAH/ha. At the same time, the cost of non-wood resources exceeds the cost of harvested wood. Among the regulating ecosystem services of the forest, carbon dioxide assimilation is most often considered, which is an economically important factor in light of the problem of climate change and the Paris Agreement. In this paper, the estimate of the average annual absorption of carbon dioxide is carried out for the generalized age of plantings due to the inability to obtain data on the age indicators of certain areas of forestry and their growth areas. The calculation of the amount of carbon dioxide absorbed determines the assimilation capacity of the forest at 13.48 t/ha. At the existing rate per ton of $ 15 US (~ 420 UAH), the price of assimilation service is 5660 UAH/ha. Directly related to the assimilation of carbon dioxide, another regulatory service is the production of oxygen. At the cost of industrial oxygen production of 110.00 UAH/m3, the cost of the service is 55000 UAH/ha. Forests act as a filter, purify atmospheric air from various kinds of harmful impurities. The object of economic assessment of the assimilation potential of forest vegetation is the limiting content of pollutants in the phyto mass of the main forest-forming rocks. At the rates of environmental tax on substances emitted into the air, the cost of assimilation of pollutants is calculated, which is 17412 UAH/ha. The total cost of regulating ecosystem services of the forest is 81767,00 UAH/ha. Thus, the consolidated assessment of the cost of providing and regulating services of the forest SE "Vovchanske forestry" is 137054 UAH/ha. Originality. An economic assessment of the ecosystem services of the Volchanske forestry was carried out, the excess of the cost of regulatory services over services for the harvesting and delivery of timber and other “gifts” of the forest was determined. Practical value. The assessment of forest ecosystem services shows that the main value of the forest is not the provision of wood, but in the assimilation potential of the forest, its ability to maintain the cycle of substances and biodiversity. This must be taken into account when making environmental decisions and in order to develop paid nature management.

Study of the process of biogas cleaning in the complex bioheat device obtained from biomass (manure substrate)

This article presents the results of a study of the process of cleaning biogas obtained from biomass (dung substrate) from carbon dioxide and other harmful impurities, using a group of crystalline aluminosilicates called zeolites. The cleaning process was carried out directly in an experimental complex device. The nomogram constructed based on the results of experimental studies, the effect of the level of biogas purification with zeolite on its composition and quality, showed that reducing the intensity of the change of the adsorbent (zeolite) in the treatment plant from 7 to 1 day, increases the degree of purification from 25 to 75 %, reducing the amount of harmful components in the composition of biogas from 33 to 12 %, and also increases the share of the useful component of biogas (methane gas) from 65 to 86 %, while increasing the calorific value of combustion from 23 to 31 mJ.

METHANATION TECHNOLOGIES FOR PRODUCING SYNTHETIC RENEWABLE METHANE

Methanation, or the generation of synthetic methane through the combination of carbon dioxide and hydrogen, has been attracting more and more attention of researchers and energy scientists in recent years due to the fact that the development of an effective and economically feasible technology for the implementation of this process will allow solving a number of energy and environmental problems. First, it is the accumulation of excess renewable electricity from solar and wind power plants by using it in the creation of another energy-intensive product, namely synthetic natural gas, which removes the problem of coordinating unstable sources of electricity with energy networks. Secondly, methanation becomes another technology for enriching biogas and turning it into biomethane, which will allow it to be used through existing gas networks and contribute to solving the problem of natural gas shortage.
 The development and improvement of methanation technologies are engaged in many organizations of the world - Germany, Denmark, France, the USA, Japan and others. Research is conducted in two main directions: catalytic methanation and biological methanation. In the first direction, methanation is carried out through the Sabatier reaction using catalysts. The problems of such methanation are: the development of catalysts with high activity, selectivity and resistance to the heat of reaction, the provision of optimal reaction modes, in particular temperature and pressure, through the use of various methods of reactor cooling, control of the reaction mechanism, the use of three-phase reactors, changing their structure, and so on. Biological methanation is carried out using of biological methanogens - so-called archaea, which act as a kind of catalyst. The methanation is carried out either directly in the biomass anaerobic digestion reactor (in-situ methanation) or in a separate reactor into which biogas and hydrogen are fed separately (ex-situ methanation). One of the main problems of in-situ methanation is the simultaneous provision of optimal conditions for both acetoclastic and hydrogenotrophic methanogens. This problem is solved by ex-situ methanation, in which the optimal conditions for anaerobic digestion and methanation processes are provided separately. It is clear that optimal conditions are also provided for biomethanation of pure CO2 and H2, when the «broth» for archaea is created separately. A comparison of catalytic and biological methanation technologies shows that catalytic methanation provides higher energy efficiency and requires much smaller reactor sizes than biological methanation for the same methane yield. However, the latter has a higher resistance to harmful impurities than the catalytic one.

Catalytic Activity of Fibrous Complexites

The ecological situation in the world requires the solution of environmental problems associated with the processes of wastewater treatment, hydrogen sulfide pollution of various industrial facilities in order to remove such harmful impurities. The unpleasant odor that appears in industrial and adjacent waste processing areas is a constant concern for the protection of the environment. To solve these problems, it is advisable to use selective sorbents - complex. The introduction of metal ions into complex fibers due to the formation of a coordinated bond between the groups of the metal and the polymer ligand gives high molecular weight complex compounds. The operational and selective properties of the materials based on high-molecular-weight complex compounds can be determined by the type of metal ion introduced into macromolecules, the nature of the polymer chain, and thermodynamic stability. By changing the action of the above factors, complexites can be synthesized for use as highly selective catalysts for various chemical processes. The paper presents data on the catalytic activity of fibers with Cu2+, Co2+, Ni2+ ions with complexing fibers containing carboxyl, amidoxime, hydroxamic groups, using the example of the decomposition of hydrogen peroxide and oxidation of H2S, Na2S. An inhibitory effect on the oxidation of fiber functional groups in the pH range 5.5 - 12.5 was revealed. The operational and selective properties of materials based on complexites can be determined by the type of metal ion introduced into the macromolecules, by the nature of the polymer chain. By changing the action of the above factors, complexites can be synthesized to be used as highly selective catalysts for various chemical processes. It was found that the catalytic activity of the complex depends on pH, the stereochemistry of the coordination centers in the fiber matrix and significantly exceeds the activity of model low-molecular-weight complex compounds.

Application of multi-stage dynamic magnetizing roasting technology on the utilization of cryptocrystalline oolitic hematite: A review

A large number of studies have shown that oolitic hematite is an iron ore that is extremely difficult to utilize because of its fine disseminated particle size, high harmful impurity content and oolitic structure. To recover iron from oolitic hematite, we developed a novel multistage dynamic magnetizing roasting technology. Compared with traditional magnetizing roasting technologies, this novel technology has the following advantages: firstly, the oolitic hematite is dynamically reduced in a multi-stage roasting furnace, which shortens the reduction time and avoids ringing and over-reduction; secondly, the novel dynamic magnetizing roasting technology has strong raw material adaptability, and the size range of raw materials can be as wide as 0–15 mm; thirdly, the roasting furnace adopts a preheating-heating process, and the low-calorific value blast furnace gas can be used as the fuel and reductant, which greatly reduces the cost. The actual industrial production data showed that the energy consumption in the roasting process can be less than 35 kg of standard coal per ton of raw ore. The iron grade of the concentrate and iron recovery reached 65% and 90%, respectively.

СУЧАСНІ ПІДХОДИ КОМПЛЕКСНОЇ ПЕРЕРОБКИ ПРОМИСЛОВИХ ТЕХНОГЕННИХ ВІДХОДІВ

This article provides information on the possibility of integrated use of phosphogypsum, metal sludge and red bauxite sludge in the manufacture of construction products.
 The aggravation of the ecological and economic situation in Ukraine requires the development of new efficient technologies for processing and use of man-made industrial waste from the chemical industry. Such technologies should ensure their maximum degree of use in the manufacture of construction products. The choice of technology for the preparation, processing and use of industrial waste depends on a number of factors, namely the chemical-mineralogical and particle size distribution and method of production. Although such wastes are mostly used as aggregates, their overall use remains low. The share of their use in the manufacture of construction products is only 10 - 12%.
 It has been established that in the presence of open dumps phosphogypsum and red bauxite sludge are a source of pollution of the surrounding areas. 
 Large-scale use of phosphogypsum is hampered by its specific features: the presence in its composition of phosphoric and sulfuric acid and water-soluble harmful compounds of phosphorus and fluorine. Therefore, before using phosphogypsum, it is necessary to neutralize harmful impurities and reduce the concentration of acid residues. The most effective method of using phosphogypsum, fine powders of sludge steel SHH-15 and red bauxite sludge is the integrated use of such waste, resulting in metal-phosphate and metal-ash-phosphate binder.
 Key words: industrial waste; building materials; complex binder.

Energy savings through rationalization of exhaust ventilation emission treatment technology

The scheme of purification of exhaust ventilation emissions from harmful impurities of production sites. Calculated energy costs according to the traditional scheme cleaning, including a cyclone and a Venturi scrubber. To reduce energy costs, it is proposed air purification scheme from fine dust using an innovative irrigated nozzle made of porous plastic plates for turbulence of air flow. It is proved by calculation that in order to achieve the required environmental dust efficiency in the innovative system, energy consumption is about 9 times less.

О неэффективности нагнетательного способа проветривания при решении задачи нормализации пылевой обстановки в тупиковом забое калийного рудника

When potash ore is mined, a large amount of the harmful impurities, including dust, are released into the mine environment. Although potash dust is not toxic, at constant high concentrations it adversely affects the miner health. Hygroscopic properties of rocks in the potash mines do not allow the use of water to control dust. Ventilation approaches to the normalization of the dust environment also do not give positive results. Forced method of the ventilation of the dead-end mine workings used in all the mines in Russia is distinguished by the long-range air jet from the ventilation stack. This allows to create intensive vortex formation in the bottomhole part of the mine working for avoiding the occurrence of stagnant zones. However, during forced ventilation, a large vortex occurs. Results of studying the dynamics of dusty air streams in the space of a dead-end tunneling and cleaning working are presented in the article. In the mining face, there are two main sources of dust formation: the working face, where the rock mass is destroyed, and the bunker-loader, where the broken ore is poured. Both the first and second sources are identical in terms of dust formation power. The vortex formed during the forced ventilation method returns to the combine operator cab through the ore pouring area into the bunker. As a result, the composition of the atmosphere in the bottom hole significantly deteriorates. The greater the amount of air supplied during the forced ventilation method, the greater the dustiness of the bottomhole part of the mine. Conducted studies allow to conclude that the injection method of the ventilation of dead-end combine workings of the potash mines is ineffective to normalize the dust environment.

"For Asia Market Only": A Green Tattoo Ink between Safety and Regulations.

Due to the increasing tattoo practicing in Eastern countries and general concern on tattoo ink composition and safety, the green tattoo inks Green Concentrate by Eternal, for European and “for Asia Market Only” were analyzed, under the premise that only the former falls under a composition regulation. A separation of the additives from the pigment was carried out by successive extraction in solvents of different polarities, i.e., water, acetone and dichloromethane. The solid residues were analyzed by IR and Raman spectroscopies, the liquid fractions by GC/mass spectrometry. The relative pigment load and element traces were also estimated. We found that the European and the Asian inks are based on the same pigment, PG7, restricted in Europe, though at different loads. They have a similar content of harmful impurities, such as Ni, As, Cd and Sb and both contain siloxanes, including harmful D4. Furthermore, they have different physical-chemical properties, the European ink being more hydrophilic, the Asian more hydrophobic. Additionally, the Asian ink contains harmful additives for the solubilization of hydrophobic matrices and by-products of the phthalocyanine synthesis. Teratogenic phthalates are present as well as chlorinated teratogenic and carcinogenic compounds usually associated to the laser treatment for removal purposes, to a larger extent in the European ink. The composition of the inks does not seem to reflect regulatory restrictions, where issued.

A Study of the Effect of Alloying Elements and Temperature on Nitrogen Solubility in Industrial Stainless Steelmaking

The role of nitrogen varies in different stainless steels from a harmful impurity to a valuable alloying element. Therefore, the strict control of nitrogen content is a very important issue in the steel making process. Better understanding about the thermodynamics of nitrogen solubility is the basis for this control. The aim of this study was to determine whether the nitrogen solubility at atmospheric pressure at any given composition and temperature in an Argon Oxygen Decarburization (AOD) converter could be reliably predicted. This was done by comparing different equations for nitrogen solubility to industrial measurements of several different steel grades with a wide range of compositions and temperatures. The test set consisted of 100 heats to ensure reproducibility and sufficient variability. The focus was on examining the effect of the main alloying elements (Cr, Ni, Mo, Mn) and temperature on nitrogen solubility. Nitrogen solubility is increased most by the chromium content, followed by manganese and molybdenum, whereas nickel decreases the solubility. The interaction effect of an alloying element on nitrogen declines at increasing temperatures, resulting in a negative temperature dependence, i.e., the maximum nitrogen solubility is obtained near the liquidus temperature. The study showed that most of the examined thermodynamic equations predicted the nitrogen solubility quite well in common stainless steels and even in high alloyed steels. On the other hand, clear discrepancies were observed for steels with a high manganese content as well as with strongly deviating temperatures. Therefore, based on the present measurements and the literature data, a new equation was developed for predicting the solubility of nitrogen in a wide range of stainless steels. This equation can be coupled with the existing process models to control the AOD process.

Efficient extraction of tungsten, calcium, and phosphorus from low-grade scheelite concentrate

• Scheelite and apatite in low-grade scheelite were digested completely by HNO 3 . • Tungsten was leached in the form of soluble phosphotungstic acid. • Calcium was leached and recovered in the form of gypsum whiskers. • The excess phosphorus can be recovered in the form of nitrophosphate fertilizer . In the traditional process for tungsten recovery from scheelite concentrate, phosphorus is regarded as a harmful impurity that should be strictly controlled. Moreover, the calcium that entered the resideue as Ca(OH) 2 or CaCO 3 was discarded or landfilled. To date, the residues from the traditional process have been listed as solid hazardous waste in China. A novel method was investigated to realize the comprehensive recovery of tungsten, phosphorus, and calcium. In the leaching process, 96% of scheelite (CaWO 4 ) and 99% of apatite (Ca 5 (PO 4 ) 3 F) were digested under the conditions of 3 M HNO 3 , at a liquid/solid ratio of 10:1, a leaching temperature of 90 °C, and leaching time of 2 h. After extracting tungsten from the leaching solution by solvent extraction, about 70% of Ca 2+ in the raffinate was recovered as calcium sulfate whiskers by adding H 2 SO 4 . Subsequently, the solution from the calcium removal process was reused to leach scheelite after adding the consumed HNO 3 . When the P 2 O 5 concentration in the circulating leaching solution was over 30%, it was discharged and neutralized by NH 3 ·H 2 O, and then used to produce a nitrophosphate fertilizer by spray granulation and drying processes.

The improvement of the thermal and acoustic insulation properties of phosphogypsum specimens by adding waste wood fibre

Given the current environmental awareness and the growing interest in advanced and sustainable materials, the use of waste wood fibre and phosphogypsum (PG) has led to the development of eco-friendly composites. This paper presents a study on a new composite material, made of phosphogypsum matrix reinforced with either waste wood fibre (WF), manufactured from used particle boards, or natural wood fibre (NF), processed from natural timber. The fibre was included in amounts from 0 to 5 wt% in the PG specimens. Besides, a certain amount of a synthetic zeolitic waste (ZW) was added to reduce the content of the harmful soluble acidic impurities of PG. It was determined that the WF improved the mechanical strength of the specimens more effectively than the NF did. The highest compressive strength (CS100) values were 25.1 and 21.9 MPa, reached when small amounts of fibre were incorporated (0.5 wt% of WF or 1 wt% of NF), due to the reinforcing performance of the fibre. A further addition of fibre reduced the compressive strength of the specimens, due to the decrease of density. The thermal conductivity (λ) was lowered by the addition of fibre, whereas the sound pressure level (SPL) did not change. Considering comprehensively the investigated properties, the optimal “compromise” recipe for the PG specimens included 3 wt% of WF, exhibiting CS100 = 13.5 MPa, λ = 0.39 W/mK and SPL = 64.5 dBA.

Zircon SHRIMP U-Pb Dating and Significance From Weathered Residual Kaolin Deposits on the Northern Margin of the Qinzhou-Hangzhou Suture Zone, China

Weathered residual Kaolin deposits on the northern margin of the Qinzhou-Hangzhou Suture Zone are characterized by more feldspar-containing minerals and fewer dark minerals. These deposits have attracted increasing attention because of their high whiteness, low harmful impurity content, low depth of weathered mineralization, and ease for mining. The ore-forming rock masses mainly include granite (granite porphyry), quartz porphyry, eurite, haplite, and other acidic veins; the ore-bearing walls are mainly of Upper Proterozoic. Previous studies suggested that dyke rocks related to Kaolin deposits in this belt belong to the Mesozoic, but there is a lack of information regarding specific mineralization ages. In this study, two dyke wall-type weathered residual Kaolin deposits were selected from the northern margin of the Qinzhou-Hangzhou Suture Zone (Dongxicun and Yinbeidong, Jiangxi Province, China) for zircon SHRIMP dating. Two zircon U-Pb-based ages were obtained: 843 ± 10 Ma from Dongxicun granite veins that intrude into the Neoproterozoic Jiuling rock masses; 152.3 ± 1.8 Ma for Yinbeidong granite porphyry veins that intrude into the Neoproterozoic Anlelin Formation. We suggest that the dykes related to the Kaolin deposits were formed in the Neoproterozoic and late Jurassic. The Neoproterozoic dyke may be related to the convergence, formation, or pyrolysis of the Rodinia Supercontinent and the late Jurassic dyke may be related to the subduction of the Paleo-Pacific Plate. These results provide a chronological basis for the investigation and evaluation of weathered residual Kaolin deposits on the Qinzhou-Hangzhou Suture Zone.

Modeling the Chemical Pollution of the Area by the Random-Addition Method

Currently, a significant group of industrial facilities can be classified as chemically hazardous facilities (CHFs). To predict the spread of harmful impurities in the programs being developed, Gaussian and Lagrangian models are actively used, on the basis of which the complexes used both in the EMERCOM of Russia and in research organizations are being implemented. These complexes require the introduction of a large amount of information, including the characteristics of the wind field in the distribution of an emergency chemically hazardous substance, which limits their use. In systems, the formation of which is influenced by a large number of different random factors, spatial scaling (similarity) is often found, and one or another parameter can be described using the methods of fractal geometry, which in the past few decades has been actively and successfully applied to the description of various physical objects. The purpose of this study is to analyze the possibility of using the random-addition method for early prediction of the distribution of harmful impurities in the surface air layer during the short-term release of a substance on the surface as a result of an emergency.

High chrome cast iron for mineral processing and conveying equipment parts

The main reasons for the formation of microand macrocracks and other defects in waterjet castings, which significantly reduce their service life, are analyzed. It has been established that the introduction of ferroalloys together with the charge to the bottom of the arc furnace bath leads to a significant segregation of elements along the height (volume) of the melt in the bath furnace, and large primary chromium carbides remain in the casting structure. They, as a rule, form eutectics with austenite in the form of large conglomerates, which contribute to the appearance of microcracks in castings during their mechanical and thermal processing. It is shown that alloying, modification and homogenizing exposure of the melt for 5 min at 1550 °C and subsequent refining have a significant effect on the structure and morphology of the carbide phase and structural components of the metal base of high-chromium cast iron and purify it from harmful impurities and non-metallic inclusions. In addition, the amount of primary carbides is reduced, the formation of austenitic-carbide eutectic conglomerates is excluded, and the dispersion of the carbide phase and the structure of high-chromium cast iron are increased. Based on the ICH300Kh28NMWFTP cast iron created by JSC «NPO «TSNIITMASH», an effective export technology for the manufacture of waterjet castings has been developed, which makes it possible

MXENES FOR ENVIROMENTAL APPLICATIONS

The development of new methods for obtaining clean water is one of the most important global problems of mankind. It is important to purify water from harmful impurities that can adversely affect human health and the environment. Natural renewable energy sources, such as solar radiation, can be perfectly used for cleaning, distilling and desalination of seawater. The analysis of the study showed that MXene with unique and customizable properties provide new strategies for effective water purification and desalination. Experimental results indicate that representatives of the two-dimensional materials family (Mxene) have demonstrated improved light absorption and water evaporation characteristics. Thus, MXenes demonstrate a huge potential in the production of solar energy in the form of steam to solve the problem of shortage of drinking water. And also, according to the results of research, MXene showed a high degree of adsorption of heavy metal ions, such as Pb (II), Cr (VI), Hg (II) and U (VI). The large surface area, abundance of active sites, good dispersibility and reducibility, and the fact that many cations can be spontaneously inserted between the layers of two-dimensional MXenes make them promising candidates for water purification from toxic oxidants associated with heavy metal ions, radionuclides, and organic dyes. Key words: Mxene, сoefficient of performance (COP), adsorption