Ash Components Research Articles

Identification of Sediment Formation Based on Magnetic Content and Element Composition of Mud Volcano in Sangiran Sediment using VSM and X-Ray Fluorescence

Based on trace geological history and several studies, the Sangiran mud volcano provides insight into the geology and hydrology of the region, aquifer system in the basin, groundwater flow patterns and characteristics, rock lithology, hydrogeology condition, and saltwater trap mapping. Related to these conditions, studies were conducted on the magnetic content and composition of the major oxide compounds in the Sangiran sediments. Sample analysis was based on geochemical methods. The methods consist of frequency dependent magnetic susceptibility and vibrating sample magnetometer (VSM) analysis. Geochemical analyses using x-ray fluorescence (XRF) analysis have been conducted and various elemental grades have been determined. VSM results confirm that the magnetic content of Sangiran sediments is partly dominated by Fe (17.66 percent) contained in hematite (Fe2O3). At the same time, the samples of Sangiran sediment were enriched by Si, Fe, Al, Ca, Cl, Ti, and K according to XRF measurements. The samples exhibited the highest Si and Fe concentrations in samples T1 (Si is 29.48 percent and Fe is 13.66 percent) and T7 (Si is 24.95 percent and Fe is 12.01 percent). Meanwhile, in the T4 sample, the highest concentrations were Si and Ca, 23.45 percent and 13.45 percent, respectively. Retrieved from the magnetic susceptibility measurement, this paper confirm that Fe content is one of the components of volcanic ash in the Sangiran sediment.DOI: 10.17977/um024v8i12023p009

Performance characteristics of 76 mm dense medium cyclone to wash high ash high NGM coal

ABSTRACT The present paper describes the detailed experiments carried out using 76 mm dense medium cyclone to determine the extent of beneficiation, ash percent reduction, recovery of ash and non-ash components in clean coal product and the effects of design parameters (Vortex finder and Spigot diameters) on the performance of the two separators have been brought out critically. Under the heading qualitative studies, the recoveries of ash (RA) and non-ash (RNA) percentages achieved in the clean coal, have been related to outlet diameters through regression equations. Further to quantify the performance of the separators, the two performance parameters has been named the efficiency index (EI) and separation efficiency index (SE) have been considered in the analysis. The performance of the separator measured using dependent (EI and SI) and the independent (Tromp or partition curves) criteria have also been discussed in detail. From the plotted tromp curves, the two performance parameters SG50 and EP have been estimated and their dependence on outlet diameters and geometric mean sizes have been depicted here. Additionally, to predict the performances of the separators, the concept of plotting generalized partition curves has been adopted for the separation of bulk coal (−3 + 0.5 mm) and the individual size fractions of the coal (1.93 mm, 1.22 mm, 0.86 mm and 0.35 mm), which have been defined mathematically by Gottfried’s model. It has been found that the coarse fraction of feed separated at lower density, whereas finer fraction have indicated to get separated at higher density.

An Experimental Study on the Conversion of CaO to CaSO4 During Diesel Particulate Filter Regeneration

The deposition of ash on a diesel particulate filter (DPF) results in an increase in pressure drop across the aftertreatment system, which leads to reduced capacity for soot and an increase in frequency of regeneration to eliminate the soot. To estimate the amount of ash and design a reduction method for the accumulated ash on the DPF, a deeper understanding of the ash generation mechanism is required. Previous studies have found that ash sampled at exhaust manifolds comprises metal sulfate and some oxides, whereas ash accumulated on DPFs primarily comprises typical metal sulfates. Although metal oxides are converted to the metal sulfates, the conversion mechanism is not well understood. Herein, the formation mechanism of calcium sulfate (CaSO4), which is the main component of ash on DPFs, from calcium oxide (CaO) was investigated using a flow reactor. CaO was made to react with SO2, SO3, O2, and H2O, when passed through a diesel oxidation catalyst. Quantitative analysis of the ash components in the products was performed using ion chromatography. The concentrations of SO2, SO3, and H2O during the reaction were analyzed by Fourier-transform infrared spectroscopy. Based on the experimental results, it was found that CaSO4 mainly formed from the reaction of CaO with SO2 and SO3; whereas, H2O inhibited CaSO4 formation owing to the change in physicochemical properties of CaO.

Evaluation of Properties for Making of Bricks by Using Granite Sludge Powder

Numerous issues arise from the discharge of waste materials. The primary issues are the spot involved by locales of capacity, significance of expenses and the natural effect. The primary objective of this preliminary work is to investigate the possibility of using stone waste as a substitute for raw materials in the production of granite sludge bricks. The exhibition of the Rock ooze block's compressive strength and a correlation of it with the ordinary dirt blocks. Clay,water,sand ,fly ash,cement, and other components make up granite sludge brick. Due to its lower cost and higher compressive strength in comparison to other bricks, its wides preaduse may become an important criterion for evaluation. Granite sludge bricks have been the subject of numerous experiments, and the results indicate that they lack compressive strength. As a result, numerous tests on the granite sludge brick's strength using various additional materials were carried out.These various additions might include fly ash, clay, cement, s and, and soon, the alterations ingranitesl udge bricks' compressive strength caused by these various additional materials.The granite bricks have a moisture content of 20% and measure 22 cm by 10 cm by 7 cm. Hence we involved a modest material for the streng thin rock ooze block. Where they have extra pieces in development, so we involved them in mud blocks. Granites ludge bricks performed better than conventional bricks, as demonstrated by the findings. Clay was added to the mixture in weight amounts of 10%,20%,30%,40%, and 50%.Test for water absorption and compressive strength.

Experimental Study on the Mechanical Properties and Microstructures of Cenosphere Concrete.

The most valuable components of coal fly ash are cenospheres. Cenospheres are hollow spherical particles produced during the coal-burning processes. As a result of their excellent characteristics, such as high workability, high heat resistance, low bulk density, and high strength, cenospheres can be used in the manufacturing of lightweight cement concrete. The research efforts and outcomes are to produce long-lasting cement-based lightweight concrete (LWC) composites with good mechanical properties. The novelty of this investigation is to determine the cement concrete strength when silica fume (SF) and cenospheres (CS) were used as a replacement for cement. Throughout the experiments, a consistent substitution of 12% silica fume was incorporated into cement mass. Silica is used as a micro filler and pozzolanic reactant to strengthen concrete. The concrete mixtures were tested to ensure they met the requirements of the lightweight concrete in terms of their mechanical, physical, and durability qualities. According to the findings, lightweight concrete standards were met, and environmental sustainability was improved with the use of these mix proportions. Concrete specimen's self-weight decreases by 35% with 30% cenosphere as a replacement. The micrograph shows the lack of portlandite is filled by mullite and other alumino silicates from the cenosphere. In order to achieve sustainability in concrete manufacturing, these mixtures can be suggested for the making of structural LWC that makes use of a large volume of industrial waste while conserving cement and natural resources.

Understanding reactive amorphous phases of fly ash through the acidolysis

It is well understood that the reactive components of fly ash (FA) in alkali cement are mainly donated by amorphous phases. The acidolysis method is typically employed to dissolve these amorphous phases for separate analysis; however, such method is not truly convincing, especially the testing and analysis processes. This paper investigates the hydrofluoric acid (HF, 1%) dissolution process (from 0.5 h to 20 h) of two Class-F FAs with different physical and chemical characteristics. The time-dependent quantitative analysis results indicate that in addition to amorphous phases, some crystalline phases are also dissolved in 1% HF solution. Further, the chemical statistics on the dissolved amorphous phases was extracted from the scanning electron microscopy images. Amorphous aluminosilicates in FA can be quantitatively classified into six groups, of which the three reactive amorphous aluminosilicates are defined.

Leaching characteristics and potential risk of heavy metals from drip irrigation pipes and mulch substrate in agricultural ecosystems

Drip irrigation is a valuable method for optimising water and fertiliser usage, motivating its increasing use. However, the ecological effects of drip irrigation fertilisation have not been sufficiently evaluated, limiting its effective and widespread use. Within this context, we aimed to determine the effects and potential ecological risks of using polyethylene irrigation pipes and mulch substrate under various drip irrigation conditions as well as burning of waste pipes and mulch substrate. Laboratory simulations of field conditions were used to determine the distribution, leaching, and migration pattern of heavy metals (Cd, Cr, Cu, Pb, and Zn) from plastic drip irrigation pipes and agricultural mulch substrate into various solutions. Maize samples obtained from drip-irrigated fields were analysed to determine the presence of heavy metal residues and assess the risk of heavy metal contamination. Heavy metal leaching from pipes and mulch substrate was high under acidic conditions, while the migration of heavy metals from plastic products was low in alkaline water-soluble fertiliser solutions. After combustion, heavy metal leaching from pipes and mulch residues increased considerably, with the migration capacity of Cd, Cr, and Cu increasing by >10-fold. Heavy metals in plastic pipes migrated primarily to the residue (bottom ash), whereas those from mulch substrate migrated to the fly ash component. Under experimental conditions, the migration of heavy metals from plastic pipes and mulch substrate had a negligible effect on the heavy metal content in aqueous environments. Although heavy metal leaching increased, the effect on water quality under actual irrigation conditions was relatively minor (in the order of 10−9). Thus, the use of plastic irrigation pipes and mulch substrate did not result in significant heavy metal contamination and potential risk to the agriculture ecosystem. Our study findings provide evidence for the effective application and widespread promotion of drip irrigation and fertiliser technology.

Progress and Challenges of Biological Leaching of Heavy Metal in Coal Ash from a Power Plant

Bioleaching is a technique for reducing the heavy metal content of coal ash by using bacteria, fungi, or yeast. Previous studies in heavy metal bioleaching of coal ash discussed the factors affecting the process, but as yet there is little information on the challenges of using microorganisms. Therefore, this study aimed to obtain comprehensive information regarding the use of microorganisms in heavy metal bioleaching. Heavy metal concentrations in coal ash are low, and the metals are diverse. The components of coal ash are complexes that cannot leach certain heavy metals according to previous studies. These low concentrations and complex components make it difficult to investigate the bioleaching mechanism. The combination of biological and chemical interactions involves various components in this system. The high concentration of iron and heavy metal leached could be toxic for microorganisms. The process is influenced by several factors, such as particle size, pH, and pulp density. Most heavy metal bioleaching studies on coal ash have been conducted on a small scale to control conditions affecting the process. Bioleaching kinetics in coal is a liquid-solid reaction that can be represented by the shrinking core model, which was mainly used in this study.

Metal Oxides Enhance the Absorption Performance of N-Methyldiethanolamine Solution during the Carbon Dioxide Capture Process.

Fly ash from coal-fired power plants can enter chemical absorbents along with flue gas. Silica and metal oxides are the main components of fly ash. To explore the effect of the metal oxides on absorbents, we analyzed the integrated CO2 absorption-desorption process using N-methyldiethanolamine (MDEA) as the standard and an amine absorbent after adding different metal oxides. The effects of each metal oxide on CO2 capture by the MDEA solution, including CO2 reaction heat, absorption rate, cyclic loading, and carbonation rate, were assessed. It was found that supplementation with appropriate calcium oxide and magnesium oxide proportions accelerates the CO2 absorption rate and shortens the saturation time of the MDEA solution by 9%-17%. Magnesium oxide and calcium oxide were precipitated as carbonates during absorption. The CO2 reaction heat of the MDEA solution increased by 95% after adding magnesium oxide, thereby significantly increasing the energy consumption of the desorption process. On the basis of the experimental studies, the increase in CO2 absorption rate by MDEA after adding MgO and CaO may be mediated through two different mechanisms.

Evaluation of current natural and anthropogenic radionuclide activity in coastal area bottom sediments of the Barents Sea (North of the Kola Peninsula)

This article is devoted to the study of the activity of technogenic 137Cs and 90Sr, as well as natural radionuclides 40K, 232Th and 226Ra in bottom sediments of the Kola coast of the Barents Sea, where a significant number of radiation objects are concentrated. In order to characterize and assess the accumulation of radioactivity in the bottom sediments, we studied the particle size distribution and some physicochemical parameters, such as the content of organic matter, carbonates and ash components. The average activities of natural radionuclides 226Ra, 232Th and 40K were 325.0, 25.1 and 466.7 Bq·kg−1, respectively. Levels of natural radionuclides in the coastal zone of the Kola Peninsula are within the range of marine sediments worldwide. Still, they are slightly higher than those observed in the central areas of the Barents Sea, most likely due to the formation of coastal bottom sediments as a result of the destruction of the natural radionuclide-enriched crystalline basement rocks that make up the Kola coast. The average activities of technogenic 90Sr and 137Cs in the bottom sediments of the Kola coast of the Barents Sea are 3.5 and 5.5 Bq·kg−1, respectively. The highest activities of 90Sr and 137Cs were found in the bays of the Kola coast, while they remain below detection limits in the open parts of the Barents Sea. Despite the presence of potential sources of radiation pollution in the coastal zone of the Barents Sea, we did not find any short-lived radionuclides in the bottom sediments, which indicates the absence of a significant influence of local sources on the transformation of the technogenic radiation background. The study of particle size distribution and physicochemical parameters showed that the accumulation of natural radionuclides is largely related to the content of organic matter and carbonates, while the accumulation of technogenic isotopes occurs in the composition of organic matter and the smallest fractions of bottom sediments.

Investigations on Single Minerals and Synthetic Ash Components for the Enrichment of Copper from Waste Incineration Bottom Ashes by Flotation

Currently, MSWI (municipal solid waste incineration) ashes are predominantly landfilled, although they can have copper contents comparable to those of low-grade ores. Based on a previously published characterization of MSWI-BA, this paper presents investigations on the identification of potential collectors for copper recovery from MSWI-BA by flotation. The studies were conducted with single minerals (mainly copper oxide and sulfide) and synthetic slag components. Collector screening included thiourea-, thiophosphate-, and thiocarbamate-based collectors. In addition to commercial collector mixtures, pure ureas were also examined. At least one representative from each collector group was selected for the more in-depth studies: the thiourea S-n-dodecyle-iso-thiourea hydrochloride, the thiophosphate Danaflot 245, AERO 3473, and AERO MX-5160 as a mixture of a thiocarbamate and thiophosphates. Studies of the influence of collector concentration and pH were carried out with these. In addition, the contact angles of various metal oxides and the matrix composition with and without collector treatment were determined. Subsequently, flotation tests were carried out with mixtures of copper oxide and the individual matrix components (quartz, glass, cement, gypsum). AERO MX-5160 proved to be the most suitable collector, although alginic acid was added as a depressant due to a lack of selectivity towards gypsum.

Valorization of food waste digestate to ash and biochar composites for high performance adsorption of methylene blue

The valorization and appropriate treatment of food waste digestate (FWD) is a critical issue for facilitating the sustainable development of anaerobic digestion and actualizing a circular economic. The FWD contains high ash contents and is conventionally considered as an inappropriate feedstock for producing high-value products such as biochar. However, this ash content may also have a chance to enhance the application performance of biochar as an adsorbent if positive synergic effect is identified. This study used industrial FWD as a widely obtainable feedstock for producing ash-biochar composites (ABCs) for methylene blue (MB) contaminated wastewater abatement. The obtained ABCs performed a maximum MB adsorption capacity of 1123.5 mg/g. Mechanism and modeling assessments demonstrated that the ash components on the surface of ABC adsorbent enhanced MB removal by providing alkaline adsorption environment and more oxygen-based n-π interaction sites. In addition, increasing pyrolysis temperature enlarged the biochar surface area and homogenously rearranged the carbon structure to strength the π-π interaction between MB and ABC adsorbent. This research suggests that FWD is principally an ideal feedstock that can be directly used for making high-performance absorbents for wastewater treatment.

Ash melting behavior and mechanism of high-calcium bituminous coal in the process of blast furnace pulverized coal injection

Abstract High-calcium bituminous coal has the advantages on combustibility, but its ash melting point is low, and it is easy to slag in blast furnace injection process. In order to explore the ash melting slag formation mechanism of high-calcium bituminous coal, the mineral evolution of ash in the combustion process of high-calcium bituminous coal and the influence of ash components on the liquid formation in the melting process were studied. The results showed that the melting behavior of ash gradually occurs with the change in the morphology, and the main mineral transformation is carried out around different deposition forms of Ca and Si. The liquid phase formation of ash at high temperature is the essential reason of its melting behavior. The higher the content of CaO, the higher the starting temperature of the liquid phase formation. The higher the content of SiO2, the lower the starting temperature of the liquid phase formation, and the more the liquid phases generated at a given temperature. Increasing the content of Al2O3 can expand the temperature range of reducing the formation of ash liquid phase to 1,473–1,673 K. When the temperature is above 1,573 K, Fe2O3 can promote ash liquid phase formation.

Гидролиз гемицеллюлоз древесины при ультранизких концентрациях серной кислоты

Studies in the field of hydrolysis of plant polysaccharides are ordinary classified according to protic reactions with diluted or concentrated acids. Such classification is based on the significant difference in the mechanisms of the reactions. The hydrolysis of polysaccharides of plant materials with the diluted acids is indicated by the concentrations of the mineral acids 0.5–10.0 % or happens by acid-free autohydrolysis, without any use of acids. Each of these reactions has considerably different kinetic and temperature-time parameters. They have both advantages and disadvantages. In particular, the hydrolysis using dilute acids is specified by a significant consumption of reagents and the presence of a large amount of carbohydrate degradation products in the hydrolysate. Autohydrolysis is characterized by a relatively low monosaccharide yield, high energy consumption for the process and the formation of many by-products. To date, studies regarding hydrolysis of polysaccharides of plant materials with acids in a concentration range of less than 0.5 % are absent. The reason for the lack of interest in research in this area, in our opinion, was the statement that acid in the process of hydrolysis is spent on the neutralization of ash components of plant materials at a flow rate of 5 to 20 g/kg of dry raw materials. Accordingly, when hydrolysis is carried out with ultra-low concentrations of acid, it is possible to completely neutralize it and switch the hydrolysis process from acid to acid-free autohydrolysis. The purpose of the work was to establish the efficiency of the hydrolysis process at ultra-low acid consumption. A study of the process of hydrolysis of hemicelluloses of birch wood at ultra-low concentrations of sulfuric acid was carried out. The possibility of almost complete hydrolysis of hemicelluloses with sulfuric acid with concentration of 0.10–0.25 % is shown. The process of hydrolysis of hemicelluloses with ultra-low acid concentrations is well described by the first order reaction. The general kinetic constants are calculated according to the experimental data. They show that the process occupies an intermediate position between acid-free autohydrolysis and traditional hydrolysis of hemicelluloses with sulfuric acid with a concentration of more than 0.5 %. The developed technique is advantageously different from the known methods of hydrolysis of hemicelluloses by low consumption of sulfuric acid (more than 5 times) and energy resources. Hemicellulose hydrolysates obtained by ultra-low acid concentration regimes have high benign properties and can be used in xylitol production.

Soot and gaseous product formation characteristics of leached high-alkali lignite pyrolysis at a high temperature

The contents of alkali and alkaline earth metals (AAEMs) in Zhundong lignite are very high, which can affect the formation of soot during coal combustion process. In this study, the effect of leaching treatment on soot and gaseous product formation characteristics from the lignite pyrolysis at 1300 ℃ is investigated. The results show that water washing only removes a small amount of water-soluble AAEMs, which has little impact on the combustion characteristics of the coal, while acid washing pretreatment largely removes Na, Mg, Ca and other ash components, causing obvious ignition delay. The acid washing obviously leads to the deterioration of oxidation characteristics and increases the yield of pyrolytic soot, and the peak diameter of soot increases from 100 nm to 200 nm. Moreover, after both water- and acid-leaching, more CO2 is produced, while CH4, CO, and H2 are reduced. The yields of C2H4 are not changed before and after leaching. However, a certain amount of C2H2 is produced for acid-leached coal pyrolysis. These phenomena indicates that there may be different soot generation and evolution paths in three cases. To a certain extent, this provides a theoretical guidance for the research of effectively reducing soot emissions and improving coal utilization under high-temperature pyrolysis.

A characteristic-based decision tree approach for sustainable energy applications of biomass residues from two major classes

The characteristic potential of biomass residues from two major classes for sustainable energy applications has been critically evaluated. These include sheesham wood dust (SWD), sheesham bark (SB), eucalyptus chips (ECLP), gamhar wood chips (GWC) from wood and woody biomass (WWB) class; and coconut shell (CS), coconut husk (CH), rice straw (RS), rice husk (RH), wheat husk (WH), bagasse (BGS), tea waste (TW), corn cob (CC), pista shell (PS), akhrot shell (AS) and mustard stalk (MS) from herbaceous and agricultural biomass (HAB) class. Overall, biomass residues cover a wide range of acceptable moisture levels for various thermal conversion processes. Fixed carbon (FC), C, and H content of all the samples showed linearity with calorific value (CV), but H/C and O/C atomic ratios, besides linearity with cellulose and hemicellulose, have non-linearity with CV and lignin. Specifically, agricultural wastes (RS, RH, and WH) have relatively less moisture, volatile matter, FC, C, and CV; and higher ash, H/C, and O/C atomic ratios, N, and S content. WWBs have higher CV than other residues (particularly agricultural residues), owing to higher lignin content (with higher heat value) than hemicellulose and cellulose.Among various ash components, assigning a clear trend is difficult. BGS, PS, and AS indicate extremely-high slagging and high fouling tendencies, and the remaining 12 samples have low to medium concerns. Amongst hemicellulose (H), cellulose (C), lignin (L), and extractives (Ext), four structural types (CLHExt > CHLExt > HCLExt > LExtHC) exist. CLHExt follows in 3WWB and 2HAB; CHLExt in 8 HAB; HCLExt in 1 HAB; LExtHC in 1 WWB sample. Thermal analysis results show that HABs are mostly more reactive and have less activation energy than WWBs. The observed experimental findings and characteristic associations form a basis for placing these feedstocks for indicator purposes linked with further advance and sustainable feedstock processing needed for gasification, combustion, and steelmaking. A novel decision tree approach has been developed for propositions about characteristic parameters, which provides a systematic means of selecting the feedstocks for sustainable energy applications.

Food availability and food selectivity of Sri Lanka Grey Hornbill Ocyceros gingalensis Shaw, 1811 in Mihintale Sanctuary, Sri Lanka

This study was focused on explaining food selectivity in endemic Sri Lanka Grey Hornbill Ocyceros gingalensis to fill the gaps in the behavioral ecology of this endemic species. The study was conducted within Mihintale Sanctuary for five months from December 2015 to April 2016. Ringed hornbills were used to monitor the number of food items that were consumed from within the Food Abundance Index (FAI) and quantify the distribution and availability of resources to examine the potential of fruit selectivity. Thirteen fruiting plant families were recorded as preferred food. Food consumption and FAI values are not significantly correlated (r = 0.60, p = 0.285). The dietary composition increased in the breeding season due to a higher requirement for nutrients by the nestlings. Nutrient analysis results revealed that moisture (H = 7.50, p = 0.006), fiber (H = 6.53, p = 0.011), and ash (H = 6.07, p = 0.013) components were significant between eaten and non-eaten fruits. The amount of all the nutrients available in the fruits as well as FAI does not directly affect the fruit selectivity of the Sri Lanka Grey Hornbill in the Mihintale Sanctuary. This fruit selection and the seed dispersal ability of the Sri Lanka Grey Hornbill contributes to maintaining the ecosystem diversity and forest regeneration, especially in the Dry Zone in Sri Lanka.

Volatile-char interactions during biomass pyrolysis: Effect of biomass acid-washing pretreatment

The purpose of this study is to investigate the effect of acid-washing pretreatment on the poplar wood (PW) pyrolysis under different volatile-char interactions, the experiment was conducted in a self-designed fixed-bed pyrolysis reactor. It was found that acid-washing pretreatment could alter the surface morphology of PW, increase the cellulose crystallinity and reduce the inorganic ash components (mainly Alkali and Alkaline Earth Metal species, AAEMs). AAEMs acted as catalysts for sugar ring fragmentation and charring reactions during both primary pyrolysis of biomass and secondary volatile-char interactions. The removal of AAEMs would increase the bio-oil yield and decrease the biochar and non-condensable gas yields, same trend was also observed with the decreasing volatile-char interactions. The removal of AAEMs and weakened volatile-char interactions both resulted in an increase of C content and a decrease of O content of biochar with more pore structures generated, especially micropores, the content of anhydrosugars in bio-oil was also largely enhanced. In addition, the decrease of volatile-char interactions would significantly reduce the effect of AAEMs in biomass on the pyrolysis process. A highest bio-oil yield of 63.37 wt% with 34.38% of anhydrosugars could be obtained even for a packed fixed-bed reactor by intentionally reducing volatile-char interactions and removing AAEMs from biomass during the process.

The Effect of Bio-Coal Agglomeration and High-Fluidity Coking Coal on Bio-Coke Quality

Metallurgical coke with high strength and low reactivity is used in the ironmaking blast furnace. Replacement of some coking coal with bio-coal was shown to result in lower strength and higher reactivity of produced coke due to introduction of reactive bio-coal carbon and ash components catalyzing the Boudouard reaction, but also due to lowering of the coking coal blend fluidity, which influences coke strength and reactivity negatively. The current study aims to investigate the possibility to counteract negative impact from bio-coal addition on fluidity and coke reactivity by using high-fluidity coking coal and by agglomeration of bio-coal before addition. Original bio-coal and micro-agglomerate of bio-coal was added at 10%, 15% and 20% to the coking coal blend. The influence of bio-coals on the coke reactivity was measured by using CO2 in a thermogravimetric analyzer. Selected cokes and bio-cokes were produced in technical scale, and their reactivity and strength were measured in standard tests. The effect on dilatation of adding bio-coal or crushed agglomerates of bio-coal to the coking coal blends was measured in an optical dilatometer. The results show that by using a coking coal blend containing high-fluidity coal with agglomerated bio-coal, the max. contraction is increased, whereas the opposite occurs by using original bio-coal. The results show overlapping between contraction occurring before dilatation and during dilation, which affects max. dilatation. The bio-coke containing high-fluidity coal with agglomerated bio-coal has lower reactivity in comparison to bio-cokes with original bio-coal or bio-coke with agglomerated bio-coal produced from a coking coal blend without high-fluidity coal. The reactivity of coke produced in technical scale, as measured in CRI/CSR tests, shows a similar trend regarding reactivity, as measured by thermogravimetric analysis, on coke produced in laboratory scale.

The use of technogenic carbon in gypsum compositions for green building

The publication is devoted to the study of the possibility of using ash and slag waste from hydraulic removal of fuel power plants in the production of building gypsum materials. These wastes are not used in industrial production due to the heterogeneity of composition and properties. This is a big and unresolved problem for many thermal power plants. However, when separating individual parts - carbon, aluminosilicate or magnetite - the possibility of using the selected part of the component increases. The paper considers the use of carbon and aluminosilicate parts as an additive in the composition of gypsum compositions. A comparative analysis of the properties of gypsum compositions modified with carbon and aluminosilicate additives is given. A higher efficiency of using a carbon additive for lightweight gypsum compositions has been established. The comparison was carried out in terms of compressive strength and average density. Additives were introduced in the amount of up to 30%. The ratio of tensile strength and density for modified mixtures was characterized by specific strength. It was higher for mixtures with a carbon additive. The introduction of porous mineral fillers - perlite and vermiculite - in a volume of up to 20% contributed to an even greater decrease in density. The best result was shown by mixtures with the carbon component of ash and slag mixtures and the addition of perlite. They can be used for green building.