Technogenic Waste Research Articles

Study of the effect of waste-based biocapsules on soil fertility

This article discusses the results of research work on the creation of biocapsules containing the optimal amount of environmentally friendly man-made waste needed to stimulate the growth of agricultural plants, their impact on soil fertility. In the course of scientific research, methods of chemical analysis were used to determine the pollutants contained in the soil, the method of pressing in the production of biocapsules, methods of detoxification and soil purification. For the manufacture of biocapsules from man-made waste, processed products were obtained, that is, biohumus, waste from the production of forest products – wood chips, limestone, and the remains of a clay deposit – clay lump. The use of biocapsules with a clear volume content of components-led to economic efficiency in saving fertilizers, did not pose a threat to the environment and the purity of products. When sowing seedlings on biocapsules, conditions are created that positively affect their yield. In all the biocapsule use cases in all the plants studied, the high product gain was observed to increase by 90 percent. According to the results of the study, it was proved that biocapsules do not show any inverse indicators of soil fertility. In the future, recommendations were developed for the acclimatization of various plants through biocapsules to local regions. The created biocapsules can be used not only in agricultural institutions, but also in the improvement of parks, various public places and courtyards of state buildings. Key words: biocapsule, growth stimulation, technogenic waste, secondary use of waste, agricultural plants, soil fertili.

Utilizing of sunflower ash in the wet conversion of phosphogypsum – a comparative study

Nowadays, there is a tendency to consider large-scale technogenic waste not as waste, but as man-made mineral deposits. For example, phosphogypsum is today considered a source of building materials, fertilizers, rare earth elements, etc. A similar problem is typical in the agricultural sector, whose waste is recycled inefficiently, especially in developing countries. Research in both directions is now on the rise, and the most relevant are those that involve the simultaneous disposal of two or more types of waste. This article critically compares the methods of wet conversion of phosphogypsum by ammonium, sodium, and potassium carbonates. Since the sunflower ash is a cheap source of potash (K2CO3 constituting up to 40% of biomass weight), simultaneous utilization of both agricultural and industrial waste could be achieved. It was found that the leaching of sunflower ash with tap water with preliminary aeration at temperatures below 30 °C provides a K2CO3 yield of about 200 kg/t. The resulting aqueous solution of potash can be processed into commercial salt or used directly for the conversion of phosphogypsum. As a result of such processing, a solution of potassium sulfate – a costly mineral fertilizer, as well as construction chalk, can be obtained. The most valuable elements of phosphogypsum are concentrated in that chalk – strontium and rare earth elements; their isolation into individual compounds can be carried out using appropriate techniques. The method of phosphogypsum conversion by potash solution obtained from water leaching of sunflower ash provides the maximum economic effect – 2300 USD per 1 t of phosphogypsum.

Geochemical modeling of soils and technogenic sediments interactions with natural waters using SELECTOR software (Chaabet-el-Hamra mine, Algeria)

In the mining complex of Kherzet Youcef, including the Chaabet-el-Hamra mine and processing plant, chemical analyzes were carried out on soil and sediment samples and exceeded the normative guidelines for zinc, lead, and cadmium except a small area in the foothills. X-ray diffractometer analyzes confirmed the presence of a considerable inclusion of sulfides (up to 20%), such as pyrite, marcasite (FeS2) and sphalerite (ZnS) especially at the liquid waste disposal site and technogenic sediments. To predict changes in the mineral composition of soils and waste under the condition of their contact with rain water and to assess the potential contamination of ground waters, a thermodynamic model SELECTOR was applied on selected samples. The results of this study conclude that the calculated equilibrium mineral composition is very close to the real phase composition only for the least polluted soils. For technogenic sediments or waste, the equilibrium mineral composition differs significantly from the experimental one. The modeling of potential transition of the main pollutants in water soluble forms allows concluding that in the study area should be feared of exceeding of normative guidelines of cadmium, zinc, and lead.

Повышение безопасности труда радикальной изоляцией источников загрязнения при подземной добыче руд

One of the ways to protect the health of the employees in the mining enterprises is the improvement of the mine atmosphere by strengthening safety measures in the underground mining of minerals, especially those that pose a particular hazard. The aim of the study is to develop a technology for the radical protection of the employees from specific pollution. To achieve this goal, a set of tasks is being solved, one of which is the use of technogenic waste as materials for the preparation of hardening filling mixtures. It is experimentally established that the process of increasing the strength of the tailings of various concentration plants is adequate, the structures of which can be used to control the geomechanics of the ore-bearing massif. Classification of the strengthening mixtures that allow to increase strength can occur when unloading from the crushing and grinding mills. Use of tailings for the manufacture of insulating massifs is possible after extracting the remaining metals from them, for example, using one of the leaching methods. Air pollution with specific substances during underground mining of ore deposits can be radically reduced by isolating workings with artificial insulating massifs. Possibility of using tailings for the manufacture of insulating artificial massifs is substantiated experimentally by comparing the capabilities of mills of various types. The issues of atmospheric air pollution during underground mining, mainly of ore deposits, are considered. Quantitative values of hazard for development systems are given. The results of experiments confirming the possibility of using tailings for the manufacture of concrete insulating artificial massifs are presented. Quantitative values are obtained related to the capabilities of mills for obtaining a product of the same size with different granulometric composition of the starting material when used in industry.

SOIL CONTAMINATION IN THE IMPACT ZONES OF ELECTRONIC AND ELECTRICAL EQUIPMENT PRODUCTION AND WASTE RECYCLING

Soil pollution in the impact zones of enterprises for the collection and processing of electronic and electrical equipment (EEE) wastes is caused by the chemicals they contain. The article presents the results of studying the content of heavy metals in soils and technogenic substrates selected in the impact zones of enterprises for the production of EEE and waste processing, located in the city of Minsk, Belarus. A total of 15 soil samples and 13 samples of technogenic deposits were taken and analyzed. Atomic absorption spectroscopy (AAS) was used in chemical analytical tests. Statistical parameters of the content of heavy metals are presented, their comparison with published data is done. It is shown that the obtained average concentrations of cadmium and lead in the soils of the investigated enterprises are
 1.2–1.5 times, and copper and zinc are 2.7–4.6 times higher than those for the industrial zones of Minsk. The maximum
 concentrations of heavy metals were detected in samples of technogenic deposits containing waste impurities, including
 plastic particles. On the example of other countries, the importance of EEE plastic waste as a source of soil contamination
 is shown.

Геополимерный бетон с использованием многотоннажных техногенных отходов

Introduction. Currently, in all countries, Portland cement is used as a binder in the production of concrete, and its global production accounts for 10 % of the total carbon dioxide emitted into the atmosphere. Therefore, Portland cement can be partially or fully replaced by new cement-free binders, made of large-tonnage technogenic waste with a cementing effect, for example, by finely ground blast furnace slag, fly ash generated by thermal power plants and ash formed during the combustion of rice hulls. Aqueous alkaline solutions (NaOH and Na2SiO3 or KOH and K2SiO3) should be used as activators of setting and hardening of such binders, and calcium sulfate dihydrate can be used to adjust the setting time. Concrete containing new cement-free binders is called geopolymer concrete. Materials and methods. In order to reduce mixing water consumption and maintain the required workability of the fine-grained concrete mixture, a polycarboxylate superplasticizer was introduced into its composition. All raw materials, except for the superplasticizer, were of the Vietnamese origin. The following research methods were used: the composition of the geopolymer concrete mixture was analyzed using the absolute volume method, the workability of the concrete mixture was determined according to ASTM C1611-18 и TCVN 3106:2007, compressive and tensile strength of the concrete, subjected to bending, were tested pursuant to GOST 10180-2012, and the average density of concrete was tested according to GOST 12730.1-78. Results. The co-authors have developed the composition of the geopolymer concrete containing the alkaline cement-free binder. As a result of the heat treatment of the 28-days-old concrete for 6 hours at 100 °C, its compressive strength reaches about 60 MPa; hence, it can be used in the hot and humid climate of Vietnam. Conclusions. This cement-free concrete, in addition to its high strength, has good water resistance and low water absorption. This concrete has economic benefits, and its production will help to protect the environment due to the lower consumption of natural resources and the applicability of large-tonnage technogenic waste.

Mineral Layer Fillers for the Production of Functional Materials.

An original method based on the use of technogenic waste from the processing of mineral-layered materials, in particular phlogopite for obtaining highly efficient functional compositions of the “mica-TiO2”, has been developed. The composition core is a nanosized mica flake coated with mesoporous titanium dioxide of an anatase or rutile structure. Energy-saving and environmentally friendly technological methods are based on the splitting of the mica followed by heterogeneous electrohydrolysis of a mixture of titanium (IV) sulfate solution and flake particles. No destruction of the mica surface, which provided the obtained uniform coatings, has been observed. Such coatings are used in photocatalysis processes and possess a self-cleaning capability. Core–shell compositions are more economically attractive compared with titanium dioxide, in particular TiO2 grade P25 (Degusse). The core of the transparent flake and the shell of the rutile titanium dioxide endows the final product with a pearlescent optical effect. This type of material is widely used in the manufacturing of paints and varnishes, printing inks, cosmetics, etc. The use of technogenic waste could significantly reduce the cost of the final product, which would ensure its widespread use in various industries.

Multi-criteria analysis of resource saving and energy efficiency in the technogenic waste processing system of the oil and gas industry

The paper proposes a new approach to multi-criteria analysis of resource and energy saving in the system of processing industrial waste of oil and gas enterprises based on the Data Envelopment Analysis (DEA) method. The DEA method is being extended by the authors to a completely new subject area of extremely important engineering applications related to the problems of processing oil and oily waste.
 The basis of the algorithm for analyzing objects of the wastes processing system considered in the article is a new methodology for sequentially solving interrelated problems of multi-factorial comparison of objects according to heterogeneous quality criteria, which differ in new formulations of related problems of mathematical programming.
 The developed algorithm for multi-criteria analysis of resource and energy saving in the processing system allows: collecting, classifying and processing information about the objects of the system; assessment and analysis of the resource value of waste in storage, which determines the degree of suitability of waste for use as material resources in processing technologies associated with their recycling and recovery; assessment and analysis of the resource potential of storage facilities and technologies, which determines the efficiency of the secondary use of industrial waste, taking into account their resource value; evaluation and analysis of the resource and energy saving in the system in general.
 The partial and generalized indicators of the efficiency of the waste processing system obtained as a result of solving interrelated problems of mathematical programming are analyzed in the decision support system and make it possible to form local control actions on the system or to justify the strategies for managing the waste processing system.
 The proposed approach can in the future receive multiple applications in the oil-bearing regions of the Russian Federation, where the growth in the formation of the technogenic waste has serious and often irreversible environmental consequences.

The Concept of Dumping Nickel Slag Processing with Preliminary Extraction of Metals

The present study considers various technological approaches to the processes of complex utilization of nickel slags with preliminary additional extraction of non-ferrous metals, iron, and ways of utilization of the obtained gangue. The valuable components are often produced from waste using the mineral acids or mixtures; the metals are extracted from acid solutions in a free form or in the form of compounds using electrochemical or chemical methods. Slag dumps have a heterogeneous structure and mineralization; the zone distribution of slag is clearly defined due to different cooling and solidification rates. The slag composition is mostly represented by dense low-porous varieties consisting of dark brown glass. The porous slag fragments are secondary. The third texture diversity in the composition of slag is represented by nodular and kidney-shaped particles. The diversity and size of the ore minerals is directly connected with the distribution of pores in slag. The major ways for utilization of nickel industrial waste are pyro-metallurgical and hydrometallurgical methods. In addition, each of the methods is usually preceded by the stage of mechanical preparation of the raw materials, where the techno-genic waste is crushed.

The Study of the Magnetic Properties of Red Mud from Alumina Production after Alkaline Treatment

In Russia, the main feedstock for producing aluminum is bauxite. During the processing of 1 ton of bauxite into alumina (Al2O3), up to 0.5–0.6 ton of techno-genic waste is formed, that is red mud. It is not currently disposed of and accumulated in mud tailing dumps. It contains valuable components: Al – 8 %; Fe – 25 %; Ti – 2.4 % and it can be considered as a potential raw material for ferrous metallurgy and as a source of vanadium, titanium, and rare-earth elements (REE) Sc, Y, La. The paper shows the possibility of obtaining red mud with an increased iron content of up to 36 %, with an additional extraction of aluminum. Red mud from the Ural Aluminum Plant (Russia) is considered. It is proposed to direct this mud to the production of pellets for the production of cast iron. To extract aluminum from red mud, it is proposed to process the mud in a highly alkaline medium by sintering in the temperature range 300–600 °C. The resulting sinter is leached with water or a slightly alkaline solution with the conversion of aluminum compounds into solution. The red mud, obtained this way, exhibits magnetic properties. A magnetic separation was carried out, and the yield of the magnetic fraction is 79.87 %. The iron content increases by 25 % and amounts to 51.88 % of Fe2O3.

АНАЛИЗ И ПЕРСПЕКТИВЫ УТИЛИЗАЦИИ ТЕХНОГЕННЫХ ШЛАКОВЫХ ОТХОДОВ СВИНЦОВОГО ПРОИЗВОДСТВА

The article presents the analysis and results of the study of technogenic slag waste of lead-zinc production. Slags of lead-zinc production contain a large number of toxic compounds: lead, zinc, osmium, cadmium, which are dangerous sources of environmental pollution. Due to the open storage of slags, it was found that the maximum permissible concentrations of lead were exceeded. Utilization of man-made slag waste is of great importance for reducing the negative impact on the safety of life and improving the environmental situation in the region. At the same time, slags are valuable raw materials containing compounds of non-ferrous and rare-earth metals. The article shows the results of laboratory studies of slags to determine the qualitative and quantitative composition of valuable components in the waste of lead production and the possibility of their further processing and disposal. Studies of the material of the heavy slag fraction were carried out on an electron probe microanalyzer of the JEOL IXA-8230 Electron Probe microanalyzer brand. X-ray diffractometric analysis of the average slag sample was performed on a DRON-4 diffractometer with Cu radiation, graphite monochromator. Samples were selected heavy fraction and manufactured artificial polished sections (briquettes). The sections were studied under the microscope of the brand LEICA DM 2500P and immersion in liquids. According to the results of research, it was found that lead slags contain a sufficiently high amount of non-ferrous metal compounds: lead oxide up to 0.7 % and zinc oxide up to 8.5 % of the weight amount of slag, which makes the process of recycling toxic waste from lead production technically and economically feasible.

МИНЕРАЛО-ПЕТРОГРАФИЧЕСКИЙ АНАЛИЗА ГЛИНИСТОГО СЫРЬЯ ТУРКЕСТАНСКОЙ ОБЛАСТИ, ИСПОЛЬЗУЕМОГО В КАЧЕСТВЕ ДОБАВОК К ТЕПЛОИЗОЛЯЦИОННЫМ МАТЕРИАЛАМ

The article discusses the contributes to the development of a new focus on the use of various mixtures of natural raw materials and waste in the construction materials industry as a strategically important direction for solving the environmental burden and recycling industrial waste with a feasibility study that improves the state of the environment. This problem is particularly relevant in the production of building materials used in environmentally distressed areas of the republic and in conditions of intense corrosion and erosion wear. The production of efficient building materials and products that meet the modern requirements of environmental friendliness, basic physical and mechanical characteristics, availability and cost is an important and not fully solved task in the field of construction and the construction materials industry. Analysis have been conducted on the current state of the local availability of perspective materials for high-quality composite construction materials, their chemical and mineralogical and granulometric properties have been studied, the influence of the granulometric composition of the basic properties of a composite material and features of the structure formation during heat treatment were studies; physical and mechanical properties of the obtained compositions were tested. Optimal compositions and technological schemes for the production of composite materials based on the use of technogenic waste, natural raw materials and their mixtures have been developed to ensure the production of high-quality construction products with specified thermomechanical properties.The optimization of compositions and properties of compositions was carried out using mathematical planning methods, which made it possible to predict changes in the properties of composite materials depending on the number, weight of the components and the size of the filler granules. Experimental batches of at least 3 main types of construction products were obtained.

Wasteless processing of ladle furnace and electric arc furnace slag

The actual problem of mineral resources depletion in ferrous metallurgy can be effectively solved by complex reuse of technogenic waste. That waste is mostly presented by EAF (electric arc furnace) slag and LF (ladle furnace) slag. These two kinds of slag have no complex full utilization. The residues of slag are going to the dump and then the slag dump locations pollute the environment. However, the residues of EAF and LF slag can be transformed into the valuable industrial product by interaction of the slag components. This work presents the research for joint wasteless processing of EAF and LF slag with production of Portland clinker and cast iron. The article describes disadvantages of known methods of each slag processing; the paper also shows the significance of LF slag utilization. Design and calculations of the research are presented as well as its experiment methodology. The final results show five chemical compositions for the mixtures, which allow the complex processing of this slag without any waste left. Such processing provides the production of cast iron and Portland clinker both meeting requirements of normative documents. The paper also describes the results of viscosity measurements of slag compositions, the obtained slag phases, and presents the final temperature conditions. The work also considers the results of industrial tests for the developed processing technology and a complete technological chain involving the use of tilt rotary furnaces.

Iron removal stations’ sludges postprocessing for its resource potential identification

Introduction. The sludge of the washing waters of the underground water iron removal station is a large-tonnage technogenic waste that is dangerous for the environment. The homogeneous chemical composition and finely dispersed structure of the sludge make it possible to consider it as a valuable raw material for the production of various products in the conditions of a forward movement towards a circular economy. Obtaining nanosized metal powders from the sludge of iron removal stations has a number of advantages over traditional physical, chemical and mechanical methods. To optimize the process of obtaining highly dispersed metal powders from the sludge of iron removal stations, it is necessary to study the influence of the main technological parameters on the size, shape and chemical composition of the final material.
 Materials and methods. Thermal treatment of the sludge of the iron removal station in the carbon monoxide medium was carried out in the temperature range of 400–600 °C. Ultrasonic dispersion was used to get an idea of the true particle size. The granulometric composition of the sludge was studied by electron microscopy and laser beam scattering.
 Results. The results of experimental studies of the granulometric composition of the treated sludge of iron removal stations are presented. The particles obtained at a temperature of 450 °C had the most pronounced spherical shape, low open porosity, and a low degree of adhesion to neighboring particles. These properties are key for micro- and nanopowder-based products. An increase in the temperature of sludge processing led to the adhesion of particles and their fusion into large aggregates with a brittle structure as a result of the development of crystallization processes.
 Conclusions. The proposed methods of physicochemical treatment in an environment of carbon monoxide and ultrasonic action of the sludge of an iron removal station, which is currently a technogenic waste, makes it possible to obtain a highly dispersed metal powder. This material has the necessary properties for use in modern high-tech industries.

Current state of the problem of soil protection and prospect of using humic acids

The article reviews the literature on the state of the problem of protecting the soil cover of the earth. Today, during the period of strong pollution of the lithosphere by technogenic wastes of various nature, leading to soil degradation and erosion, in measures to improve the physical, chemical, hydrological, agronomic and other properties of soils, preference should be given to the least harmless natural raw materials. These include humic acids (HA) and their derivatives, which are good adsorbents, stabilizers and fixers of dispersed systems. The study of the composition of humic acids with various water-soluble polymers and surfactants is another not fully understood area of interdisciplinary nature. Literary search for the works of Kazakh scientists shows the underdevelopment of both the extraction of humic acids and the formation of HA interpolymer complexes (IPC) with polymers and surfactants, as well as their use as fixers, structure formers of soils subject to wind and water erosion. Having large reserves of coal in the republic, a source of humic acids, it is not forgivable not to develop an integrated approach to research on the extraction of HAs, the formation of IPC on their basis and the use of new structure-forming agents to improve the degraded soils of the republic's structures.

Optimization of fresh properties and durability of the green gypsum-cement paste

Despite the fact that gypsum materials have many advantages, such as fast hardening, low cost, environmental friendliness, their field of application is limited by low values of compressive strength, water resistance and durability. An urgent task is to increase the efficiency of the gypsum composite through the use of Portland cement, as well as a natural and man-made waste. The novelty of the work lies in the identification of scientific regularities of the influence of industrial waste on the structure formation and properties of green gypsum-cement paste (GGCP). For the first time, the genesis and technogenesis of quartz in the waste of ferruginous quartzites is generalized and studied. The features of the formation of the structure and hardening of GGCP are studied taking into account the chemical, structural and morphological features of dehydrate gypsum, Portland cement and man-made waste of various genesis. Gypsum β-modification of the G-5B II grade and technogenic wastes were used as a binder component and mineral additives, respectively. The fresh properties and durability of the GGCP were studied according to standardized test methods. However, the influence of different fineness of grinding of components on the performances of GGCP was investigated. It was revealed that with a decrease in the fineness of concrete waste, from 200 to 600 m2/kg, the compressive strength significantly increases, 4 times. This is due to the fact that when concrete waste is ground; previously unhydrated cement particles are exposed, which undergo hydration later. It was revealed that the maximum compressive strength of 22 MPa of the GGCP is achieved at a specific surface area of 600 m2/kg, a further increase in the specific surface area would lead to a decrease in compressive strength, which is explained by an increase in water demand. As a result of research for two years, both in water and air, it was found that there were no signs of destruction and decrease in the strength of the specimens. In accordance with the experimental data obtained, a three-stage model of the structure formation of the GGCP with mineral additives of industrial waste was proposed.

Application of data envelopment analysis for multi-criteria evaluation of system for technogenic waste recycling in oil refining industry

The paper proposes an approach based on the DEA method (Data Envelopment Analysis) to a multi-criteria evaluation of a complex structured system for the processing of technogenic waste in the oil refining industry. The special algorithm is considered for assessing environmental safety and energy efficiency of operating waste processing system facilities, taking into account their resource value and reuse potential. According to the developed algorithm, five interconnected mathematical programming problems are solved. These problems formulated using CCR and Super-efficiency models of DEA method allow to obtain the assessments of the disposal system regarding the chosen efficiency criteria. A new approach to the analysis of the results on the basis of total effectiveness estimates using the Super-efficiency model of the DEA method is proposed. The results of testing the developed algorithm on an oil-containing waste processing system in the Samara region make it possible to form appropriate control decisions in the region’s oil refining industry.

Combined Refractory Materials with Addition of Technogenic Waste for Metallurgical Assemblies

Combined refractory materials due to their physical and mechanical properties and high stability have been widely used in recent years in metallurgical assemblies with sudden changes in temperature regime, as well as during prolonged downtime or temporary shutdown. Silica refractory can be prepared from clay, chamotte with the addition of silicon production waste (microsilica), as well as with addition of aluminum fluoride production waste (silica gel). In the course of research samples of refractories with different content of modifying additions of technogenic waste in the form of microsilica and silica gel are prepared. The physical and mechanical properties of samples are studied. Examples of using microsilica and silica gel are considered, and based on the results obtained an optimum composition is proposed providing refractory material with high strength and thermal conductivity. Improved properties suggest that microsilica and silica gel may be used as raw materials for the manufacture of combined refractory materials.

Combined refractory materials with the addition of technogenic waste for metallurgical devices

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Effective building materials using technogenic waste and mineral raw materials

The results of research on the development of compositions of construction materials for structural purposes based on technogenic waste and mineral raw materials are presented. The possibility of obtaining materials with a wide range of operational properties by the methods of slip casting (compressive strength of the samples based on chamotte and sand is 53.0–95.9 and 50.0-69.5 MPa, bending strength is 8.1–16.5 and 8.5–15.3 MPa, abrasion is 0.2–0.36 and 0.15–0.39 g/cm2, respectively) and semi-dry pressing (compressive strength of the samples based on chamotte and sand are 19.1–43.5 and 18.3–32.6 MParespectively) isdemonstrated.