Coal Ash Slag Research Articles

Research status of building materials utilization and CO2 curing technology on typical coal-based solid waste: A critical review

Coal, one of China's most abundant natural resources, plays a crucial role in providing substantial energy and promoting economic growth. However, the disposal and storage of large quantities of coal-based solid waste (CBSW), such as coal gangue (CG), fly ash (FA), and coal gasification slag (CGS), generated during coal production and utilization processes, pose serious social and environmental challenges. The application of solid waste in the construction materials field has garnered significant attention and is anticipated to become a primary treatment method in the future. This paper comprehensively reviews the characteristics, pretreatment methods, and utilization performance of typical CBSWs, aiming to offer a basis and valuable reference for optimizing the inherent properties of solid waste and its utilization. Additionally, it discusses the influence of various carbonation curing parameters on CO2 capture and elucidates the impact mechanism of carbonation curing on the performance of CBSW concrete. This study holds great significance for the utilization of CBSW in building materials and carbon reduction, particularly in regions with substantial solid waste and high CO2 emissions.

The Use of Ground Coal Bottom Ash/Slag as a Cement Replacement for Sustainable Concrete Infrastructure.

Cement production requires considerable energy and natural resources, severely impacting the environment due to harmful gas emissions. Coal bottom ash (CBA) and coal boiler slag (CBS), byproducts of coal-fired powerplants having pozzolanic properties, can be mechanically ground and replace cement in concrete, which reduces waste in landfills, preserves natural resources, and reduces health hazards. This study was performed to determine the optimum cement replacement amount of ground CBA (GCBA) and ground CBS (GCBS) in concrete, which was 10% for GCBA and 5% for GCBS. GCBA-based concrete exhibited superior tensile strength, modulus of elasticity, and durability compared to the control. In the Rapid Chloride Penetration Test, 10% GCBA concrete resulted in 2026 coulombs at 56 days, compared to 3405 coulombs for the control, indicating more resistance to chloride penetration. Incorporating 2.5% nanoclay in GCBA-based concrete increased the optimum GCBA content by 5%, and the compressive strength of 15% GCBA concrete increased by 4 MPa. The mortar consisting of the finest GCBA(L1) having Blaine fineness of 3072 g/cm2 yielded the highest compressive strength (32.7 MPa). The study discovered that the compressive strength of GCBA and GCBS-based mortars increases with fineness, and meeting the recommended fineness limit in ASTM C618 enhances concrete or mortar properties.

Performance of coal gangue concrete with fly ash and ground-granulated blast slag: Rheology, mechanical properties and microstructure

This paper aims to examine the effect of coal gangue aggregate (CGA), fly ash (FA), and ground-granulated blast slag (GGBS) on the rheological, mechanical and microstructure properties of concrete. The rheological properties, compressive strength, splitting tensile strength, flexural strength, and uniaxial tensile behaviour of coal gangue concrete (CGC) were determined, and the microstructure of the concrete mixtures were investigated by use of XRD and SEM analyses. The results revealed the action mechanism of CGA and mineral admixtures on the microstructure and macroscopic properties of CGC. FA first increased and then decreased the yield stress and plastic viscosity, while GGBS considerably increased the yield stress and plastic viscosity. Furthermore, a constitutive model was established for CGC containing FA and GGBS under compression. The proposed stress–strain model for CGC is accurate and can be used for nonlinear analysis of structures made of this type of concrete. Moreover, the addition of FA and GGBS consumes calcium hydroxide, but increases products such as hydrated calcium silicate aluminate. These findings elucidate the understanding and optimisation of CGA use in concrete production, while contributing to lowering carbon emissions.

Valorization of steelmaking slag and coal fly ash as amendments in combination with Betula pubescens for the remediation of a highly As- and Hg-polluted mining soil

Soil pollution by As and Hg is a pressing environmental issue given their persistence. The intricate removal processes and subsequent accumulation of these elements in soil adversely impact plant growth and pose risks to other organisms in the food chain and to underground aquifers. Here we assessed the effectiveness of non-toxic industrial byproducts, namely coal fly ash and steelmaking slag, as soil amendments, both independently and in conjunction with an organic fertilizer. This approach was coupled with a phytoremediation technique involving Betula pubescens to tackle soil highly contaminated. Greenhouse experiments were conducted to evaluate amendments' impact on the growth, physiology, and biochemistry of the plant. Additionally, a permeable barrier made of byproducts was placed beneath the soil to treat leachates. The application of the byproducts reduced pollutant availability, the production of contaminated leachates, and pollutant accumulation in plants, thereby promoting plant development and survival. Conversely, the addition of the fertilizer alone led to an increase in As accumulation in plants and induced the production of antioxidant compounds such as carotenoids and free proline. Notably, all amendments led to increased thiolic compound production without affecting chlorophyll synthesis. While fertilizer application significantly decreased parameters associated with oxidative stress, such as hydrogen peroxide and malondialdehyde, no substantial reduction was observed after byproduct application. Thermal desorption analysis of the byproducts revealed Hg immobilization mechanisms, thereby indicating retention of this metalloid in the form of Hg chloride. In summary, the revalorization of industrial byproducts in the context of the circular economy holds promise for effectively immobilizing metal(loid)s in heavily polluted soils. Additionally, this approach can be enhanced through synergies with phytoremediation.

The distribution and enrichment characteristics of rare earth elements between coals and coal ashes from four coal-fired power plants.

Coal and coal ash (slag and fly ash) have emerged as important potential sources for rare earth elements (REY). The distribution and enrichment of REY during coal combustion from coal-fired power plants are of great significance for the recovery of REY. In this study, the concentration of REY in coal and coal ash from four coal-fired power plants in China was determined using microwave digestion-inductively coupled plasma mass spectrometry. The distribution and enrichment characteristics of REY in coal and coal ash were studied. The coal ash contains 310-683 μg g-1 of REY, and the proportion of critical REY was greater than 30%, which is higher than the extraction concentration (300 μg g-1) recommended by the United States Department of Energy, indicating significant REY recovery potential. The concentration of REY in coal was positively correlated with ash yield, which could be explained by the fact that REY are mainly distributed in minerals. Coal and coal ash show similar REY distribution patterns, indicating that REY were not fractionated during the coal combustion. In addition, the enrichment coefficient of REY in fly ash was greater than that in slag, which revealed that REY were mainly enriched in fly ash. Therefore, the REY in fly ash has more recycling potential.

Synergistic effect from combined use of scrap-recycling slag and hydrated lime to stabilize Pb and Zn in highly contaminated soil.

For the soil in an area which has been repeatedly chosen as one of the 10 most polluted places in the world, stabilization of Pb and Zn was assessed in batch, incubation, and column experiments. Single and combined amendment of scrap-recycling slag (Slag-R), charcoal, coal ash, hydrated lime, and basic oxygen furnace (BOF) slag were applied for the stabilization. Notably, the combined amendment of Slag-R and hydrated lime exhibited superior stabilization efficiencies than the individual use of all stabilizing agents and combined use of charcoal and hydrated lime. The combined amendment of Slag-R and hydrated lime decreased Pb levels by 92-99% and Zn levels by 63-88% in the incubation experiments and by 75% and 89-93%, respectively, in the column experiments. In particular, the combined amendment showed a synergistic effect for Pb stabilization because a higher pH enhanced sorption onto the slag and because sorption onto Fe (hydr)oxides of the sorbent possibly helped to remove Pb. Zinc had a relatively lower sorption tendency, so it was mainly controlled by the pH increase from hydrated lime. Although the addition of hydrated lime was very effective in stabilizing high concentrations of Pb and Zn, the dosage should be controlled carefully because excessively high pH redissolves Pb and Zn as anions.

Geopolymer pervious concrete with recycled Coal Bottom Ash (CBA) and Ground Granulated Blast furnace (GGBF) slag in urban flooding solution

Pervious concrete is known as a high content formation of open void to allow for fast drainage of water. The main compositions of pervious concrete are coarse aggregate and binder to obtain a high volume of hollow area. In this research, the coal bottom ash (CBA) is used as coarse aggregate in mix proportion. Ground Granulated Blast furnace (GBBF) slag is used geopolymer binder to replace cement in geopolymer pervious concrete (GPC). They are known as waste industrial materials from thermal power plant and steel factory. The characteristics of geopolymer pervious concrete in compressive strength, porosity and permeability are considered. The reaction between GGBF slag and CBA is investigated. The results are shown that compressive strength GPC is about 2 MPa to 8 MPa with CBA 5 mm to 10mm and can be higher about 30 % to 40 % with CBA 10 mm to 20 mm. The water permeability is about 0.7 cm/s to 1.8 cm/s to belong to CBA type

Carbonation and permeation behaviour of geopolymer concrete containing copper slag and coal ashes

The current study primarily evaluates the carbonation and permeation resistance of coal bottom ash (CBA) and copper slag (CS) based geopolymer concrete (GPC). The strength parameters along with non-destructive tests were also performed for reference. CS and CBA were used as a 10%, 30% and 50% replacement of natural fine aggregates (NFA). Fly Ash (FA) was used as a binder and all seven mixes were subjected to oven curing at 65 °C for 24 h. The molarity of NaOH was kept constant (12 M) along with Sodium Silicate/Sodium Hydroxide ratio of 2. With inclusion of CS the carbonation depth, initial and capillary absorption has been decreased by 30%, 23% and 19% respectively with respect to control mix. The above-mentioned values have been increased by 28%, 27% and 58% in CBA based GPC. GPC mix containing 30% replacement of CS as sand has been considered to be appropriate for carbonation and permeation aspects.

Preparation of hierarchically porous carbon ash composite material from fine slag of coal gasification and ash slag of biomass combustion for CO2 capture

With the spread and development of industrialization, CO2 emissions are increasing dramatically, posing a serious threat to the global ecosystem. Based on coal gasification fine slag (CGFS) pore structure characteristics, CGFS was used to prepare carbon-ash composite hierarchically porous material by chemical activation and hydrothermal methods for CO2 capture. It would achieve comprehensive and high value utilization of CGFS. In addition, the biomass combustion ash slag (BCA) is rich in alkali and metal elements, there are extremely important influence on CGFS pore formation. Therefore, the alkali and potassium sources were extracted in leaching experiments for CGFS-based porous materials preparation. It was found that the prepared porous material had a large specific surface area (1270 m2/g), a graded porous structure and excellent CO2 adsorption capacity (4.06 mol/kg at 0 °C), while the pores of the BCA-impregnated porous material were further developed with a larger specific surface area (1406 m2/g) and more functional groups on porous material surface. All these results indicate the relevance between using BCA impregnates and material performance enhancement. Furthermore, the CGFS-based graded porous composite porous materials have great potential for repurposing in practical and industrial CO2 adsorption applications.

Effect of Minor Oxide and Residual Carbon on Coal Ash Crystallization Behavior and Slag Properties during Coal Gasification: Critical Literature Review and Thermodynamic Simulation.

Coal-ash-associated problems seriously limit the industrial application of entrained flow coal gasification. There have been many studies of this issue. However, many problems still need to be fully understood, especially regarding the effect of minor oxides and residual carbon on the crystallization of slag in coal ash systems. Crystals formed in slag affect the slag properties, especially its viscosity. This article reviews the crystallization behavior of coal ash slag and its impact on ash fusion temperature (AFT) and temperature of critical viscosity (Tcv). A thermodynamic simulation using FactSage 7.3 thermochemical software was performed to study the effect of minor oxides (i.e., Na2O, K2O, and TiO2) and residual carbon at a temperature range of 1000-1700 °C on the phase transformation in the oxide system. The literature review reveals that the minor oxides and residual carbon in coal ash affect the AFT and the coal slag's Tcv. The thermodynamics simulation indicated that Na2O, K2O, and TiO2 tend to decrease Tcv, while the residual carbon increase Tcv.

Distribution and impacts of contamination by natural and artificial radionuclides in attic dust and urban soil samples from a former industrial Hungarian city: A case study from Salgótarján

Primordial radionuclides can be found in all environmental compartments. Since coal-fired power plants (CFPP) can be a source of additional radionuclide contamination because coal contains natural radioactive isotopes such as 238U (226Ra) and 232Th. This study investigated the impact of such possible radionuclide contamination from former heavy industrial activities, namely a former local coal-fired power plant, in urban soils and attic dust in Salgótarján, Hungary. Even today, industrial by-products, e.g., coal ash, in this city represent significant threat to its residents. A total of 36 attic dust samples (family houses, kindergartens, churches and blockhouses) were collected and 19 urban soil samples (playgrounds, kindergartens, parks and others) were selected no further than 500 m from the corresponding attic dust sampling sites. Additionally, a coal ash and a brown forest soil sample were also collected to differentiate between the anthropogenic and geogenic sources in the residential area. The sampled houses, built between 1890 and 1990, are considered to be representative sampling sites for long-term accumulations of attic dust. The mean values of the total U, Th and Cs (mg kg−1) concentrations as well as those of K (m/m %) in attic dust and urban soil samples are 2.4, 3.6, 1.7 and 0.6 and 1.1, 4.4, 1.2 and 0.3, respectively, measured using ICP-MS. The mean activity concentrations of 226Ra, 232Th, 40K and 137Cs in attic dust and urban soil samples are 43.3, 34.0, 534.4 and 88.5 and 25.1, 32.8, 386.4 and 5.6 Bq kg−1, respectively, by using a low-background iron chamber with a well-type HPGe and a n-type coaxial HPGe detector.The elemental compositions (U, Th) and activity concentrations (226Ra, 232Th) along with their abundances in coal ash from the CFPP increase in both studied media as the distance of the sampling sites from the CFPP decreases. Two outlier attic dust samples in particular show significantly high activity concentrations of 226Ra: 145 and 143, of 232Th: 83 and 94 Bq kg−1, which can be considered as a proxy of unweathered coal ash. The calculated total absorbed gamma dose rate (D) and annual effective dose (E) received from urban soils indicate that the presence of the CFPP, coal ash cone and slag dumps does not cause an increase in the level of background radiation in Salgótarján. However, the concentrations of the studied radionuclides are much higher (except for 232Th) and exhibit higher degree of variability in the samples of attic dustthan in those of urban soils. The study suggests that attic dust preserves the undisturbed ‘fingerprints’ of long-term atmospheric deposition thanks to its chemical and physical properties unlike urban soil.

Exploring influence of MgO/SiO2 on viscosity-temperature property of coal ash slags under entrained flow gasification condition

To realize smooth slag discharge of Zhundong coals in entrained-flow-bed gasifier, the viscosity-temperature characteristics of slags with different MgO/SiO2 ratios were studied. The results show that low MgO/SiO2 ratio causes high BO content in liquid slag, resulting in excessive polymerization degree and viscosity. As the MgO/SiO2 increases, the activation energy of liquid slag increases, occurrence form of oxygen transforms from BO to NBO, more structural depolymerization reactions occur, and [SiO4] tetrahedra obtains more O2− and show more NBO. NBO is more likely to react with Mg2+, Ca2+, Al3+, and Fe2+ to form crystals, thus increasing the crystallization reaction activity of slag and cause the initial crystallization temperature and crystal content increasing. An increasing MgO/SiO2 causes a characteristic transition of slag from weak crystallinity and high polymerization degree to strong crystallinity and low polymerization degree, meanwhile, the poor viscosity-temperature characteristics with high viscosity of liquid slag is first improved, and then the problem of strong crystallinity leading to poor viscosity-temperature characteristics with high Tcv occurs. Therefore, the viscosity-temperature characteristics first improve and then deteriorate. The crystal size increases as MgO/SiO2 increases, which also cause Tcv increasing. Large ΔT and low Tp25 make 0.28MS become the most suitable for slag discharge.

Properties and microstructure development of alkali- activated coal bottom ash and titanium- extraction tailing slag binder

In this study, ground coal bottom ash (CBA) and titanium-extraction tailing slag (TS) were used as source materials to prepare alkali- activated materials (AAMs). The effects of grinding time on the properties of CBA and TS were investigated, and it was found that the optimum reactivity of CBA and TS appeared at specific surface areas of 700 ∼ 800 m2/kg. The influence of alkali content and modulus of water glass, water–solid mass (w/b) ratios and TS content on the fresh and hardening properties of AAMs were investigated. Furthermore, the reaction process of the binder was conducted by using XRD, FT-IR, SEM and hydration heat. Results showed that increasing the alkali content, reducing modulus of water glass, and adding TS into system could promote the reaction of AAM. A binder with more desirable properties was prepared at alkali content of 12%, water glass modulus of 1.2, w/b ratio of 0.45 and TS content of 20%. Its compressive strength at 7 d and 28 d was 20.8 MPa and 25.9 MPa, respectively. Microstructure analysis showed that the reaction products of binder contained AFm, N-A-S-H gel, C-S-H gel and C-A-S-H gel. This research tried to provide a fundamental basis for preparing clinker-free cement concrete from local industrial wastes to achieve sustainable development.

Synergistic and competitive adsorption of NOx and SO2 using a microwave-assisted approach with industrial waste materials fly ash and carbide slag as sorbents

A novel catalytic adsorption approach for microwave-assisted synergistic utilization of coal fly ash (FA) and carbide slag (CS) as adsorbents and Na2O/Na2O2 as a catalyst was proposed as an efficient and low-cost De-SO2 and De-NOx technology. The highest SO2 and NOx adsorption capabilities under these circumstances were 0.55 and 0.06 mg/g under 2% Na2O/FA-CS adsorbent at 150 °C respectively. The experimental results shows that the loaded Na2O2 as adsorbent in the Na2O2/FA-CS was strongly oxidized and decomposed into reactive oxygen (O∗), in which the conversion behavior of NOx (ads) and SOx (ads) contributed to the catalytic activation and adsorption performance. In the synergistic adsorption process, both NOx (ads) and SOx (ads) were present on the adsorption interface of the X% Na2O/FA-CS adsorbent, which also facilitated the production of unstable nitrogen and sulfur compounds. In the competitive adsorption process, NOx and SOx readily occupied the active adsorption spots of CaO used as an adsorbent in FA-CS while also contaminating the active catalytic spots of the coexisting Na2+/Na1+ ions, thus reducing the activity and efficiency of the adsorbent.Environmental implications: Coal fly ash is the main solid waste discharged from coal-fired power stations. The large amount of coal fly ash occupies land resources, while solid fine particles and heavy metals pollute the surrounding air. In addition, calcium carbide slag is a kind of industrial waste slag mainly comprising calcium hydroxide. Calcium carbide slag exhibits the characteristics of high humidity and alkalinity, leading to stockpiling and land pollution. To achieve resource utilization and high-value utilization, synergistic microwave-assisted utilization of industrial waste materials coal fly ash and carbide slag was assessed for high-efficiency desulfurization and denitrification.

Simulation and experimental study on the effect of iron on the structure and flow properties of coal ash slag

Slag fluidity is an important parameter affecting the stable operation of the gasifier. Above liquid temperature, slag fluidity is closely related to its structure. In the present study, the effect of iron on the three-dimensional connection state between [SiO4]4- and [AlO4]5- tetrahedrons in the SiO2-Al2O3-FeO-CaO slag system at 1773 K was deeply discussed by applying molecular dynamics (MD) simulation and ring statistics methods, and the slag network structure was divided into three rings with different functions according to the three-dimensional connection state. It was found that Fe2+ operated as a network modifier ion and substituted Si4+ and Al3+ in the slag and combined with O2–, thereby continuously depolymerizing higher-order rings into lower-order rings. This phenomenon simplified slag structure, reduced internal friction force, and improved fluidity. Finally, the ring distribution coefficient (Rdc) was defined and it was found that there was a linear relationship between Rdc and viscosity.

Synergistic effects and mechanism of the ternary flux system Fe2O3-CaO-MgO on the coal ash slag fluidity

Basic oxides are usually widespread in low-rank coals and cause many ash-related problems in gasification applications. In this paper, the synergistic effects of the ternary flux system of Fe2O3-CaO-MgO in lowering the ash fusion temperature and improving the viscosity-temperature characteristics were verified by testing the properties of samples with different Fe2O3/(CaO + MgO) ratios. The flow temperatures and temperatures of the critical viscosity decreased and then increased with the decrease of Fe2O3/(CaO + MgO) ratio and reached the lowest point when the iron oxide and alkaline earth metal oxide (CaO, MgO) contents were close to each other. From the perspective of mineral transformation, the formation of low melting point ferroan spinel and the eutectic between anorthite and ferroan spinel are the main mechanisms of synergism. No severe crystallization was observed in the iron-rich slags because Fe2+ could reduce the crystallization tendency. As CaO and MgO dominated the basic oxides, a CaO/MgO ratio of 4:6 effectively limited the crystallization and lower the temperature of critical viscosity (TCV). Thus, when regulating the coal ash fluidity, the content of iron oxide and the ratio between CaO and MgO should be consciously balanced to meet the requirements of the gasifier for slag removal.

Effect of phosphorus on viscosity-temperature behavior of high-sodium coal ash slag

Co-gasification of P-rich fuels and coal would reduce the large-scale usage of fossil fuels and pollution emissions, and fit the “carbon neutrality” goal in 2060. However, the effect of phosphorus on the viscosity-temperature behavior and structure of high-sodium coal ash slag is not yet completely characterized. In this work, the effect of phosphorus on the viscosity and structure of slag was investigated, and the crystallization tendency was also elevated. Results indicate that the high-sodium coal ash slag has a low viscosity as the Na2O can provide O2− ions and break Si-O-Si bonds, leading to decreasing the slag viscosity. The slag viscosity gradually increases as the PO43−/Na molar ratio increases because the phosphorus acts as a network former and enhances the slag viscosity. The temperature of critical viscosity rises from 1206 °C to 1305 °C and 1127 °C to 1207 °C, respectively, for Group 1 and Group 2 when the PO43−/Na molar ratio rises from 0/0 to 2/1. With the addition of phosphorus, the cations of Na are removed from the silicate network and form Na phosphate complexes and Si-O-Si linkages, and the content of Q3(Si) and Q4(Si) units increases while the contents of Q0(Si), Q1(Si), and Q2(Si) units decrease, increasing the slag viscosity. In addition, the Si-O-P and P-O-P linkages are formed due to the phosphorus atoms being introduced into the slag structure. Resulting in decreases the content of non-bridging oxygen and rises the degree of polymerization of slag. Furthermore, the viscous flow activation energy of slag increases while reducing the crystallization tendency after the application of phosphorus.

Influence of coal bottom ash and copper slag as a fine aggregate substitute on the characteristics of mortar

In recent decades, the global demand for sand has increased dramatically, and further increases are anticipated. Natural sand of acceptable quality is in short supply and diminishing at an alarming rate. It is essential that we find safe waste disposal methods and make prudent use of the available natural resources. The findings of this study shed light on the performance of mortar mixtures containing coal bottom ash (CBA) and copper slag (CS) as complete replacements for natural river sand. This study investigated the variations in compressive strength, flexural strength, abrasion resistance, the volume of permeable pore voids, and water absorption of mortar containing coal bottom ash and copper slag as fine aggregate. Flow values vary significantly among mixes, with the mix containing 70% copper slag and 30% coal bottom ash (RC7B3) exhibiting the highest flow by 43.5% compared to the Normal Mortar mix (NM). RC7B3 has the greatest density. Testing for compressive strength reveals that all mixtures gain strength at comparable rates. Additionally, flexural strength attainment rates are consistent. Notably, all mixtures experience negligible strength gains after 56 days. Mix RC7B3 absorbs much less water than Mix NM. Additionally, the volume of permeable voids is diminished. Abrasion tests reveal that the wear depths of all mixtures are less than 1 mm. The study concludes that it is feasible to use a mixture of 70% CS and 30% CBA as a replacement for natural sand, with compressive and flexural strengths that are acceptable. RC7B3 is characterised by its exceptional strength, low water absorption, and permeable voids. These results highlight the need for innovative technological approaches to incorporate industrial waste materials into modern mortar and concrete practises, indicating the potential of the investigated mixes for a variety of applications in the construction industry.

Mechanical and durability performance of sustainable concrete with the inclusion of alternative fine aggregate

Natural river sand has become less readily available in recent years due to the expansion of the building sector. Due to the scarcity of river sand, researchers seek an alternative fine aggregate material that does not compromise strength and durability. The sustainability advantages of using coal bottom ash, steel slag, eco sand, and quarry dust as a potential substitute for traditional fine aggregates can be attributed to the following: the eradication of the necessity to discard these wastes in landfills, as well as the provision of an alternate source for natural raw materials. Consequently, the adverse environmental effects linked with the processing and mining of natural aggregates are avoided. Natural river sand and quarry sand are utilised to partially replace them with industrial residues such as Steel Slag (SS), Coal Bottom Ash (CBA), and Eco Sand (ES). Microstructural characteristics of alternative fine aggregates, such as SEM and EDS were analysed. This article discusses the mechanical, fresh, and durability characteristics of concrete using alternative fine aggregate. The test findings were compared with those of concrete made from a control mix. Mix-A with 17.5% coal bottom ash and 12.5% eco sand achieved the highest mechanical strength properties, while Mix-B with 15% steel slag and 85% quarry sand achieved the highest mechanical strength properties. The test findings from this study showed that concrete made from industrial waste materials including CBA, ES, and SS performed well in terms of durability and strength. Therefore, the well-graded coal bottom ash, eco sand, and steel slag improved the concrete’s strength and provided a reliable source for concrete production.

Utilization of lignite coal ash and steel slag in fly ash brick manufacturing: A review

Brick plays an important role in the construction industry due their excellent properties like compressive strength and durability. From the earliest times they were considered an important factor in the purpose of the building. Considering the different types of bricks, fly bricks are the best in recent times because they are resource intensive and cost effective. This article provides an up-to-date review of current studies of bricks, categorizing these publications according to the materials used and the methods used for the production of invention bricks. In addition, this article makes an important note about coal ash, which may be the focus of future brick products as an alternative to fly-gray bricks with some amount of steel slug, and the main challenge is to go one step further in the properties of the bricks by implementing the respective requirements.