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Date submitted2024-03-30
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Date accepted2024-06-03
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Date published2024-07-04
Preparation and use of complex titanium-containing coagulant from quartz-leucoxene concentrate
- Authors:
- Evgenii N. Kuzin
The search for the new high-efficiency reagents for wastewater treatment is a challenging and urgent task. Titanium-containing coagulants represent a new trend in water treatment and have a much higher efficiency that the traditional aluminium and iron-containing coagulants. The high cost of reagents significantly hinders their implementation. Complex titanium-containing reagents are coagulants prepared by modifying the traditional coagulants by adding 2.5-10.0 wt.% titanium compounds. In this work, titanium tetrachloride prepared from quartz-leucoxene concentrate was prehydrolyzed with subsequent double decomposition with sulfuric acid. The resulting mixture of hydrochloric and sulfuric acids was neutralized with aluminium hydroxide/oxide to form a self-hardening mixture (chemical dehydration). The sample of a complex sulfate-chloride titanium-containing coagulant was a mixture of AlCl3·6H2O – 5-20 wt.%, Al2(SO4)3·18H2O – 70-90 wt.% and TiOSO4 – 2.5-10.0 wt.%. It was proved that by changing the ratio of aluminium oxide/hydroxide and titanium tetrachloride at the stage of prehydrolysis and double decomposition, it is possible to obtain samples of a complex coagulant with different contents of the modifying additive of titanium compounds. An assessment of the coagulation properties of the complex reagent demonstrated its higher efficiency in cold water compared to aluminium sulfate. Studies on the use of the complex titanium-containing coagulant in the process of wastewater treatment from phosphate anions and suspended matter demonstrated its higher efficiency as compared to that of traditional reagents. The advantages of the prepared reagent are a reduction in the effective dose of the reagent, minimization of residual concentrations of pollutants in purified water, intensification of the processes of sedimentation and filtration of coagulation sludge. Purified water can be reused in the recycling water supply system. The use of quartz-leucoxene concentrate and titanium tetrachloride obtained from it as the source material would not only minimize the cost of the resulting complex coagulant, but also take a step towards the implementation of the Zero Waste concept.
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Date submitted2024-05-02
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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 submitted2024-04-25
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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 submitted2023-04-06
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Date accepted2023-12-27
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Date published2024-04-25
Localization of sites for the development of geomechanical processes in underground workings based on the results of the transformation and classification analysis of seismic data
The paper considers an approach to localizing the intervals of development of geomechanical processes in underground structures based on the classification and transformation of seismic data. The proposed approach will make it possible to identify the intervals of fracturing, rock decompression, water inflow and other geomechanical processes when interpreting the results of seismic surveys. The technique provides for the formation of matrices of longitudinal (Vp), transverse (Vs) velocities and velocity ratios (Vs/Vp) along the research profile to perform sequential filtration. The filtration results serve as the basis for the formation of a bank of informative materials for further classification. Based on the domestic KOSKAD 3D software, four approaches have been implemented for a combined digital model of the Vp, Vs and Vs/Vp parameters. One of the key elements in the classification process is to combine grids to increase the probability of detecting intervals with heterogeneous identification features. The result of the application of this methodical approach is the construction of a comprehensive interpretative model, on which potential zones of geomechanical risks development are clearly manifested.
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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 submitted2023-03-20
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Date accepted2023-09-20
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Date published2023-10-27
Experimental simulation of a system of swamp biogeocenoses to improve the efficiency of quarry water treatment
Mining activities were producing large quantities of wastewater contaminated with nitrogen compounds and metals. With insufficient treatment, these pollutants are released into the environment and have a toxic effect on living organisms. Constructed wetlands are now widely adopted as wastewater treatment systems because of the combination of physical, chemical and biological processes for the removal of contaminants. In this study, an experimental system was modeled to improve the efficiency of the quarry wastewater treatment of a mining enterprise by sharing the higher aquatic vegetation: broad-leaved cattail (Typha latifolia L.), common water-plantain (Alisma plantago-aquatica L.), jointed rush (Juncus articulatus L.) and lower aquatic vegetation (Chlorella sp.). Concentrations of nitrogen compounds and metal were analyzed both in the model and in the treated solution of quarry wastewater for calculation of treatment efficiency. Concentrations of the pollutants in the tissues of the higher aquatic vegetation were analyzed to assess the accumulation capacity and efficiency of translocation of the pollutants. The results of the experimental study showed the practical applicability of the constructed integrated treatment system to reduce the concentration of pollutants in quarry wastewater, as well as increasing the efficiency of treatment by introducing lower aquatic vegetation into the system
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Date submitted2022-10-30
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Date accepted2023-09-20
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Date published2024-02-29
Combined method of phytoremediation and electrical treatment for cleaning contaminated areas of the oil complex
The scale of land pollution with oil waste necessitates the use of economical and effective methods of recultivation. Phytoremediation is one of the simplest methods, but it has a number of limitations, so additional preparation of the territory is often required before it is carried out. Preliminary electrical preparation and subsequent seeding of special phytoremediants are of interest. Passing a constant electric current through the soil volume under a low voltage removes toxicants from deep soil layers even with flooding. In addition, it reduces pollutant content in the upper layer, where the plants root system is located, which creates more favorable conditions for phytoremediants. Adequately selected types of plants will ensure additional soil cleaning, improve its structure and air exchange. The results of two research directions are presented. Experiments on the study of plant resistance to oil-contaminated soil substrate allowed establishing contamination thresholds at which it is advisable to sow a particular species, and to choose optimal phytoremediants. The study of the oil-containing soil cleaning in a monocathodocentric electrochemical installation with the fixation of main characteristics (oil products concentration, soil temperature, volt-ampere characteristics) allows us to develop technical measures to prepare territories for phytoremediation taking into account the relief features.
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Date submitted2023-03-14
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Date accepted2023-06-20
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Date published2023-07-19
The wireless charging system for mining electric locomotives
The electric vehicles development has a high potential for energy saving: an energy-saving traffic control can reduce energy resource consumption, and integration with the power grid provides the ability of daily load pattern adjustment. These features are also relevant for underground mining. The critical element of vehicle-to-grid integration is the charging infrastructure, where wireless charging is promising to develop. The implementation of such systems in underground mining is associated with energy efficiency issues and explosion safety. The article discusses the development and research of a wireless charging system for mining electric locomotive A-5.5-600-U5. The analytic hierarchy process is used for justification of the circuitry and design solution by a comparison of different technical solutions based on energy efficiency and safety criteria. A complex computer model of the wireless charging system has been developed that gives the transients in the electrical circuit of a wireless charging system and the high-frequency field density distribution near the transmitting and receiving coils in a 3D setting. An approach to ignition risk evaluation based on the analysis of high-frequency field density in the charging area between the coils of the wireless charging system is proposed. The approach using a complex computer model is applied to the developed system. The study showed that the wireless charging system for mining electric locomotives operating in the gaseous-and-dusty mine is technically feasible and there are designs in which it is explosion safe.
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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 submitted2022-08-10
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Date accepted2023-02-28
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Date published2024-02-29
Selection of the required number of circulating subs in a special assembly and investigation of their performance during drilling of radial branching channels by sectional positive displacement motors
The task of sludge removal to the surface during construction of directional and horizontal wells and strongly curved radial channels is relevant. For stable operation of technical system “Perfobore”, it is proposed to use a circulating sub that ensures efficient cleaning of channel wellbore from the drilled rock. Two schemes of technical system “Perfobore” are considered, consisting of two seven-meter coiled tubing, a positive displacement motor, a bit and one circulating sub in the first scheme and two subs in the second scheme. For each of the schemes CFD modeling was implemented to determine values of pressure and speed. It was found out that the use of two circulating subs in the assembly is more efficient. In order to confirm the numerical experiment, bench tests were carried out. It was determined that the designed circulating sub can eject up to 25 % of pumped drilling fluid. The bench tests of full-size technical system “Perfobore” for drilling 14-meter channels with two circulating subs showed that the axial load on positive displacement motor produced by hydraulic loader was 3000 N and pressure drop depending on flow rate was 1.5-2.0 MPa. This allows the motor to operate at maximum power.
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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 submitted2022-10-10
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Date accepted2023-01-19
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Date published2023-12-25
Assessment of the possibility of using leucoxene-quartz concentrate as raw material for production of aluminium and magnesium titanates
Leucoxene-quartz concentrate is a large-tonnage by-product of development of the Timan oil-titanium field (oil-saturated sandstones) which is not commercially used at present. High content of titanium compounds (to 50 % by weight) and lack of industrial, cost-effective, and safe technologies for its processing determine a high relevance of the work. Conventional processing technologies allow increasing the concentration of TiO2, but they are only a preparation for complex and hazardous selective chlorination. The process of pyrometallurgical conversion of leucoxene-quartz concentrate into aluminium and magnesium titanates was investigated. It was ascertained that the temperature of solid-phase reaction in Al2O3-TiO2-SiO2 system necessary for the synthesis of aluminium titanate (Al2TiO5) is 1,558 °С, and for MgO-TiO2-SiO2 system – 1,372 °С. Scaling up the process made it possible to synthesize a significant number of samples of titanate-containing products, the phase composition of which was studied by X-ray phase analysis. Two main phases were identified in the products: 30 % aluminium/magnesium titanate and 40 % silicon dioxide. In products of pyrometallurgical processing in the presence of aluminium, phases of pseudobrookite (3.5 %) and titanite (0.5 %) were also found. It was ascertained that in magnesium-containing system the formation of three magnesium titanates is possible: MgTiO3 – 25, Mg2TiO4 – 35, MgTi2O5 – 40 %. Experiments on sulphuric acid leaching of samples demonstrated a higher degree of titanium compounds extraction during sulphuric acid processing. An integrated conceptual scheme for processing leucoxene-quartz concentrate to produce a wide range of potential products (coagulants, catalysts, materials for ceramic industry) was proposed.
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Date submitted2022-05-26
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Date accepted2022-11-17
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Date published2022-12-29
Renovation method of restoring well productivity using wavefields
A stagewise theoretical substantiation of the renovation vibrowave method of influencing the near-wellbore zone of reservoir for restoring well productivity is presented. The area of treatment by the proposed method covers the reservoir with a heterogeneous permeability with fractures formed by fracking. In this method a decrease in concentration of colmatants occurs due to a change in direction of contaminants migration. Under the influence of pressure pulses, they move deep into the reservoir and disperse through the proppant pack. The results of mathematical modelling of the propagation of pressure wave and velocity wave and the calculations of particles entrainment in wave motion are presented.
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Date submitted2022-04-14
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Date accepted2022-07-21
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Date published2022-11-03
Technological mineralogy: development of a comprehensive assessment of titanium ores (exemplified by the Pizhemskoye deposit)
Technological mineralogy of titanium ores is the basis for assessing their complexity. It enables, from a unified standpoint, to trace the entire course of changes in mineral matter through operating procedures, including beneficiation, processing, and obtaining target industrial products. The study targets are Pizhemskoye ilmenite-leucoxene sandstones, which are distinguished by a complex polymineral composition. Along with the main ore components, there are other metals with different speciation (isomorphic admixture, independent mineral phases). The optimal set of mineralogical analysis methods for the predictive assessment of their further use is substantiated exemplified by titanium ores of the Pizhemskoye deposit, which are complex, noted for a variable content of iron oxides and contain rare earth metals. Examinations by X-ray phase analysis and scanning electron microscopy confirm that the main titanium phases of sandstones are pseudorutile and a polymineral aggregate, “leucoxene”. Considering the granulometric peculiarities of the magnetic and non-magnetic fractions of the gravity concentrate, the prospects of technologies for processing titanium raw materials are discussed. Along with the problems of obtaining high-quality raw materials, the transformations of mineral phases as a result of extreme impacts and their physicochemical properties as a consequence of isomorphic substitution of a part of Ti atoms with natural modifier agents (Fe and V) in the synthesis of titanium oxide nanostructures for industrial applications are considered (photocatalytic nanoreactor).
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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 submitted2021-09-02
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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 submitted2019-06-02
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Date accepted2019-09-02
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Date published2020-04-24
Sorption of nickel (II) and manganese (II) ions from aqueous solutions
Mine water from non-ferrous metal deposits is often contaminated with nickel and manganese ions. The entry of these ions, especially nickel, into surface waters and underground aquifers is undesirable since it has a negative effect on living organisms and worsens the condition of drinking water sources. One of the promising methods for selectively extracting nickel ions and obtaining an eluate suitable for further use is sorption by weakly acid cation exchangers with chelate groups of iminodiacetic acid. As part of the study, sorption isotherms of nickel and manganese ions by Lewatit MonoPlus TP 207 cation exchanger in mono- and bicomponent systems were obtained. In monocomponent systems, the maximum static exchange capacity (SEC) of the cation exchanger for nickel ions is 952 mmol/dm 3 , and in bicomponent systems – 741 mmol/dm 3 ; for manganese ions– 71 mmol/dm 3 and 49 mmol/dm 3 , respectively. It is obvious that the studied cation exchanger has a greater capacity for nickel ions than for manganese ions. The influence of a temperature increase from 300 to 330 K on the sorption of nickel and manganese ions was established: in monocomponent systems, the maximum degree of extraction of the former increases from 65 to 77 % (SEC from 337 to 399 mmol/dm 3 ), and the latter from 21 to 35 % (SEC – from 140 to 229 mmol/dm 3 ); in bicomponent systems, the extraction of nickel ions increases from 59 to 78 % (SEC – from 307 to 429 mmol/dm 3 ), and manganese ions decreases from 20 to 17 % (SEC – from 164 to 131 mmol/dm 3 ). The predominant increase in the indicators is due to the filling of the sorption centers of the ion-exchange resins, which are energetically unfavorable for the exchange of counterions at a lower temperature. The influence of the pH of the solution on sorption was determined: the intensification of the process for nickel ions is observed in the pH range of 8.0-8.5 in a monocomponent solution and 8.0-9.0 in a bicomponent solution, for manganese ions in the range of 8.0-9.5 in both cases. The increase in the degree of extraction of ions and the exchange capacity of the ion exchanger with increasing pH is associated with the appearance of singly charged hydroxocations, dissociation of the functional groups of the sorbent and, to some extent, with the subsequent formation of insoluble forms of nickel and manganese. However, with increasing pH, a decrease in the selectivity of nickel extraction is observed: the ion separation coefficient decreases from 14.0 to 6.0 in the pH range of 6.0-11.0.
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Date submitted2017-09-17
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Date accepted2017-11-06
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Date published2018-02-22
Collaborative interpretation of the data obtained by resistivity and ground penetrating radar methods for assessing the permeability of sandy clay soils
- Authors:
- D. A. Lalomov
- V. V. Glazunov
A method for estimating the filtration factor of sandy clay soils is considered on the basis of a joint interpretation of the data of a set of methods of engineering electrical exploration, including electrical resistivity tomography and ground penetrating radar studies. The solution of this problem is based on the use of known empirical connections between the imaginary and real parts of the complex dielectric permittivity, specific electrical resistance, and Q factor. An example of the effective joint use of the ground penetrating radar and non-contact electrical resistivity tomography shows how to obtain qualitative and quantitative estimates of a changing filtration factor in a draining road layer. It is necessary to use precise engineering geological information in order to provide the required estimates. The proposed approach makes it possible to describe continuous profiles of a pavement and underlying layers by ground penetrating radar and electrical resistivity tomography, as well as to assess soil properties when conducting an electrical survey from the surface of asphalt concrete pavement. Recommendations for the implementation of the developed methods of complex engineering and geophysical research are given for solving issues of repair work design, supervision, and quality control of road construction.
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Date submitted2016-10-30
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Date accepted2017-01-14
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Date published2017-04-14
HYDRO-IMP technology for upgrading of heavy petroleum
- Authors:
- Khorkhe Anchita
Hydroprocessing is one of the most important processes in petroleum refining industry, not only for upgrading of heavy oils but also for producing low-impurity content fuels and preparing feeds for various conversion processes. Experimental results obtained in pilot plant and semi-commercial scales for hydroprocessing of heavy oils are reported in this work. Mexican heavy crude oils (10, 13 and 16°API) with high amount of impurities were used for all tests. Hydroprocessing was conducted at moderate reaction severity in two fixed-bed reactors in series. Removals of sulfur, metals and asphaltenes, as well as changes of API gravity and viscosity were monitored at different reaction conditions with time-on-stream. Upgraded oils with reduced amounts of impurities and increased API were obtained, keeping sediment formation below maximum allowable content. Removal of impurities was higher in semi-commercial scale compared with pilot plant test. Have been proved that the heavier the feed the greater the gain in product quality. For instance, 10°API crude can increase its gravity up to ~22°API (Δ°API = 12), while 16°API crude increases its gravity up to ~25°API (Δ°API = 9). Sediment formation was also kept below 0.05 wt % and no other problems (excessive reactor delta-P, plugging, etc.) were observed during the test.
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Date submitted2015-10-01
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Date accepted2015-12-11
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Date published2016-08-22
The technology of extracting gaseous fuel based on comprehensive in situ gasification and coalbed degassing
The study considers a comprehensive technology (designed and patented by the authors) of developing coal and methane deposits which combines in situ gasification of lower coalbeds in the suite of rock bump hazardous gassy beds, extraction of coal methane and mechanized mining of coal. The first stage of the technology consists in mining gaseous fuel that enables one to extract up to 15-20 % of total energy from the suite of coalbeds. Geodynamic zoning is used to select positions for boring wells. Using the suggested technology makes it possible to solve a number of tasks simultaneously. First of all that is extracting gaseous fuel from the suite of coalbeds without running any mining works while retaining principal coalbeds in the suite and preparing them for future processing (unloading and degassing). During the first phase the methane-coal deposit works as a gas deposit only, the gas having two sources – extracted methane (which includes its locked forms, absorbed and adsorbed) and the products of partial incineration of thin coalbeds, riders and seams from thee suite. The second stage consists in deep degassing and unloading of coal beds which sharply reduces the hazards of methane explosion and rock bumps, thus increasing the productivity of mechanized coal mining. During the second stage coal is mined in long poles with the account of degassing and unloading of coal beds, plus the data on gas dynamic structure of coal rock massif.
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Date submitted2015-10-14
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Date accepted2015-12-18
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Date published2016-08-22
Complex utilization of treatment wastes from thermal power plants
- Authors:
- A. N. Shabarov
- N. V. Nikolaeva
The paper investigates present-day challenges related to accumulation, processing and disposal of the coal combustion wastes. The analysis of technogenic materials beneficiation practices using gravitation, magnetic and flotation beneficiation methods has been carried out. Quantitative and qualitative microscopic analysis of materials has been conducted. The study target were ash and slag wastes (ASW) from thermal power plant and coal combustion ash. Most metals are contained in coals and coal ashes in fine-dispersed (1-10 μm) mineral form. Various native metals and intermetallic compounds, sulfides, carbonates, sulfates, tungstates, silicates, rare earths phosphates and niobates have been discovered. Each metal may occur in several mineral phases, for instance tungsten may be in the form of wolframite, stolzite, ferberite, scheelite and represented by impurities. Not only composition of compounds is diversified, but also morphology of grains: well-defined and skeleton crystals, aggregates and polycrystalline structures, crystal twins and fragments; druses, globules and microspherules; porous shapes, flocculous and splintery clusters, lumpy aggregations, etc. Based on chemical silicate analysis of main ASW components the petrochemical properties of material have been assessed. Preliminary analyses have shown that concentration of ferrum-bearing components in ASW is around 5-11 %. The magnetic method of technogenic waste beneficiation with the help of high-gradient magnetic separation has been studied. The obtained evidences show that fine ASW are most efficiently separated in separators with high-gradient magnetic system. The studies provided justification of a process flow for complex treatment of technogenic carbon-containing material, including flotation, gravitation separation, magnetic heteroflocculation enrichment and high-gradient magnetic separation. The determined complex utilization ratio has proven the efficiency of complex processing.
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Date submitted2015-08-17
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Date accepted2015-10-25
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Date published2016-04-22
Ecological aspects of vehicle tunnels ventilation in the conditions of megalopolises
- Authors:
- S. G. Gendler
The characteristic of Russia and foreign vehicle tunnels are provided in paper and advantages of their placement in the conditions of the city are noted. It is shown that one of the main factors defining negative impact on environment in the period of tunnels driving is mine equipment, and at operation – vehicles. The analysis of essential differences of features of pollution of atmospheric air at construction of tunnels from its pollution at construction of buildings on a surface is given. The examples illustrating levels of negative impact of the upcast ventilation shaft airflow on atmospheric air are given and the ventilation schemes reducing this influence are offered. It is shown that during operation of road tunnels of pollution of the air environment can extend on considerable distances from tunnel portals. Numerical calculations of concentration of carbon oxides and nitrogen during removal of the upcast ventilation shaft airflow through portals and through the mines built near them are executed. Technical solutions on purifications of tunnel air by means of electrostatic filters are described.
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Date submitted2015-07-14
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Date accepted2015-09-27
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Date published2016-02-24
Chemical and technological mechanisms of a alkaline aluminum silicates sintering and a hydrochemical sinter processing
- Authors:
- V. M. Sizyakov
Complex mineral raw material, as alkali aluminum silicates, is an interest for aluminum industry, chemical industry and for the production of constructional materials. They are well represented in the earth's crust, characterized by the complexity of material composition and variable content of the main components such as alumina, silica and alkalies. They often occur where due to the geological conditions there is no bauxite, for instance, in the United States, Canada, Venezuela, Mexico, Iran, Egypt, Portugal, Spain, Bulgaria and other countries. At the present time for the Russian economy the nephelines from this list are the most valuable and have the great concern for the raw materials balance of the national aluminum industry. Because of limited reserves the bauxites proportion of alumina produced from nephelines by sintering is 40 % and in time this proportion will increase due to the involvement in the production of new deposits of alkali aluminum silicates. Many of foreign companies have also shown interest to the complex processing of ores. The investigation of technology is based on the method of sintering ore with limestone. As a result, the after-sintering mixture consists of alkali metal aluminates and dicalcium silicate; after-sintering mixture is leached by circulating alkaline aluminate solution, alumina, soda and potash are thrown out from the solution. Dicalcium silicate (nepheline sludge) is processed to Portland. For the investigated after-sintering mixture the tendency shows the increasing of optimum sintering temperature with the lowering Al 2 O 3 content. With the increasing of silicate module (SiO 2 / Al 3 O 3 ) of the initial alkali aluminum silicates charges the temperature of after-sintering mixture formation increases. After-sintering mixtures that are on base of alkali aluminum silicates have different microstructure and the degree of crystallization in which b-С 2 S and sodium aluminate is improved with a decrease of the aluminate phase amount. Results of investigations show a very limited solubility of aluminate phase in dicalcium silicate, which theoretically justifies a sufficiently high level of useful components chemical extraction in the processing of different types of alkali aluminum silicates by sintering.
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Date submitted2014-11-24
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Date accepted2015-01-02
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Date published2015-10-26
Complex processing of apatite-nepheline ores based on the creation of closed-loop process flow sheets
- Authors:
- A. I. Alekseev
The article presents the chemical and engineering fundamentals of processing apatite and nepheline concentrates directly on the Kola Peninsula. Implementation of the existing separate processing of nepheline and apatite concentrates demonstrates inefficiency of these technologies due to the formation of waste calcium sulfate and calcium silicate, which have so far not found a practical use and are wastes stored in sludge repositories of the Russian Federation. Suggested new scientific and technical solutions will allow enterprises to significantly increase the volume of production of new in-demand marketable products due to rational and complex use of mineral raw materials of the Kola Peninsula, reduce their costs while decreasing the volume of rock extraction and eliminate waste creating a closed-loop technological cycle of processing apatite and nepheline ores.