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Date submitted2024-04-24
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Date accepted2024-09-24
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Date published2024-11-12
Study and justification of the combination of beneficiation processes for obtaining flake graphite from technogenic carbon-containing dusts
The most important task of modern production development is to provide the mineral and raw materials sector of the economy with resources included in the list of strategic raw materials, including flake graphite. In addition to natural raw materials, the source of its obtaining can be metallurgical production wastes not involved in processing. Development of metallurgical dust beneficiation technology will solve the problem of obtaining high-purity flake graphite with a crystal structure close to ideal and in demand in the production of high-tech materials. It will allow creating a renewable raw material base of graphite and utilising metallurgical production wastes. The research included the study of dust beneficiation by coarseness, magnetic and flotation methods, the influence of dust disintegration processes on beneficiation indicators. Based on the established technological properties of the components of dusts, magnetic, flotation and gravity beneficiation methods can be applied for their separation in different sequence. It is shown that dusts from different sites have different enrichability by these methods, and it should be taken into account when developing a complex technology of their processing. The degree of beneficiation increases in a row of dusts from the blast furnace shop (BF) – electric steel smelting shop (ESS) – oxygen-converter shop (OCS). The method of grinding has a significant influence on the separation indicators – at dry grinding in a centrifugal-impact mill with subsequent pneumatic classification the quality of graphite concentrates increases by 22.7 % of carbon for BF dust and by 13.48 % of carbon for ESS dust. OCS dust beneficiation indicators are high at coarse grinding with steel medium – mass fraction of carbon 96.1 %.
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Date submitted2023-11-15
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Date accepted2024-09-24
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Date published2024-12-25
Development and validation of an approach to the environmental and economic assessment of decarbonization projects in the oil and gas sector
- Authors:
- Nadezhda A. Sheveleva
This article addresses the problem of selecting a priority decarbonization project for an oil and gas company aiming to reduce greenhouse gas emissions. The wide range of decarbonization options and assessment methods prompted the development of a comprehensive ranking system for project selection. This system incorporates both internal and external factors of project implementation, a two-stage algorithm that filters out unsuitable projects taking into account sustainable development goals, and a quantitative evaluation approach using absolute and relative indicators. The proposed system evaluates decarbonization projects by considering not only the reduction of emissions in both absolute and relative terms, but also the broader environmental, social, and economic aspects relevant to the oil and gas company and the national economy. It includes a ranking mechanism for identifying priority projects and integrates carbon regulation incentives and green taxonomy tools into the economic assessment for more precise comparative analysis. The quantitative assessment in absolute terms involves a specialized net present value calculation, which accounts for revenue from both carbon credit sales and the potential sale of new low-carbon products, if applicable. The proposed assessment provides for targeted analysis of specific performance indicators, such as the cost per unit of emissions reduced, tax and social security contributions per unit of emissions reduced, energy efficiency improvements, and other indicators used for additional assessments of projects under otherwise equal conditions.
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Date submitted2024-01-31
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Date accepted2024-06-03
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Date published2024-07-04
Rationale for a possibility of using humic preparations production waste for wastewater purification from metals (Cd2+, Zn2+, Mg2+, Cu2+) aimed at developing efficient measures on environmental rehabilitation
Results of studying optimal conditions and parameters for afterpurification of underspoil waters from metal ions using humic acids production waste are presented with a view to develop the efficient measures on environmental rehabilitation of ecosystems disturbed by the development of copper pyrite deposits. The influence of contact time and waste dosage on the purification process was analysed, changes in the pH of wastewater and its impact on the growth and development of plants were studied. The key factors were identified allowing to achieve the efficiency of the purification process – the optimal contact time in the range from 120 to 180 min and waste dosage of 10 g/l. The study showed that the use of waste resulted in a neutral pH value of 7.03 compared to the initial pH value of 5.95. It was ascertained that the use of iron-magnesium production waste in combination with waste from humic preparations production made it possible to achieve the MPC of commercial fishing importance (with the exception of magnesium). Wastewater after the afterpurification process with high magnesium concentrations did not have a stimulating effect on the growth and development of Lepidium sativum L. plants. From biotesting results it can also be stated that there is no negative impact on the growth and development of Lepidium sativum L. The results obtained indicate a potentiality of using afterpurified wastewater for watering plants in the process of initiating the environmental rehabilitation of the disturbed ecosystems.
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Date submitted2024-05-02
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Date accepted2024-06-03
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Date published2024-07-04
Iron ore tailings as a raw material for Fe-Al coagulant production
The paper presents the results of experimental research into the recovery of Fe-Al coagulant from iron ore tailings (IOTs). The variables investigated in the laboratory tests included sulphuric acid concentration, temperature, leaching time, solid/liquid phase ratio (S:L) and the presence of stirring. The experiment determined the composition of the coagulant and the solid residue after leaching. The maximum iron content in the solution after leaching was obtained using 40 % H2SO4 at a temperature of 100 °C (or with stirring at 75 °C) and a contact time of 60 minutes. In this case, the iron yield was at the level of 25 % of the total content in the iron ore tailings. Chemical analysis of the solution obtained after leaching showed Fe and Al sulphate contents of 11 and 2 % respectively. In the next step, the efficiency of the coagulant was evaluated on model solutions of colour. The experimental results showed that the coagulant obtained from the iron ore tailings can be used for wastewater treatment in a wide pH range from 4 to 12 pH units. The solid residue after leaching is a fine-grained powder rich in silica, which can potentially be used as an artificial raw material in the construction industry. The research carried out in this thesis has shown that the extraction of coagulants from iron ore tailings can be considered as a way to extend the production chain of iron ore mining and to minimise the amount of tailings to be stored in tailing ponds. The technical solution presented in this work allows to comprehensively solve the problem of environmental protection by creating new target products for wastewater treatment from IOTs.
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Date submitted2024-07-04
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Date accepted2024-07-04
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Date published2024-07-04
Environmental safety and sustainable development: new approaches to wastewater treatment
In 2015, the UN member states adopted the 2030 Agenda for Sustainable Development. Despite significant progress, billions of people – one in three people – do not have access to safe, clean drinking water. Modern wastewater treatment methods include a wide range of biological, chemical and physical processes, each having its own advantages and applications. This thematic volume considers the latest achievements in wastewater treatment technologies, wastewater purification and treatment as well as their potential applications at the local level. The problem of surface water pollution is relevant for all regions of the world. One of the largest sources of pollutants is mining and processing industry. The first stage in the development of wastewater treatment technologies is monitoring of anthropogenically modified water bodies.
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Date submitted2024-03-29
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Date accepted2024-06-03
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Date published2024-07-04
Potential use of water treatment sludge for the reclamation of small-capacity sludge collectors
- Authors:
- Olga M. Guman
- Irina A. Antonova
In small settlements, collectors for the sludge produced during water treatment processes are small-sized and located in the vicinity of drinking water storage reservoirs or in coastal areas. Sludge removal is not economical. Besides, the relief depressions formed after sludge disposal are required to be reclaimed. In ore mining regions, where the main settlements of the Urals are located, sludge produced in water treatment has high contents of heavy metals typical of ore mining provinces. Consequently, places of sludge accumulation are potential sources of water pollution. The article discusses the possibility to mix sludge with slaked lime and local overburden with the help of special equipment. So far water treatment sludge in the region has been used to reclaim the surface of solid waste landfills by creating anaerobic conditions for waste decomposition. When placed inside the embankment dams as an independent object, sludge needs to be improved for the increase of its bearing capacity and the ability to bind heavy metals. The article aims at the substantiation of the composition and properties of the reclamation material made of the water treatment sludge mixed with local overburden and slaked lime (technosoil). For this reason the paper describes the composition of the sludge in a sludge collector, the composition and properties of the overburden rocks as a component of the mixtures with water treatment sludge, the composition and properties of the mixtures of water treatment sludge with overburden rocks and Ca(OH)2 as a component dewatering sludge and neutralizing toxicants. Furthermore, the research work provides the technology created for the optimal processing of the water treatment sludge in the process of the reclamation of a sludge collector. The research results and the experience obtained in reclamation of disturbed lands in the region have confirmed the possible use of technosoil for the reclamation of small-capacity sludge collectors. The analysis of the chemical composition and physical and mechanical properties of the mixtures under study has shown that the most economical and environmentally sound reclamation material is a mixture of water treatment sludge, loose overburden dump soils and Ca(OH)2 in a ratio of 60 : 30 : 10 %.
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Date submitted2023-07-25
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Date accepted2024-05-02
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Date published2024-08-26
Finite element analysis of slope failure in Ouenza open-pit iron mine, NE Algeria: causes and lessons for stability control
Slope failures in mining engineering pose significant risks to slope stability control, necessitating a thorough investigation into their root causes. This paper focuses on a back analysis of a slope failure in the Zerga section of the Ouenza – Algeria open-pit iron mine. The primary objectives are to identify the causes of slope failure, propose preventive measures, and suggest techniques to enhance stability, thereby providing crucial insights for monitoring slope stability during mining operations. The study commenced with a reconstruction of the slopes in the affected zones, followed by a numerical analysis utilizing the Shear strength reduction method within the Finite element method (SSR-FE). This approach enables the examination of slope stability under both static and dynamic loads. The dynamic load assessment incorporated an evaluation of the vibrations induced by the blasting process during excavation, introducing seismic loading into the finite element analysis. The findings reveal that the primary triggering factor for the landslide was the vibration generated by the blasting process. Furthermore, the slope stability was found to be critically compromised under static loads, highlighting a failure to adhere to exploitation operation norms. The challenging geology, particularly the presence of marl layers where maximum shear strain occurs, contributed to the formation of the landslide surface. The study not only identifies the causes of slope failure but also provides valuable lessons for effective slope stability management in mining operations.
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Date submitted2023-11-27
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Date accepted2023-12-27
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Date published2024-02-29
Physico-chemical aspects and carbon footprint of hydrogen production from water and hydrocarbons
Physico-chemical aspects determine the efficiency and competitiveness of hydrogen production technologies. The indicator of water consumption is especially relevant, since water is one of the main sources of hydrogen in almost all methods of its production. The article analyzes comparative water consumption indicators for various technologies based on published research and actual data from production plants. The volume of water consumption depends on the quality of the source water, which should be taken into account when implementing hydrogen projects in order to minimize the negative impact on the environment. Based on the operating industrial plant, the material balance of hydrogen production by steam reforming was demonstrated, which made it possible to determine the proportion of hydrogen (48.88 %) obtained from water. Currently, the carbon footprint indicator is becoming more important, reflecting greenhouse gas emissions throughout the production chain. According to the results of the total greenhouse gas emissions assessment for hydrogen production by steam reforming (about 10.03 kg CO2-eq/kg H2), the carbon footprint of hydrogen from water (4.2-4.5 kg CO2-eq/kg H2) and hydrogen from methane (15.4-15.7 kg CO2-eq/kg H2) has been determined. Consequently, almost half of the hydrogen produced by steam reforming is produced from water, corresponds to the indicators of “low-carbon” hydrogen and can be considered as “renewable” hydrogen. To make management decisions, an objective assessment in terms of energy and water costs is necessary based on a system analysis by the development of hydrogen energy and the growth of global hydrogen production. The impact of these indicators on the water cycle and global water resources will increase.
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Date submitted2023-03-16
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Date accepted2023-06-20
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Date published2023-07-19
Energy efficiency of the linear rack drive for sucker rod pumping units
- Authors:
- Oksana Yu. Ganzulenko
- Ani P. Petkova
At present, in order to increase oil production and reduce economic costs in the development of marginal fields, the development of a cluster method using compact mobile drives of sucker rod pumping units (SRPU) is relevant. The aim of the work is to analyze the ways to improve the energy efficiency of the SRPU by reducing the loss of mechanical and electrical energy, to select the most energy-efficient compact drive for the development of marginal fields in the cluster method, to carry out the kinematic and strength calculations of the drive of the selected size, to develop an adaptive control system for a group of drives in the cluster development of drillings. According to the results of the performed calculations, the linear rack-and-gear drive has the highest efficiency of the drive mechanism. The kinematic and strength calculations of a linear rack-and-gear drive with a stroke length of 1120 mm and a load of up to 8 tons are presented. It was shown that the usage of a direct torque control system and a kinetic energy storage system for the SRPU drive elements and a rod string is an effective means of reducing energy costs in oil production from marginal fields. The use of the developed system for storing and redistributing the potential energy of the rods between the SRPUs that lift oil made it possible to eliminate fluctuations in the power consumption, reduce the power peak value by three times, the peak value of the current consumed from the electric network by two times, and reduce losses in the input converter and cables by three times.
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Date submitted2022-10-23
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Date accepted2023-02-13
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Date published2023-12-25
Sorption purification of acid storage facility water from iron and titanium on organic polymeric materials
Obtaining and production of metals from natural raw materials causes a large amount of liquid, solid, and gaseous wastes of various hazard classes that have a negative impact on the environment. In the production of titanium dioxide from ilmenite concentrate, hydrolytic sulphuric acid is formed, which includes various metal cations, their main part is iron (III) and titanium (IV) cations. Hydrolytic acid waste is sent to acid storage facilities, which have a high environmental load. The article describes the technology of ion exchange wastewater treatment of acid storage facility from iron (III) and titanium (IV) cations, which form compounds with sulphate ions and components of organic waste in acidic environments. These compounds are subjected to dispersion and dust loss during the evaporation of a water technogenic facility, especially in summer season. Sorption of complex iron (III) cations [FeSO4]+ and titanyl cations TiO2+ from sulphuric acid solutions on cation exchange resins KU-2-8, Puromet MTS9580, and Puromet MTS9560 was studied. Sorption isotherms were obtained both for individual [FeSO4]+ and TiO2+ cations and in the joint presence. The values of the equilibrium constants at a temperature of 298 K and the changes in the Gibbs energy are estimated. The capacitive characteristics of the sorbent were determined for individual cations and in the joint presence.
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Date submitted2023-04-25
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Date accepted2023-04-25
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Date published2023-04-25
Ecological security and sustainability
- Authors:
- Mariya A. Pashkevich
- Alexandr S. Danilov
In 2015, UN Member States adopted the 2030 Agenda for Sustainable Development, aimed at balancing initiatives by the world community and individual countries in the environmental, social, and economic spheres. The global sustainable development goals are to promote the well-being of the world population, preserve the planet’s resources, and maintain ecological security, which is vital in the age of the rapid industrial growth and ever-increasing anthropogenic pressure on the environment. For the successful achievement of sustainability goals in the manufacturing sector, integrated measures should be undertaken for monitoring and assessing the technogenic impact of industrial facilities. Additionally, it is necessary to develop environmentally-friendly technologies in the fields of gas and water treatment, land reclamation, and waste disposal. Therefore, fundamental and applied research in these related spheres is of particular importance. Currently, environmental monitoring of all components of the environment, along with anthropogenic objects and processes, receives considerable attention, which is determined by the vector of development in science and technology. In this regard, the latest innovations in green technology in this area are becoming increasingly significant.
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Date submitted2022-10-19
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Date accepted2023-02-14
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Date published2023-04-25
Electric steelmaking dust as a raw material for coagulant production
The paper describes the issues associated with waste generated during steel production and processing, in particular the dust from electric arc furnaces (EAF). An effective solution for the disposal of such waste is its involvement in processing to obtain valuable products. This paper studies the physical and chemical properties of EAF dust produced during the smelting of metallized pellets and captured by the dust and gas cleaning system of the steel-smelting shop at the Oskol Electrometallurgical Combine, Belgorod Region. The results obtained in the study of the chemical and disperse compositions of dust, the microstructure of the surface made it possible to propose the use of dust as a raw material for coagulant production. The conditions of acid-thermal treatment of dust are determined, contributing to the partial dissolution of iron (II), (III), and aluminium compounds, which ensure the coagulation processes during wastewater treatment. Model solutions show high efficiency (> 95 %) of water treatment from heavy metal ions by modified EAF dust.
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Date submitted2022-10-17
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Date accepted2023-02-13
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Date published2023-04-25
Environmental geotechnology for low-grade ore mining with the creation of conditions for the concurrent disposal of mining waste
Due to the constantly deteriorating environmental situation in the regions with mining enterprises, the article considers the topical issue of disposing the maximum possible volume of waste from the mining and processing of low-grade ferrous ores through the creation of an effective underground environmental geotechnology. Traditional procedure with descending mining of reserves with a caving system does not allow waste to be disposed of in a gob. The idea is to use geotechnology based on the ascending order of mining the ore body, room excavation, leaving truncated pillars, and staggered arrangement of adjacent rooms in height, which makes it possible to form containers for waste disposal in the form of a cementless backfill. The main characteristics of the proposed procedure are investigated and compared with the traditional procedure of low-grade iron ores mining. It was established that from the point of view of the complete extraction of reserves and the unit costs for the preparatory-development operations, the processes are comparable, while in terms of the mining quality, the proposed option is much more efficient. Evaluation of environmental geotechnology by the criterion of waste disposal, performed according to the proposed methodology, showed that the combination of these technical solutions ensures the placement in the formed gob from 80 to 140% of all waste generated during the mining and beneficiation of low-grade iron ores.
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Date submitted2022-05-12
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Date accepted2022-11-17
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Date published2023-04-25
Microbiological remediation of oil-contaminated soils
- Authors:
- Irina D. Sozina
- Aleksandr S. Danilov
Microbiological remediation is a promising technology for the elimination of environmental contamination by oil and petroleum products, based on the use of the metabolic potential of microorganisms. The issue of environmental contamination by crude oil and its refined products is relevant in the Russian Federation since the oil industry is one of the leading sectors of the country. Mechanical and physico-chemical methods of treatment are widely used to clean oil-contaminated soils. However, the methods belonging to these groups have a number of significant drawbacks, which actualizes the development of new methods (mainly biological), since they are more environmentally friendly, cost-effective, less labor-intensive, and do not require the use of technical capacities. Various bio-based products based on strains and consortia of microorganisms have been developed that have proven effectiveness. They include certain genera of bacteria, microscopic fungi, and microalgae, substances or materials acting as sorbents of biological agents and designed to retain them in the soil and increase the efficiency of bioremediation, as well as some nutrients. Statistical data, the most effective methods, and technologies, as well as cases of using microorganisms to restore oil-contaminated soils in various climatic conditions are presented.
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Date submitted2022-04-15
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Date accepted2022-11-17
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Date published2023-04-25
Uranium in man-made carbonates on the territory of Ufa
The paper presents the results of analyzing uranium content in man-made carbonates (scale crusts) on the territory of Ufa based on examination of 42 samples. The median uranium content in the investigated samples stands at 1.44 mg/kg, which is significantly lower than the background values (scales from the Lake Baikal water, a clarke of sedimentary carbonate rocks) and data on other settlements of the Republic of Bashkortostan. Low values of uranium content are probably associated with the effects of the three leading factors, i.e. specific subsurface geology of the territory (gypsum, limestone); types of water supply; water treatment processes for the centralized type of water supply. Spatial distribution of uranium in man-made carbonates is characterized with uniformity, which is disturbed in two cases, i.e. a change of the water supply type (from centralized to individual); and material of the vessels used for boiling the water. No significant differences were detected when comparing samples of man-made carbonates associated with different sources of water supply (the bucket and infiltration types of water intake) and the types of household filters.
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Date submitted2022-05-17
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Date accepted2022-09-06
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Date published2022-11-03
Methodological substantiation of the choice for optimal modes of equipment operation during the stage-wise concentrate removal in iron ores beneficiation
- Authors:
- Alexandr S. Opalev
- Svetlana A. Alekseeva
The urgent task of improving the quality of iron ore concentrates was studied. We propose to use the stage-wise removal of the concentrate by combining fine screening, regrinding, and magnetic-gravity separation. Exemplified by magnetite ore from the Stoilensky GOK, a scientific and methodological approach to the search for optimal separation parameters and modes was substantiated. It includes several stages: studying the particle size distribution and release of useful components in the feed product to select classification parameters; a series of experiments on grinding oversize products to diverse sizes; beneficiation of the obtained products by MG separation. To select the optimal parameters of ore preparation, an analysis of the beneficiation efficiency was used, which is calculated according to the Hancock – Luyken criterion. The results of the research are experimental dependences that connect the process parameters of beneficiation with those of fine vibratory screening. For the studied ferruginous quartzite ore processed at the Stoilensky GOK, the obtained dependences can be described by a second-order polynomial with a high accuracy of approximation. The best performance is achieved with a particle size of 0.1 mm: Fe tot content in the concentrate is 69.7 %, recovery is 85 %, classification efficiency is 80.4 %. The top size of the product in this case is 0.076 mm, which corresponds to 70-73 % grinding size of –0.045 class.
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Date submitted2022-04-20
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Date accepted2022-07-21
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Date published2022-11-03
Iron ore beneficiation technologies in Russia and ways to improve their efficiency
- Authors:
- Aleksei E. Pelevin
Increasing the efficiency of crushing circuits is associated with a decrease in the particle size of finely crushed ore and the use of dry magnetic separation of crushed ore. Reducing grinding costs is achieved by using drum mills jointly with mills of other designs. The use of automation systems, slurry demagnetization, technologies with staged concentrate separation, and beneficiation and fine screening in a closed grinding cycle lead to a reduction in grinding costs. The main industrial technology for improving the quality of concentrate is its additional beneficiation using regrinding, fine screening, flotation, and magnetic-gravity separators. Increasing the integrated use of iron ore raw materials is associated with an increase in the yield of iron concentrate and the production of hematite concentrate during the beneficiation of hematite-magnetite ores and ilmenite concentrate during the beneficiation of titanomagnetite ores. Incremented concentrate yield is possible by using magnetic separators with an increased magnetic induction up to 0.25-0.5 T in the first stages of beneficiation. To obtain hematite and ilmenite concentrates, combined technologies can be used, including fine screening, high-gradient magnetic, gravity, flotation, and electrical separation.
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Date submitted2022-04-13
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Date accepted2022-05-25
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Date published2022-11-03
Mineralogical and technological features and patterns of selective disintegration of ferruginous quartzites of the Mikhailovskoye deposit
The growing demand for ferrous metallurgy products necessitates the introduction of technologies that increase the efficiency of the processing of iron-bearing raw materials. A promising trend in this area is the implementation of solutions based on the possibility of selective disintegration of ores. The purpose of this work was to establish the laws of selective disintegration of ferruginous quartzites based on the results of the study of mineralogical and technological properties of raw materials. We present data on the study of mineralogical and technological features of ferruginous quartzites of the Mikhailovskoye deposit. The data were obtained using X-ray fluorescence analysis and automated mineralogical analysis. Based on studies of the nature of dissemination and the size of grains of rock-forming and ore minerals, the tasks of ore preparation are formulated. The parameters for the iron and silicon oxide distribution by grain-size classes in the grinding products were established during the study. Based on empirical dependences, the grain size of grinding was predicted, at which the most effective release of intergrowths of ore minerals and their minimum transition to the size class of –44 µm should be achieved.
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Date submitted2021-03-31
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Date accepted2022-04-26
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Date published2022-11-03
Features of obtaining metallurgical products in the solid-state hydride synthesis conditions
- Authors:
- Andrey G. Syrkov
- Lyudmila A. Yachmenova
A scientific substantiation of solid-phase feedstock choice and preparation has been carried out, and the thermodynamic and kinetic aspects of solid-state hydride synthesis (SHS) of metal products have been analyzed using the nickel dichloride reduction as an example. The preliminary dehydration modes and methods for controlling the complete removal of crystalline water from chloride raw materials and Olenegorsk superconcentrate, which is natural oxide raw material, are described. Conditions, including initial solid chloride particle sizes, are established under which diffusion complications of reduction to metal in methyldichlorosilane vapor are minimized. Thermodynamic estimates of nickel chlorides and oxides reduction possibility, iron and copper with ammonia and methane at temperatures of 400-1000 K in equilibrium conditions have been carried out. It has been shown that the stoichiometric coefficients of the nickel dichloride in ammonia overall reduction reaction calculated by thermodynamic modeling are in agreement with experimental data. In contrast to the copper dichloride reduction, for nickel dichloride the formation of metal monochloride at the intermediate stage is uncharacteristic, which is associated with a higher thermal stability of nickel dichloride. The main kinetic regularities of the reduction of nickel, copper, and iron to metal under SHS conditions in ammonia, monosilane, and methane, as well as the nickel dichloride with methyldichlorosilane vapor and methane successive reduction, are considered. Approximation of experimental data by topochemical equations in a linear form showed that for reduction degrees a up to 0.7-0.8, these data are satisfactorily described by the Roginsky – Schultz equation. For a > 0,8 the “shrinking sphere” model works better, which confirms the localization of the solid-state reduction reaction at the interface, moves deep into the crystal with the formation of a of interlocked metal germs. The importance and prospects of the results obtained for the theory development of metallurgical processes, deep complex processing of natural iron oxide raw materials, metal products and new generation materials production, including superhydrophobic ones, are discussed. The relevance of the study from the point of view of applying the method of physical and chemical analysis to the study of complex heterogeneous metallurgical processes is noted.
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Date submitted2021-04-20
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Date accepted2022-04-26
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Date published2022-07-13
Prediction of the stress-strain state and stability of the front of tunnel face at the intersection of disturbed zones of the soil mass
The article presents a numerical solution of the spatial elastic-plastic problem of determining the stability of the tunnel face soils at the intersection of disturbed zones of the soil mass. The relevance of the study is related to the need to take into account the zones of disturbed soils when assessing the face stability to calculate the parameters of the support. Based on the finite element method implemented in the PLAXIS 3D software package, the construction of a finite element system "soil mass-disturbance-face support" and modeling of the intersection of the disturbed zones of the soil mass were performed. To assess the condition of soils, deformation and strength criteria are taken. The deformation criterion is expressed by the value of the calculated displacement of the tunnel contour in the face, and the strength criterion - by the safety coefficient until the maximum values of the stress state are reached according to the Coulomb–Mohr criterion. The results of the study are presented in the form of histograms of the safety coefficient dependences on the distance to the disturbance at different bending stiffness of the face support structure, as well as the isofields of deformation development. The parameters of rockfall formation in the face zone at the intersection of zones of disturbed soils were determined. The local decrease in strength and deformation properties in the rock mass along the tunnel track should be taken into account when assessing the stability of the tunnel face and calculating the parameters of the support. Within the framework of the constructed closed system, a qualitative agreement of the simulation results with the case of a collapse in the face during the construction of the Vladimirskaya-2 station of the St. Petersburg Metro was obtained.
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Date submitted2021-10-08
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Date accepted2022-01-24
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Date published2022-04-29
Methodology for thermal desorption treatment of local soil pollution by oil products at the facilities of the mineral resource industry
- Authors:
- Mariya A. Pashkevich
- Marina V. Bykova
The analysis of the main environmental consequences of leaks and local spills of petroleum products at the enterprises of the mineral resource complex is presented. It is established that the problem of soil contamination with petroleum products at the facilities of the mineral resource complex and enterprises of other industries is caused by significant volumes of consumption of the main types of oil products. Based on the results of the author's previous field research, a series of experiments was carried out, consisting in modeling artificial soil pollution with petroleum products such as gasoline, diesel fuel, highly refined oil, motor oil, and transmission oil, followed by their purification by heat treatment at temperatures of 150, 200, and 250 °C. The 250 °C limit of the heating temperature was set due to the need to partially preserve the structure and quality of the soil after heat treatment to preserve its fertility. When the processing temperature rises to 450 °C, all humates are completely burned out and, as a result, productivity is lost. Confirmation is provided by the results of experiments to determine the humus content in uncontaminated soil and soil treated at different temperatures. It was found that at a maximum processing temperature of 250 °C, about 50 % of the initial organic carbon content is preserved. According to the results of the conducted experimental studies, the dependences of the required processing temperature on the concentration of petroleum products to reduce the concentration of petroleum products to an acceptable level have been established. The methodology of thermal desorption cleaning of soils with varying degrees of contamination at enterprises of the mineral resource complex is presented.
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Date submitted2021-03-11
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Date accepted2021-04-12
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Date published2022-04-29
Operation mode selection algorithm development of a wind-diesel power plant supply complex
- Authors:
- Yaroslav E. Shklyarskiy
- Daria E. Batueva
The power supply system is affected by external disturbances, so it should be stable and operate normally in compliance with power quality standards. The power supply system goes into abnormal modes operation when, after a short-term failure or disturbance, it does not restore normal mode. The electrical complex, which includes a wind power plant, as well as a battery and a diesel generator connected in parallel, is able to provide reliable power supply to consumers which meets the power quality indicators. The article develops an algorithm that is implemented by an automatic control system to select the operating mode depending on climatic factors (wind) and the forecast of energy consumption for the day ahead. Forecast data is selected based on the choice of the methods, which will have the smallest forecast error. It is concluded that if the energy consumption forecast data is added to the automatic control system, then it will be possible to increase the efficiency of the power supply complex. In the developed algorithm the verification of normal and abnormal modes of operation is considered based on the stability theory. The criteria for assessing the normal mode of operation are identified, as well as the indicators of the object’s load schedules for assessing the load of power supply sources and the quality standards for power supply to consumers for ranking the load by priority under critical operating conditions and restoring normal operation are considered.
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Date submitted2021-03-30
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Date accepted2021-07-27
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Date published2021-10-21
Integrated development of iron ore deposits based on competitive underground geotechnologies
- Authors:
- Vladimir L. Trushko
- Olga V. Trushko
The article presents an analytical review of the current state of the iron ore base of the ferrous metallurgy of Russia and the world, identifies the largest iron ore provinces and iron ore producers. The promising directions of development and improvement of the quality of the iron ore base of Russia and the features of the development of new deposits of rich iron ores are identified. Effective technologies for the development of rich iron ores deposits that ensure an increase in production volumes are proposed. The geomechanical justification of rational technological parameters that are easily adapted to changes in mining and geological conditions has been performed. Based on the results of field studies, the use of an elastic-plastic model with the Coulomb – Mohr strength criterion for modeling changes in the stress-strain state of an ore rock mass during mining operations is justified and recommendations for ensuring the stability of mine workings are developed. Effective engineering and technical solutions for the complex development and deep processing of rich iron ores with the production of fractionated sinter ore, which increases the efficiency of metallurgical processes, the production of high-grade iron oxide pigments and iron ore briquettes, which increase the competitiveness of iron ore companies and the full use of the resource potential of deposits, are presented.
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Date submitted2021-03-31
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Date accepted2021-09-29
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Date published2021-10-21
Methodology of modeling nonlinear geomechanical processes in blocky and layered rock masses on models made of equivalent materials
- Authors:
- Boris Yu. Zuev
The research purpose is to develop a methodology that increases the reliability of reproduction and research on models made of equivalent materials of complex nonlinear processes of deformation and destruction of structured rock masses under the influence of underground mining operations to provide a more accurate prediction of the occurrence of dangerous phenomena and assessment of their consequences. New approaches to similarity criterion based on the fundamental laws of thermodynamics; new types of equivalent materials that meet these criteria; systems for the formation of various initial and boundary conditions regulated by specially developed computer programs; new technical means for more reliable determination of stresses in models; new methods for solving inverse geomechanical problems in the absence of the necessary initial field data have been developed. Using the developed methodology, a number of complex nonlinear problems have been solved related to estimates of the oscillatory nature of changes in the bearing pressure during dynamic roof collapse processes; ranges of changes in the frequency of processes during deformation and destruction of rock mass elements, ranges of changes in their accelerations; parameters of shifts with a violation of the continuity of the rock mass under the influence of mining: secant cracks, delaminations, gaping voids, accounting for which is necessary to assess the danger of the formation of continuous water supply canals in the water-protection layer.
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Date submitted2020-07-29
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Date accepted2021-03-29
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Date published2021-09-20
Critical analysis of methodological approaches to assessing sustainability of arctic oil and gas projects
Development of hydrocarbon resources in the Arctic is one of the priority tasks for the economy of the Russian Federation; however, such projects are associated with significant risks for the environment of nearby regions. Large-scale development of hydrocarbon resources in the Arctic should be based on the principles of sustainable development, which imply a balance between socio-economic benefits and environmental risks. The purpose of this study is to analyze the gaps in scientific knowledge on the issues of assessing sustainability of Arctic oil and gas projects (OGPs) and systematize the key problematic elements of such assessments. The analysis was carried out in terms of four key elements that determine the feasibility of implementing Arctic OGPs in the context of sustainable development: economic efficiency, social effects, environmental safety and technological availability. The methodology for conducting bibliometric analysis, which included more than 15.227 sources from the Scopus database over the period of 2005-2020, was based on PRISMA recommendations for compiling systematic reviews and meta-analyses. Methodological problems of assessing sustainability of Arctic OGPs were mapped and divided into four key sectors: consideration of factors that determine sustainability; sustainability assessment; interpretation of assessment results; sustainability management. This map can serve as a basis for conducting a series of point studies, aimed at eliminating existing methodological shortcomings of the sustainable development concept with respect to Arctic OGPs.