The electronic structure of the atom as a classification criterion of mineral technogenic waste

Today, the total scientific classification of solid industrial waste is absent because of their diversity. The task of universal of mineral technogenic waste recycling is complicated by the difference in their composition. The nature of the chemical elements that make up building materials is always taken into account to predict their properties. In this regard, the purpose of the study was to determine the classification characteristics of mineral technogenic waste recycling on the basis of natural-scientific ideas about the electronic structure of the atom. Studies were conducted on model systems with ceramic oxides entering s-, p-, d- elements in ceramic matrix to test the impact of the electronic structure of the mineral waste cation on operational characteristics of building materials. The experimental results showed that the strength of the samples changes in the series s → p → d of the belonging of the introduced oxide cation to the electronic family. Additionally, such an indicator as the energy-gap width was used to study the nature of the contacting solid phases. It is possible to identify which substances in technogenic raw materials have the greatest effect on the performance of the material in value of the energy-gap width.

Beneficiation of fine chromite slurry at Donskoy Mining and Beneficiation Plant JSC on concentration tables to produce hard chromite pellets

Processing industrial products and technogenic waste is an important task in the mining and metallurgical industry. In Kazakhstan, the processing of chrome ore from the Kempirsay group of deposits has produced more than 15 million tonnes of slurry tailings containing up to 30 wt% chrome oxide. The best results in the world for the processing of fine chromium raw materials are shown by Turkish enterprises with the use of the separation of slurries by size classes and beneficiation on concentration tables. The authors conducted researches for beneficiation of chrome slurry from Dubersay tailings pond (Kazakhstan) with the use of similar technological methods that enabled to obtain concentrates with chrome oxide content of 51 wt% and increasing the yield of beneficiated fine-graded chrome concentrates by 14% as compared with the existing beneficiation process. Strong chromium pellets with a crushing resistance of over 5000 N/pellet were produced from the rich chromium concentrates with the use of the ferrofluxing iron-calcium-silica binder technology by roasting the composition consisting of rich chromium concentrate, ferrous diatomite, and intermediate products and wastes of the chromium industry.

IMPROVING THE WEAR RESISTANCE OF PAINT AND VARNISH MATERIALS FOR ROAD MARKINGS BY INTRODUCING HIGHLY DISPERSED ADDITIVES

Возможность управления качеством продукции, улучшение эксплуатационных характеристик, адгезии, износостойкости являются приоритетными направлениями в лакокрасочной промышленности. Один из способов влияния на качество лакокрасочных материалов (ЛКМ) – введение высокодисперсных добавок (ВДД) в полимерную основу. В работе осуществлялся подбор ВДД и способ их введения в краску с целью улучшения ее износостойкости, что важно при использовании, например, для дорожной разметки. Было изучено влияние трех типов ВДД: электровзрывного оксида алюминия, ультрадисперсных алмазов детонационного синтеза и оксида алюминия – глинозема (техногенные отходы Ачинского глиноземного комбината). Наибольший интерес в качестве высокодисперсной добавки для улучшения износостойкости полученных композитов представляет электровзрывной оксид алюминия. Установлено, что введение 0,05 масс. % взрывного Al2O3 позволяет увеличить износостойкость в лабораторных условиях на 25 % при сохранении других эксплуатационных характеристик в пределах требования нормативных документов. The ability to manage product quality, improve performance, adhesion, and wear resistance are priorities in the paint and varnish industry. One of the ways to influence the quality of paint and varnish materials (LCM) is the introduction of highly dispersed additives (HDA) into the polymer base. In the work, the selection of HDA and the method of its introduction into the paint was carried out in order to improve its wear resistance, which is important when used, for example, for road markings. The influence of three types of HDA was studied: electroexplosive aluminum oxide, ultrafine diamonds of detonation synthesis, and aluminum oxide-alumina (technogenic waste of the Achinsk alumina combine). Electroexplosive aluminum oxide is of the greatest interest as a highly dispersed additive for improving the wear resistance of the obtained composites. It was found that the introduction of 0.05 wt. % explosive Al2O3 allows you to increase the wear resistance in the laboratory by 30% while maintaining other properties.

Improvement of the Occupational Safety by Radical Isolation of Pollution Sources during Underground Ore Mining

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.

Geopolymer concrete made using large-tonnage technogenic waste

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.

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.