Ash Composition Research Articles

Melting and Flow Behavior of Coal Ash at High Temperatures Based on SiO2-Al2O3-CaO/Na2O Pseudoternary Phase Diagram.

The entrained-flow gasifier has a better adaptability to various coals. The composition of coal ash is an important factor affecting the high-temperature flow characteristics of molten slag. Based on the SiO2-Al2O3-CaO/Na2O ternary phase diagram, the high-temperature molten flow characteristics of slag located in the main phase regions of feldspar, melilite, diopside, and mullite were investigated by experiments and thermodynamic software calculations. The results indicate that the melting process of ash in the three phase zones is influenced by different factors. It was discovered by infrared spectroscopy analysis that the slag was dominated by Si2O52- ion clusters in the feldspar region. The slag in the diopside region had a slightly higher proportion of simple silicate ion clusters than the slag in the feldspar region, resulting in better fluidity. This is significant for revealing the mechanism of coal ash melting and flowing and guiding industrial coal blending.

Chemical and Thermal Analysis of Fly Ash-Reinforced Aluminum Matrix Composites (AMCs)

Fly ash has been utilized as a reinforcing material in the production of aluminum matrix composites, and in this investigation, Al-Si (LM6) fly ash composites were fabricated using the compocasting method. Various compositions of fly ash were incorporated into the samples (4, 5 and 6 wt%), and the preparation temperature ranged from 560 to 800°C. This study investigated the thermal (CTE and DTA) and chemical properties (XRD) of fly ash reinforcement and the aluminum melt in the composites. The results revealed that composites with 5 wt% of fly ash exhibited the lowest CTE value compared to those with 4 and 6 wt%. This observation was corroborated by XRD analysis, indicating a reaction between the fly ash particles and the aluminum melt. However, the DTA analysis did not find a significant impact of the addition of fly ash on the melting temperature of the prepared composites. In contrast, this study identified and investigated the existence of reaction effects between the fly ash particles and the aluminum melt.

Optimizing the Composition of Basalt and Heat Treatment of Fly Ash-Based Mullite Ceramics Using the Taguchi Method

The development of industrial activities has an impact on the increase in waste produced, and fly ash, aluminum dross, and basalt dust are no exception. This research studies the potential of these three materials as ceramic materials. Basalt dust from East Lampung was used as filler. The effect on the physical and mechanical properties of mullite (3Al<sub>2</sub>O<sub>3</sub>-2SiO<sub>2</sub>) ceramics was studied. The manufacture of mullite ceramics based on Taguchi design includes fly ash compositions of 40%, 50%, and 60% and basalt content of 0%, 5%, and 10%. sintering temperatures of 600°C, 900°C, and 1,200°C. Taguchi and Anova were used to determine the effect of independent variables on hardness and density. In addition, macro and microphoto tests were carried out to determine the physical and topographic changes of mullite ceramics. Chemical composition tests with X-ray fluorescence were carried out on raw materials and ceramics that have been formed. Changes in the crystal phase in mullite ceramics were studied through the X-ray diffragment test. XRF test results obtained for raw fly ash (SiO<sub>2</sub> + Al<sub>2</sub>O<sub>3</sub> + Fe<sub>2</sub>O<sub>3</sub>): 84.84 wt%. The composition of raw basalt is predominantly 48.42% SiO<sub>2</sub>, 18.82% Al<sub>2</sub>O<sub>3</sub>, 12.60% Fe<sub>2</sub>O<sub>3</sub>, and raw aluminum dross with 67.821% Al<sub>2</sub>O<sub>3</sub> content. The mullite ceramic specimen consists of 38.24–45.30% SiO<sub>2</sub>, 34.72–48.73% Al<sub>2</sub>O<sub>3</sub>, 6.3–9.99% Fe<sub>2</sub>O<sub>3</sub>, and 2.31–5.31% CaO. The crystal phases formed are mullite, pyroxene, and diopside. Analysis of variance shows that hardness is significantly affected by sintering temperature, with a P-value of 0.013 and a contribution of 93.77%. This modeling is acceptable with an error value of 1.26%, or R-sq: 98.74%. The addition of basalt increases the density of mullite ceramics, with a P-value of 0.033 and a contribution of 96.05%. The addition of basalt as a filler is not able to increase the hardness significantly, but it affects the higher ceramic density value. However, the formation of mullite is interesting to study further as a refractory material

Utilization of fly ash and bottom ash from TanjungJati B Coal-Fired Power Plant in Jepara, Central Java, on the quality of cellular lightweight concrete

The research aims to address waste-related issues by producing Cellular Lightweight Concrete (CLC) bricks using fly ash and bottom ash as fine aggregates. The variations used encompass cement, fly ash, bottom ash, and sand compositions. The ratio between cement and fine aggregates utilized is 1:3. The variations in the composition of fine aggregates include P (100% sand), F (100% fly ash), B (100% bottom ash), F1B1 (50% fly ash and 50% bottom ash), F1B2 (33.3% fly ash and 66.7% bottom ash), F1B3 (25% fly ash and 75% bottom ash), F2B1 (6.7% fly ash and 33.3% bottom ash), and F3B1 (25% fly ash and 75% bottom ash). The parameters employed comprise compressive strength testing, density, and water absorption evaluation of the CLC bricks at ages 14, 28, and 35 days, also thermal conductivity at the 35-days sample. The sample age exhibits a proportional relationship with compressive strength and water absorption, while displaying an inverse relationship with density. At the 35-day sample age, the F composition demonstrates the highest compressive strength (14.74MPa) and the lowest water absorption (11%). Meanwhile, the B composition exhibits a compressive strength value of 5.9MPa and the lowest density (1.12g/cm2). Conversely, the P composition showcases the highest density (1.59g/cm2). Density affects thermal conductivity, the lower the density, the lower the thermal conductivity, which means that the heat conductivity will be smaller.

Potential of rice husk ash as cement alternative in constructing bricks: Utilization for “Gulayan sa Paaralan” program

This research aims to investigate the “Potential of Rice Husk Ash as Cement Alternative in Constructing Bricks: Utilization for ‘Gulayan sa Paaralan’ Program”. The success of this study provides cheaper option of construction materials. The pandemic experience of the Philippines, economic deterioration became a challenge. Prices of prime commodities continuously increases, including the construction industry. Nowadays, there are various cement alternative being utilized inside and outside of the country. Some part here in the Philippines use fly ash as a cement alternative. But fly ash is not readily available in Laguna. That is why the researchers look for an alternative that is readily available, inexpensive and do not harm the environment. In this study, the researchers examine the potential of rice husk ash and they constructed bricks in which they plan to use for the beautification of school’s garden. In accordance with the governing specification of American Standard of State Highway and Transportation Officials (AASHTO) and American Society for Testing and Materials (ASTM), the researchers conducted a standardized laboratory test. After series of test, researchers concluded that rice husk ash is not a significant alternative to cement as it reduce the strength and durability of the brick made out of it. However, since the chemical composition, fineness test, and water absorption test of rice husk ash and rice husk ash bricks passed the requirements of American Society for Testing and Materials, the researchers inferred that rice husk ash could still be used as additive in creating a decorative bricks.

Sustainable production of eco-friendly roofing tile using methyl ester residue as the alternative binder – A preliminary study

Making full use of industrial by-products is an effort to achieve ‘zero waste’ and promote greener development. Methyl ester residue (MER) is a waste commonly found in oleochemical manufacturers, such as palm oil mills. Contrary to conventional cement and clay, MER was employed as an alternative binder to fabricate a novel eco-friendly roofing tile, henceforth referred to as MER-RT. Parameters tested were transverse strength, water absorption, sulfate resistance, and fire resistance. During the optimization phase, a range of 6–11% of MER was mixed with a fixed composition of fly ash and fine sand, compacted and cured at 190° C for 12–48 hours. Considering the electrical energy consumption, the optimal curing duration chosen was 24 hours as this MER-RT achieved a dry transverse strength of 4112 N whereas curing for an additional 18 hours further contributed to only 16% strength gain. The optimal MER-RT was found to contain 10% MER as it showed the highest dry transverse strength (6410 N), the highest wet transverse strength (3681 N) and the lowest water absorption percentage (2.67%), meeting the American Society for Testing and Materials (ASTM) standards. Besides exhibiting minimal corrosion under the sodium sulfate test, the optimal MER-RT was non-flammable and did not undergo structural changes when exposed to fire. The study reveals the potential of both MER and fly ash as green binders and fillers for roof tiles, despite their origins as industrial waste.

Karakteristik Kimia Kopi Arabika Bubuk dari Varietas Linie-S dan Sigararutan

One of eastern Indonesia's top places for producing high-quality coffee, particularly Arabica coffee, is Gowa Regency. Ground coffee's chemical composition is significantly influenced by the post-harvest and coffee harvesting procedures used to produce it. The Indonesian National Standard (SNI) 01-3542-2004 compares a range of values about ground coffee that can be used to evaluate the coffee's quality. This study's goals are to determine which arabica coffee varieties have chemical attributes that are in line with (SNI) 01-3542-2004 and to look into the chemical makeup of ground arabica coffee from the Gowa Regency's linie-S and sigararutan kinds. The Sigararutan and linie-S types of arabica coffee beans, both from the Tinggimoncong District, were utilized in the study. In the research investigation, a non-factorial fully randomized design (CRD) was used in three replications. Chemical analysis examines the composition of coffee extract, moisture, ash, and caffeine. The results showed that powdered arabica coffee of the Linie-S variety differed considerably from powdered arabica coffee of the Sigararutan type in terms of water content, ash content, and caffeine content. The amounts of coffee extract in the two samples, however, were not substantially different from one another. The water, ash, caffeine, and coffee essence contents of the Linie-S and Sigararutan varieties of powdered arabica coffee satisfy the requirements outlined in (SNI) 01-3542-2004 for ground coffee.

Study on the Properties of Waste Stone Powder-clay Slurry based on the Influence of Filter Press

A grouting material pressure effect simulation device (FSD) was used to study the performance of grout considering grouting pressure, slurry rheology, clay ash, slurry concentration and particle size composition of waste stone powder (FSD influencing factors). After the effect of filter pressing, the alkaline environment of the slurry became stronger, the number of active particles increased, and the CaCO3 and clay crystals were fully agglomerate, and the degree of crystallization increased. The cation exchange capacity increased, and the formation of calcium-silicon-aluminum matrix phase and aluminosilicate aggregates increased. The surface water between the matrix particles supports the crystal layer, and the plastic viscosity and yield stress are reduced. The free calcium oxide decreased, and the consolidation shrinkage rate after slurry hardening was less than 1%. The water-cement ratio is reduced, and the total time for slurry to be poured into the fracture to consolidate and form a mold and intermittent is shortened. The use of waste stone powder and clay in the coal mine grouting industry can not only reduce project costs, but also reduce soil erosion and soil pollution.

Mix design and performance of low-carbon alkali-activated slag/bagasse ash cementitious materials

The utilization of sugarcane bagasse ash (SCBA) in alkali-activated materials (AAMs) is currently limited due to its subpar mechanical properties and the absence of a mix design approach. This study aimed to develop a high-strength, cost-effective, and low-carbon alkali-activated slag/bagasse ash (AASL/BA) composites through multi-objective optimization (MOO) models. The results showed that increasing SCBA content reduced the compressive strength of AASL/BA, particularly beyond 50 %. Moreover, elevating the SiO2/Na2O molar ratio to 1, along with a Na2O content of 6 %, notably increased the compressive strength by 276 % and the proportion of C-(A)-S-H to 31 %. Furthermore, a comprehensive MOO model, considering SCBA content, SiO2/Na2O molar ratio, Na2O dosage, cost index (CI) and environmental index (EI), was established. Optimal parameters were identified as SCBA content below 50 %, SiO2/Na2O molar ratio ranging from 0.5 to 1.0, and Na2O dosage between 4 % and 6 % to achieve produce high-strength, cost-effective, and environmentally friendly AASL/BA. This work lays a solid groundwork for the sustainable design of AASL/BA materials.

Ecologically Friendly Building Materials: A Case Study of Clay–Ash Composites for the Efficient Management of Fly Ash from the Thermal Conversion of Sewage Sludge

The European Union’s initiative to reduce carbon dioxide emissions has paved the way for the exploration of innovative building materials that are environmentally friendly and meet all requirements of durability and strength. These criteria can be met by combining natural resources used in the production of building materials with waste materials that would otherwise be landfilled, having a negative impact on the environment. This study focuses on such materials and presents the results of recent research conducted at the Warsaw University of Life Sciences. The aim was to develop a new generation of materials fully compliant with the principles of the circular economy and sustainable development. Simultaneously, these materials should have no adverse effects on human health and be strong enough to carry the required loads. This study proposes the combination of a natural raw material—in the form of clay—with fly ash from the incineration of sewage sludge to produce a new generation of materials. Several samples were prepared using fly ash from two sources and then were fired at 950 °C. The resulting composites underwent physico-chemical and strength tests. These tests not only confirmed the high strength and durability of the obtained product but also the neutralization of the heavy metals originally present in the fly ash.

Pyrolysis characteristics and kinetic investigation of waste groundnut shells using thermogravimetric analyzer, Py-FTIR, and Py-GC-MS

The objective of the present study was to investigate the bioenergy and resource recovery potential of groundnut shells (GNS) through pyrolysis. The release of vapours at short time scales and their composition were investigated using analytical pyrolysis coupled with Fourier transform infrared (FTIR) spectroscopy and gas chromatography/mass spectrometry (GC/MS). The thermal decomposition behaviour and kinetic evaluation were carried out using a thermogravimetric analyzer (TGA). Five iso-conversional models and master plots method were utilized to explore the kinetic parameters and reaction mechanism at dynamic heating rates (10, 20, and 30 °C min−1). X-ray fluorescence spectroscopy (XRF) was employed to detect the ash composition, which is essential to evaluate the slagging and fouling potential of the biomass when used for bioenergy. TG data revealed three distinct stages of decomposition, while an immense amount of biomass disruption was observed at a higher heating rate (30 °C min−1). Further, the average apparent activation energy of pyrolysis determined using KAS, ST, DAEM, and VZ were 223.26, 214.57, 207.97, and 117.24 kJ mol−1, respectively. The extreme emission of carbon dioxide and carbonyl compounds was discovered through Py-FTIR. The increased formation of hydrocarbons (14.22–34.26%), alcohols (1.41–9.43%), and reduction in phenols (19.13–18.67%) at different temperatures (450, 550, and 650 °C) were validated by Py-GC-MS. Overall, the findings demonstrate that GNS is a promising feedstock for pyrolysis to produce valuable fuel molecules and chemicals.

The Influence of Location on the Nutritional Composition of the Rind of Watermelon (<i>C. lanatus</i>) in Parts of Selected Geographical Zones in Nigeria

Watermelon (C.lanatus)), which was formerly only grown in the Northern part of Nigeria, is now grown in Southern parts also. It is known that weather patterns and soil composition vary as we move from the northern to the southern parts of Nigeria. However, there is little to no data demonstrating how C.lanatus' nutritional composition is influenced by its geographic location. This study therefore sought to assess the nutritional composition of the rind of C.lanatus produced in parts of four states that corresponded to four geopolitical areas of Nigeria. Samples of C. lanatus were gathered from four geopolitical zones of Nigeria which include; North-East, South-West, South-East, and SouthSouth. Fruits were cleaned before the rind was removed, blended, and freeze-drying carried out. The freeze-dried samples were subjected to established methods for the determination of the amino acid profile, vitamins, proximate, and mineral components. The results of the amino acid profile showed that distinct amino acids were present in each zone, with the southwest sample providing the highest quantities and the south-south zone providing the lowest concentrations. The rind of C. lanatus contained calcium, magnesium, potassium, sodium, iron, phosphorus, and manganese in varying amounts, and samples from the south- west and north-east having the highest concentrations of both vitamins and minerals. The results of the proximate composition determination showed that the southwest sample had the highest (p < 0.05) percentage of moisture, protein, and ash when compared to other zones, and that the northeast sample had a higher percentage composition of carbohydrate, ash, and fat when compared to other zones. Thus, the C. lanatus samples' nutritional value were distributed as follows: southwest > northeast > southeast > south-south. According to the findings, C.lanatus rind's nutritional qualities can vary depending on where it is cultivated.

Effect of friction stir processing parameters on mechanical properties of Al8011/CeO2/SiC/RHA metal matrix composite

ABSTRACT In this research work, the FSP route opted to fabricate the metal matrix composite (MMC) on the surface of an aluminium 8011 alloy sheet by incorporating different volumetric compositions of silicon carbide (SiC) and cerium oxide (CeO2) with a constant 5% volumetric composition of rice husk ash (RHA). The fabrication process was based on the L27 design of experiments. Taguchi-coupled grey relational analysis (GRA) was employed for process optimisation with four factors: tool rotation speed, tool travel speed, reinforcement volume, and tool type, each with three levels, while tensile strength and micro-hardness were taken as the response variables. The optimal parameter setting for fabrication of Al8011 MMC was 600 RPM of rotational speed (level 3), 20 mm/min travel speed (level 1), reinforcing volume% (level 2), and straight cylinder pin profile (level 1). The corresponding values of the optimised response variables were 181.91 MPa tensile strength and 139.09 Hv microhardness. The tensile strength and microhardness of base Al8011 were found to be 175.77 MPa and 92.72 Hv, respectively. Meanwhile, the microstructure of the optimal FSP-processed MMC was analyzed through the scanning electron microscopy (SEM) technique, which confirmed a homogeneous distribution of reinforcing agents and refined grain structure.

Agglomeration behaviour of various biomass fuels under different air staging conditions in fluidised bed technology for renewable energy applications

The most common technology for thermochemical conversion of solid fuel through the process of gasification, such as coal, varieties of residues from biomass and agriculture are the bubbling fluidised bed or fluidised bed systems. However, there are some disadvantages within these systems including the formation of eutectic mixtures, increased process of melting and bed agglomeration. Hence, the current study aimed to evaluate the agglomeration behaviour of various biomass fuels. Characteristics of five biomass fuels (miscanthus, peanut, straw, domestic wood and industrial wood) in a bubbling fluidised bed (BFB) combustor were studied by SEM-EDX, XRD and XRF analysis of bed materials and ash samples. The influence of bed temperatures on the fuel ash composition and bed particles was evaluated, as well as fuel ash components, their interaction with the particles from the bed sand and morphology of the bed material. The combustion efficiency ranged from 95.5 to 99.5% with the highest value obtained for miscanthus under SA conditions. The peanut and straw had the highest K content, whereas the industrial wood ash contained the highest Ca content compared to other biomasses. The XRF results showed that most of the potassium (K) from the wheat straw biomass was converted to K2O with 19%. No bed agglomeration was noticed without staging-air (WSA) and with staging-air (SA) combustion conditions, even with temperatures up to 850 °C during the testing period. Overall obtained results demonstrated that agglomeration is unlikely expected to be a major problem during fluidised bed combustion of tested biomass fuels.

USE of Thermal Power Engineering Waste to Reduce the Average Density of Ceramic Wall Materials with a Matrix Structure

It has been presented the results of studies on reducing the average density of ceramic wall materials through the use of ash granules. The chemical, granulometric, and mineral compositions of clay raw materials and fly ash are given. It has been considered the compositions of ceramic charges with different contents of thermal power waste and sample preparation techniques. In the first case, mechanical mixing of the charge components was used, in the second case, granulation of the components and creation of a shell on the surface of the granules was used. The physical and mechanical properties of ceramic samples produced by both methods are presented. It has been established that an increase in the fly ash content in the charge leads to a decrease in the average density and compressive strength of ceramic samples. The use of the developed method for producing ceramic materials increases the strength characteristics of the samples, which makes it possible to increase the content of the ash component to 70–80 wt. % in the composition of the charge. It has been shown that the content of fly ash in the charge is more than 60 wt. % leads to an increase in water absorption of more than 20%, which practically indicates the absence of sintering processes in ash granules. Prospects and main directions for further research are formulated.

Elemental composition and mineralogical characteristics of volcanic ash and soil affected by the eruption of Mount Semeru, East Java

Elemental composition and mineralogical characteristics of volcanic ash and soil affected by the eruption of Mount Semeru, East Java

Analysis Stability Of Asphalt Concrete Binder Course (AC-BC) With Fly Ash And Bottom Ash Substitution Material

Fly ash and bottom ash are ash produced from the process of burning coal as a source of energy in the steam generating unit of a coal-fired power plant (PLTU). Bottom ash is ash that forms at the bottom of a coal-burning furnace and settles there. In this research, fly ash is used as filler substitution and bottom ash is used as fine aggregate substitution (sand). The purpose of the study was to obtain a suitable Job Mix Design (JMD) for Asphalt Concrete - Binder Course (AC-BC) with fly ash and bottom ash substitution materials. To determine the effect of optimum asphalt content on the values of stability, flow, Marshall Quotient, VMA, VIM and VFB obtained from result of the Masrhall test. Based on the results of Marshall testing, the results show that Analysis Stability Of Binder Course Asphalt Concrete (AC-BC) With Fly Ash And Bottom Ash Substitution Material produces the highest VMA value of 14.462% and the highest VIM value of -1.88%, meaning that there are many gaps in the mixture containing asphalt so that it becomes waterproof and hermetic. The highest stability and MQ values are stability of 1955.55.34 kg and MQ of 1241.13 kg/mm. The appropriate Job Mix Design (JMD) for Asphalt Concrete - Binder Course (AC-BC) with fly ash and bottom ash substitution materials is the composition of Fly Ash at 0%, 50%, and 60% of the total cement while for the use of Bottom Ash from the total sand at 0%, 50%, and 60%.

Harnessing Abuja's Municipal Solid Waste as a Renewable Energy Source: Scanning Electron Microscopy Analysis

A study of Abuja’s municipal solid waste (MSW) samples using the scanning electron microscopy analysis was undertaken in this work. In the face of the severe energy poverty being experienced in Nigeria which largely depends on diminishing fossil fuel resources coupled with the associated problem of greenhouse gas emission, the energy potential available in municipal solid wastes needs to be investigated. Using MSW as a fuel source for electric energy production will also positively impact on Abuja’s waste management. This present study requires the analysis of the MSW with aim of confirming that products of its incineration will not be hazardous to the environment. ASTM E 1508 procedures for utilizing the scanning electron microscope (SEM) were followed to identify elements that would be contained in the bottom ash of the incineration process of samples of Abuja’s municipal solid wastes obtained from selected districts of the city. Elemental composition of the bottom ash that will be formed from incineration of Abuja’s MSW was obtained by the use of energy dispersive x-ray analysis. The micrographs plotted indicate that silicon and iron are the principal elements present in the samples with values for silicon and iron being highest at 49.5 and 19.55%, respectively, for the sample from Dutse-Alhaji. The tests also show the presence of silver in the organic wastes generated in Abuja, while presence of sulphur is very minimal. The silicon levels present in Abuja’s municipal solid waste compare well with values for Nigerian coals which have percent silicon contents ranging from 39.0 – 49.4% (Enugu coal – 39.0%; Okaba – 44.8%; Maiganga – 49.4%). The test results also show that Abuja’s MSW samples had grain sizes ranging from 3.5 mm 16 mm. The results indicate Abuja’s MSW combustion rate will be lower than for pulverised coal which is known to have much lower grain size in the range of 75 μm to 106 μm and will need shredding before firing since grain size is a very critical determinant factor in solid fuel combustion rate and burn-out time. The tests conclusively show that Abuja’s MSW will be a more environmentally friendly fuel than coal because of its lower sulphur content.

Оценка золошлаковых отходов как источника загрязнения окружаюшей среды и источника вторичного сырья

Introduction. Currently, more than 500 million tons of fly ash have been accumulated on the territory of the Republic of Kazakhstan, the volume of which will increase to one billion tons by 2030. Such accumulation of fly ash in storages creates a powerful anthropogenic impact on the biogeocenosis. A significant proportion of these man-made materials are formed during the burning of Ekibastuz coals. There is practically no processing of ash and slag waste on an industrial scale. For various reasons, ash dumps are not used in Kazakhstan, because the physico-chemical properties have been very poorly studied, in addition, during their processing, other wastes or ash dumps unsuitable for use are obtained from these wastes, because they contain a lot of unburned coal. As of 01.01.2020, the share of recycled, reused, burnt ash and slag waste in Kazakhstan amounted to 0.7%. The relevance and significance of this problem is due to the fact that man-made waste from CHP plants is not sufficiently processed, and current ash waste accumulates and occupies huge areas, which removes them from land use. Knowledge of the chemical composition of the ash will allow it to be used to obtain building materials. The purpose of this work is to study the properties of ash and slag waste during the burning of coal from the Ekibastuz deposit in Kazakhstan, to assess them as a source of environmental pollution, to determine the possibility of obtaining demanded building materials from them. Research methods. To determine the phase composition of the studied material, an upgraded diffractometer DRON-3M on CuKa radiation with software was used. Radiographs of the sample were obtained in the range of 2° (angles) from 10 to 70°. The chemical composition was determined using an energy dispersion spectrometer “EDX-8000”. Micrography of fly ash was taken on a scanning electron microscope Superprob-733. Research materials. Ash and slag waste from the burning of coal from the Ekibastuz deposit in Kazakhstan. Research results and discussion. The physical characteristics of ash have been established: specific surface area – ~200 m2/kg, true density – 2.1 g/cm3, bulk density – ~780 kg/m3. Fractional composition: the highest content of particles with a size of 100 microns (25.8%), 80 microns (12.12%), 50 microns (21.46%) and 45 microns (21.38%); at the same time, unburned carbon is concentrated in large fractions, glass phase – in small ones. Analysis of the chemical composition of Ekibastuzky ash allowed to find out the composition of coal minerals. The main components are silicon and aluminum oxides, and there is also a large amount of iron oxide. Knowledge of the chemical composition of ash allows it to be used in the production of building materials. Conclusion. The results of the conducted studies have shown the possibility of using ash and slag waste as secondary raw materials in the construction of road materials in order to reduce the anthropogenic load on the environment.

Evaluation of the nutritional properties and the antioxidant activity of rice bean (<i>Vigna umbellata</i>) seeds collected in Sơn La province

Vigna umbellata is an underutilized species in Vietnam, and more information about its nutritional values needs to be provided. This study investigated the nutritional composition and antioxidant activity of the seeds of 10 rice bean varieties collected from different districts of Son La province. Moisture content, ash and nutritional composition, including total protein, lipid, and carbohydrate were estimated. The 2,2-Diphenyl-1-picrylhydrazyl (DPPH) scavenging assay, total phenolic content (TPC), and total flavonoid content (TFC) were carried out to assess the antioxidant activity. The results showed as follows: moisture content ranged from 0.44% to 1.23%, total ash values were obtained in the range between 38.46 and 45.72 mg/g DW, total protein content spread from 106.65 to 156.77 mg/g; total lipid varied from 7.37 to 11.90 mg/g, and total carbohydrate dominated the nutritional profile with 786.10 to 834.73 mg/g. Remarkably, there were significant differences (p < 0.05 using ANOVA) among the rice bean species from various districts of Son La province regarding moisture and protein content. Still, similar values were observed for other parameters (p > 0.05). The IC50 of the DPPH assay ranged from 259.06 µg/mL to 479.99 µg/mL, while the TPC varied from 2.85 to 4.98 mg GAE/g, and TFC values were in the range between 6.46 and 13.73 mg QE/g DW. Both TPC and TFC were significantly negatively correlated to antioxidant activity. This study is the first report on the nutritional compositions and antioxidant activity in the seeds of 10 rice bean varieties collected in Son La province. The findings in this study contribute to valorizing the V. umbellata species, which might be a promising plant as a low-priced staple food for ethnic people in mountainous regions.