Fluidized Bed Combustion Ash Research Articles

Phase identification and micromechanical properties of non-traditional and natural pozzolan based alkali-activated materials

Four groups of non-traditional and natural pozzolan (NNP) based (aluminosilicate-based) materials, calcined clays, ground bottom ashes, volcanic ashes, and fluidized bed combustion ashes, were alkali activated using a hybrid solution of sodium silicate and sodium hydroxide. The microhardness and reduced modulus of the phases present in eleven alkali-activated pastes were measured using nanoindentation. At least 800 data points were collected from 28-day old ambiently cured paste samples. Unsupervised machine learning techniques i.e., k-means clustering and Gaussian mixture modeling (GMM) were used for the classification of the micromechanical properties supplemented by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The clustering of micromechanical and EDS data revealed five distinct phases in these hardened pastes. The alkali-activated gels identified had reduced modulus values ranging from 12 to 34 GPa. The remnant phases were partly reacted grains and unreacted minerals exhibiting reduced modulus values ranging from 35 to 105 GPa. Micromechanical property contour plots and SEM image pixel count plots were used to validate the phase assemblage. Additionally, the identification capabilities and advantages of the method are assessed by direct comparison with experimental results for different alkali-activated gels.

Non-traditional aluminosilicate based alkali-activated mortars - statistical optimization of solution parameters and processing conditions for optimal compressive strength, workability and setting time

The recent shortage of traditional fly ash and slag, commonly used precursors in alkali-activated binders, prompted a rigorous search for alternative materials. This study evaluated four groups of currently underused supplementary cementitious materials (SCMs) as precursors for producing alkali-activated mortars. The materials evaluated include three calcined clays, three ground bottom ashes, three volcanic ashes, and two fluidized bed combustion ashes, collectively named non-traditional and natural pozzolans (NNPs). Firstly, the compositions of the NNPs were optimized using trial-and-error methods to minimize the concentration of the activating solution. Then, the two solution parameters i.e., silica modulus and Na2O% were optimized for compressive strength using a central composite design. The compressive strength (ASTM C109), the workability (ASTM C1437), and the setting time (ASTM C191) of the mortar were determined. The results show that all 11 materials could produce mortar mixtures with compressive strength in the 20–40 MPa range at 28 days, satisfactory workability of at least 50 % (flow value), and at least 30 min of initial setting time without heat curing and without blending with conventional SCMs. Most of the materials were activated with lower solution parameters than those used in the literature. The binder optimization suggested Si/Al range 1.0–3.0 and a minimum Ca/Al of 0.25 as favorable molar ratios for potentially reactive aluminosilicate precursors. Multiple linear regression models validated by higher R2 and minimum RMSE and MAE could accurately predict the compressive strength of NNP mortar. Furthermore, calcium hydroxide and shrinkage-reducing admixtures were identified as set regulators in alkali-activated NNP mortars.

Experimental study on dynamic resilient modulus of subgrade with circulating fluidized bed combustion ash as filler

Using circulating fluidized bed combustion ash (CFBCA) as roadbed filler can solve the problem of secondary utilization, and dynamic resilient modulus (DRM) can match the dynamic performance of roadbed filler under driving load. In order to explore the dynamic performance of the subgrade with CFBCA as filler under driving load, based on the dynamic triaxial test and mercury intrusion porosimetry test, the DRM of the sample under different curing ages, compaction, moisture content, stress, dry-wet and freeze–thaw cycle conditions were studied, and the pore distribution characteristics of the sample were analyzed. The results show that the DRM of CFBCA samples increases significantly in the 0 ∼ 7d age curing period, and increases slowly in 7 ∼ 28d; with the increase of f-CaO and SO3 content, the DRM of CFBCA samples increased; after the dry-wet cycle and freeze–thaw cycle, the DRM of the CFBCA sample decreased, and the decrease was more obvious under the dry-wet cycle. With the increase of f-CaO and SO3 content, the total porosity and macropore of CFBCA samples decreased; with the decrease of moisture content, the total porosity and macropore of CFBCA samples increased, the DRM becomes smaller. Under different moisture content and compaction, the DRM fitting of the CFBCA sample shows that the prediction results of the three-parameter theoretical model with volume stress and octahedral shear stress as variables are compared with the test results with a high correlation (R2 > 0.96), it can effectively predict the DRM of the subgrade with CFBCA used as filler.

Role of CO2 in enhancing geopolymer properties formulated with fluidized bed combustion ash

Fluidized bed combustion coal ash was used together with conventional coal ash and alkaline materials to synthesize geopolymer cement. The production process was performed in a carbon dioxide-rich environment to integrate carbon dioxide into the cement. The presence of carbon dioxide was found to enhance the formation of crystalline carbonates during the hydration reaction yielding an enhanced geopolymer matrix with improved binding characteristics. The non-crystalline (metastable) carbonates formed undergo crystallization processes that complement the hydration reactions, and yield carbonate with beneficial binding effects. Experimental optimization was designed and implemented to select the desired formulation of raw materials for achieving high levels of carbon capture and engineering properties. The optimized formulation produced a geopolymer cement with 7.4 wt% CO2 content, which produced concrete materials with a flow table of 68 cm, an initial set time of 34 min, and 28-day compressive strength reaching 28.2 MPa with acceptable residual compressive strength.

Effect of ultrafine pozzolanic powders on durability of fabricated hydraulic lime

Fabricated hydraulic lime (FHL), prepared by fully mixing hydrated lime and hydraulic components containing activated Si/Al, shows quicker strength development and better water resistance than that of hydrated lime, and has the advantage of raw material supply to replace natural hydraulic lime (NHL) for the restoration of ancient sites. As ultrafine pozzolanic powders such as nano-SiO2, silica fume, slag, fly ash and circulating fluidized bed combustion ash can not only improve the hydraulic activity, but also be beneficial for the permeability of FHL paste in the ancient sites, this study investigated the influence of the above ultrafine pozzolanic powders on the durability of FHL, and obtained an optimal FHL through orthogonal test, and its durability was compared with NHL. The results showed that nano-SiO2 had a significant improvement on the water and sulphate resistance of FHL paste as well as its early compressive strength; silica fume greatly influenced the water resistance and later compressive strength; slag is the most important factor to improve the sulphate resistance of FHL; fly ash and circulating fluidized bed combustion ash had a smaller effect on the durability of FHL. The optimum FHL is composed of 1% nano-SiO2, 2% silica fume, 10% slag, 10% fly ash, 6% circulating fluidized bed combustion ash and 69% hydrated lime, which owned much better water and sulphate resistance than NHL mortar. The superior durability of FHL pastes was mainly due to the diversification of the internal hydration products and the close connection from XRD and SEM analysis. FHL with excellent durability proposed in this paper may have a positive impact on the restoration of ancient sites. In the future, the reinforcement effect of FHL prepared in this study on cultural relics sites will be discussed.

Utilization of circulating fluidized bed combustion ash to prepare supersulfated cement

The present study aims to introduce the circulating fluidized bed combustion (CFBC) ash as the source of aluminosilicate material for supersulfated cement (SSC). Contour maps were designed to optimize the proportion of CFBC ash-anhydrite-clinker by comprehensive considerations of strength, expansion and pore structure. The hydration products were characterized by XRD, TG-DSC and SEM methods. The CFBC ash content in SSC could be increased up to 70%, the corresponding clinker and added anhydrite contents should be set to approximately 20% and 10%, respectively. The main hydration products of SSC are ettringite, C-S-H, gypsum and portlandite. A value of [SO3]/[Al2O3] molar ratio in the range 0.8–1.2, is recommended for proportion optimization of SSC.

The Impact of Variable Curing Conditions on the Properties and Microstructures of Mixtures of Ground Granulated Blast Furnace Slag and Circulating Q1 Fluidized Bed Combustion Ash

The use of Portland cement, an important construction material, is encountering growing challenges because of its adverse environmental impacts. In this study, a new hydration system without Portland cement, which blends ground granulated blast furnace slag (GGBFS) and circulating fluidized bed combustion (CFBC) ash, was developed and tested. The variables included the effect of different types of CFBC ash, the mass ratios between CFBC ash and GGBFS, and different curing temperatures. The mortar properties were determined through the compressive strength test, absorption test, shrinkage test, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The main results were as follows: (1) The compressive strength of mortar specimens made with this ecologically friendly hydration system reached at least 40 MPa under a 35°C curing temperature. (2) Mortar with finer CFBC ash as an activator had higher compressive strength and lower absorption. (3) A proper mass ratio of GGBFS to CFBC ash is necessary for engineering applications. The present findings indicate that to maximize compressive strength, the particle size and the mass ratio of CFBC ash to GGBFS must be considered. According to the result, the type A ash with 3:7 mass ratio of CFBC ash to GGBFS is recommended.

Effect of ground rice husk ash on engineering properties and hydration products of SRC eco‐cement

AbstractThe effect of ground rice husk ash (GRHA) (R) on engineering properties and hydration products of eco‐cements containing ground granulated blast furnace slag (GGBFS) (S) and circulating fluidized bed combustion ash (CFA) (C) was studied. Four mixture proportions of SRC eco‐cements with GRHA replacement at levels of 0%, 15%, 30%, and 45% by mass of binder were investigated. A reference mixture proportion of paste with 100% ordinary Portland cement (OPC) was prepared for comparison purposes. A series of laboratory tests including setting time, compressive strength, water absorption, porosity, thermal conductivity, scanning electron microscope coupled with energy dispersive spectroscopy, X‐ray diffraction, and Fourier‐transform infrared spectroscopy analysis was carried out. Measured results showed that the GRHA increased setting time and porosity in the SRC eco‐cements having a water‐to‐powder (w/p) of 0.4, leading to the decrease in compressive strength and thermal conductivity while the increase in water absorption. The GRHA increased the cristobalite amount and decreased the portlandite amount in the SRC eco‐cements at the age of 28 days, resulting in the more significant long‐term compressive strength development when compared with the reference paste with 100% OPC. Consequently, the GRHA could be used at a level of 15% by mass of binder to produce the SRC eco‐cement with the compressive strength at 28 days of higher than 30 MPa and the thermal conductivity of 0.713 W/mK, resulting from the formations of AFt, C–S–H, and C–A–S–H gels.

Effect of cement and fluidized bed combustion ashes on properties of phosphogypsum composite cementitious materials

The effect of fluidized bed combustion ashes (FBC) and cement by monodoping and compound doping on the mechanical properties and water resistance of phosphogypsum composite cementitious materials was studied, and the mechanism was explored by SEM. The results showed that the cement and fluidized bed combustion ashes by monodoping have a negative effect on the compressive strength of phosphogypsum, but can effectively improve its softening coefficient. When cement and fluidized bed combustion ashes mixed together, the softening coefficient increased with the increase of cement from 0 to 10%. But the softening coefficient decreased with the increase of cement from 0 to 20%, however, the compressive strength increased. Through the ANOVA analysis, the optimal dosage of cement, fluidized bed combustion ashes and phosphogypsum was obtained. Through the SEM, the hydration products covered on the surface of gypsum crystal, increased the compactness of the hardened body.

Development of a cementless eco-binder as an alternative to traditional Portland cement in construction activities

In this research, the performance of a cementless eco-binder, a mixture of waste materials including slag, circulating fluidized bed combustion ash (CFA), and rice husk ash (RHA) was investigated, in which CFA acted as an activator. One hundred and twenty paste samples were prepared by using the RHA/(slag + RHA) ratios of 0, 15, 30, 45% while keeping a constant ratio of CFA/(slag + RHA) at 25%. The setting period, compressive strength, the ultrasonic pulse velocity (UPV), and drying shrinkage of paste samples were determined at the samples’ age of up to 91 days. In addition, the microstructures of all paste samples were also characterized by scanning electron microscopy (SEM). It was found that the use of cementless eco-binder significantly increased the setting times, lower compressive strength, drying shrinkage, and UPV values compared to the control OPC sample. The maximum 91-day-old compressive strength gained by the binary binder of slag and CFA (R00C25) was 90% of that of the control specimen. Incorporation of RHA with higher replacement levels up to 45% resulted in a significant decrease in compressive strength up to 50%. Moreover, the SEM analysis revealed that there was a large difference in the microstructures of the control and the cementless eco-binder samples, in which the main hydration products were C-S-H/C-A-S-H gels and ettringite (AFt) due to relatively high amount of SO3 and SiO2 in the CFA and RHA, respectively. Thus, it can be realized that the potential for the use of slag, CFA, and RHA as a sustainable cement-free binder is promising in the construction industry, especially for lower strength or no required early high strength structures.
 Keywords:
 cementless eco-binder; circulating fluidized bed combustion; rice husk ash; slag; microstructure; compressive strength; drying shrinkage; setting time; ultrasonic pulse velocity.

Investigation on physical properties, strength and phase evolution of binary cementitious materials made of CFBC ash and lime

Circulating fluidized bed combustion ash (CFBC ash) is the wasteof coal-firedcirculating fluidized bed power plant boiler.CFBC ash contains amounts of free limeand anhydrite, which has a self-hardening andexpansion property. This paper studies the influence of CFBC ash fineness and lime or slaked lime dosage on the physical properties, strength and phase evolution of binary cementitious materials (lime or slaked lime-CFBC ash). The experimental results show that when lime or slaked lime dosage is below 30%, throughCFBC ash getting finer, setting timeof binary cementitious materials becomes shorter and compressive strength of that increases, butwater requirement of normal consistency of that decreases to some extent. And when CFBC ash fineness is constant, with the increment of lime dosage, setting timeof binary cementitious materials becomes shorter and water requirement of normal consistency of that increases, butcompressive strength of that declines first and then increases. But when CFBC ash fineness is constant, with the increment of slaked lime dosage, setting timeof binary cementitious materials becomes longer and compressive strength of that declines, butwater requirement of normal consistency of that increases.

Mechanical Properties and Durability of High‐Performance Concretes Blended with Circulating Fluidized Bed Combustion Ash and Slag as Replacement for Ordinary Portland Cement

This study investigates the mechanical properties and durability of three families of high‐performance concrete (HPC), in which the first was blended with fly ash, the second with circulating fluidized bed combustion (CFBC) ash, and the third with CFBC slag. In addition to each of the three mineral additives, silica fume and a superplasticizer were also incorporated into the HPC. Hence, three families of HPC, containing 10%, 20%, and 30% mineral admixtures and 9% silica fume of the binder mass, respectively, were produced. The microstructure and hydration products of the HPC families were examined by scanning electron microscopy (SEM) and X‐ray diffraction (XRD) to explore the influence of fly ash, CFBC ash, and CFBC slag on the compressive strength and frost resistance of HPC. The experimental results show that the compressive strength of HPC could reach 60 MPa at 28 d age. When the fly ash content was 30%, the compressive strength of HPC was 70.2 MPa at 28 d age; after the freeze‐thaw cycle, the mass loss and strength loss of HPC were 0.63% and 8.9%, respectively. When the CFBC ash content was 20%, the compressive strength of HPC was 75 MPa at 28 d age. After the freeze‐thaw cycle, the mass loss and strength loss of HPC were 0.17% and 0.81%, respectively.

Utilization of the circulating fluidized bed combustion ash in autoclaved aerated concrete: Effect of superplasticizer

This paper aims to solve the problem of high water absorption in the use of circulating fluidized bed combustion ash. Meanwhile, the feasibility of using the circulating fluidized bed combustion ash to prepare autoclaved aerated concrete was studied. The circulating fluidized bed combustion ash autoclaved aerated concrete samples with different water consumption and different dosages of water reducing agent were prepared. The rheological properties and gas-foaming results of the slurry, the compressive strength, the dry density, specific strength, pore structure and hydration products of the products were analyzed. The results show that the incorporation of polycarboxylate superplasticizers has a positive effect on the rheological properties of the slurry, the gas generation, and the physical properties of the sample. Its water reducing effect not only can improve the rheological properties of the slurry to match the gas generation rate of the aluminum powder, but also optimize the pore structure to reduce the number of harmful pores (less than 50 nm) and improve the strength of the product. Because a large number of uneven macropores are introduced, the high water consumption is unfavorable to the compressive strength of the product to a certain extent. However, too low water consumption would hinder cement hydration to produce C-S-H gel and reduce the formation of tobermorite. It is noticed that the reasonable combination of water consumption and water reducing agent can improve the strength of aerated concrete products without significantly changing the bulk density of the sample. This paper provides a theoretical basis for use of other high-water-demand solid wastes similar to circulating fluidized bed fly ash in the preparation of autoclaved aerated concrete.

Effects of High CaO Fly Ash and Sulfate Activator as a Finer Binder for Cementless Grouting Material.

The effects or high CaO fly ash and sulfate activator on cementless grouting material were investigated through Labiles Waterglass (LW) grouting applied at an actual construction field. Circulating fluidized bed combustion ash was used as CaO fly ash, and petro cokes desulfurization gypsum was used as sulfate activator. Cementless grouting material (CGM) could decrease the gel time by about 16.7% compared with ordinary Portland cement (OPC). This characteristic improved the average daily workload and construction period per meter by about 13.5% with CGM. Furthermore, when constructing 1000 holes of LW grouting, the construction time could be reduced by 19 days (20% of the total construction period of LW grouting). Meanwhile, CGM could increase the homogel strength by about 48.4% after 28 days compared with OPC. After X-ray diffraction analysis and scanning electron microscope analysis, CGM was found to produce cement hydrate by chemical reaction mechanism of high CaO fly ash and sulfate activator, even though cement was not used. The matrix structure properties of CGM and OPC specimens were similar, but CGM, with 134.3% fineness, exhibited higher compressive strength and lower air permeability than OPC. As a result, CGM could reduce the leakage length per square meter by 74.4% compared with OPC. Using CGM as a substitute for OPC in LW grouting in actual sites could be beneficial in terms of securing construction speed and durability, as well as reducing CO2 emissions due to reduction of OPC usage.

Development of a new ammonium nitrate composition: an attempt to prevent misuse of explosives for antisocial activities

ABSTRACTThe importance of ammonium nitrate (AN) in the production of explosive materials is similar to that in the agricultural industry. However, its use as in explosives has led to it being used for destructive purposes. Therefore, efforts are being made to develop the means to suppress the detonation potential of AN. In this study, AN is diluted with calcium carbonate and dolomite, which serves to increase its nutrient content and decrease its detonation enthalpy. Applying a coating of fluidized bed combustion ash can prevent its application in areas other than the agricultural industry.

Acid Leaching of Rare Earth Elements from Coal and Coal Ash: Implications for Using Fluidized Bed Combustion To Assist in the Recovery of Critical Materials

High-temperature pretreatment of coal-based mineral matter in an oxidizing environment significantly enhances the leaching characteristics of rare earth elements (REEs). A research study has found that the temperatures used in fluidized bed combustion (FBC) of coal to produce electricity are near optimum for pretreating the associated mineral matter prior to leaching to maximize the recovery of critical materials. Tests were performed on representative samples collected from preparation plants treating West Kentucky No. 13, Illinois No. 6, and Fire Clay coal seam sources as well as fly ash and bed ash samples from two FBC power plants. Acid leaching tests using 1.2 M HCl at 75 °C were performed on both the coal and the FBC ash samples. Prior to leaching, the coal samples were pretreated at temperatures of 600, 750, and 900 °C in an oxidizing environment to study the effect on leaching characteristics. The results showed that pretreatment at 600 °C for 2 h resulted in a significant increase in REE recovery from a range of 20–40 to ∼80% for all coal sources. The leaching kinetics is characterized by a quick release of rare earth elements within the first few minutes of the process. For the West Kentucky No. 13 coal source, ∼75% of the REEs were leached in the first 15 min from the 1.4–1.8 specific gravity (SG) fraction that was calcined at 600 °C. Additionally, the leaching kinetics of the major contaminant, that is, Fe, was much lower than that of the REEs, which significantly benefits the efficiency of leaching and the downstream upgrading processes. REE leaching characteristics of the FBC ash samples were similar to those of the calcined coals. Mineralogy characterization showed that the degree of crystallinity for both the calcined coal and FBC samples was similar to the original associated mineral matter, which provided evidence for the advantage of using the FBC byproducts as REE feedstocks over pulverized coal boilers that utilize temperatures greater than 1200 °C. These findings were used to develop a conceptual flowsheet that incorporates FBC technology and its typical combustion environment to enhance the feasibility of recovering critical materials from coal-based sources.

Fluidized bed combustion coal fly ash: comparative evaluation for potential use in alkali-activated binders

ABSTRACT The physical, chemical, mineralogical and toxicity attributes of two fluidized bed combustion (FBC) coal fly ashes were evaluated, and were compared against that of a conventional coal fly ash. The potential use of the FBC ash in alkali-activated binders was also evaluated. Alkali-activated mortars were prepared and tested for compressive strength at different ages. The alkali-activated binders were also evaluated using SEM, TGA and FTIR methods. This investigation accounted for: (i) the differences in the combustion temperatures of FBC versus conventional methods of coal combustion; (ii) capture of sulfur from combustion emissions in the FBC method, and its incorporation into fly ash as crystalline solids; and (iii) the type and particle size of the sorbent used in the FBC process for capture of sulfur from combustion emissions. FBC ashes were found to differ from the conventional coal fly ash in terms of chemical composition, crystalline phases and carbon content. The higher crystallinity and carbon content and the larger particle size of FBC ashes were noted to challenge their potential use in alkali-activated binders. Suggestions are made based on the experimental results towards effective use of FBC ashes in alkali-activated binders.Abbreviations: FBC: Fluidized Bed Combustion; SEM: Scanning Electron Microscope; TGA: Thermogravimetric Analysis; DTA: Differential Thermal Analysis; XRF: X-Ray Fluorescence; XRD: X-Ray Diffraction; LOI: Loss-On-Ignition; TDS: Total Dissolved Solids; EPA: Environmental Protection AgencyI; CP-OES: inductively couple plasma spectroscopy; DI: Deionized; CFB: Circulating Fluidized Bed; ASTM: American Society for Testing and Materials

Properties of Controlled Low Strength Material with Circulating Fluidized Bed Combustion Ash and Recycled Aggregates.

This study aims to investigate the effect of adding circulating fluidized bed combustion (CFBC) ash, desulfurization slag, air-cooled blast-furnace slag and coal bottom ash to the controlled low-strength material (CLSM). Test methods include slump flow test, ball drop test, water soluble chloride ion content measurement, compressive strength and length change measurement. The results show that (1) the use of CFBC hydration ash with desulfurization slag of slump flow is the best, and the use of CFBC hydration ash with coal bottom ash and slump flow is the worst; (2) CFBC hydration ash with desulfurization slag and chloride ion content is the highest; (3) 24 h ball drop test (diameter ≤ 76 mm), and test results are 70 mm to 76 mm; (4) CFBC hydration ash with desulfurization slag and compression strength is the highest, with the coal bottom ash being the lowest; increase of CFBC hydration ash can reduce compressive strength; and (5) the water-quenched blast furnace slag and CFBC hydration ash would expand, which results in length changes of CLSM specimens.

Steam jet mill—a prospective solution to industrial exhaust steam and solid waste

Bulk industrial solid wastes occupy a lot of our resources and release large amounts of toxic and hazardous substances to the surrounding environment, demanding innovative strategies for grinding, classification, collection, and recycling for economically ultrafine powder. A new technology for grinding, classification, collection, and recycling solid waste is proposed, using the superheated steam produced from the industrial exhaust steam to disperse, grind, classify, and collect the industrial solid waste. A large-scale steam jet mill was designed to operate at an inlet steam temperature 230-300°C and an inlet pressure of 0.2-0.6MPa. A kind of industrial solid waste fluidized-bed combustion ashes was used to grinding tests at different steam temperatures and inlet pressures. The total process for grinding, classification, and collection is drying. Two kinds of particle sizes are obtained. One particle size is d50 = 4.785μm, and another particle size is d50 = 8.999μm. For particle size d50 = 8.999μm, the inlet temperature is 296°C and an inlet pressure is 0.54MPa for the grinding chamber. The steam flow is 21.7t/h. The yield of superfine powder is 73t/h. The power consumption is 3.76kWh/t. The obtained superfine powder meets the national standard S95 slag. On the basis of these results, a reproducible and sustainable industrial ecological protocol using steam produced by industrial exhaust heat coupled to solid waste recycling is proposed, providing an efficient, large-scale, low-cost, promising, and green method for both solid waste recovery and industrial exhaust heat reutilization.

Effect of fineness and components of CFBC ash on performance of basic magnesium sulfate cement

The effect of fineness and components of circulating fluidized bed combustion ash (CFBC ash) on compressive strength, setting time and fluidity of basic magnesium sulfate cement was studied. The results showed that with the increment of the fineness of CFBC ash, the fluidity of cement paste increased, the setting time shortened and the compressive strength was slightly enhanced. The effects of the dosage of active SiO2, f-CaO and SO3 in CFBC ash on setting time, compressive strength and softening coefficient were also investigated. The experimental results indicated that with the increment of the active SiO2 dosage in CFBC ash, the setting time would prolong and softening coefficient would reduce. When the f-CaO dosage increased, the setting time would shorten. When the SO3 dosage increased, the setting time would prolong firstly and then shorten. Softening coefficient increased firstly and then reduced with the increment of the f-CaO dosage, but the softening coefficient firstly reduced and then slightly increased when the SO3 dosage increased. With the increment of the active SiO2, f-CaO and SO3 dosage in CFBC ash, compressive strength increased at first and then decreased. CFBC ash still has the filler effect, the morphology effect and the chemical effect. Comprehensive comparison, the superior fineness of CFBC ash is origin ash, and the optimum composition of CFBC ash is active SiO2 < 5%, f-CaO < 3% and SO3 < 1.75%. The results showed that CFBC ash could serve as favorable source materials for preparing basic magnesium sulfate cement, which may promote comprehensive application of basic magnesium sulfate cement and resource utilization of CFBC ash.