Coal Preparation Wastes Research Articles

Use of coal preparation waste as a reducing agent in the Romelt process

Use of coal preparation waste as a reducing agent in the Romelt process

Recycling of waste of coal enrichment and inter-shale clay used for producing ceramic bricks

The research purpose is to produce ceramic bricks using intershale clay as a clay binder and coal preparation waste as a lean and burnable additive without the use of traditional raw materials. According to the environmental monitoring of segments of the fuel and energy industry, including the adjacent territories, the level of environmental pollution was high even in specially protected areas. Efficient disposal of largetonnage fuel and energy waste is one of the urgent environmental problems. The industry that produces ceramic materials for the construction industry has unlimited possibilities for using large-tonnage waste. Since natural raw materials are depleted, the production of ceramic bricks requires the use of waste coal and intershale clay. The costs of geological exploration, construction and operation of quarries are excluded, signifi cant land plots are freed from the impact of negative technogenic factors. The use of interslate clay and coal preparation waste in the production of ceramic bricks makes it possible to obtain products with thermal conductivity and density, less than 0.250 W/(m ºС) and less than 1300 kg/m3, respectively. The use of largetonnage waste from the fuel and energy industry contributes to the environmental protection and expansion of the raw material base of building materials.

Spraying of Composite Liquid Fuels Based on Types of Coal Preparation Waste: Current Problems and Achievements: Review

This article discusses the atomization of composite liquid fuels. A large group of injectors is considered. A comparative analysis of the atomization characteristics (droplet sizes and velocities, jet opening angles) and the influence of the fuel characteristics (density, viscosity, component composition) and the process parameters (the ratio of the fuel–air mass flow rates, the features of the jet formation) has been carried out. Finally, the most effective types of injectors, which provide for the necessary characteristics of fuel atomization for its combustion, have been determined. The most favorable conditions for the applicability of each type of atomization have been formulated. Possible mechanisms of secondary fragmentation of droplets of composite fuels have been analyzed: those resulting from mutual collisions of droplets in the flux and from the interaction with a solid surface as well as those resulting from thermal overheating in the presence of a phase boundary or a large gradient of component volatility. A conclusion is made about the need of using a synergistic effect of primary and secondary atomization of fuel suspension droplets.

Theoretical and experimental studies of energetics of the dolomite decarbonization process

One of the known advantages of magnesia binders is a significant reduction in energy consumption for the production of such binders compared to the production of lime and Portland cement. The theoretical costs of thermal energy for firing dolomite, which amount to 220-230 kcal/kg (for Portland cement – 420-430 kcal/kg), are almost halved under equal conditions of raw material moisture and furnace efficiency. This study examines the screening of dolomite waste and coal waste materials as raw materials for the production of dolomite cement. Coal preparation wastes in this case are both the initial raw material and, in part, can be used as fuel to ignite the raw charge. Theoretical and experimental studies of the influence of the organic component of coal waste on the process of decarbonization of dolomite have been carried out. The results of thermodynamic studies show that the participation of carbon and its gasification products in the reactions of dissociation of magnesium carbonate makes it possible to reduce the temperature of the beginning of the decomposition reaction of MgCO3 and CaCO3. The energy feasibility of obtaining dolomite binders has been theoretically substantiated.

Restoration of vegetation cover in reclaimed areas with coal preparation waste in Kuzbass

The paper presents the results of research and assessment of the degree of restoration of vegetation cover in reclaimed areas with the use of coal preparation waste in Kuzbass. Reclamation of disturbed lands was carried out by backfilling the depleted pits of the former coal mine with coal preparation waste and forming a root layer on the leveled surface of the waste using materials of the fertile soil layer (FSL) and potentially fertile rocks (PFR). During the field survey of reclamation sites, it was found that when sowing perennial grasses (Bromopsis inermis, Medicago sativa, etc.) or planting trees and shrubs (Hippophae rhamnoides, Pinus sylvestris, etc.) on the root layer formed of FSL and/or PFR, favorable conditions are created in the reclaimed areas for the formation of the primary phytocenosis. Studies have also shown that in reclaimed areas where a fertile soil layer was used to form a root layer, a gradual restoration of soil properties is recorded in the surface fill layers, which in some parameters are close to natural soils common in the adjacent territories.

Assessment of revegetation with waste coal on the reclaimed sites in the Kemerovo Region – Kuzbass

The paper presents the results of research and assessment of the revegetation degree in reclaimed areas using coal preparation waste in the Kemerovo region – Kuzbass. Reclamation of disturbed lands was carried out by backfilling the worked-out pits of the former coal mine with coal preparation waste and forming a root layer on the leveled surface of the waste using materials of the fertile soil layer (FSL) and potentially fertile rocks (PFR). During the field survey of reclamation sites, it was found that when sowing perennial grasses (Bromopsis inermis, Medicago sativa, etc.) or planting trees and shrubs (Hippophae rhamnoides, Pinus sylvestris, etc.) on the formed root layer from the PFR and / or FSL, favorable conditions are created for the formation of the primary phytocenosis in the reclaimed areas. The studies also showed that in reclaimed areas using a fertile soil layer for the formation of a root layer, a gradual restoration of soil properties is recorded in the surface covered layers, which in some parameters are close to natural soils common in the adjacent territories.

Formation of a commodity fuel portfolio of Kuzbass on the basis of coal preparation waste

The Kemerovo Region development strategy until 2035, updated in September 2020, is a forecast of the global technological leadership of Kuzbass, diversification of transport communications with other regions and states, adaptation to the conditions of the 2019 coal industry crisis. To solve these strategic tasks, coal mining and processing enterprises must balance their fuel portfolio and look for new ways to market their products, including the possibility of using production waste. Within the framework of the research carried out by the team of authors: the ecological, technological and economic advantages of using a coal-water suspension as a fuel component have been systematized; identified potential areas of its application; an analysis of the world experience of transporting coal through pipelines was carried out; a proposal was formulated for a project for the construction of the Kuzbass-Ural pipeline for the supply of coal-water fuel to Western Siberia and the Eastern Urals, and the advantages and disadvantages of coal hydrotransportation in comparison with its railroad delivery were identified.

Facultative-anaerobic microbial digestion of coal preparation waste and use of effluent solids to enhance plant growth in a sandy soil

Coal preparation solid waste, which is a major environmental issue for coal-producing areas in China, may be microbiologically digested and transformed into a product suitable as a soil amendment to increase soil organic matter content and prevent and enhance plant/crop growth. Coal preparation waste collected from a coal sorting plant in Inner Mongolia, China was digested in bioreactors inoculated with microbial enrichments prepared from activated sludge and cow manure. The effluent solids from the coal preparation waste bioreactors were analyzed for their suitability as organic soil amendments, which complied with China standards. Plant growth tests were conducted in sandy soil from a semi-arid region in Colorado, which was amended with the effluent solids. Kentucky bluegrass (Poa pratensis L.) and chives (Allium schoenoprasum) were used as the representative plants for the growth tests, where results indicated substantially higher yields of Kentucky bluegrass and chives for the sandy soils amended with the effluent solids when compared to a commercial organic fertilizer. The number and average length of Kentucky bluegrass shoots were 10 and 5.1 times higher, respectively, in soils amended with the effluent solids. Similarly, the number and average length of chives shoots were 10 and 1.7 times higher, respectively, in soils amended with the effluent solids. Overall, the microbial digestion of coal preparation waste for application as an organic soil amendment is a viable alternative and beneficial use of coal preparation solid waste.

Improvement of Technology and Jar Mills for Preparation of Coal-Water Fuel from Waste Coal

The process and equipment have been developed for preparation and burning (at small and medium capacity boiler plants) of slurry coal-water fuel, produced from finely dispersed coal preparation waste (filter cakes) from coal preparation plants of Komsomolets Mine and Named after S. M. Kirov Mine. It was shown that, based on these wastes, it is possible to produce slurry coal-water fuel with solids content of 56-60 %, the required structural and rheological characteristics, and lower heating value of up to 13 MJ/kg. Based on the research findings, detail design was developed for creation of the pilot process complex for processing of waste coal to produce slurry coal-water fuel for burning at boiler plant. Assessment of using the whole volume of the SUEK Kuzbass coal preparation plants waste coal at the nearby Belovskaya SDPP was performed, which showed high economic and environmental efficiency of the proposed project.

Development and creation of an innovative scientific and educational cluster for the integrated use of coal and its products

The article proposes to implement a cluster approach to training, development and creation of high-tech industries in the field of processing of coal raw materials with obtaining end products with high added value. The main technological processes used are: preparation and burning of coal water slurry, based the finely dispersed coal preparation waste as well, liquefaction of demineralized coal and coal slime using a complex of high-energy influences (cavitation, ultrasonic and electric pulse), processing of waste from coal processing plants, bottom ash wastes as a basis for filling mixtures in the dead underground workings and open-pit mines. The implementation of the proposed cluster approach will allow the current scientific and practical problems facing the region in the field of coal mining and processing to be solved.

OPTIMIZATION OF THE COMPOSITION OF THE RAW MATERIAL MIXTURE OF LOW-TEMPERATURE CEMENT ON THE BASIS OF FUEL-CONTAINING COAL PREPARATION WASTE

The article presents a method for calculating the composition of a two-component raw material mixture for producing lime-clay cement based on fuel-containing technogenic waste - gravitational waste of coal enrichment. A method for determining the optimal ratio of components in the charge, taking into account the calorific properties of the waste, is given. The key parameter, in this case, is the energy efficiency ratio. The purpose of the calculation is to determine the ratio of components in the charge, which ensures maximum economy of process fuel. The results indicate the possibility of complete elimination of process fuel from the production cycle at the steady-state thermal process through the use of coal preparation waste.

OPTIMIZATION OF THE COMPOSITION OF THE RAW MATERIAL MIXTURE OF LOW-TEMPERATURE CEMENT ON THE BASIS OF FUEL-CONTAINING COAL PREPARATION WASTE

The article presents a method for calculating the composition of a two-component raw material mixture for producing lime-clay cement based on fuel-containing technogenic waste - gravitational waste of coal enrichment. A method for determining the optimal ratio of components in the charge, taking into account the calorifi c properties of the waste, is given. The key parameter, in this case, is the energy effi ciency ratio. The purpose of the calculation is to determine the ratio of components in the charge, which ensures maximum economy of process fuel. The results indicate the possibility of complete elimination of process fuel from the production cycle at the steady-state thermal process through the use of coal preparation waste.

Study of the Distribution of Macroand Microelements in Coal Preparation Wastes of the Kuznetsk Coal Basin

Study of the Distribution of Macroand Microelements in Coal Preparation Wastes of the Kuznetsk Coal Basin