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Date submitted2024-03-11
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Date accepted2024-09-24
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Date published2025-04-25
Comparative analysis of nitrogen and carbon isotopic fractionation during diamond formation based on β-factor determination
- Authors:
- Dmitrii P. Krylov
First quantitative estimates are presented for nitrogen isotopic fractionation during diamond crystallization with respect to nitrogen-bearing fluid components using quantum-mechanical (DFT) calculations on the defect (with the substitutional nitrogen) diamond lattice. Provided equilibrium isotopic fractionation, 15N/14N ratio decreases within the sequence of compounds NH4+ > N2 > (diamond, NH3) > CH3N > CN− > NH2. At temperatures of 1,100 to 1,200 °C fractionation among diamond and fluid N-compounds are estimated at –2.23, –0.77, 0.01, 0.44, 1.31 and 2.85 ‰ and substantially (over 1 ‰) exceed the already available estimates based on the modeling diamond C-N bonds by analogy with HCN or CN – molecules. Depending on the dominant nitrogen and carbon substance in the mineral-forming fluid, diamond formation can be accompanied by different isotope compositional trends, as expressed either by zoned patterns within individual diamond grains or by isotopic δ15N vs δ13C covariations during successive crystallization. Provided the dominance of NH3 component (the reduced conditions, high pressures and the cold geotherm) nitrogen isotope fractionation between diamond and fluid does not exceed 0.1-0.2 ‰ and the isotope shifts at temperature ca. 1100 °C Δ15N << Δ13C. In nitrogen depleted reduced mantle fluids possible existence of compounds with low heavy isotope affinity at temperature of diamond formation (especially NH2) implies high isotope fractionation between diamond and the fluid and hence, evolved Δ15N/Δ13C ratios. Oxidized fluids dominated by CO2 or CO3 coupled with N2 component are characterized by close to zero Δ15N/Δ13C ratios as inferred by prevailing carbon isotope fractionation with respect to nitrogen isotopes, the latter change considerably with nitrogen distribution coefficient among diamond and the growth media.
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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 submitted2024-04-12
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Date accepted2024-09-05
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Date published2024-11-12
Promising reagents for the extraction of strategic metals from difficult-to-enrich mineral raw materials
The need of the mining and processing industry for new types of directional reagents is due to the deterioration of the material composition of the processed ores. Low Au content (less than 0.5-1.0 g/t), finely dispersed Au inclusions (0.1-10.0 microns) in the ore, similar properties of the separated minerals have an extremely negative effect on flotation performance when using traditional reagents, which leads to significant losses of valuable metal with enrichment tailings. Expanding the range of domestic flotation reagents based on the latest achievements of fundamental research and their targeted application at mining and processing companies will compensate for the negative impact of the mineral composition of raw materials and ensure maximum extraction of strategic metals from difficult-to-enrich ores. The use of modern research methods (scanning electron and laser microscopy, UV spectrophotometry, XRF and chemical analysis) made it possible to visualize the adsorption layer of new reagents-collectors of a number of dithiocarbamates with different structures of a hydrocarbon radical and an organic modifier on the surface of gold-containing sulfides. The amount of adsorbed reagents on the surface of minerals has been experimentally determined. The specific features of the fixation of reagents on minerals of various compositions led to optimal correlations of their consumption in the flotation process. Scientifically based reagent regimes ensured an increase in the gold content in the concentrate and a decrease in the loss of gold with tailings by 5-6 % during flotation enrichment of the refractory ore of the Malinovskoe deposit.
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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 submitted2023-07-05
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Date accepted2024-06-03
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Date published2024-12-25
Complete extraction of conditioned ores from complex-structured blocks due to partial admixture of substandard ores
- Authors:
- Bayan R. Rakishev
The paper presents mining-technological substantiation of complete extraction of conditioned ores from complex-structured blocks of benches by mixing a layer of substandard ores of certain sizes. The relevance of the work consists in the development of innovative methods of establishing the parameters of the substandard layer of ores to be added to the conditioned ores. The main problem is to ensure complete extraction of useful components into concentrate from shipped ore with acceptable deviations from the required ones. A new typification of complex-structured ore blocks of the bench has been carried out. Analytical dependences of mining and geological characteristics of complex-structured ore blocks were obtained. Theoretical dependences for determining the main indicators of mineral processing are derived. Analytical dependences for determination of the content of useful component in shipped ore α' – mixture of conditioned ore with the content of useful component α and admixed layer of substandard ore with the content of useful component α'' are offered. For the first time in mining science, a new approach of complete extraction of conditioned ores from complex-structured blocks of benches by grabbing a certain part of substandard ores during excavation, increasing the volume of extracted ore and expanding the extraction of useful components in the concentrate has been substantiated. The increment of useful components can reach 10-15 % of the total volume of extraction, which allows predicting a significant increase in the completeness of mineral extraction from the Earth's interior.
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Date submitted2023-02-07
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Date accepted2023-06-20
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Date published2024-02-29
Origin of carbonate-silicate rocks of the Porya Guba (the Lapland-Kolvitsa Granulite Belt) revealed by stable isotope analysis (δ18O, δ13C)
- Authors:
- Dmitrii P. Krylov
- Ekaterina V. Klimova
Carbonate-silicate rocks of unclear origin have been observed in granulites of the Porya Guba of the Lapland-Kolvitsa Belt within the Fennoscandinavian Shield. The present work aims to reconstruct possible protoliths and conditions of metamorphic transformation of these rocks based on oxygen and carbon isotopic ratios combined with phase equilibria modeling. Isotope analysis and lithochemical reconstructions suggest that carbonate-silicate rocks of the Porya Guba represent metamorphosed sediments (possibly marls) with the isotopic composition corresponding to the Precambrian diagenetically transformed carbonates (δ18O ≈ 17.9 ‰, SMOW and δ13C ≈ –3.4 ‰, PDB). The chemical composition varies depending on the balance among the carbonate, clay, and clastic components. Significant changes of the isotopic composition during metamorphism are caused by decomposition reactions of primary carbonates (dolomite, siderite, and ankerite) producing CO2 followed by degassing. These reactions are accompanied by δ18O and δ13C decrease of calcite in isotopic equilibrium with CO2 down to 15 ‰ (SMOW) and –6 ‰ (PDB), respectively. The isotopic composition is buffered by local reactions within individual rock varieties, thus excluding any pronounced influence of magmatic and/or metasomatic processes.
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Date submitted2022-05-17
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Date accepted2023-04-03
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Date published2024-02-29
Improvement of concentrate quality in flotation of low-rank coal
- Authors:
- Sergei A. Kondratev
- Tatyana A. Khamzina
Percentage of high-rank coal with low content of ash, moisture, and sulfur in total coal production output is low. Most of the produced coal has a low quality (lignite, bituminous coal: long-flame and fiery). Under increasing requirements for ecological cleanness of coal, the efficient use of coal products is only possible after improvement of their processing properties. The authors discuss the enhancement of flotation efficiency of low-rank coal using the mechanism of physisorption of a collecting agent in particle – bubble attachment. It is explained why the yield of concentrate with low ash content increases as a result of combination of collectors having different physical properties. It is shown that the surface activity of a heteropolar agent relative to the gas – liquid interface and the adsorption density of the agent govern its collecting properties. Based on the recovery – surface activity relationship, the correlation is found between the collecting activity of a chemical compound and the structure of its molecules. The combination of the collectors with different surface activity enables adjusting collectability and selectivity of the blend. The physisorption mechanism of collectors can be a framework for developing recommendations on modification of concentrate yield and ash content, and on selection of optimized ratios of surface activities of miscible collectors relative to the gas – liquid interface.
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Date submitted2023-03-14
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Date accepted2023-06-20
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Date published2023-07-19
A reliability study of the traction drive system in haul trucks based on failure analysis of their functional parts
The efficiency of a mining and processing plant depends on the level of complex mechanization of the production process. In mineral extraction, haulage is a major cost category, with haul trucks being the key component of the mining transportation system. To improve production performance, mining operations can increase their haulage turnover and reduce transportation costs, which necessitates making haul trucks more reliable. This can be done by improving their mean time to first failure (MTFF) indicators. This article analyzes the reliability status of the traction drive system inhaul trucks operating in the mineral resources sector. It provides a quantitative assessment of traction drive system failures resulting from part defects and discusses the associated repair costs. By examining failure data from 2018 to 2022 and the results of vibration tests performed on a diesel generator, the study reveals that the most expensive failures are associated with defects in the synchronous generator, which are primarily caused by elevated external vibrations. Based on basic vibration tests and vibration spectra tests at different operating modes, recommendations have been formulated concerning the generator’s robustness to external mechanical forces and the ways to increase the generator’s protection grade to prevent dust intrusion. The study also identifies the frequency range that poses the greatest risk of damage to the windings.
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Date submitted2022-10-28
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Date accepted2023-03-02
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Date published2023-04-25
Assessment of the possibility of using iron-magnesium production waste for wastewater treatment from heavy metals (Cd2+, Zn2+, Co2+, Cu2+)
Relevant problems associated with treatment of industrial wastewater from heavy metal ions are considered. Due to industrial development, the amount of wastewater increases as well as the risks of heavy metals getting into surface and groundwater, accumulating in water bodies and becoming aggressive environmental pollutants, which affect the animal and human organisms. To assess the possibility of extracting metal ions (Cd 2+ , Zn 2+ , Co 2+ , Cu 2+ ) from industrial wastewater and their further treatment, studies were carried out on redistribution of heavy metals in the “wastewater – waste” system using iron-magnesium production waste. Samples of the investigated waste weighing 0.1; 0.2; 0.5; 1; 1.5; 2 g were taken for wastewater volume of 50 ml per each subsample. Contact time varied from 5 to 180 min, waste fraction was 1 mm. The interaction process showed that the waste efficiently removes metal ions (Cd 2+ , Zn 2+ , Co 2+ , Cu 2+ ) from industrial wastewater. The efficiency of removing a pollutant from the solution depends on the weight of the waste subsample, initial concentration of metal ions, and contact time.
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Date submitted2022-02-22
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Date accepted2022-05-11
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Date published2022-11-03
Scientific substantiation and development of innovative processes for the extraction of zirconium and rare earth elements in the deep and comprehensive treatment of eudialyte concentrate
- Authors:
- Valentin A. Chanturiya
Based on a package of modern analysis methods, the influence of various acids and energy effects on the morphology, elemental composition, structural and chemical transformations of the mineral surface, and the efficiency of eudialyte concentrate leaching was studied. The mechanism and the optimal conditions and specific features of the destruction of eudialyte and rock minerals and the extraction of zirconium and REE under the influence of various acids, powerful nanosecond pulses, dielectric barrier discharge, electrochemical processing, mechanochemical activation and ultrasound were revealed. The mechanism of formation and the optimal conditions for the dispersion of silica gel, depending on the methods and parameters of energy effects, was theoretically and experimentally substantiated. A combined three-stage circuit of nitric acid leaching of eudialyte concentrate with ultrasonic treatment of the suspension, providing 97.1 % extraction of zirconium and 94.5 % REE, were scientifically substantiated and tested. The conditions for the selective deposition of zirconium and REE were theoretically and experimentally substantiated.
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Date submitted2021-11-17
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Date accepted2022-04-06
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Date published2022-11-10
Method for predicting the stress state of the lining of underground structures of quasi-rectangular and arched forms
- Authors:
- Maksim A. Karasev
- Tien Tai Nguyen
A method for predicting the stress-strain state of the lining of underground structures, the shape of the cross-section of which is different from the circular outline, is considered. The main task of the study is to develop a methodology for assessing the influence of the parameters of the cross-section shape of underground structures on the stress state of the lining. To solve this problem, a method for calculating the stress state of the lining for arched tunnels with a reverse arch and quasi-rectangular forms is substantiated and developed. The methodology was tested, which showed that the accuracy of the prediction of the stress state of the lining is sufficient to perform practical calculations. An algorithm for multivariate analysis of the influence of the cross-sectional shape of underground structures of arched and quasi-rectangular shapes on the stress state of the lining is proposed. Parametric calculations were performed using the developed algorithm and regularities of the formation of the stress state of the lining of underground structures for various engineering and geological conditions, as well as the initial stress state field, were obtained. A quantitative assessment of the influence of geometric parameters of tunnels on their stress-strain state was performed.
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Date submitted2021-09-29
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Date accepted2022-05-11
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Date published2022-07-13
Tensor compaction of porous rocks: theory and experimental verification
Compaction in sedimentary basins has been traditionally regarded as a one-dimensional process that ignores inelastic deformation in directions orthogonal to the active load. This study presents new experiments with sandstone demonstrating the role of three-dimensional inelastic compaction in cyclic true triaxial compression. The experiments were carried out on the basis of a triaxial independent loading test system in the Laboratory of Geomechanics of the Ishlinsky Institute for Problems in Mechanics of the Russian Academy of Science. The elastic moduli of the material were estimated from the stress-strain curves and the elastic deformations of the sample in each of the three directions were determined. Subtracting the elastic component from the total deformation allowed to show that inelastic compaction of the sandstone is observed in the direction of active loading, whereas in the orthogonal directions there is a expansion of the material. To describe the three-dimensional nature of the compaction, a generalization of Athy law to the tensor case is proposed, taking into account the role of the stress deviator. The compaction tensor and the kinetic equation to describe the evolution of inelastic deformation, starting from the moment of the load application are introduced. On the basis of experiments on cyclic multiaxial compression of sandstone, the identification and verification of the constructed model of tensor compaction were carried out. The possibility of not only qualitative, but also quantitative description of changes in inelastic deformation under complex cyclic triaxial compression is shown.
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Date submitted2021-06-08
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Date accepted2021-11-30
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Date published2021-12-27
Management of groundwater resources in transboundary territories (on the example of the Russian Federation and the Republic of Estonia)
Groundwater, as a source of water supply, the most important mineral and geopolitical resource, , is often the only source of high-quality drinking water that is protected from pollution under conditions of increasing deterioration of surface water quality. Transboundary groundwaters are the focus of hydrogeological researchers for a number of reasons, including the reduction and pollution of water resources as a result of economic activities. The increased controversy between states over transboundary water issues has necessitated the development of international legal documents on issues related to water conflict prevention and the sustainable use of fresh water. As part of the analysis of the problem of legal regulation of groundwater extraction from transboundary aquifers and complexes, it is proposed to consider this aspect on the example of Russia. The problems of regulation of rational use and protection of fresh water in the bilateral treaties of the Russian Federation were revealed; a methodology for the management of groundwater extraction in the territory of the transboundary aquifer was developed, the size, parameters, and factors influencing the formation of the transboundary zone have been determined (based on research and analysis of water intake activities in the border areas of the Russian Federation and the Republic of Estonia) were determined.
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Date submitted2020-09-15
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Date accepted2021-11-30
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Date published2021-12-27
Evaluating the effectiveness of fine gold extraction technologies on the example of titanomagnetite beach placers of the western coast of Kamchatka
- Authors:
- Valentina E. Kungurova
The material on the gold content of coastal-marine deposits of the western coast of Kamchatka is analyzed and the resource potential is briefly characterized. A review of gold technological estimates obtained from the study of gold-bearing samples taken in promising areas of the coastal-marine strip, from the Bolshaya Vorovskaya River in the north to Cape Levashova in the south, is presented. Stock materials supplemented by our studies were used. Gold-bearing deposits with very fine (0.05-0.1 mm) and fine (0.1-1.0 mm) gold amounting to 94.6 % were tested, as well as samples with gold up to 2 mm and more in addition to fine gold The content of freely recoverable gold reached 91.9 %. In the case of significant gold reserves in placers, prospects for their commercial development open up. experiments on the enrichment of gold-bearing coastal-marine deposits of Western Kamchatka indicate the possibility of extraction of free gold and other valuable components from them. Gravity technologies and modern equipment developed by ОАО Irgiredmet and JSC ITOMAK are the most effective for their extraction. enrichment of gold-bearing formations with simultaneous extraction of several useful components from them, which is possible with the use of fluoride technology, can also become economically advantageous.
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Date submitted2021-06-22
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Date accepted2021-11-30
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Date published2021-12-27
Increasing the efficiency of rare earth metal recovery from technological solutions during processing of apatite raw materials
The issues of complex processing of mineral resources are relevant due to the depletion of available raw materials. So, it is necessary to involve technological waste, generated during the processing of raw materials, to obtain valuable components. In the process flow of apatite concentrate treatment using the sulfuric acid method, a large amount of phosphogypsum is produced with an average content of light rare earth metals (REMs) reaching 0.032-0.45 %. When phosphogypsum is treated with sulfuric acid solutions, a part of REMs is transferred to the sulfate solution, from which it can be extracted by means of ion exchange method. The study focuses on sorption recovery of light REMs (praseodymium, neodymium and samarium) in the form of anionic sulfate complexes of the composition [ln(SO 4 ) 2 ] – on polystyrene anion exchanger AN-31. The experiments were performed under static conditions at a liquid-to-solid ratio of 1:1, pH value of 2, temperature of 298 K and initial REM concentration in the solutions ranging from 0.83 to 226.31 mmol/kg. Thermodynamic description of sorption isotherms was carried out by the method based on linearization of the mass action equation, modified for the ion exchange reaction. As a result of performed calculations, the authors obtained the constants of ion exchange equilibrium for Pr, Nd and Sm, as well as the values of the change in the Gibbs energy for the ion exchange of REM sulfate complexes on the AN-31 anion exchanger and the values of total capacity of the anion exchanger. Calculated separation factors indicated low selectivity of AN-31 anionite exchanger for light REMs; however, the anion exchanger is suitable for effective recovery of a sum of light REMs. Based on the average value of ion exchange equilibrium constant for light REMs, parameters of a sorption unit with a fluidized bed of anion exchanger were estimated.
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Date submitted2021-06-15
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Date accepted2021-10-18
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Date published2021-12-16
Study on hydrometallurgical recovery of copper and rhenium in processing of substandard copper concentrates
- Authors:
- Denis S. Lutskiy
- Aleksander S. Ignatovich
Over the past decade, there has been a steady growth in demand for rare metals, with rhenium being one of the most highly demanded, but also one of the most expensive and difficult to obtain. The high demand for rhenium is due to its use as a key component of metallurgical alloys or as a component of catalysts used in the oil refining industry. The aggregate of facts causes profitability of processing of the rhenium-containing mineral resources, which also are the copper substandard concentrates obtained at processing of the Zhezkazgan sandstones. The study focuses on the processes of extraction of copper and sorption recovery of rhenium from solutions of ammonia leaching of copper substandard concentrates. Model solutions similar in the elemental composition to solutions of ammonia leaching solutions of copper substandard concentrates obtained during the processing of Zhezkazgan sandstones were used as an object of the study. The paper estimates extraction characteristics of copper recovery using LIX 84-I solution in kerosene, as well as sorption characteristics of the rhenium recovery process using the Purolite PPA100 anion exchanger. Based on the obtained characteristics the possibility of hydrometallurgical processing of ammonia leaching solutions of substandard copper-sulfide concentrates, and recovery of the obtained commercial products is shown.
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Date submitted2021-02-20
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Date accepted2021-10-18
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Date published2021-12-16
Thermal protection implementation of the contact overheadline based on bay controllers of electric transport traction substations in the mining industry
The article presents the principle of thermal protection of the contact overheadlineand substantiates the possibility of practical implementation of this principle for rail electric transport in the mining industry. The algorithm for the implementation of modern digital protection of the contact overhead line as one of the functions of the controller is described. A mathematical model of thermal protection is proposed, which follows from the solution of the heat balance equation. The model takes into account the coefficient of the electrical networktopology, as well as the coefficient of consumption of the current-carrying core of the cable, which determines the reduction in the conducting section from contact erosion and the growth of oxide films. Corrections for air flows are introduced when receiving data from an external anemometer, via telemechanics protocol. The mathematical model was tested by writing a real thermal protection program in the C programming language for the bay controller, based on the circuitry of which is the STM32F407IGT6 microcontroller for the microcontroller unit. Verification tests were carried out on a serial bay controller in 2020. The graphs for comparing the calculated and actual values of temperatures, with different flow rates of the current-carrying conductor of the DC cable, are given. To obtain data, telemechanics protocols IEC 60870-104 and Modbus TCP, PLC Segnetics SMH4 were used.
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Date submitted2020-05-18
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Date accepted2020-06-16
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Date published2021-04-26
Traction asynchronous electric drive of mine electric locomotivesimulation model structure improvement
The article discusses the solution to the problem of underground railway transport slipping in dynamic modes, which occurs when there is a significant difference in the speeds of the driving and driven pairs of wheels. The state of the rail surfaces largely determines the coefficient of adhesion, therefore, using a mathematical model, the condition for the dependence of the magnitude of slipping and tractive effort is selected. For effective acceleration and deceleration of an electric locomotive, it is necessary to control the coefficient of adhesion at a certain level. A simulation model of rolling stock has been created, which for the first time takes into account a mechanical system with distributed parameters. In the structural diagram of the automatic control system of traction electric drives with frequency regulation, such factors as the volume of goods being moved, rolling friction, slope (rise) levels and the state of the rail track are taken into account. The simulation results show the features of the movement and stops of the freight train not only by the diagrams of speed and forces in the modes of acceleration-deceleration and uniform movement, but also the positions of the plungers and tractive forces on the couplings of the electric locomotive and all trolleys involved in the movement of goods. The practical application of the proposed method lies in the possibility of starting a heavily laden train from its place on the ascent section in conditions of insufficient adhesion coefficient with contaminated roads.
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Date submitted2020-02-19
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Date accepted2020-04-17
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Date published2020-10-08
Decrease in coal losses during mining of contiguous seams in the near-bottom part at Vorkuta deposit
- Authors:
- Oleg I. Kazanin
- Valeriy V. Yaroshenko
The problem of formation of extended zones with high rock pressure (HRP) from safety pillars at the boundaries of extraction pillars formed due to the mine layout of complex geometry is considered at the example of JSC Vorkutaugol mines. A detailed analysis of the remaining reserves of the near-bottom part of the deposit was carried out to estimate losses and the impact of HRP zones from the Chetvertyi protective seam to mining operations on the Troinoi upper seam along with the possibilities for the reduction of sizes of HRP zones at the account of expanding the underworked space. Due to research on the near-bottom part of the Vorkuta deposit, within the framework of the accepted layout, a zone at the Komsomolskaya mine and two zones at the Zapolyarnaya-2 mine were singled out, at which losses at the boundaries of the extraction pillars amount up to 13-22 % of the total resources of the mine field. The high volume of losses in these pillars indicates the relevance of research on the priority extraction impact of protective seams on the efficiency and safety of mining operations in the working area of underworked and HRP zones. Based on the analysis of foreign and Russian experience in the pillar cleaning-up at the boundaries of working areas and the methodical guidelines and instructions, a technological scheme was developed that allows increasing the coal mining recovery factor in the near-bottom part of the Vorkuta deposit from 0.75 to 0.9 without fundamental changing of the ventilation and transport networks and also without purchasing any additional mining equipment. The conducted economic calculations confirmed the effectiveness of implementing the new technological scheme for cleaning-up reserves at the boundaries of extraction districts. The economic effect is from 0.079 to1.381 billion rubles of additional profit from coaxial extraction pillars, depending on the mining and geological conditions and the size of the pillars.
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Date submitted2019-06-06
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Date accepted2019-08-09
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Date published2020-04-24
Studies of enrichment of sulfide and oxidized ores of gold deposits of the Aldan shield
The paper presents the analysis of studies of the enrichment of sulfide and oxidized ores in Yakutia deposits. The ore of the deposit is a mixture of primary, mixed and oxidized ores. The main useful component of the studied ore samples is gold with a content of 1.5 to 2.8 g/t, the silver content is low – 5-17 g/t. Ore minerals are represented by sulfides, among which pyrite predominates. The total sulfide content does not exceed 3-5 %. The presence in the ore of free and associated gold with a grain size from fractions of a micron to 1.5 mm. Gold is represented by nuggets in intergrowth with sulfides and also forms independent inclusions. Ores are classified as easily cyanidable. It was found that the content of amalgamable gold is 10-49, the share of cyanidable gold ranges from 66.67-91, the share of refractory gold is 9.0-33.33 %, which in absolute amount equals to 0.24-0.8 g/t. The extraction of gold in gravitation concentrate varies depending on the gold content in the ore and the yield of concentrate and for ores with a gold content of 1.5-2.8 g/t from 40 to 60 %. The direct cyanidation of all studied ore samples established the possibility of extracting gold into solution up to 86.7-92.9 %, the gold content in cyanidation cakes is 0.2-0.3 g/t. Investigations of the gravitation concentrate by the method of intensive cyanidation showed that with an initial gold content of ~ 500 g/t, up to 98.9 % is extracted into the solution. The gold content in intensive cyanide cakes will be 6-15 g/t. A set of studies carried out by the authors of the article at various institutes showed that it is advisable to process ore from the deposit using cyanidation technology with preliminary gravitational extraction of gold.
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Date submitted2019-07-11
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Date accepted2019-09-11
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Date published2020-04-24
Research of lithium sorption by KU-2-8 cation exchanger from model solutions simulating geothermal fluids in the dynamic mode
- Authors:
- Tatiana P. Belova
- Tatiana I. Ratchina
The extraction of chemical compounds from hydromineral raw materials is currently a promising objective. The geothermal deposits in the Kamchatka Territory should be considered as possible sources of lithium, boron and other chemical compounds. Their economic efficiency is justified by the complexity of the use of resources of geothermal fluids. The article presents data obtained as a result of experimental studies of lithium sorption by KU-2-8 cation exchanger from model solutions that simulate geothermal fluids in the dynamic mode. It was shown that in the first phase of sorption, ion exchange results in the absorption of lithium and sodium ions by the hydrogen form of cation exchanger up to the degree of cation exchanger saturation by 78 %. After that, the displacement of lithium ions by sodium ions is observed. The intermediate solutions were obtained in which the molar ratio of Li/Na is 80 times higher than in the initial solution. To separate sodium and lithium, it is proposed to use the lithium form of cation exchanger obtained using a portion of lithium chloride concentrate. The separation occurs due to the displacement of lithium ions by sodium ions. The effluent has a molar ratio of Li/Na = 10.4. The regeneration is carried out with 1 n hydrochloric acid, while the concentration coefficient of sodium chloride equals three.
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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 submitted2019-05-24
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Date accepted2019-07-15
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Date published2019-10-23
Effective Power and Speed of Mining Dump Trucks in Fuel Economy Mode
- Authors:
- V. I. Alexandrov
- M. A. Vasileva
- V. Y. Koptev
Existing methods for determining the effective power, based on the calculation of the average indicator operation of the engine during the piston stroke, do not take into account the change in thermodynamic parameters and the polytropic operation of the engine, the value of which depends on the polytropic efficiency of the duty cycle. This is the reason that the calculation of the effective power leads to some error – the margin of the engine features. The identification of this stock allows us to review the entire line of dump trucks in the direction of increasing their pass- port effective capacity, which will lead to a reduction in capital purchase costs due to the choice of a previously un- derestimated and cheaper option, as well as a reduction in current operating costs due to a decrease in the specific fuel consumption rate. Taking into account the stochastic nature of the transport process and assessing the influence of all external and internal factors when calculating the rational mode of operation of a mining truck can further reduce specific fuel consumption by choosing the rational speed of its movement in loaded and empty directions.
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Date submitted2019-05-26
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Date accepted2019-07-23
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Date published2019-10-23
Ensuring Stability of Undermining Inclined Drainage Holes During Intensive Development of Multiple Gas-Bearing Coal Layers
At high rates of production face advance, requirements towards reliable operation of undermining drainage holes get raised. The issue of maintaining high intensity of gaseous seams development under naturally increasing gas content, mining depth and capacity of production equipment poses a problem. The greatest threat comes from the loss of hole stability in the bearing pressure affected zone (in front of the face) and in the intensive shift area of overhanging rock corbels (behind the face). Intensification of air leaks due to deformation of borehole channel leads to impoverishment of removed methane-air mixture and an increasing risk to disturb safe aerogas regime in the mining area. The paper describes a mechanism of how coal-face operations affect the state of underground holes and formation of overhanging rock corbels. A typification of basic kinds of borehole deformations is presented. Authors point out critical disadvantages of the most widely-used technological schemes of gaseous seams development under high load on the production face, which hinder normal operation of a gas drainage system. As a result of research, a dependency of shot hole number, as well as the distance between shot hole axes and the borehole, on the stress state of the borehole outline has been defined more precisely. Basing on that, a formula to calculate drilling parameters of the discharge hole system has been suggested. Implementation of these measures will allow to increase the efficiency of underground gas drainage and to maintain growing intensity of gaseous coal seam development.
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Date submitted2018-05-16
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Date accepted2018-07-22
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Date published2018-10-24
Extraction of copper, cobalt and nickel ions from aqueous solutions by extractant CYANEX 272
- Authors:
- L. A. Voropanova
- V. P. Pukhova
The extractant CYANEX 272, which active component is di(2,4,4-trimethylpentyl)-phosphinic acid (C 8 H 17 ) 2 POOH, is effective for extraction of copper (II), cobalt (II) and nickel (II) ions. The extraction of metal ions using di(2,4,4-trimethylpentyl)-phosphinic acid as an extractant is carried out due to the formation of an organophosphorus complex with wide pH range: copper at pH > 2, cobalt at pH > 3, and nickel at pH > 5. They are extracted with an organic phase: copper at pH = 3-7, cobalt at pH = 4-7, and nickel at pH = 6-9, and precipitate in the organophosphorus compound: copper at pH > 7, cobalt at pH ≥ 8, and nickel at pH ≥ 10. The possibility of separation of copper (II) and cobalt (II) is insignificant, the stripping of copper (II) and nickel (II) happens at pH = 4-6, and the stripping of cobalt (II) and any of nickel (II) – at pH = 5-6. The obtained results of ion extraction of the investigated metals can be used not only for processing of technological solutions, but also for purification of effluents from industrial enterprises and mine waters, heap and underground leaching solutions, etc. from the ions of studied metal ions.