Technogenic Waste Research Articles

Efficiency of caoutchouc concrete with technogenic waste: Review

One of the directions of modern technological development of the construction industry is the focus on energy efficiency and sustainability. Mankind and its economic activities over the past century have led to serious pollution of our planet with a variety of industrial waste. Technogenic waste, as well as waste from renovation, are widely used as part of building materials, in this regard, the material called “Green concrete” has found wide application. However, elements of structures are often affected by force and environmental conditions which prevent the utilization of cement composites. A promising and actual way to solve this problem is to make such structures from composite materials, for example, polymer concrete - materials in which polymers of various nature are used as a binder. For expanding the range of polymer compositions used in construction, a polymer concrete based on liquid caoutchouc or rubber was developed, which has high strength characteristics, high resistance to aggressive environments, etc. The purpose of this review paper is to demonstrate that polymer concretes are promising building materials in terms of waste utilization in their composition due to the high filling capacity of the mixture. In particular, this study will determine the place in the construction industry of such a material as caoutchouc concrete, the newest of polymer concretes, which has a high potential for the utilization of various types of waste while maintaining high mechanical properties. As this takes placer, a comparative analysis of materials similar to caoutchouc concrete, which include difficult-to-recycle components, is carried out, and an assessment is made of the potential of caoutchouc concrete in waste disposal. It was revealed that caoutchouc concrete up to 89.8% can consist of production waste.

Heat-resistant concretes based on cement binders and waste from the metallurgical industry

The main direction of the development of heat-resistant concrete production is the use of new materials, ensuring mechanization and industrialization of construction, increasing the performance characteristics of refractory compositions, reducing material consumption, introducing waste-free technologies in the production of concrete with increased physical and mechanical characteristics under prolonged exposure to high temperatures on cement binders and waste from the metallurgical industry and reducing environmental pollution. A significant environmental impact on the environment is exerted by large-tonnage technogenic waste produced by JSC «Aluminum of Kazakhstan» – bauxite sludge obtained by processing bauxite into alumina containing 42.7% Fe2O3. The prospects of its application as a filler in heat-resistant concretes are considered, which makes it possible to increase the physico-mechanical and thermal characteristics. The composition and properties of this waste and the change in the properties of heat-resistant concrete during the introduction of filler have been studied. Reactive alumina has been studied, which is 99.9% submicron alumina with a very low content of Na2O oxide. It is shown that the properties of concrete change after the introduction of iron-containing waste in the amount of 5% and reactive alumina – 37.5% and 38.8%. Their volumetric weight, control strength, and other properties are increased. The improvement of physical, mechanical, and thermal characteristics depends on the structure and neoplasms in the obtained samples. Samples of heat-resistant concrete were analyzed using electron probe X-ray spectral qualitative and quantitative microanalysis and X-ray fluorescence spectrometry and it was shown that the iron-alumina waste contributes to the compaction of the structure due to its resistance to delamination and has increased fluidity at low humidity in the cementing mass. For further investigation of the physical-thermal characteristics, depending on the structure and neoplasms in the obtained samples, a petrographic method using a polarization microscope in transmitted and reflected light is required.

Influence of torrefaсtion on the characteristics of fuel blends of biomass and high-ash carbon-containing waste

The influence of torrefaction on the characteristics of binary fuel blends consisting of plant biomass and high-ash carbon-containing technogenic waste is considered. It has been shown that through torrefaction it is possible to compensate for the decrease in the heating value of fuel blends associated with the addition of a high-ash component. A criterion for choosing a torrefaction mode is proposed and the corresponding analytical expression is obtained that allows one to calculate the minimum permissible biomass content in the fuel blend. This expression can be used in relation to fuel blends of various types of plant biomass and high-ash carbon-containing waste. There are presented quantitative data demonstrating the improvement of the hydrophobic properties of fuel blends as a result of torrefaction.

Concretes based on technogenic wastes formed during the mechanical processing of carbonate rocks

Concretes based on technogenic wastes formed during the mechanical processing of carbonate rocks

Research and Development of Obtaining Scandium from Waste Cake by Aluminothermal Method

To study and obtain scandium, we used technogenic waste (waste cake) from the Kadamzhai antimony plant. For the experiment, we took 0.05 μm enriched fine fraction of the cake. To carry out the aluminothermic reaction, we weighed 90 g of enriched cake and 10 g of aluminum powder on technical scales. To obtain scandium, we used a quartz crucible as a reactor, since the reaction in it does not pollute the obtained product, the reaction will begin at 810° C. Complete recovery of scandium occurs at 935° C, in 7-8 minutes. For the aluminothermic reaction, we used enriched cake from the Kadamzhai antimony plant.

EXTRACTION OF CHROME FROM FERROCHROME PRODUCTION SLAG USING THE SULFURIC ACID METHOD

Currently, the development of industrial waste recycling processes that reduce the anthropogenic load on the biosphere and ensure the rational use of natural resources is an urgent task. Technogenic waste from ferrochrome production contains chromium, which is one of the most toxic components of industrial waste. To extract chromium from them, the most acceptable method is acid leaching. The purpose of the work is to study the influence of temperature, process duration and H2SO4 concentration on the extraction of chromium from high-carbon ferrochrome slag into a sulfuric acid solution. Using mathematical planning of a 3-factor experiment, experiments were carried out to extract chromium from the slags of high-carbon ferrochrome production. The H2SO4 concentration was varied from 5 to 95% by diluting the concentrated acid. The duration of the process ranged from 10 to 180 minutes at S:L = 1:30, the temperature varied from 22 to 90 °C. Results and discussion. The maximum transition of chromium into acid occurs at a temperature of 76-90 °C and a process duration of 145-180 minutes. The degree of extraction reaches 97.9%. The smallest amount of chromium, about 20 mg/L, passes into the weakly concentrated H2SO4 solution, the degree of leaching is low and equal to 20.6%. When using 50% H2SO4, the highest degree of transition of Cr (94.8%) from ferrochrome slag to sulfuric acid occurs at a high temperature of 90 °C in 150-180 minutes. Deeper extraction of chromium cations into acid occurs at 80-90 °C. The maximum content of Cr3+ in the acid is achieved in 46-107 minutes and amounts to (0.33-0.68)%. Conclusions. It was revealed that with increasing process duration and increasing temperature, the degree of extraction increases. The maximum transition of chromium into acid from high-carbon ferrochrome slag occurs at a temperature of 76-90 °C and a process duration of 145-180 minutes. The degree of extraction reaches 97.9%. An increase in the temperature of the process of leaching chromium from VUVC with concentrated sulfuric acid initiates the extraction of chromium from the raw material.

Dynamics of backfill compressive strength obtained from enrichment tails for the circular waste management

At the current stage of development, the transition to a circular economy is a single option to achieve sustainable mining. Purpose was to identify a direction for mining tailings usage based on the circular waste management. The novelty of the author's approach lies in regulation of mechanical treatment of slag to optimize the backfill composition. The methodology involved a study of mining waste (slag) obtained from major (eight) metallurgical plants in Russia. For mathematical processing primary data, smoothing and deterministic three-dimensional interpolation methods were used. As a result, for the first time it has been established that the ultimate uniaxial compressive strength after mechanical treatment of slag increases by logarithmic laws. As the curing time increases from 10 days to 90 days (with the addition of Ca or Si) the strength increases by 21 % (7 % and 23 %). The possibility of completely replacing the traditional cement binder with metallurgical slag in the backfill composite has been proven. It has been established that the use of activation treatment (both mechanical and chemical) makes it possible to increase the strength characteristics of backfill samples after their curing. The principle of organizing mining production has been implemented, which provides for the use of intermediate products (blast furnace granulated slag), previously classified as technogenic waste, in a closed production cycle. The introduction of this principle will eliminate (minimize) the formation of man-made waste. The scientific merit of replacing traditional cement binder with technogenic waste (blast furnace granulated slag) allows implementation of circular economy in mining.

Red mud in high-strength ceramics production

The work is devoted to the creation of high-strength ceramic materials with technogenic waste fillers.Purpose: Investigation of the ceramic and composite production based on chemical and metallurgical wastes to create new types of high quality constructional ceramics.Methodology/approach: The use of refractory clay with the addition of high-iron bauxite sludge as the main raw material. Bauxite sludge functions in compositions with aluminosilicate raw materials at burning at 1100 to 1200 °С, reduce to sintering due to its melting at 1150 °С.Research findings: Refractory clay compositions with red mud in the amount of 20 to 50 % at the burning temperature of 1050 °С, provide the ceramic formation possessing the compressive strength 1.3 to 1.5 times higher than that of clay samples without additives, i.e., 91 and 122–132 MPa, respectively.Value: The obtained ceramic compositions based on red mud determine a production of high-strength anorthite and anorthite-helenite ceramics using dry pressing.

Reductive leaching of bauxite residue and subsequent scandium extraction by sulphuric acid leaching – Preliminary evaluation

Bauxite residue (BR) is a by-product of bauxite refining using Bayer process for alumina production, which contains numerous valuable components: iron (Fe), aluminum (Al), and rare earth elements such as scandium (Sc). The main issue of previous research for the Sc extraction from BR was the low extraction efficiency or high Fe co-extraction. This article shows that Fe co-extraction can be significantly reduced after reductive leaching of BR in the presence of Fe(II). This effect was achieved due to the formation of magnetite (Fe3O4) after reductive leaching of bauxite. Magnetite is practically insoluble in H2SO4 at pH > 2. The effect of temperature (T), time (t) and liquid to solid ratio (L:S ratio) on the leaching process was revealed. The results show that under optimum conditions (pH = 2, T = 90 °C, t = 2 h, L:S ratio = 10:1), Sc extraction can reach 57%, with a simultaneous co-extraction of Fe <1.3%. At the same parameters about 10% of Fe is extracted from the raw BR. The Fe content in the residue after leaching increased from 58.3 to 66.2 wt%, corresponding to the iron concentrate. Thus, the Sc extraction from a modified BR by dilute H2SO4 creates the conditions for the complete valorization of this technogenic waste, and improved extraction selectivity.

Modified concrete: reality and prospects

Aim. To review the history of concrete technology over the past 30 years and to analyze current trends in the field.Reality. New concepts and terms that manifest the level of modern science in the field of concrete technology are given. It is shown that the use of complex organomineral modifiers produced on an industrial scale, which are characterized by unique compositions, forms, and processability, allowed Russia to organize promptly mass production of concrete with high performance properties in the amount of about 5 million m3. Examples of construction of unique structures from new modified concretes are presented. The list of such structures includes high-rise buildings, sports facilities, bridges, overpasses, tunnels, etc.Prospects. Priority tasks for further development of concrete technology in Russia have been formulated. Among them are the development and improvement of physical and technical characteristics of concretes; extended use of large-tonnage technogenic wastes in production of concrete mixtures; updating and development of new normative documents for calculation, design, and erection of modern structures with high operational reliability, durability, and aesthetic properties.

Scientific substantiation of complex extraction and processing of secondary resources for the development of alternative sources of energy

Scientific research on the integrated extraction and processing of secondary resources, such as mine water, technogenic waste, and others, in order to develop alternative energy sources in the diversification of coal mines is an urgent scientific task that will help solve the issues on the economic, social and environmental transformation of coal mining regions. In practice, it is necessary to consider several alternative options and assess the possibility of obtaining different end products from the targeted processing of secondary raw materials. The choice of a rational processing option to obtain the target product is very complicated due to the different composition of the feedstock, as well as a significant variety of primary processing methods and parameters of intermediate processes, which causes certain difficulties in forecasts and calculations. Developing a methodology for typifying actions when choosing options for integrated processing of recyclable materials of different states, defining the basic principles and its structure for comparative analysis of the input, intermediate, and output parameters in terms of composition, physical, chemical, and technological characteristics are urgent modern tasks.

Depletion of converter slags to waste in the Vanyukov furnace during pyrometallurgical copper production at JSC Almalyk MMC

The article shows the possibility of involving man-made formations in the pyrometallurgical production of copper in the form of slag and clinker-zinc production for the purpose of comprehensive extraction of non-ferrous and precious metals from them at Almalyk MMC JSC. Clinker, a technogenic waste from zinc production, contains a significant amount of reducing elements in the form of metallic iron and carbon, as well as gold in the amount of 2.3 g/t and silver 250 g/t. In research, clinker works as a reducer of magnetite contained in the converter slag during its depletion and in the process of depletion (reduction) of the converter slag, noble metals are extracted into matte, and then into blister copper up to 95-98%. Converter slags from copper production of Almalyk MMC JSC contain 2.0-3.5% copper, and they, as a circulating product, are depleted in a reverberatory furnace with copper extraction of 75%. To increase the yield of copper from converter slag in Vanyukov furnaces, it is necessary to first deplete the converter slag in reduction processes and then transfer it for processing. It was found that using clinker, a technogenic waste from zinc production with a particle size of +5 - -10 mm, the recovery of converter slag in a converter from magnetite to wustite using the developed technology in 10-15 minutes exceeded more than 50.0% (the amount of magnetite decreased from 21.9 % to 9.8%). As a result of processing recovered converter slags in the Vanyukov furnace, it was possible to reduce the copper content in converter slags of copper production from 2.2-3.5% to 0.58-0.72% in waste slag. To increase the yield of copper from converter slag in the reverberatory and Vanyukov furnaces, it is necessary to first deplete the converter slag in reduction processes and then transfer it for processing.

Cementless concretes, based on anthropogenic wastes of the Irkutsk Oblast

The accepted global trend of transition from a linear economy to a closed-loop one stimulated the development of regulatory documents, such as “Strategy for the development of building materials in the Russian Federation and Irkutsk Oblast”, Decree of the Government of the Russian Federation dated 08/02/2023 No. 2094, both at federal and regional levels. Further, the Baikal interregional scientific and educational centre was established. All this aims at obtaining technologies for developing effective building materials, based on technogenic wastes, and establishing the production. It is planned to obtain effective building materials, based on the accumulated high-tonnage waste of the Usolye-Sibirskoye priority development area, such as ash and slag mixtures of the combined heat and power plant (90 million tons) and lime-containing waste, generated during the production of acetylene at the Khimprom PJSC (more than nine million tons). The paper represents a fundamentally new approach to obtaining artificially synthesised newgrowths of cementless concrete, based on technogenic wastes, which meets the requirements of regulatory standards in terms of frost and water resistance and allows using this concrete in enclosing structures. At a rationally selected ratio between lime-containing wastes and an ash-slag mixture, subject to the pre-established principles of technological preparation in terms of their mechanical activation, mixing technology, conditions and synthesis duration, it is possible to obtain high-quality cementless concrete that meets the basic requirements of regulatory documents for quality indicators.

Utilization of technogenic waste from energy enterprises

The paper shows that the use of nano-additives can reduce the content of harmful impurities in flue gases. It is demonstrated that the waste of the water treatment process of thermal power plants can be used as a cheap and environmentally friendly nanostructured additive to improve the properties of hydrocarbon fuel. If necessary, the effect of carbonate sludge can be enhanced by adding other nanoparticles. The composition and properties of carbonate sludge are presented. The prospectivity of extraction of valuable, rare-earth metals from technogenic wastes generated during combustion of fuel oil at power enterprises is proved.The results of the obtained experimental powder diffractogram of fuel oil ash are discussed.

Geoecological and geochemical assessment of the impact of NMMC mining enterprises on the environment

Study of the dynamics of natural and man-made processes and their impact on the environment in the hills of Uzbekistan; study of ecological and geochemical processes occurring in technogenic and natural landscapes of mining enterprises of the NMMC; Conducting geochemical and analytical studies to identify the contents and distribution of toxic and other associated elements in technogenic waste from NMMC mining enterprises, soils, and plants in connection with their impact on the ecology of the environment. Study of geochemical features of the productive valuable and toxic element`s behavior in space and time in industrial waste area Geological and geochemical mapping of soil, plants and water sources. Study of the chemical composition, behavior and forms of occurrence of toxic elements (in soils, water streams, dust, gases, smoke) in the water area and in the vicinity of the Navoi Mining and Metallurgical Combine - geochemical ecology. As a result of investigations of initial samples by using mass spectrometric analysis, the limits of fluctuations and average contents of not only toxic elements, but also other associated elements were revealed.

Development of resource-saving technology for copper production at “Almalyk MMC” JSC

This article discusses the possibility of introducing man-made waste from the production of nonferrous metals from metallurgical processing into copper production. Industrial tests have shown that with the use of technogenic waste from the production of nonferrous metals when smelting copper in metallurgical furnaces, it was possible to reduce the copper content both in the converter slag and in the slag of the reverberatory furnace with the possibility of additional extraction of noble metals. Based on the research carried out, a technological scheme for energy- and resourcesaving copper production technology was developed.

Мониторинг состояния растительности в районе разработки Тасеевского месторождения (Забайкальский край)

The article presents the results of an environmental survey conducted in the development area of the Taseyev gold deposit of the Baleysky district of the Trans-Baikal Territory. Environmental monitoring was carried out on the most vulnerable component of the natural environment in order to ensure the environmental safety of the facility during the implementation of the construction of a heap leaching complex on the basis of the technogenic waste deposit “Baleyskoy ZIF‑1” of the Trans-Baikal Territory. The current state of the vegetation cover was studied. An analysis of the flora of the technogenically disturbed territory of the Taseevskoye field was carried out. As part of the local monitoring of the gold deposit and its environs, 4 types of plant complexes were identified – forest, meadow-steppe, near-river and synanthropic. According to the results of the study, a satisfactory state of plant communities was revealed. A quantitative indicator of diversity has been established, which is more than 80 species within the boundaries of the allotment. Species listed in the Red Book of the Trans-Baikal Territory, growing in the background areas of this field, are noted. A change in the natural vegetation cover on the area of the technogenically disturbed landscape was recorded as a result of industrial work – the movement of soil masses, dumping and excavation. The territory is covered by a chaotic network of country roads that disturb the soil and soil cover. Along the roads gully erosion is developed. There is a negative impact and a decrease in the recreational ecosystem services of the Baleisky district due to the production activities of gold mining enterprises (insufficient formation of a comfortable environment for the population). The presence of synanthropic communities in the anthropogenically disturbed area with traces of household waste dumps, sewage disposal, changes in the microrelief during industrial development on the river is traced Unda. In general, despite the adverse factors affecting the vegetation, plants adapt to stressful situations, all disturbed areas are capable of self-healing.

Study of clay raw materials with Korolek technogenic waste for the production of ceramic bricks

The use of industrial waste in the production of building materials is an urgent task at present. Studies on the use of mineral wool waste in the manufacture of ceramic bricks have been carried out. For the preparation of experimental samples of ceramic bricks used clay deposit, as heaters and intensifiers of sintering – waste production of mineral wool. Chemical composition of investigated components is given. The study of mineralogical and phase composition of raw materials was carried out by petrographic, X-ray phase, IR-spectroscopic, electron-microscopic methods of analysis and DTA. During the experiment such properties of samples as cracking temperature; end shrinkage moisture; relative shrinkage; drying time to residual moisture content of 8%; mechanical strength in compression were tested. As a result of the tests, the influence of Korolek on the drying properties of ceramic samples was established. Thus, an increase in the content of Korolek in the samples, improved the crack resistance, relative shrinkage, drying time to residual moisture. The results of the research showed a non-linear dependence of physical and mechanical properties of the samples on the content of Korolek. The best values of mechanical strength were achieved when the Korolek content was 40% of the total mass of the manufactured sample. The proposed composition corresponds to the properties of ceramic bricks above grade M150-175.

ДРІБНОЗЕРНИСТІ ЗАПОВНЮВАЧІ АСФАЛЬТОБЕТОННИХ СУМІШЕЙ З ПРОДУКТІВ РЕСАЙКЛІНГУ БУДІВЕЛЬНОГО ЛОМУ

The substantiation of the need to develop and implement new resource-saving technologies for the production of construction mixtures using aggregates obtained as a result of complex processing of solid inorganic construction waste is provided. Analytical studies of technogenic waste processing technologies for obtaining building materials have been conducted. The results of the study of the experience of construction scrap processing are presented, with confirmation of the expediency of the fact that the technology of recycling accumulated construction scrap dumps in the territory where the destroyed buildings were located does not require any new specialized measures. The projected volumes of building materials in the composition of residential construction objects with various quantitative parameters of the constituent components of the elements of the fencing structures are presented. Analytical studies have established that the accumulated volumes of construction scrap from the destruction of elements of buildings and structures in the vast majority include the remains of concrete, reinforced concrete, expanded clay concrete, brickwork made of ceramic and silicate products. Experimental series of aggregate samples were made using experimental samples of construction scrap, their granulometric characteristics were determined and physical parameters were investigated. With the use of regulatory and technical literature, the predicted prescription parameters of the concrete mixture using a new variety of aggregates obtained by re-processing of construction scrap were compiled. The presence of reactive substances on the surface of the obtained aggregates was substantiated and the presence of increased physical and mechanical characteristics of the samples with a decrease in the binder content was confirmed. Recipe and technological parameters for the production of wall building materials using the obtained multicomponent building mixtures are proposed. The results of tests of physical and mechanical characteristics of test samples of concrete using aggregates from solid inorganic waste are presented.

The transformations of thiols and their dimers in the redox-mediated thiol-disulfide exchange reaction

A search for new approaches to sulfurous waste utilization is one of the urgent tasks of chemical technology. Thiol-disulfide exchange reaction (TDE) is one of the possible ways to involve technogenic wastes in organic synthesis. Electricity can promote such type of interactions. In this paper, we have studied TDE reactions involving low molecular weight thiols or their dimers under electrochemical conditions. The exchange processes were examined using the model reaction between 1-propanethiol and phenyl disulfide. Electrolysis was performed in the presence of redox mediators such as arylphosphines, substituted amines, o-, p-aminophenols or catechol. These compounds can initiate a TDE process with a formation of unsymmetrical disulfides. 4-Amino-2,6-diphenylphenol was chosen as the most effective redox mediator, which reduces the anodic overvoltage of a thiol oxidation by 1.20 V. The advantage of electrolysis in an undivided cell is the increased yield of target unsymmetrical disulfides due to the possibility of reduction ofhomodimers at the cathode. The involvement of refining waste, such as C3–C4 disulfide oil, in the reaction with substituted thiophenols made it possible to obtain a number of unsymmetrical arylalkyl disulfides with biologically active fragments in a high yield (up to 97%) under indirect electrolysis conditions.