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Date submitted2024-05-08
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Date accepted2024-11-07
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Date published2025-04-25
The effect of mechanical and thermal treatment on the characteristics of saponite-containing material
Solving the problems of modern building materials science is reduced to obtaining high-quality materials, expanding and searching for a rational raw material base, which can be carried out through the use of various industrial wastes. In this paper, the possibility of using waste from the mining industry – saponite-containing material (SCM) obtained during the enrichment of kimberlite ores from the Lomonosov diamond deposit, as an active mineral additive for cement binders and concretes is considered. The influence of mechanical and thermal treatment on a number of properties of the material selected from the tailings dump and in its initial state was studied. The study of the surface activity of SCM samples consisted in determining the sorption capacity, acid-base centers and their distribution. An increase in the activity of the surface of the material particles as a result of mechanical activation and its decrease during temperature treatment were determined. These effects are associated with phase rearrangements and structural changes in the sandy-clay rock, which was confirmed during thermal analysis. The temperature effect has no pronounced effect on the microstructure, the “smoothness” of the particles and the formation of a consolidated surface of the structural elements of the saponite-containing material are noted.
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Date submitted2024-03-11
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Date accepted2024-11-07
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Date published2025-04-25
Geochemical characteristics of weathering crusts on the Dzhezhimparma Ridge and the Nemskaya Upland (South Timan)
Numerous local varieties of weathering crusts are known in the South Timan. They differ in their position in the section, type of weathering products, substrates, and occurrence. The aim of the research is to identify patterns in the distribution of rock-forming, rare and rare earth elements and the composition of clay minerals in clay formations of the weathering crusts. The main task is to describe the occurrence and geochemical features that enable determining the genetic type and formation conditions of weathering crusts. The paper presents the results of a study of the distribution of petrogenic, rare earth, rare elements, and clay minerals in weathering crust of different ages, genetic types and occurrence conditions on the Dzhezhimparma Ridge and the Nemskaya Upland in the South Timan. We found that hydromica-kaolinite-type weathering crust is developed after the Late Riphean Dzhezhim Fm. rocks in the basement-cover contact zone on the Dzhezhimparma Upland, and the layer of fine-grained rock at the base of the Devonian section previously considered a weathering crust was formed as a result of mechanical destruction of the Devonian sandstones during movement in the thrust zone. In the Vadyavozh quarry located on the Nemskaya Upland, we studied and described the formations of Mesozoic-Cenozoic areal and linear weathering crusts after the Late Riphean Dzhezhim Fm. rocks. We found that micaceous siltstones in the siltstone-sandstone strata of the Dzhezhim Fm. are associated with the Riphean stage of crust formation and are composed of weathering crust material redeposited in the epicontinental basin.
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Date submitted2023-10-28
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Date accepted2024-11-07
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Date published2025-02-25
Radiation characteristics of coals at different stages of metamorphism
The formation of deposits and subsequent metamorphic processes that affect concentrations of radioactive elements in coal can indicate ongoing geological activities, therefore, analyzing trends in the radiation characteristics of coal throughout the metamorphic series is highly relevant. The aim of this work is to experimentally evaluate the radiation characteristics of different coal ranks (metamorphic stages) using thermoluminescent (TL) dosimetry and beta activity measurements, and to identify correlations between these radiation characteristics and data obtained from technical, elemental, and thermogravimetric analyses, as well as mass spectrometric and electron paramagnetic resonance spectroscopy (EPR) measurements. For dosimetric measurements that indirectly characterize the content of radionuclides in coal, a modified dosimetric complex and original soil-equivalent thermoluminescent detectors based on SiO2 were used. The analysis of the obtained results supports the use of TL studies to determine the ash content of coals at low and medium stages of metamorphism (coal rank B→G), while indicating that this method is not feasible for coals at higher stages of metamorphism. The correlation dependencies in the metamorphism series suggest abrupt change in the conditions of coal formation during the time range corresponding to transformation from high to low volatile bituminous coals (coal rank G→Zh→K). These abrupt changes in regional metamorphism conditions (time, temperature, pressure, oxidation-reduction conditions) are confined to the boundary of the Permian and Triassic periods (~250 million years ago), during which both the transformation of existing coal deposits and the formation of new deposits occurred.
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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 submitted2024-04-22
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Date accepted2024-06-13
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Date published2024-07-04
Lithification of leachate from municipal solid waste landfills with blast furnace slag
- Authors:
- Mariya A. Pashkevich
- Yuliya A. Kulikova
The article presents an alternative method of utilization of blast furnace slag and leachate from solid municipal waste landfills, the formation of which occurs during the infiltration of atmospheric precipitation through the thickness of deposited waste. The method is based on the conversion of leachate from the liquid phase to the solid aggregate state by lithification using blast furnace slag as an astringent material. The hydraulic activity of slag, which depends on the amount of oxides contained in it, has been estimated. The investigated slag belongs to the 3rd grade, which confirms the possibility of its use as an astringent material. The filtrate was analyzed for the content of various elements, and the maximum permissible concentrations for each element were found to be exceeded. Chemical and biological oxygen demand were determined, and critically high values were installed (17200 mgO2/l and 4750 mgO2/l, respectively). The lithification process was divided into two stages. The first stage was to reduce the organic component in the filtrate using a coagulant, aluminum sulfate; the second stage was slag hydration. The optimum ratio of lithificate components in terms of mixture solidification rate was established at 1:0.03:1.25 (leachate, coagulant, blast furnace slag). The obtained material was analyzed for the solubility and content of various forms of metal. It is established that at infiltration of atmospheric precipitations through lithificate only 3 % of material will be washed out; concentrations of gross and mobile forms of heavy metals do not exceed the maximum permissible, except for the gross content of arsenic, mobile, and water-soluble forms of which were not found. The values of chemical (687 mgO2/l) and biological (173 mgO2/l) oxygen demand in the aqueous extract from lithificate decreased more than 25 times in comparison with the initial filtrate. According to the results of toxicological studies, lithificate was assigned an IV class of waste hazard, which confirms the possibility of its use as bulk material at landfills.
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Date submitted2024-04-25
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Date accepted2024-06-13
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Date published2024-07-11
Evaluation of the effectiveness of neutralization and purification of acidic waters from metals with ash when using alternative fuels from municipal waste
- Authors:
- Polina A. Kharko
- Aleksandr S. Danilov
The problem of pollution of natural water objects with heavy metals is extremely relevant for the areas where industrial enterprises are located. Unauthorized discharge of contaminated wastewater, inefficient operation of sewage treatment plants, as well as leakage of drainage waters from man-made massifs lead to changes in the hydrological system affecting living objects. The article studies the composition of ash from the combustion of alternative fuels from municipal waste, and also considers the possibility of using it to neutralize sulfuric acid drainage waters and extract metal ions (Cu, Cd, Fe, Mn, Zn) from them. It has been established that the efficiency of water purification from metals depends on the pH value achieved during the purification process. The pH value is regulated by the dose of the introduced ash, the contact time and depends on the initial concentration of metal ions and sulfates in the solution. Studies on the neutralization and purification of a model solution of sulfuric acid drainage waters of a tailings farm of known composition have shown that in order to achieve a pH of 8-9, optimal for precipitation of metal hydroxides Cu, Cd, Fe, Mn, Zn and Al washed out of ash, and water purification with an efficiency of 96.60 to 99.99 %, it is necessary to add 15 g/l of ash and stir the suspension continuously for 35 minutes. It was revealed that exposure to ash with sulfuric acid waters leads to the transition of water-soluble forms of metals into insoluble ones and their “cementation” with calcium sulfate. The amount of Zn and Fe ions washed out of the ash decreases by 82 and 77 %, Al, Cd, Cu, Mn – by 25 %. This reduces the toxicity of ash, which is proved by a decrease in the toxic multiplicity of dilution of the water extract by 14 times.
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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 submitted2023-04-11
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Date accepted2023-10-25
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Date published2024-07-04
Acid mine water treatment using neutralizer with adsorbent material
One of the biggest issues in the mining sector is due to acid mine drainage, especially in those abandoned mining operations and active ones that fail to adequately control the quality of their water discharge. The removal degree of copper, iron, lead, and zinc dissolved metals in acid mine drainage was investigated by applying different proportions of mixtures based on neutralizing reagent hydrated lime at 67 % calcium oxide (CaO), with adsorbent material – natural sodium bentonite, compared to the application of neutralizing reagent without mixing, commonly used in the neutralization of acid mining drainage. The obtained results show that the removal degree of dissolved metals in acid mine drainage when treated with a mixture of neutralizing reagent and adsorbent material in a certain proportion, reaches discharge quality, complying with the environmental standard (Maximum Permissible Limit), at a lower pH than when neutralizing material is applied without mixing, registering a net decrease in the consumption unit of neutralizing agent express on 1 kg/m3 of acid mine drainage. Furthermore, the sludge produced in the treatment with a mixture of the neutralizing reagent with adsorbent material has better characteristics than common sludge without bentonite, since it is more suitable for use as cover material, reducing the surface infiltration degree of water into the applied deposit.
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Date submitted2022-09-26
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Date accepted2023-09-20
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Date published2024-04-25
Technology of absorption elimination with cross-linking plugging material based on cement and cross-linked polymer
The peculiarity of the geological structure of carbonate reservoirs is their complex permeability and porosity characteristics, reflecting the simultaneous presence of cavities variety (fractures, caverns, pores). Loss of circulation during penetration of fractured rock intervals significantly increases well construction time due to lack of efficient plugging isolation compositions. The main disadvantages of traditional compositions are high sensitivity to dilution in the process of their injection into the absorption zone, as well as insufficient structural strength to prevent the isolation composition from spreading during the induction period. For efficient isolation of catastrophic absorption zones in conditions of high opening of absorption channels a new cross-linking plugging isolation composition has been developed, which allows to exclude disadvantages of traditional isolation compositions. Application of the composition will allow to reduce the injection volume of the isolation composition and the time of isolation works due to its resistance to dilution and movement of formation water in the absorption interval.
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Date submitted2021-05-08
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Date accepted2022-07-21
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Date published2023-12-25
Technologies of intensive development of potash seams by longwall faces at great depths: current problems, areas of improvement
- Authors:
- Vladimir P. Zubov
- Denis G. Sokol
The results of the analysis of practical experience in the development of potash seams using longwall mining systems at the mines of OAO “Belaruskali” are presented. Positive changes in the technical and economic indicators of mines and an increase in the safety of mining operations were noted with the introduction of resource-saving technologies without leaving the pillars between the excavation columns or with leaving the pillars between the columns with dimensions at which they are destroyed by mining pressure in the goaf. It is noted that the use of mechanized stoping complexes characterized by high energy capacity, combined with large depths of development, is the main reason for the temperature increase in longwalls to values exceeding the maximum permissible air temperature regulated by sanitary standards. Based on production studies, it was concluded that the temperature regime along the length of the longwall face is determined by the temperature of rocks in the developed longwall space, heat emissions from the equipment of the power train, and the temperature of the rock mass ahead of the longwall. The conclusion has been drawn about the feasibility of using developed technological schemes in deep mining conditions, which provide a reduction in longwall temperature by 6-9 °C or more through isolated ventilation of longwall and power trains, as well as heat exchange between the airflow entering the longwall and the rocks in the developed space.
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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 submitted2022-10-31
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Date accepted2023-03-02
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Date published2023-12-25
Lightweight ash-based concrete production as a promising way of technogenic product utilization (on the example of sewage treatment waste)
- Authors:
- Tatyana E. Litvinova
- Denis V. Suchkov
The study is devoted to the development of a method for the technogenic raw materials utilization. Special attention is paid to the prospect of involving products based on them in the production of new building materials. The results of Russian and foreign studies on the reuse of wastes, such as phosphogypsum, metallurgical slag, waste from municipal and industrial wastewater treatment, etc., in the building materials industry are considered. It has been established that the use of incinerated sewage sludge ash in construction is a promising direction in terms of environmental and economic efficiency. The research confirmed the compliance of the lightweight ash-based concrete components to the regulatory documentation requirements for a number of indicators. As a result of the research, the composition of the raw mixture for the lightweight concrete production with incinerated sewage sludge ash as a replacement for a part of the cement has been developed. In terms of parameters, the developed concrete corresponds to standard lightweight concrete, marked in accordance with the regulatory documents of the Russian Federation as D1300 (density not less than 1.3 g/cm3), Btb2 (flexural strength not less than 2 MPa), M200/B15 (compressive strength not less than 15 MPa). Lightweight ash-based concrete is suitable for use in construction, repair of roads and improvement of urban areas.
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Date submitted2022-11-08
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Date accepted2022-11-21
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Date published2023-02-27
Assessment of the role of the state in the management of mineral resources
Mineral resources as natural capital can be transformed into human, social and physical capital that guarantees the sustainable development of a country, exclusively through professional public management. Public management of a country's mineral resource potential is seen as an element of transnational governance which provides for the use of laws, rules and regulations within the jurisdictional and sectoral capabilities of the state, minimising its involvement as a producer of minerals. The features of the ideology of economic liberalism, which polarises the societies of mineral-producing countries and denies the role of the state as a market participant, have been studied. The analysis of the influence of the radical new order of neoliberal world ideology on the development of the extractive sector and state regulation has been 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 submitted2022-06-17
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Date accepted2022-10-18
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Date published2022-11-03
Scientific experimental bases for dry beneficiation of mineral ores
The article presents the results of research on the development of processes and equipment for ore preparation and pneumatic dry beneficiation of mineral ores. The methods of crushing and grinding before enrichment of minerals have been considered, dry enrichment of geomaterials is investigated. Highly efficient prototypes of beneficiation equipment are developed and tested: crushers of multiple dynamic impact RD-MDV-900, DKD-300, centrifugal grinders CMVU-800 and VCI-12, pneumatic separator POS-2000. Fundamental designs are created, and a number of new ore preparation and pneumatic beneficiation instruments are being designed. The efficiency of approbation of an autonomous dry beneficiation complex with new safe environmental standards for the processing of gold-bearing ores, which makes it possible to fully release and extract free gold with a particle size from 10,000 to 100 µm, is shown. The introduction of the dry beneficiation method is very promising for the mining industry. It will allow to reduce capital costs for the construction of stationary beneficiation plants, completely or partially withdraw from the use of process water, the construction of a water supply system, a traditional tailing dam, etc.
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Date submitted2022-05-17
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Date accepted2022-09-06
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Date published2022-11-03
On the need to classify rock mass fed to dry magnetic separation
The hypothesis of a possible use of dry magnetic separation is substantiated on the example of ores from ferruginous quartzite deposits operated by plants of PAO “Severstal” Holding. Size class of ore after medium crushing is –80+0 mm when the vibrating feeder is used for feeding ore mass to the separation zone. The rationale is based on the analysis of video recording of physical simulation on a laboratory drum magnetic separator of SMBS-L series, in the VSDC Video Editor, and simulation modelling of dry magnetic separation on its virtual prototype in Rocky DEM software package. It has been proved that the use of a vibrating feeder for feeding the material to the working area of a magnetic separator makes it possible to: form a monolayer on the surface of the vibrating feeder chute with a thickness close to the maximum size of a lump of separated ore; implement batch feed of material to the separation zone; increase the spacing between lumps in the separation zone when passing through the free fall area, thereby allowing dry magnetic separation of ferruginous quartzites of size class –80+0 mm without pre-preparation.
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Date submitted2022-05-13
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Date accepted2022-09-24
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Date published2022-11-03
Rapid detection of coal ash based on machine learning and X-ray fluorescence
Real-time testing of coal ash plays a vital role in the chemical, power generation, metallurgical, and coal separation sectors. The rapid online testing of coal ash using radiation measurement as the mainstream technology has problems such as strict coal sample requirements, poor radiation safety, low accuracy, and complicated equipment replacement. In this study, an intelligent detection technique based on feed-forward neural networks and improved particle swarm optimization (IPSO-FNN) is proposed to predict coal quality ash content in a fast, accurate, safe，and convenient manner. The data set was obtained by testing the elemental content of 198 coal samples with X-ray fluorescence (XRF). The types of input elements for machine learning (Si, Al, Fe, K, Ca, Mg, Ti, Zn, Na, P) were determined by combining the X-ray photoelectron spectroscopy (XPS) data with the change in the physical phase of each element in the coal samples during combustion. The mean squared error and coefficient of determination were chosen as the performance measures for the model. The results show that the IPSO algorithm is useful in adjusting the optimal number of nodes in the hidden layer. The IPSO-FNN model has strong prediction ability and good accuracy in coal ash prediction. The effect of the input element content of the IPSO-FNN model on the ash content was investigated, and it was found that the potassium content was the most significant factor affecting the ash content. This study is essential for real-time online, accurate, and fast prediction of coal ash.
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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 submitted2022-03-03
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Date accepted2022-04-27
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Date published2022-07-26
Peculiarities of rare-metal mineralization and genetic relationship of mineral associations in the eastern rim of Murzinsko-Aduysky anticlinorium (the Ural Emerald Belt)
- Authors:
- Mikhail P. Popov
The paper presents features of the location and composition, as well as a generalization of data on the age of rare-metal mineralization developed at the deposits and occurrences of rare metals and gemstones in the eastern rim of Murzinsko-Aduysky anticlinorium, within the Ural Emerald Belt, which is a classic ore and mineralogical object and has been studied for almost two hundred years. With a significant number and variety of prospecting, research and scientific works devoted mainly to emerald-bearing mica complexes and beryl mineralization, as well as rare-metal pegmatites, scientific literature has so far lacked generalizations on the formation of numerous mineral associations and ore formations that represents a uniform genetic process in this ore district. The aim of the work is a comprehensive geological-mineralogical analysis of mineral associations of the eastern rim of Murzinsko-Aduysky anticlinorium and studying their age, formation conditions and characteristic features to determine the possibility of expanding and using the mineral resource base of the Urals through developing new prognostic and prospecting criteria for rare-metal and gemstone ore formations and creating the new devices for promising objects prospecting
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Date submitted2022-03-14
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Date accepted2022-05-13
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Date published2022-07-26
Unique titanium Deposits of Timan: genesis and age issues
The article critically analysesthe hypotheses about the formation, age, and sources of material of large Timan titanium deposits, which were previously considered ancient buried placers formed along the weathering crusts of the Riphean shales. We discuss an alternative hydrothermal-metamorphic hypothesis about the formation of these deposits and the source of ore material. It is established that the incoming zircon of different ages (570-3200 Ma), as well as two other geochronometers, rutile and monazite, underwent a thermal effect common for all varieties as a result of a hydrothermal process about 600 Ma ago. According to modern concepts, the closing temperature of the U-Pb system in rutile exceeds 500 °С, which suggests high-temperature conditions for the hydrothermal processing of rutile during the formation of the considered deposits in the Riphean.
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Date submitted2021-04-19
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Date accepted2022-05-25
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Date published2022-07-13
Development of the technology of stowing the developed space during mining
- Authors:
- Evgenii R. Kovalskii
- Kirill V. Gromtsev
An analysis of the world experience in the development of potash deposits shows that the main problems arising during their development are a high level of mineral losses, an increased risk of flooding of mine workings as a result of water-proof layer discontinuance and the development of emergency water inflows in the mined-out spaces. Reduction of potash ore losses can be achieved by using a long-pillar mining system, but this method is limited by the peculiarities of the geological structure of the potash deposits and the need to preserve the continuity of the water-proof layer during its underworking. The safety of underworking of the water-proof layer can be improved by using the stowing of the developed longwall space. However, the question of the influence of the stowing on the height of the zone of water supply cracks development remains little-studied. The world experience of stowing the developed spaces in the development of layers with long pillars is analyzed and the technology of placing the stowing masses, which can solve these problems, is proposed. The considered technology and the proposed solutions are supported by laboratory tests of stowing materials and mathematical modeling of deformation zones in the overlying rocks.
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Date submitted2021-09-02
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Date accepted2022-01-24
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Date published2022-04-29
Complex processing of high-carbon ash and slag waste
The paper considers a current issue of ash and slag processing for the Polyus Aldan JSC, that has accumulated over 1 million tons of this waste. Following the results of the review of Russian and foreign literature, four promising areas of their use were selected: road construction, building materials, reclamation of disturbed lands, and inert aggregates. To assess the possibility of implementing the selected disposal directions, the samples of ash and slag waste of the enterprise were sampled and analyzed. Fuel characteristics, chemical and mineral composition, as well as physico-chemical and mechanical properties of waste were determined. Taking into account the results of complex laboratory studies and the requirements of regulatory documents, each of the selected areas of using ash and slag waste was evaluated. It was found that their disposal by traditional methods has limitations, mainly related to the high content of unburned fuel residues. The high content of combustible substances and the high specific heat of combustion with a relatively low ash content suggested the possibility of thermal disposal of the studied waste. Based on the literature data, the characteristics of the preparation of organic coal-water suspensions based on the studied ash and slag waste were selected. As a result of a series of experiments on their flaring, the expediency of using the obtained fuel at the enterprise under consideration has been proved. The authors note the possibility of using ash obtained after thermal waste disposal in the road construction industry. The prospects for further research of technologies for the preparation and combustion modes of suspension fuel based on ash and slag waste are determined.
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Date submitted2021-06-24
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Date accepted2021-11-30
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Date published2021-12-27
Development of a methodology to assess the hydrocyclone process with account of the rheological properties of the mineral slurry
- Authors:
- Tatiana N. Aleksandrova
- Vadim A. Potemkin
The paper studies the possibility of assessing the separation of mineral raw materials, taking into account the rheology of the mineral slurry. The ores of the Mayskoye deposit were chosen as the object of the study, characterized by a thin impregnation of the valuable component – gold in the host minerals, which determines the use of fine and ultrafine milling. This fact is essential because the presence of a fine grade seriously affects the rheology of the mineral slurry used in subsequent mineral processing stages. This predetermines the necessity to take into account rheological parameters. The research performed provides the development of a methodology for assessing the separation of minerals in the hydrocyclone based on the interpretation of numerical and mathematical modeling data. using the object-oriented programming language Python, a program for calculating empirical coefficients of the rheological equation, theoretically describing the dynamics of internal transformations of the mineral slurry, was developed. Taking into account the process parameters of the laboratory unit with hydrocyclone and ore properties, three concentrations of solids in the mineral slurry were selected, conditionally corresponding to the minimum, average and maximum values. Rheological equations successively composed for three concentrations, i.e., 400, 500, and 700 g/l, made it possible to calculate the critical shear rates corresponding to the maximum dispersion of the mineral slurry in the hydrocyclone flow. Subsequent numerical simulation using Ansys Fluent software, as well as statistical evaluation of the shear rates at different levels of solids content showed that the shear rate profile in the cross-section of the hydrocyclone corresponding to the maximum dispersion of the mineral slurry is obtained at the content of 400 g/l.
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Date submitted2021-06-17
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Date accepted2021-10-18
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Date published2021-12-16
Dissolution kinetics of rare earth metal phosphates in carbonate solutions of alkali metals
- Authors:
- Tatyana E. Litvinova
- Ivan L. Oleynik
Treatment of apatite raw materials is associated with the formation of large-tonnage waste – phosphogypsum. The content of rare earth metals in such waste reaches 1 %, which makes it possible to consider it a technogenic source for obtaining rare earth metals and their compounds. Up to the present moment, there are neither processing plants, nor an efficient process flow to handle phosphogypsum dumps. It is rational to use a way that involves extraction of valuable components and overall reduction of phosphogypsum dumps. Such process flow is available with carbonate conversion of phosphogypsum to alkali metal or ammonium sulfate and calcium carbonate upon the condition of associated extraction of rare earth metal (REM) compounds. Associated extraction of REM compounds becomes possible since they form strong and stable complexes with hard bases according to Pearson, which among other things include carbonate, phosphate and sulfate anions. Formation of lanthanide complexes with inorganic oxygen-containing anions is facilitated by the formation of high-energy Ln-O bonds. The study focuses on the dissolution of lanthanide phosphates in carbonate media. It was established that formation of REM carbonate complexes from their phosphates is a spontaneous endothermic process and that formation of lanthanide carbonates and hydroxides serves as thermodynamic limitation of dissolution. A shift in equilibrium towards the formation of carbonate complexes is achieved by increasing the temperature to 90-100 °C and providing an excess of carbonate. The limiting stage of REM phosphate dissolution in carbonate media is external diffusion. This is indicated by increasing rate of the process with an intensification of stirring, first order of the reaction and the value of activation energy for phosphate dissolution from 27 to 60 kJ/mol. A combination of physical and chemical parameters of the process allowed to develop an engineering solution for associated REM extraction during carbonate conversion of phosphogypsum, which included a 4-5 h conversion of phosphogypsum at temperature of 90-110 °C by an alkali metal or ammonium carbonate solution with a concentration of 2-3 mol/l. As a result, a solution with alkali metal (ammonium) sulfate is obtained, which contains REMs in the form of carbonate complexes and calcium carbonate. The rate of REM extraction into the solution reaches no less than 93 %. Rare earth metals are separated from the mother liquor by precipitation or sorption on anion exchange resins, while the excess of alkali metal or ammonium carbonate is returned to the start of the process.
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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.