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Date submitted2024-05-08
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Date accepted2024-11-07
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Date published2024-12-12
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 submitted2024-01-31
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Date accepted2024-06-03
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Date published2024-07-04
Rationale for a possibility of using humic preparations production waste for wastewater purification from metals (Cd2+, Zn2+, Mg2+, Cu2+) aimed at developing efficient measures on environmental rehabilitation
Results of studying optimal conditions and parameters for afterpurification of underspoil waters from metal ions using humic acids production waste are presented with a view to develop the efficient measures on environmental rehabilitation of ecosystems disturbed by the development of copper pyrite deposits. The influence of contact time and waste dosage on the purification process was analysed, changes in the pH of wastewater and its impact on the growth and development of plants were studied. The key factors were identified allowing to achieve the efficiency of the purification process – the optimal contact time in the range from 120 to 180 min and waste dosage of 10 g/l. The study showed that the use of waste resulted in a neutral pH value of 7.03 compared to the initial pH value of 5.95. It was ascertained that the use of iron-magnesium production waste in combination with waste from humic preparations production made it possible to achieve the MPC of commercial fishing importance (with the exception of magnesium). Wastewater after the afterpurification process with high magnesium concentrations did not have a stimulating effect on the growth and development of Lepidium sativum L. plants. From biotesting results it can also be stated that there is no negative impact on the growth and development of Lepidium sativum L. The results obtained indicate a potentiality of using afterpurified wastewater for watering plants in the process of initiating the environmental rehabilitation of the disturbed ecosystems.
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Date submitted2024-04-22
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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 submitted2022-10-29
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Date accepted2023-10-25
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Date published2024-04-25
Assessment of rock massif sustainability in the area of the underground research laboratory (Nizhnekanskii Massif, Enisei site)
The study presents the results of the research on geodynamic and geological conditions of the Enisei site (Krasnoyarsk Krai), chosen for the construction of an underground research laboratory. The laboratory is being built at a depth of 500 m to assess the suitability of the rock mass for burying high-level radioactive waste. The rocks consist of weakly fractured gneisses, granites, and dikes of metadolerites. Field observations were conducted on bedrock outcrops. They included the determination of rock mass quality indicators, measurement of rock fracturing, and a rating classification of stability using N.Barton's method. GNSS observations were also made to monitor surface deformations. These data were used to develop a three-dimensional structural model, including lithology, fault disruptions, intrusive bodies, elastic-strength properties of rocks, and the sizes of zones influenced by faulting. It will serve as a basis for boundary conditions and the construction of three-dimensional variational models of stress-strain states, identifying zones of concentration of hazardous stresses, and planning in situ geomechanical experiments in underground mines of the laboratory. The obtained values of the modified QR index for the main types of rocks allowed their classification as stable and moderately stable, corresponding to strong and very strong rocks on Barton's scale and the massif rating according to geomechanical classification.
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Date submitted2022-05-20
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Date accepted2023-06-20
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Date published2024-02-29
Increasing the quality of zeolite-bearing rocks from Eastern Transbaikalia by applying directed energy
This paper presents the use of accelerated electrons to treat zeolite-bearing rocks from Eastern Transbaikalia to increase the efficiency of separating zeolites from rock-forming minerals via electromagnetic separation. The effectiveness of the liberation of zeolite minerals using accelerated electrons was analyzed. The results of dry electromagnetic separation of zeolite-bearing rocks are presented. The dependence of the extraction of iron-bearing minerals from zeolite-bearing rocks by electromagnetic separation on the magnetic field intensity for different particle sizes has been established. The main methods of zeolite-bearing rock enrichment and ore preparation were determined. A technological scheme for processing zeolite-bearing rocks, based on the use of accelerated electron treatment at the ore preparation stage, is presented, significantly improving the zeolite production quality.
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Date submitted2022-10-24
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Date accepted2023-03-03
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Date published2023-04-25
Use of clay-containing waste as pozzolanic additives
Growing productivity of mining and processing enterprises entails an increase in the volumes of liquid tailings impoundments and upstream impoundments of ore processing waste. Enterprises face the challenge of minimizing the environmental impact of waste and guaranteeing the sanitary and epidemiological safety of population. The article presents a possibility of recycling one type of such waste (clay-containing concentration tailings of apatite-nepheline and sylvinite ores, coal beneficiation tailings) by using them after preliminary thermochemical treatment as pozzolanic additives to cements and concretes, including concrete mixtures used for soil stabilization, development of territories, reclamation of mine workings, as a component of the insulating layer of landfills for the disposal of municipal solid waste. An analysis of the phase changes of kaolinite, one of the main minerals that make up clay-containing waste, in the temperature range of 200-1,000 °С showed that a change in its mineral form during heat treatment is the main factor in changing its pozzolanic activity. The effect of heat treatment of clay minerals at temperature of 700-800 °C on their pozzolanic activity, estimated by the ability to absorb calcium hydroxide (0.7 g Ca(OH) 2 per 1 g of modified kaolinite), is considered. It is shown that the addition of heat-treated samples (20 % by weight) improves the quality of cement increasing its activity by 15 %, in comparison with the use of unmodified clay minerals. It was proved experimentally that partial replacement of Portland cement with thermally modified kaolinite increases the strength of consolidating stowing mixture by up to 15 %. This approach to processing of ores containing layered silicates, which provides for thermochemical modification of run-of-mine ore, intensifies the processes of tailings thickening and filtering.
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Date submitted2022-10-28
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Date accepted2023-03-02
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Date published2023-04-25
Assessment of the possibility of using iron-magnesium production waste for wastewater treatment from heavy metals (Cd2+, Zn2+, Co2+, Cu2+)
Relevant problems associated with treatment of industrial wastewater from heavy metal ions are considered. Due to industrial development, the amount of wastewater increases as well as the risks of heavy metals getting into surface and groundwater, accumulating in water bodies and becoming aggressive environmental pollutants, which affect the animal and human organisms. To assess the possibility of extracting metal ions (Cd 2+ , Zn 2+ , Co 2+ , Cu 2+ ) from industrial wastewater and their further treatment, studies were carried out on redistribution of heavy metals in the “wastewater – waste” system using iron-magnesium production waste. Samples of the investigated waste weighing 0.1; 0.2; 0.5; 1; 1.5; 2 g were taken for wastewater volume of 50 ml per each subsample. Contact time varied from 5 to 180 min, waste fraction was 1 mm. The interaction process showed that the waste efficiently removes metal ions (Cd 2+ , Zn 2+ , Co 2+ , Cu 2+ ) from industrial wastewater. The efficiency of removing a pollutant from the solution depends on the weight of the waste subsample, initial concentration of metal ions, and contact time.
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Date submitted2022-10-17
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Date accepted2023-02-13
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Date published2023-04-25
Environmental geotechnology for low-grade ore mining with the creation of conditions for the concurrent disposal of mining waste
Due to the constantly deteriorating environmental situation in the regions with mining enterprises, the article considers the topical issue of disposing the maximum possible volume of waste from the mining and processing of low-grade ferrous ores through the creation of an effective underground environmental geotechnology. Traditional procedure with descending mining of reserves with a caving system does not allow waste to be disposed of in a gob. The idea is to use geotechnology based on the ascending order of mining the ore body, room excavation, leaving truncated pillars, and staggered arrangement of adjacent rooms in height, which makes it possible to form containers for waste disposal in the form of a cementless backfill. The main characteristics of the proposed procedure are investigated and compared with the traditional procedure of low-grade iron ores mining. It was established that from the point of view of the complete extraction of reserves and the unit costs for the preparatory-development operations, the processes are comparable, while in terms of the mining quality, the proposed option is much more efficient. Evaluation of environmental geotechnology by the criterion of waste disposal, performed according to the proposed methodology, showed that the combination of these technical solutions ensures the placement in the formed gob from 80 to 140% of all waste generated during the mining and beneficiation of low-grade iron ores.
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Date submitted2021-02-24
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Date accepted2022-04-06
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Date published2022-07-13
Study of the kinetics of the process of producing pellets from red mud in a hydrogen flow
The reduction kinetics of serial phase transitions of iron oxides during reduction to a metallized state with different modes of technical hydrogen supply has been studied and substantiated. The results of the pellets formation when 3-5 % molasses is added to the red mud as a binding reagent are presented. The dependences of the reduction rate of iron oxides on the hydrogen flow rate are obtained. Based on the results of the experiments, a kinetic model was constructed, and with the help of X-ray phase and spectral analysis, it was proved that the agglomerates formed after heat treatment received high strength due to the adhesion of reduced iron particles with red mud particles. The use of a new type of charge materials in melting units will reduce the amount of emissions and dust fractions, as well as increase the metal yield.
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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 submitted2021-03-05
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Date accepted2021-09-07
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Date published2021-12-16
Utilization of sewage sludge as an ameliorant for reclamation of technogenically disturbed lands
- Authors:
- Tatyana A. Petrova
- Edelina Rudzisha
When rehabilitating technogenically disturbed lands of mining facilities, fertilizers and ameliorants are to be applied due to the lack of organic matter and nutrients required for the restoration of the soil and vegetation layer. The use of unconventional fertilizers (ameliorants) based on sewage sludge is one of the actual directions of land reclamation at mining sites. The purpose of the work is to summarize and analyze up-to-date information on the effectiveness of the use of sewage sludge for the reclamation of technogenically disturbed lands of mining and processing industries. The analysis is based on a review of recent studies aimed at assessing the impact of introduced sediment on soils, plant communities, and rehabilitated areas. The introduction of sewage sludge has a positive effect on the physical and chemical parameters of the soil (optimizes density and aggregation), saturates it with nutrients, i.e. N, P, K, Ca, Mg, and Na, thus improving plant growth indicators. However, it may contain a number of heavy metals and pathogens; therefore, studies of each sediment and conditions of reclaimed areas are necessary.
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Date submitted2020-06-12
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Date accepted2020-06-12
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Date published2020-06-30
Management of hardening mixtures properties when stowing mining sites of ore deposits
Underground mining is characterized by the weakening of the bearing rock mass strata competence and the accumulation of mineral waste. The full use of subsurface resources is ensured by the use of technologies with filling voids by hardening mixtures, which requires high-quality raw materials to obtain the required strength. The deficit of the binding component can be filled with the use of granulated slags of blast-furnace process, mill tailings, ash-slags and other wastes. Most often, voids are laid by mixtures with a combination of cement and a binding component. Mixtures with ash-slag additives to cement in an equivalent amount are not inferior to the strength of the mixture only with cement, especially when grinding ash-slag. The properties of stowing rock masses when using composite binding components and inert fillers are controlled by mechanical, chemical, physical and energy effects at the stages of preparation and transportation of hardening mixtures. To obtain the active fraction of cement substitutes, disintegrators are used that apply the inertia forces of materials at a high speed of rotation with an increase in high activity indicators and lower energy costs. The components of hardening mixtures can be the majority of waste from mining and related industries, which is determined experimentally in specific conditions.
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Date submitted2018-09-13
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Date accepted2018-11-09
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Date published2019-02-22
Lignin sludge application for for-est land reclamation: feasibility assessment
- Authors:
- M. A. Pashkevich
- T. A. Petrova
- E. Rudzisha
The article analyses waste generation of pulp and paper industry in North-Western Russia. The environmental impact of waste storage facilities of the pulp and paper mill was assessed, the need for utilization of lignin sludge was justified. In North-Western Russia, 1.21 million hectares of disturbed areas are in need for reclamation; they are abandoned quarries and lands alienated for pipeline and road construction. The suitability of lignin sludge for preparation of artificial fertile soils for reclamation purposes is estimated. For this purpose, experiments were carried out to create an artificial mixture with different ratios of lignin sludge and soil, to detect the maldevelopment of several plant species grown on various compositions of lignin sludge and soils. It was revealed that lignin sludge as an organic additive to soils is not toxic to vegetation and living organisms, allowing improving fertility of artificial soils.
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Date submitted2015-12-28
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Date accepted2016-02-08
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Date published2016-12-23
Bulk density and aggregate stability assays in percolation columns
The restoration technologies in areas degraded by extractive activities require the use of their own mine spoils. Reducing deficiencies in physical properties, organic matter, and nutrients with a contribution of treated sewage sludge is proposed. This experiment was based on a controlled study using columns. The work was done with two mine spoils, both very rich in calcium carbonate. Two sewage sludge doses were undertaken (30,000 and 90,000 kg/ha of sewage sludge) in addition to a different mine spoils used as restoration substrates. The water contribution was provided by a device that simulated short duration rain. The leached water was collected 24 hours after the last application. The experiment saw the bulk density decrease and the aggregate stability increase, thereby improving the structure. The improved soil structure decreases its vulnerability to degradation processes such as erosion and compaction.
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Date submitted2015-10-12
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Date accepted2015-12-26
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Date published2016-08-22
Use of various types of carbon-containing raw materials to produce thermal energy
- Authors:
- V. B. Kuskov
- V. Yu. Bazhin
Many types of carbon-containing organic compounds and all possible carbon-containing products or wastes in low demand can be used to produce thermal energy. A technology has been developed for producing highly flammable briquettes on the basis of bituminous coal. These briquettes have a special incendiary layer. It is easily ignites from low energy heat sources (e.g. matches), and then flame spreads to the rest of briquette. Use of coal slacks and paper wastes as carbon-containing components playing the role of binders provides an opportunity to get a fuel briquette easy in terms of production and plain in composition while at the same time dispose of coal and paper wastes. Such briquettes may also have a special incendiary layer. Technology for fuel briquettes production from wood and slate wastes employed no binding agents, as wood products acted as binders. Thus technologies have been developed to produce fuel briquettes from various carbon-containing materials in low demand. The briquettes are intended for household boilers, fireplaces, different ovens in order to cook food, heat residential and utility premises, cabins, etc.
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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.
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Date submitted2014-07-09
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Date accepted2014-08-31
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Date published2014-12-22
Properties of electric arc furnace dust and methods of utilizing it
- Authors:
- M. A. Pashkevich
- T. A. Lytaeva
The least utilized recyclable wastes from mining and processing enterprises are dispersed wastes, which are in the form of dust captured by systems of gas purification. This dust is a technogenic raw material for the production of zinc and other metals. Various ways of utilizing the steelmaking dust are presented. For utilization of the steel-making dust, a hydrometallurgical method with the use of autoclave technologies is proposed. The results of experiments in sulfate autoclave leaching are described.
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Date submitted2010-07-27
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Date accepted2010-09-09
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Date published2011-03-21
Utilization of enrichment waste of diamondiferous rock accounting peculiarities of M.V.Lomonosov deposit
- Authors:
- A. Yu. Oblitsov
In given article the questions of enrichment waste utilization of M.V.Lomonosov diamond deposit are considered taking in account some important peculiarities of this deposit and prospective of obtaining building materials on basis of enrichment waste products is stated.
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Date submitted2008-10-12
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Date accepted2008-12-17
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Date published2009-12-11
Principles of development of geological engineering and geological criteria for safe burial of low radioactive wastes in lower cambrian blue clays in the Leningrad region
- Authors:
- R. E. Dashko
It is noticed that the chosen territory for nuclear-waste disposal in Lower Cambrian clay massif nearby Koporje of Leningrad region takes place in a tectonic zone. Lower Cambrian clays are considered as the block-fractured rock mass having a depth zone structure. The long radioactive irradiation of dark blue clays has led to transformation of their structure, physical-chemical and physical-mechanical properties, and also to activization of microbial activity. Nine criteria to the geoenvironmental and engineering geological characteristics allowing in a complex to estimate safety and reliability of a nuclear-waste disposal in clay formations on an example of dark blue clays are suggested.