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Date submitted2024-03-11
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Date accepted2024-11-07
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Date published2025-03-06
Geochemical characteristics of weathering crusts on the Dzhezhimparma Ridge and the Nemskaya Upland (South Timan)
Numerous local varieties of weathering crusts are known in the South Timan. They differ in their position in the section, type of weathering products, substrates, and occurrence. The aim of the research is to identify patterns in the distribution of rock-forming, rare and rare earth elements and the composition of clay minerals in clay formations of the weathering crusts. The main task is to describe the occurrence and geochemical features that enable determining the genetic type and formation conditions of weathering crusts. The paper presents the results of a study of the distribution of petrogenic, rare earth, rare elements, and clay minerals in weathering crust of different ages, genetic types and occurrence conditions on the Dzhezhimparma Ridge and the Nemskaya Upland in the South Timan. We found that hydromica-kaolinite-type weathering crust is developed after the Late Riphean Dzhezhim Fm. rocks in the basement-cover contact zone on the Dzhezhimparma Upland, and the layer of fine-grained rock at the base of the Devonian section previously considered a weathering crust was formed as a result of mechanical destruction of the Devonian sandstones during movement in the thrust zone. In the Vadyavozh quarry located on the Nemskaya Upland, we studied and described the formations of Mesozoic-Cenozoic areal and linear weathering crusts after the Late Riphean Dzhezhim Fm. rocks. We found that micaceous siltstones in the siltstone-sandstone strata of the Dzhezhim Fm. are associated with the Riphean stage of crust formation and are composed of weathering crust material redeposited in the epicontinental basin.
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Date submitted2024-05-17
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Date accepted2024-10-14
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Date published2024-11-12
Black shales – an unconventional source of noble metals and rhenium
The content of noble metals and rhenium in the Lower Paleozoic black shales of the eastern Baltic paleobasin in Russia was estimated. Shales are enriched in platinoids (PGM to 0.12 g/t) and rhenium (to 1.54 g/t). The main accessory elements of noble metals and Re are U, V, Mo, Cu, and Ni. Black shales consist of organic (9-26 rel.%), clay (40-60 rel.%), and silt-sandy (25-50 rel.%) components and a nodule complex (2-5 rel.%) (carbonate, sulfide, phosphate and silicate nodules). Noble metals occur sporadically in the silt-sandy admixture as native forms and intermetallics: Aunat, Au-Ag, Au-Cu, Au-(Cu)-Hg, Au-Hg, Ag-Cu, Pt-Fe. Micromineral phases of noble metals were found in diagenetic sulfides: Aunat, chalcopyrite with Au admixture, pyrite with platinoid admixture. Clay fraction is 10-fold enriched in noble metals as compared to shale – to 0.28 g/t Au, 0.55 g/t Pt, 1.05 g/t Pd, and 1.56 g/t Re. Organic matter sorbs noble metals to a limited extent but accumulates rhenium. Pore space of black shales contains a colloidal salt component (submicron fraction) which is represented by particles smaller than 1,000 nm. The share of submicron fraction in black shales is 0.1-6 wt.%. The submicron fraction contains on average: PGM – 14 g/t, Au – 0.85 g/t, and Re – 4.62 g/t. The geochemical resource of noble metals (Au, Pt, Pd), Re and the accessory elements (U, V, Mo, Cu, and Ni) for black shales as a whole and their submicron fraction was estimated. Black shales are recommended as an integrated source of raw materials.
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Date submitted2024-05-03
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Date accepted2024-09-05
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Date published2024-11-12
Platinum group elements as geochemical indicators in the study of oil polygenesis
This study examines elements of the platinum group (PGE), primarily platinum and palladium, as geochemical indicators in the investigation of oil polygenesis. It has been found that, like other trace elements such as nickel, vanadium, and cobalt, platinum group elements and gold can occur in oil fields at both background levels and in elevated or even anomalously high concentrations. The objective of this research is to analyze PGE and trace elements as geochemical markers to identify the geological factors, including endogenous processes, responsible for these unusually high concentrations in oil. A comprehensive review of the literature on this subject was conducted, along with new data on the presence of precious metals in oils from Russia and globally. The study explores the geological mechanisms behind elevated PGE concentrations in oils, utilizing atomic absorption spectroscopy with atomization in the HGA-500 graphite furnace to measure PGE content. Previously, the tellurium co-deposition method (ISO 10478:1994) was used to isolate noble metals from associated elements. Possible geological origins of abnormally high concentrations of platinum metals in oils have been identified. These include endogenous factors such as the spatial proximity of oil fields to ultrabasic rock massifs, the effects of contact-metasomatic processes, and influences from mantle dynamics. Moreover, data concerning mantle elements can serve as indicators of the depth origins of certain hydrocarbon fluids, thus contributing to the study of oil polygenesis.
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Date submitted2024-10-29
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Date accepted2024-10-29
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Date published2024-11-12
Study of thermodynamic processes of the Earth from the position of the genesis of hydrocarbons at great depths
In the context of significant depletion of traditional proven oil reserves in the Russian Federation and the inevitability of searching for new directions of study and expansion of the raw material base of hydrocarbon raw materials in hard-to-reach regions and on the Arctic shelf, a scientific search is underway for accumulations in complex geological conditions and in manifestations that differ significantly from traditional ones, which include the processes of oil and gas formation and preservation of oil and gas in low-permeability “shale” strata and in heterogeneous reservoirs at great and super-great depths. Within the oil and gas provinces of the world, drilling of a number of deep and super-deep wells has revealed deposits at great depths, established connections between hydrocarbon deposits and “traces” of hydrocarbon migration left in the core of deep wells, which has made it possible to significantly re-evaluate theoretical ideas on the issue of oil and gas formation conditions and the search for technologies aimed at solving applied problems. Modern geochemical, chromatographic, bituminological, coal petrographic and pyrolytic methods of studying oil and bitumoids extracted from the host rocks of deep well cores give a hope for identifying correlations in the oil-source system, revealing processes that determine the possibility of hydrocarbon formation and accumulation, and defining predictive criteria for oil and gas potential at great depths.
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Date submitted2023-09-29
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Date accepted2023-10-25
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Date published2024-08-26
Laboratory studies of transformation of porosity and permeability and chemical composition of terrigenous reservoir rocks at exposure to hydrogen (using the example of the Bobrikovskii formations in the oil field in the northeast Volga-Ural oil and gas province)
The article describes the methodology for laboratory studies of reservoir rock exposure to hydrogen. The stages of sample research and the instruments used in the experiments are considered. A comparative analysis of the results of studies on porosity and permeability of core samples was performed. It was shown that after exposure to hydrogen, the porosity decreased by 4.6 %, and the permeability by 7.9 %. The analysis of correlation dependencies demonstrated a typical change in the relationship of these characteristics: after the samples exposure to hydrogen the scatter of the values increased and the correlation coefficient decreased, which indicates a change in the structure of the void space. Based on the research results, it was concluded that the decrease in porosity and permeability of the core samples occurred due to their minor compaction under the action of effective stresses. The chemical analysis of the rock showed no major difference in the composition of the basic oxides before and after exposure to hydrogen, which points to the chemical resistance of the studied formation to hydrogen. The experimental results showed that the horizon under consideration can be a storage of the hydrogen-methane mixture.
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Date submitted2024-04-10
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Date accepted2024-06-03
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Date published2024-07-19
Combined method for processing spent acid etching solution obtained during manufacturing of titanium products
Possessing high strength, low density and significant chemical resistance, titanium has found wide application in various fields of the national economy – the chemical industry, aviation and rocket technology, mechanical engineering, medicine, etc. The production of titanium products is hampered by a fairly strong oxide film covering its surface. Removal of the oxide film from the surface of titanium workpieces is carried out by etching in solutions of mineral acids of various compositions. A spent acid etching solution (SAES) is formed, containing titanium salt and the remainder of unreacted acids. Almost all etching solutions contain HF and one of the strong acids. This is H2SO4, HCl or HNO3. Thus, the SAES includes ions of titanium, fluorine or chlorine, orsulfate, or nitrate. SAES is quite toxic and must be diluted or cleaned several times before being discharged into a reservoir. Most of the methods used to extract impurities contained in SAES lead to a decrease in their content. As a result of such purification, there is a loss of substances contained in SAES in significant quantities and of interest for further use. The work presents experimental results obtained from the combined processing of SAES containing titanium fluoride, hydrofluoric and hydrochloric acids. At the first stage, SAES is treated with sodium hydroxide. The resulting titanium hydroxide precipitate is filtered off. At the second stage, the filtrate containing sodium fluoride and chloride is processed in a membrane electrolyzer. In this case, not only the extraction of sodium salts from the filtrate occurs, but also the production of sodium hydroxide and a mixture of hydrofluoric and hydrochloric acids. Sodium hydroxide can be used for processing SAES, and a mixture of acids for etching titanium workpieces.
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Date submitted2024-03-30
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Date accepted2024-06-03
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Date published2024-07-04
Preparation and use of complex titanium-containing coagulant from quartz-leucoxene concentrate
- Authors:
- Evgenii N. Kuzin
The search for the new high-efficiency reagents for wastewater treatment is a challenging and urgent task. Titanium-containing coagulants represent a new trend in water treatment and have a much higher efficiency that the traditional aluminium and iron-containing coagulants. The high cost of reagents significantly hinders their implementation. Complex titanium-containing reagents are coagulants prepared by modifying the traditional coagulants by adding 2.5-10.0 wt.% titanium compounds. In this work, titanium tetrachloride prepared from quartz-leucoxene concentrate was prehydrolyzed with subsequent double decomposition with sulfuric acid. The resulting mixture of hydrochloric and sulfuric acids was neutralized with aluminium hydroxide/oxide to form a self-hardening mixture (chemical dehydration). The sample of a complex sulfate-chloride titanium-containing coagulant was a mixture of AlCl3·6H2O – 5-20 wt.%, Al2(SO4)3·18H2O – 70-90 wt.% and TiOSO4 – 2.5-10.0 wt.%. It was proved that by changing the ratio of aluminium oxide/hydroxide and titanium tetrachloride at the stage of prehydrolysis and double decomposition, it is possible to obtain samples of a complex coagulant with different contents of the modifying additive of titanium compounds. An assessment of the coagulation properties of the complex reagent demonstrated its higher efficiency in cold water compared to aluminium sulfate. Studies on the use of the complex titanium-containing coagulant in the process of wastewater treatment from phosphate anions and suspended matter demonstrated its higher efficiency as compared to that of traditional reagents. The advantages of the prepared reagent are a reduction in the effective dose of the reagent, minimization of residual concentrations of pollutants in purified water, intensification of the processes of sedimentation and filtration of coagulation sludge. Purified water can be reused in the recycling water supply system. The use of quartz-leucoxene concentrate and titanium tetrachloride obtained from it as the source material would not only minimize the cost of the resulting complex coagulant, but also take a step towards the implementation of the Zero Waste concept.
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Date submitted2024-04-09
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Date accepted2024-06-03
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Date published2024-07-04
Analysis of the geochemical barriers effectiveness as the basis for the use of nature-like water purification technologies
Nature-like technologies are being introduced into many human activities including mining wastewater treatment. This work is based on long-term studies of the Sibay copper-zinc-pyrite deposit development. It is dedicated to assessment of geochemical barriers effectiveness in Cu, Zn, Cd removal from water of the Karagayly River (receiving quarry and dump drainage water). The research is based on the elements’ content and forms in water and bottom sediments, pH values etc. Four types of hydrogeochemical environment (formed due to changes in the water use over the past 20 years) were distinguished using discriminant analysis. The mechanisms of barriers formation and destruction were described. Statistical modeling of the metals’ precipitation was performed by multivariate regression analysis. Cu is adsorbed by recently formed Fe hydroxides, and, to a lesser extent, precipitates with sulfates as water pH increases. Antagonism to Mn hydroxides has been demonstrated, due to different physicochemical conditions for their precipitation. Zn enters solid phase mainly with sulfates, this element also forms its own mineral phases. The second mechanism is adsorption by recently formed Mn hydroxides, which corresponds to the idea of similar conditions for the precipitation of metal hydroxides. Cd behavior reflects conditions intermediate between these of Cu and Zn. Contribution of both mechanisms (related to Fe hydroxides and aqueous sulfates) is equal. Antagonism to Mn is absent. According to the assessment results using of nature-like technologies in situ in watercourses, canals and other water drainage systems is promising. Developed statistical models can be used for needs of experimental studies and artificial geochemical barriers engineering.
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Date submitted2024-01-18
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Date accepted2024-05-02
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Date published2024-12-25
Industrial clusters as an organizational model for the development of Russia petrochemical industry
The article explores the challenges facing Russia petrochemical industry over the past decade and examines the reasons behind its significant lag compared to other industrialized nations. It presents a review of academic research on clusters accompanied by a comparative analysis, generalization, and consolidation of factors influencing the development of the petrochemical industry in Russia. It is argued that advancing the petrochemical industry from production plants to integrated production complexes necessitates a shift towards clustering, which will improve resource utilization efficiency, bolster product competitiveness, and reduce production costs. The article examines and consolidates key cluster concepts, encompassing definitions, characteristics, composition, and constituent elements. It also examines strategic documents guiding the development of the petrochemical sector, assesses the progress made in forming petrochemical clusters in Russia, and draws upon European and Asian experiences and government support tools in the domain of petrochemical clusters. The successful development of petrochemical clusters in Russia is argued to be strongly dependent on state initiatives and support for infrastructure development. Additionally, the presence of research organizations within clusters is crucial for fostering high-tech product innovation and forming an efficient value chain that integrates research and development with specific assets. When establishing petrochemical clusters in Russia, it is essential to consider the unique characteristics of each cluster, including the types of raw materials and resources used, the necessary infrastructure, and the specific support measures and incentives provided by the state.
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Date submitted2023-04-13
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Date accepted2023-10-25
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Date published2025-02-25
Assessment of the ecological state of aquatic ecosystems by studying lake bottom sediments
- Authors:
- Mariya A. Chukaeva
- Tatyana V. Sapelko
The article presents the results of coupled palynological and geochemical studies of five various genesis lakes, located along the route of the expedition “In the footsteps of Alexander von Humboldt in Siberia, Altai and Eastern Kazakhstan”, dedicated to the double anniversary: the 190th anniversary of the expedition across Russia of the famous scientist and his 250th birthday. A geochemical analysis of water and bottom sediments of Ik Lake (Siberia), Lakes Kolyvanskoe and Beloe (Altai), Lake Bezymyannoe (Kazakhstan) and Nagornyi Pond (Altai) was carried out. Based on their results an assessment of studied lakes ecological state was given through single and integral criteria. A high level of pollution was noted for Nagornyi Pond and Lake Bezymyannoe, which is caused by a significant technogenic load from nearby mines. This is consistent with the data of palynological research. The aquatic ecosystems of Lakes Kolyvanskoe and Beloe are characterized by a satisfactory ecological situation, but they experience an increased recreational load. The results of spore-pollen analysis and analysis of non-pollen palynomorphs showed the low ability of these lakes to self-healing. The most favorable ecological state and high self-cleaning capacity were noted for Lake Ik, which is consistent with the data of palynological studies. It is being confirmed with the results of palynological studies. It was therefore concluded about the ability to make a quick assessment of the aquatic ecosystems’ ecological state by studying lakes using coupled palynological and geochemical analysis.
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Date submitted2022-10-30
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Date accepted2023-09-20
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Date published2024-02-29
Combined method of phytoremediation and electrical treatment for cleaning contaminated areas of the oil complex
The scale of land pollution with oil waste necessitates the use of economical and effective methods of recultivation. Phytoremediation is one of the simplest methods, but it has a number of limitations, so additional preparation of the territory is often required before it is carried out. Preliminary electrical preparation and subsequent seeding of special phytoremediants are of interest. Passing a constant electric current through the soil volume under a low voltage removes toxicants from deep soil layers even with flooding. In addition, it reduces pollutant content in the upper layer, where the plants root system is located, which creates more favorable conditions for phytoremediants. Adequately selected types of plants will ensure additional soil cleaning, improve its structure and air exchange. The results of two research directions are presented. Experiments on the study of plant resistance to oil-contaminated soil substrate allowed establishing contamination thresholds at which it is advisable to sow a particular species, and to choose optimal phytoremediants. The study of the oil-containing soil cleaning in a monocathodocentric electrochemical installation with the fixation of main characteristics (oil products concentration, soil temperature, volt-ampere characteristics) allows us to develop technical measures to prepare territories for phytoremediation taking into account the relief features.
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Date submitted2022-07-10
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Date accepted2023-06-20
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Date published2024-02-29
Mathematical modeling of the electric field of an in-line diagnostic probe of a cathode-polarized pipeline
A mathematical model of the in-line control of the insulation resistance state for cathodically polarized main pipelines according to electrometry data is considered. The relevance of the work is caused by the opportunity to create in-line internal isolation defects indicators of the main pipelines for transported liquids that are good conductors and expand the functionality of monitoring and controlling cathodic protection systems of the main pipelines. Features of the mathematical model are: consideration of the electric conductivity of transported liquid influence on electric field distribution; consideration of the influence of external and internal insulating coating resistance; use of the electric field of an in-line diagnostic probe for quality control of internal insulation. Practical significance consists in the development of modeling methods for control subsystems of main pipeline protection against corrosion and the development of special mathematical and algorithmic support systems for monitoring and controlling the operating modes of the cathodic protection station of main pipelines.
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Date submitted2022-04-11
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Date accepted2022-06-15
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Date published2022-07-26
Magma feeding paleochannel in the Monchegorsk ore region: geochemistry, isotope U-Pb and Sm-Nd analysis (Kola region, Russia)
A comprehensive study of a 340 m thick lenticular-sheet body of ultramafic composition penetrated by structural well M-1 at a depth of about 2.2 km was accomplished. Its main volume is composed of plagioharzburgite; fine-grained rocks of norite and orthopyroxenite chilling zones are preserved on endocontacts. The rocks of the body are similar in composition to the rocks near the underlying ore-bearing layered intrusion – the Monchepluton. The age of intrusion of the ultramafic body is 2510 ± 9 Ma (U-Pb, ID-TIMS, zircon) and, taking into account analytical errors, is comparable with the formation period of the Monchepluton (2507-2498 Ma). According to the study of the Sm-Nd system in rocks and minerals, a positive value of the e Nd (+1.1) parameter was established, similar to that in dunites and chromitites of the Monchepluton. Based on these results, the ultramafic body penetrated at depth was assigned to the magma feeding paleochannel through which the ultramafic, weakly contaminated magma entered the overlying magma chamber. This body is a unique example of a magma-feeding system for the ore-bearing layered intrusion of Precambrian age.
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Date submitted2021-04-27
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Date accepted2021-11-30
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Date published2021-12-27
Regularities of electrochemical cleaning of oil-contaminated soils
Electrochemical cleaning of oil-contaminated soils is a promising area of environmental safety, as it can be easily organized even in locations remote from settlements. For this purpose, a power source and a system of electrodes are necessary as equipment. It is possible to use an electric generator if there are no power supply lines nearby. The material of electrodes affects the features of redox processes, which can affect the energy consumption and the degree of soil cleansing from oil or oil products. Therefore, the correct choice of electrode materials is one of the important tasks in the field of engineering electrochemical methods of purification. Changes in the main parameters (humidity, temperature, degree of acidity) in an oil-contaminated model soil, similar in composition to one of the oil fields, were investigated. Measurements of parameters when using graphite and metal electrodes were carried out at several fixed sections of the interelectrode space depending on the treatment time. The established patterns of parameter changes in the purification of oil-contaminated soils allow us to draw conclusions about the stages of the electrochemical process, its speed, and energy efficiency. The results obtained form a basis for designing industrial facilities for soil treatment.
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Date submitted2021-04-30
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Date accepted2021-11-30
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Date published2021-12-27
Methodology for testing pipeline steels for resistance to grooving corrosion
- Authors:
- Viktor I. Bolobov
- Grigoriy G. Popov
The methodology for testing pipeline steels is suggested on the assumption that for the destruction of pipes in field oil pipelines by the mechanism of grooving corrosion the simultaneous fulfillment of such conditions as the occurrence of scratches on the lower generatrix of the pipe, eventually growing into a channel in the form of a groove, emulsion enrichment with oxygen, presence of pipe wall metal in a stressed state, presence of chlorine-ion in the oil-water emulsion is required. Tests are suggested to be carried out in 3 % aqueous solution of NaCl with continuous aeration by air on bent plates 150×15×3 mm, made of the analyzed steel, the middle part of which is under the action of residual stresses σ res , close to the level of maximum equivalent stresses σ eqv in the wall of the oil pipeline, with the presence of a cut on this part on the inner side of the plate as an initiator of additional mechanical stresses. Using the value of the modulus of normal elasticity of the analyzed steel, the degree of residual strain of the elastic-plastic body from this material, corresponding to the value σ res ≈ σ eqv is calculated, based on which the plates are bent to the required deflection angle, after which the cut is applied to them. After keeping the plates in the corrosive medium for each of them the increase in depth of the cut as a result of corrosion of the walls by the corrosive medium is analyzed, from which the rate of steel K by the mechanism of grooving corrosion is calculated taking into account the duration of tests. Corrosion rate values for two pipe steel grades determined by the suggested procedure are given. The comparison of K values obtained leads to the conclusion about the higher resistance to grooving corrosion of 09G2S steel.
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Date submitted2021-04-11
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Date accepted2021-10-18
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Date published2021-12-16
Comprehensive assessment and analysis of the oil and gas potential of Meso-Cenozoic sediments in the North Caucasus
- Authors:
- Igor I. Bosikov
- Andrey V. Мaier
At the present stage, the development of the oil and gas industry in the Russian Federation is impossible without replenishing the raw material base, so the urgent task is to conduct investigations, prospecting and evaluation of oil and gas bearing capacity prospects in undiscovered areas. The purpose of the investigations is to analyze facies and thicknesses, choose the methodology of prospecting and exploration in reservoirs, make a comprehensive assessment of oil and gas bearing capacity prospects based on experimental investigations and construct a map of oil and gas bearing capacity prospects of the studied sediment structure. The methodology of the conducted investigations was to identify and trace zones of increased fracturing by qualitative interpretation of time seismic sections. Methods for qualitative interpretation of time seismic sections, the model of physical, chemical and geochemical criteria developed by I.A.Burlakov, gas and geochemical surveying and correlation analysis were used in the investigations. A number of prospecting criteria, established based on the analysis of reference seismic materials on well-studied areas in comparison with the results of well tests, were also used. Structural plan for forecast prospects of oil and gas bearing capacity in the studied area was made; zonal and local objects with prospects for oil and gas were identified. Graphical plotting of Eh and pH concentrations distribution and various gas and geochemical indicators allowed identifying zones of possible oil and gas accumulations and starting their detailed survey. Processing of gas and geochemical materials by means of software allowed efficient assessment of prospects for oil and gas bearing capacity of the investigated objects.
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Date submitted2020-10-13
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Date accepted2021-03-02
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Date published2021-04-26
Trace element accumulation by soils and plants in the North Caucasian geochemical province
Long-term studies of the North Caucasian geochemical province allowed to establish regional abundances and calculate accumulation (dispersion) factors for chemical elements in rocks, soils, and plants. Certain natural regional patterns characterize the province. Associations of elements in high and low concentrations are often determined by the predominant composition of rocks: carbonate-terrigenous, terrigenous, and igneous. The study of the average contents of several chemical elements in the soils of the province showed that the association of accumulated elements includes metals with different migration characteristics. Thus, despite the rather close values of the ionic radii, Pb, Zn, Cu, and Li (judging by the ionic potential) are characterized by the formation of cations, while Mn, Mo, and Zr form complex ions. Such elements as Zn, Cu, and Pb are mainly accumulated on hydrosulfuric barriers, while Mo, Co, and Mn are stopped by oxygenous barriers. For Cu, Zn, Mo, and Co, biogenic accumulation plays a significant role, while for Pb and Ni it is practically absent. The absolute dispersion of the elements did not reach environmentally hazardous values, although it indicates a fairly intensive migration. In woody plants, Ba, Nb, Sc, Sr, and Zn are accumulated most intensively.
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Date submitted2020-03-20
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Date accepted2020-05-24
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Date published2020-06-30
Landscape monitoring studies of the North Caucasian geochemical province
The data on the geochemical features of the bedrocks and soils of the province are given. Considerable attention is paid to regional abundances, as well as enrichment and dispersion factors of the chemical elements in landscapes. Using the example of the North Caucasus, it is shown that for such indicators as phytomass, geological, geomorphological, and geobotanical features, it is possible to make a preliminary outlining of regional structures corresponding to geochemical provinces. At the same time, a subsequent geochemical study of these structures remains mandatory. Upon determining certain geochemical associations, geochemical provinces can be basically distinguished; to a large extent, geochemical properties of these accumulated and scattered associations of elements contribute to the regional soil geochemistry. The results of long-term monitoring studies of the North Caucasus geochemical province have shown that the key features of the regional landscapes are due to the composition of bedrock and the presence of a large number of ore deposits and occurrences. The data obtained are the basis for assessing the state of the environment in conditions of increasing anthropogenic impact, and the established regional abundances can be used to assess the degree of pollution in agricultural, residential, and mining landscapes.
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Date submitted2020-06-14
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Date accepted2020-06-14
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Date published2020-06-30
Geochemical approach in assessing the technogenic impact on soils
- Authors:
- Galina I. Sarapulova
The soil assessment was carried out in the technogenically-affected area of Irkutsk Oblast with the geochemical approach as a key geoecological method using physical and chemical techniques of analysis and ecodiagnostics. Diagnostic signs of the disturbed natural properties of the soil were revealed up to a depth of 40 cm in the profile based on macro- and micromorphometric parameters. The content of heavy metals (HM) – Pb, Zn, Hg, and Cu with an excess of standards was determined, and empirical HM – pH correlations were obtained by statistical clustering of the data array. The contributions of additional factors affecting the chemical element distribution in the soil layer were investigated. Significant soil contamination with sulfates and the possibility of implementing the ion-exchange of HM andfor element immobilization were revealed. It was shown that reactions with sulfates and the influence of pH, HM exchange processes involving mobile K and P can determine the nature of the described chemical element distribution in the multi-factor-contaminated technogenic soil. However, the effectiveness of such types of interaction is different for each metal and also depends on the quantitative ratio of substances and soil characteristics, even under a minor change in pH. Two-parameter correlations of HM distribution in sulfate-contaminated soils confirmed the different degrees of involvement of chemical elements in these types of interactions. The results obtained and the identified factors are of applied significance and can be used as the basis for geoecological differentiation of the contaminated soil, as well as for determining local geochemical fields in the technogenesis zone. Areas of advanced research are related to three-dimensional modeling for a more complete study of the cause-and-effect relationships of geochemical parameters.
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Date submitted2019-04-04
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Date accepted2019-08-04
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Date published2020-04-24
Chemical heterogeneity as a factor of improving the strength of steels manufactured by selective laser melting technology
The aim of this paper was to establish the causes of the heterogeneity of the chemical composition of the metal obtained by the LC technology. The powdered raw material was made from a monolithic alloy, which was fused by the SLM, the initial raw material was a laboratory melting metal of a low-carbon chromium-manganese-nickel composition based on iron. To determine the distribution pattern of alloying chemical elements in the resulting powder, electron-microscopic images of thin sections were combined with X-ray analysis data on the cross-sections of the powder particles. As a result, it was found that transition (Mn, Ni) and heavy (Mo) metals are uniformly distributed over the powder particle cross-sections, and the mass fraction of silicon (Si) is uneven: in the center of the particles, it is several times larger in some cases. The revealed feature in the distribution of silicon is supposedly due to the formation of various forms of SiO 4 upon the cooling of the formed particles. The internal structure of the manufactured powder is represented by the martensitic structure of stack morphology. After laser fusion, etched thin sections revealed traces of segregation heterogeneity in the form of a grid with cells of ~ 200 μm.
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Date submitted2020-01-10
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Date accepted2020-01-14
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Date published2020-02-25
Biogeochemical assessment of soils and plants in industrial, residential and recreational areas of Saint Petersburg
Soils and plants of Saint Petersburg are under the constant technogenic stress caused by human activity in industrial, residential, and recreational landscapes of the city. To assess the transformed landscapes of various functional zones, we studied utility, housing, and park districts with a total area of over 7,000 hectares in the southern part of the city during the summer seasons of 2016-2018. Throughout the fieldwork period, 796 individual pairs of soil and plant samples were collected.A complex of consequent laboratory studies performed in an accredited laboratory allowed the characterization of key biogeochemical patterns of urban regolith specimens and herbage samples of various grasses. Chemical analyses provided information on the concentrations of polluting metals in soils and plants of different land use zones.Data interpretation and calculation of element accumulation factors revealed areas with the most unfavorable environmental conditions. We believe that a high pollution level in southern city districts has led to a significant degree of physical, chemical, and biological degradation of the soil and vegetation cover. As of today, approximately 10 % of the Technosols in the study area have completely lost the ability to biological self-revitalization, which results in ecosystem malfunction and the urgent need for land remediation.
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Date submitted2019-05-12
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Date accepted2019-07-22
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Date published2019-10-23
A Modern View of Anomalies in the Metal Groups of the Periodic System of D.I.Mendeleev
The article is devoted to the 150 th anniversary of the Periodic Table of Chemical Elements by D.I.Mendeleev. The fundamental law of nature, discovered by D.I.Mendeleev has anomalies and paradoxes associated with certain groups of metals. When studying the physical and chemical properties of complex metal compounds, many discrepancies can be found, namely, the location of elements in groups, which primarily relate to metals with different valences. By studying the approaches and methods for predicting the arrangement of chemical elements, it can be established that D.I.Mendeleev eliminated many differences for some metals during the formation of the Periodic system of chemical elements. D.I.Mendeleev developed a principle that excludes such errors when finding and discovering new elements. Analytical studies conducted by a Russian scientist helped to calculate the atomic masses and describe the properties of three elements not known at that time – «eka-boron», «eka-silicon», «eka-aluminum», the existence of which was proved and confirmed by subsequent discoveries of scandium, germanium, boron, and gallium. The paper provides a significant assessment of the forecasting of metals in various groups of the periodic system. Changes in the properties of some metals significantly influenced their location in the table of D.I.Mendeleev.
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Date submitted2018-09-02
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Date accepted2018-10-28
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Date published2019-02-22
Factors affecting bacterial and chemical processes of sulphide ores processing
- Authors:
- T. S. Khainasova
Extraction of valuable components from sulphide ores using microorganisms is a recognized biotechnological method, combining several advantages over traditional methods of mineral processing. This paper presents the main factors affecting the bacterial-chemical leaching and methods of leaching with the participation of microorganisms. Some physical-chemical (temperature, pH, oxygen, carbon dioxide, nutrients, metals and other chemical elements) and microbial (cell count and microflora activity) properties are given, either directly or indirectly (suppressing or contributing to the growth and oxidative capacity of microorganisms) affecting the kinetics of the process. The paper discusses the characteristics of the mineral substrate, including galvanic interaction of sulfide minerals and the formation of passivating layers on the surface of the ore during oxidation, emphasizing the importance of the electrochemical interaction of the components of the leaching system. Bioleaching is a complex process, which is a combination of mainly chemical reactions mediated by the microbial component, therefore, to improve the kinetics, it is necessary to consider, monitor and regulate the listed range of factors.
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Date submitted2018-07-12
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Date accepted2018-09-16
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Date published2018-12-21
Environmental Geochemical Assessment of Technogenic Soils
- Authors:
- G. I. Sarapulova
The purpose of this study was to obtain diagnostic features and criteria for the distribution of heavy metals in technogenically altered soils in the area of industrial facilities, depending on their altered geochemical properties, which make it possible to fix chemical elements in landscapes (the formation of geochemical barriers). On the basis of the geoecological assessment, disturbance of the soil buffer properties, which is reflected in the ionic composition change, alkalization, pH increase, and sulfate-chloride salinization have been revealed. This forms the heavy metals alkaline barrier. For example, in case of Cu, Pb, Zn, and N, it contributes to their accumulation and subsequent concentration in the soil layer due to the exchange interactions between chemical elements and Na + , K + , Ca 2+ cations. Soil saturation with sulphates also increases the probability of metals demobilization in the soil layer. It has been shown that intra-sectional soil migration of oil products (one of the most common pollutants of industrial areas) and chemical elements occurs at a depth of 30-50 cm, where the oil products based on a clay sorption layer form a technogenic barrier.
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Date submitted2018-07-04
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Date accepted2018-09-17
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Date published2018-12-21
Secondary dispersion halos as a prospecting indicator of platinum metal mineralization on the example of the Kamenushinsky massif (Middle Urals)
- Authors:
- A. M. Minibaev
The paper discusses the results of bulk rock geochemical sampling of the Kamenushinsky massif eluvial-deluvial deposits and the massifs bedrocks spectral analysis data. Evaluation of secondary dispersion halos using two-dimensional modeling and multivariate statistic processing of the results have allowed establishing the spatial collocation of platinum and chromium anomalies and high correlation between these elements. These facts confirm the considerable contribution of chromite-platinum mineralization to the primary ores of the entire Kamenushinsky massif. The geological observations and rocks chemical composition analysis has revealed that uranium and barium anomalies are associated with the areas of gabbro and granitoids dike bodies. The insignificant overlapping of uranium and barium anomalies with platinum and chromium ones, as well as the negative correlation between these two groups of elements, is inconsistent with earlier conclusions on the spatial association of platinum mineralization with gabbro and granitoids dikes and a possible connection between these dikes and platinum metal mineralization zones.