Gasification Fine Slag Research Articles

Synthesis of carbon/P-zeolite composites from coal gasification fine slag and studies on adsorption characteristics for methylene blue

Synthesis of carbon/P-zeolite composites from coal gasification fine slag and studies on adsorption characteristics for methylene blue

Investigation of the Heteroatom Doping Effect on Gasification Fine Slag Residue Carbon Oxygen Reduction Reaction Catalysts

Coal gasification fine slag (GFS) is a kind of solid waste that is produced from industrial entrained‐flow gasification plants. Using the GFS flotation residue as a carbon source for the oxygen reduction reaction (ORR) catalyst is therefore an effective recycling method that will gain great attention. Herein, the carbon residue after the flotation of GFS is used as the precursor to prepare ORR catalysts through CO2 activation. Combined with the characterization of Raman spectroscopy, X‐ray photoelectron spectroscopy, and scanning electron microscopy, the influence of N, P, Fe, Ca, and other doped elements on the physical and chemical structure of the catalyst is explored. The results demonstrate that calcium chloride causes the decrease of reactive nitrogen, and has a negative effect on the development of pore structure. The active nitrogen content of ammonium phosphate as a nitrogen source is lower than that of ammonium chloride as a nitrogen source. The codoping of ammonium phosphate and ferrocene produces a mutual inhibitory effect, resulting in lower doping levels of phosphorus and iron. This study has great significance for the activation and heteroatom doping treatment of ORR catalysts prepared from gasification residue carbon.

Coal gasification fine slag residual carbon decorated with hollow-spherical Fe3O4 nanoparticles for microwave absorption

Reasonable design and optimization of the dielectric and magnetic properties of materials are important to achieve excellent electromagnetic wave (EMW) absorption capacities. Residual carbon (RC) derived from coal gasification fine slag-loaded hollow-spherical Fe3O4 nanoparticles (Fe3O4 NPs@RC) was synthesized via hydrothermal strategy. The chemical compositions, morphologies, structures, and electromagnetic parameters of the as-prepared RC and Fe3O4 NPs@RC revealed that the phase components (RC and Fe3O4 phases) and microstructure (hollow spherical and micro/nano blocks) were well modified by modulating the content of Fe3O4. Such modifications result in variations in the hierarchical structure, defects, electromagnetic parameters, and EMW absorption performance. The Fe3O4 NPs@RC composites (S1 and S2) exhibited superior EMW absorption capacity. The binary composite with an additive amount of FeCl3·6H2O of 2.66 g (S2) exhibited the minimum reflection loss (RLmin) of −32.6 dB at 2.0 mm and a broad absorption bandwidth (fe, RL less than −10 dB) of 4.64 GHz at a lower thickness value of 1.65 mm under a filler content of 40%. In addition, the ultra-broad fe reached 14.35 GHz, which contained the entire Ku, X, and C bands by easily regulating the thicknesses from 1.5 mm to 5 mm. A possible EMW absorption mechanism was proposed. This study offers an effective strategy for designing novel coal gasification solid waste-based materials for high-performance absorbers.

Innovative flotation separation considering pores blocking to facilitate residual carbon recovery from coal gasification fine slag

The conventional flotation of coal gasification fine slag has the dilemma of large collector dosage and low carbon recovery due to the developed porosity of the residual carbon. In this study, an innovative method to enhance the flotation recovery of residual carbon was proposed by pores blocking with pulverized coal. Flotation experiments were carried out to verify the effect of pore blocking on the recovery of residual carbon, and scanning electron microscope, X-ray photoelectron spectroscopy, and mercury intrusion porosimetry were used for mechanism analysis. The results showed that the addition of pulverized coal did play a role in pores blocking in the novel flotation, and its carbon recovery rate was improved by 14.11% (absolute value) compared to that of conventional flotation at the same ash content of the concentrates. On the one hand, the pulverized coal adheres on the pore openings on the residual carbon surface, thus preventing the collector adsorption into the pore channels; on the other hand, the adhesion of pulverized coal to the residual carbon surface increases the adsorption sites for collector. Therefore, pores blocking is beneficial for more adsorption of the collector on the outer surface of the residual carbon and thus improving its flotation recovery. This paper provides significant inspiration for efficient flotation of coal gasification fine slag.

Catalytic upgrading of cow manure pyrolysis vapors over zeolite/carbon composites prepared from coal gasification fine slag: High quality bio-oil obtaining and mechanism investigation

The resource utilization of solid waste not only reduces the environmental pollution, but also reduces the use of fossil energy. In this study, three low-cost zeolite/carbon composites, including Y-type zeolite/carbon, Beta zeolite/carbon and ZSM-5 zeolite/carbon, were prepared from coal gasification fine slag (CGFS), which were used for catalytic upgrading of pyrolysis vapors of cow manure (CM). The composition and distribution of products from the catalytic pyrolysis of CM over different types composites were explored, and the relationship between catalysts structure and product selectivity was clarified. The results show that different types of catalysts have virous effects on the composition and distribution of products due to different physiochemical structures such as pore size and acid site. Among them, ZSM-5 zeolite/carbon is more conducive to the formation of monocyclic aromatics due to its shape selective catalysis, Beta zeolite/carbon has relatively large pore size and has high selectivity for polycyclic aromatics, and Y-type zeolite/carbon is more conducive to the removal of nitrogen and oxygen-containing compounds. Moreover, vanillin, glucose and valine, which are the main components of lignin, cellulose and protein in CM were selected as model compounds to reveal the reaction mechanism of catalytic upgrading. The results of this study can provide reference and theoretical guidance for the comprehensive utilization of solid waste and the development of low-carbon green industry.

Waste coal gasification fine slag disposal mode via a promising “efficient non-evaporative dewatering & mixed combustion”: A comprehensive theoretical analysis of energy recovery and environmental benefits

Coal gasification technology is an important starting source for the clean conversion and utilization of coal. Gasification fine slag (GFS) is the waste produced in the coal gasification process, its production and storage volume are increasing with the large-scale promotion of coal gasification technology. Currently, the GFS black water is processed by the horizontal belt filter and the moisture content of the obtained filter cake exceeds 50%, which has posed challenges to the environment and energy security. The study aims to solve the problems of environmental pollution and resource waste caused by high moisture GFS filter cake. The analysis of the basic physical properties of GFS and the recommendation of a high-efficiency dehydration technology of GFS under the combined action of “vacuum force-mechanical pressure-vibration force” was promoted, and the moisture of filter cake was reduced to 30% at lower energy consumption. By establishing a thermodynamic model, the quality and energy balance of GFS dehydration and mixed combustion process were studied, and the energy consumption and calorific value characteristics of mixed combustion in the two dehydration routes of “horizontal belt filter dehydration-high moisture filter cake mixed combustion” and “multi-energy field dehydration-low moisture filter cake mixed combustion” were compared. Based on comparing the energy consumption of multi-energy field dehydration and evaporation drying, the CO2 emission reduction was evaluated by unifying energy grades and a high-efficiency energy-saving path was analyzed. The studies showed that the GFS can be efficiently dehydrated through the multi-energy field, and the energy-saving is 47.3% compared with the current dehydration method. Through the establishment and analysis of thermodynamic models, it is found that the low-moisture GFS filter cake mixed combustion with coal has energy advantages. With standard coal consumption compared and CO2 emissions estimated, the multi-energy field dehydration technology reduces carbon dioxide emissions by 87.09% compared with evaporation drying. The research results will provide theoretical and technical support for the technical integration of efficient dewatering, carbon resource utilization and energy recovery of GFS.

Controlled design of Na–P1 zeolite/ porous carbon composites from coal gasification fine slag for high-performance adsorbent

Low-cost and concentrated industrial wastes have been recognized as a sustainable resource for preparation of new functional materials. Here, a new method was designed for the synthesis of porous composites containing high-purity Na–P1 zeolite and porous carbon from waste coal gasification fine slag (CGFS), which was treated first by acid leaching to controllably remove metal impurities and adjust Si/Al ratio, followed by NaOH fusion and hydrothermal treatment. By leaching with 1.0 mol/L HCl solution, the Si/Al ratio of the raw CGFS increased to 5.7, and the obtained CZ-1.0 consisted of high-purity Na–P1 zeolite with a typical cone-shaped flower cluster shape. The residue carbon in CGFS can be further activated to form porous carbon and graphite carbon layers interposed in the zeolite structure. The specific surface area and pore volume of CZ-1.0 reached 153.91 m2/g and 0.18 cm3/g, respectively. CZ-1.0 exhibited remarkable adsorption performance for methylene blue (MB) with the adsorption capacity reaching 137.5 mg/g for 100 mg/L MB solution. The adsorption process is mainly controlled by the chemisorption mechanism, and the adsorption of MB by CZ-1.0 may include ion exchange, hydrogen bond interaction, π-π bond interaction and van der Waals force. NaCl solution was successfully used as the desorption agent to regenerate the composite material, and the removal rate remained above 92% after five cycles. This work provides an effective strategy to synthesize a practically applicable adsorbent from the waste coal gasification fine slag for the purification of MB wastewater.

Processing of coal gasification fine slag by different physical separation methods: Fate of typical heavy metals and comparison analysis on products

The separation of carbon-mineral components in coal gasification fine slag (CGFS) is an important prerequisite for achieving large-scale utilization of the CGFS resources. This study aims to reveal the influence of three physical separation methods on the distribution features, occurrence modes, and environmental risk of typical heavy metals (i.e., V, Cr, Mn, Ni, Cu, Zn, Ba, and Pb) in the CGFS. The results show that all three physical separation methods can separate carbon-rich or mineral-rich fractions from the CGFS at different enrichment levels. Thereinto, froth flotation has a high balance between high yields and excellent separation performance. Furtherly, Ni, Cu, Zn, and Pb are more concentrated in the two carbon-rich fractions obtained by froth flotation while other heavy metals are mostly enriched in the mineral-rich fractions. Density separation is possible to obtain carbon-rich fractions with a fairly high fixed carbon content (68.29 %, dry basis). In addition, a rough separation of the carbon-mineral fractions in CGFS can be performed by particle size classification. The various concentrations and distribution features of typical heavy metals in different separated products are associated with their specific structures. The carbon particles derived through the froth flotation have a higher specific surface area than those produced from the density separation and size classification. It is found a high correlation between mineral content and typical heavy metal concentrations, while porous carbon particles with a high specific surface area and particle size effect could reduce the dependence of some heavy metals (e.g., semi-volatile or volatile heavy metals Ni, Cu, Zn, and Pb) concentrations on mineral content. In addition, the typical heavy metals in separated fractions with a high content carbon particles as well as small-sized particles tend to have a high proportion of mobile fractions. Moreover, the eco-risk assessment code (RAC) analysis results indicate that priority attention should be given to the potential environmental impacts of Mn, Ni, Cu, Ba, and especially Zn in high-carbon content products and small-sized fractions during their resource utilization process.

Extraction of Al and preparation of polyaluminum chloride from coal gasification fine slag by high-pressure HCl leaching method

ABSTRACT With the widespread promotion of coal gasification technology, the mass-produced solid waste coal gasification slag has caused serious threat to the environment. Coal gasification fine slag (CGFS) is rich in aluminosilicates, which can be used as a source of aluminum (Al). In this study, a hydrothermal method with enhanced mass and heat transfer was used to extract Al from CGFS. The Al3+-rich acid leaching solution was polymerized with calcium aluminate powder to obtain polyaluminum chloride (PAC). Orthogonal test results show that when the extraction rate of Al ions from CGFS reaches 78.9%, the Al2O3 content and basicity of PAC are 30.95% and 58.09%, respectively. When the prepared PAC is added to domestic sewage at 100 mg/L, the turbidity of the sewage drops from 68 to 12 NTU, and the removal rates of chemical oxygen demand and ammonia nitrogen reach 60% and 52.5%, respectively. It is a promising approach for environmental protection and high value-added utilization of CGFS.

Enrichment of Residual Carbon in Coal Gasification Fine Slag via Wet Sieving Separation with Ultrasonic Pretreatment.

To overcome the environmental and economic challenges posed by the increasing amounts of the coal gasification slag, here, a simple and efficient method for enriching the residual carbon from the coal gasification fine slag was proposed. The residual carbon enrichment pattern in the particle size distribution of coal gasification fine slags after the ultrasonic pretreatment was mainly enriched toward the 500-250 μm and 250-125 μm particle size classes by analyzing the changes in the particle size distribution and apparent morphology. The pulp pretreatment at the ultrasonic output power of 270 W for 4 min was determined as the optimal experimental condition with respect to the yield, ash content, and ash rejection of the concentrates. Compared to the conventional wet sieving separation, the yield and ash content of the final concentrates were reduced by 7.99 and 14.96%, respectively. Moreover, the ash rejection of the final concentrates was as high as 88.51%, indicating an increment of 11.63% than the conventional wet sieving separation. Furthermore, thermogravimetric analysis confirmed that the final concentrates exhibited the lowest reactivity; however, these demonstrated had the highest carbon content (nearly 70%) with 27.27% ash content. The combustion characteristics analysis showed that the wet screening concentrate after ultrasonic pretreatment had the highest composite combustion characteristic index (S) of 3.17 × 10-8, as compared to the raw and conventional sieving concentrates.

Mesoporous Spherical Silica Filler Prepared from Coal Gasification Fine Slag for Styrene Butadiene Rubber Reinforcement and Promoting Vulcanization.

Coal gasification fine slag (CFS) is a solid contaminant produced by an entrained flow gasifier, which pollutes fields and the air in the long term. CFS is a potential polymer reinforcement filler and has been used in polypropylene and acrylonitrile butadiene styrene resins. Coal gasification fine slag mesoporous silica (FS-SiO2) was prepared by acid leaching, calcination, and pH adjustment, with a larger specific surface area and less surface hydroxyl compared to the commercial precipitated silica (P-silica). The cure characteristics, crosslink density, mechanical properties, the morphology of the tensile fractures, dynamic mechanics, and rubber processing of the prepared styrene butadiene rubber (SBR) composites filled with P-silica and FS-SiO2 were analyzed, respectively. The results indicated that FS-SiO2 was dispersed more uniformly in the SBR matrix than P-silica owing to its smaller amount of surface hydroxyl and spherical structure, resulting in a better mechanical performance and wet skid resistance. In particular, the SBR composites with a filler pH of 6.3 exhibited the highest crosslink density and tensile strength, being superior to commercial P-silica. Significantly, the curing time decreased with the increase in the pH of FS-SiO2, which caused the rubber processing to be more efficient. This strategy can reduce the cost of rubber composites and the environmental pollution caused by CFS.

Facile and scalable synthesis of mesoporous composite materials from coal gasification fine slag for enhanced adsorption of malachite green

The recycling of the solid wastes produced in the industrial process and converting them into functional materials with unique structures are of great significance for the sustainable development of human society. In this study, a facile and scalable synthesis method was designed for the preparation of mesoporous composite materials from waste coal gasification fine slag using K2CO3 as a mild chemical additive to chemically recombine SiO2 and Al2O3. At a fine slag to K2CO3 mass ratio of 1:1, a mesoporous composite material (OMB-KB) mainly composed of faujasite-Na and amicite was obtained, which possessed a uniformly porous and loose structure with a specific surface area of 40.26 m2/g and the pore size range of 2–50 nm. Metals inherited from the raw slag and various chemical groups existed on the surface of OMB-KB, making the materials have unique surface chemical properties. OMB-KB exhibited ultra-high adsorption performance on malachite green (MG), and the adsorption capacity reached 7218.31 mg/g when 0.01 g of OMB-KB and 300 ml of MG solution with a concentration of 300 mg/L were used for the adsorption at 298K. The increase of pH was beneficial to the adsorption of cationic MG, and the removal efficiency reached an excellent state at pH ≥ 6. The good fitting of the pseudo-second-order kinetic model and the Freundlich isotherm model suggested that the adsorption process was dominated by chemisorption. The thermodynamic analysis showed that the adsorption of OMB-KB to MG was endothermic, entropy-increasing and entropy-controlled. The adsorption of MG by the material was realized through the exchange interactions between cations, as well as the electrostatic attraction and van der Waals forces between –OH groups and MG. Meanwhile, the oxygen-containing groups and π-electrons in the carbon layer could also adsorb MG molecules by electrostatic attraction.

Recycling of coal gasification fine slag as ultra-high capacity adsorbents for the removal of Rhodamine B dye: Graded synthesis method, kinetics and adsorption mechanism

Maximizing the utilization of elements in coal gasification fine slag (CGFS) and converting them into high-value-added materials is of great significance for the resource utilization and harmless disposal of CGFS. In this study, SBA-15 and hierarchical X-type zeolite/carbon composite were prepared from CGFS by a graded synthesis method, and their pore structures were modulated by 1,3,5-trimethylbenzene and CO2 pre-activation, respectively, and then the materials were then amino-modified. Both materials have a regular structure and large specific surface area (586.32 m2/g and 460.97 m2/g). The adsorption efficiency of the material increases due to the increased mass transfer capacity in the pores, while the surface amine group functionalization can further improve the adsorption performance of the material. The Langmuir model and the Pseudo-second-order kinetic model provided an accurate description of the adsorption behavior of the materials, which showed a good adsorption capacity of 147.93 mg/g and 157.98 mg/g, respectively. The XPS and FT-IR results demonstrate that hydrogen bonding and electrostatic attraction play a key role in the adsorption process. The results proved the CGFS can be converted into high performance adsorption materials for efficient dye removal, which achieves the “waste to treat waste” effect.

Using One-Step Acid Leaching for the Recovering of Coal Gasification Fine Slag as Functional Adsorbents: Preparation and Performance.

Coal gasification fine slag (FS), a kind of by-product of coal chemical industry, was recovered for the preparation of functional adsorbents by acid leaching process, which was orthogonally optimized by HCl, HNO3, HF, HAc, and H2SO4. Methylene blue (MB) was used to evaluate the performance of functional adsorbents. The results demonstrated that 57.6% of the leaching efficiency (RLE) and 162.94 mg/g of adsorption capacity (CAC) of MB were achieved under the optimal conditions of HNO3 of 2.0 mol/L, acid leaching time of 2.0 h, and acid leaching temperature of 293K. The detections on X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and BET surface area (SBET) indicated that the synthesized functional adsorbents were characterized by mesoporous materials. The good fitting of adsorption process using pseudo-second-order and Langmuir models demonstrated that the chemisorption contributed to MB removal. The results of thermodynamics further revealed that the adsorption process of MB occurred spontaneously due to the exothermic properties. The work is expected to develop a novel and cost-effective strategy for the safe disposal of FS, and potentially offer an alternative pathway to increase the additional value for the coal chemical industry.

Study on the property and airflow grading of Ningxia coal gasification fine slag

Coal gasification fine slag (FS) is a solid waste of difficult-to-separate nature. In order to improve the reuse rate of coal gasification fine slag resources, so as to improve the value-added utilization and clean transformation for coal chemical industry, which is necessary to deeply study the composition characteristics and effective separation of FS. In this study, the dry pulverized coal gasification fine slag (DPFS) was divided into different particle sizes by wet screening, and the composition and structure characteristics of components with different particle sizes were investigated. Then a combined treatment method of airflow crushing and classification was used to separate DPFS. The results showed that the fixed carbon content, the ash composition, the micro morphology and the pore structure of FS were related to the particle size distribution. The fixed carbon content of particles with particle sizes ranging between 74–98 μm was the highest (about 39.98%), the particles with a size grade of 13–74 μm and larger than 98 μm was between 11.85 and 30.85%, The minimum fixed carbon content of 0–13 μm particle size is 8.69%. The microstructure of DPFS was composed of several relatively independent particle units with special morphology, including porous irregular particles, spherical particles, floccule, and the element contents of these particle units were very different. The residual carbon and ash components in the DPFS could be effectively separated and enriched in different products by airflow crushing and classification. When the grinding gas pressure was set to 0.5 MPa, the low carbon product with fixed carbon content of 4.99% and yield of 19.86% could be obtained. The mechanism of airflow crushing of FS showed that airflow crushing based on impact force and shear force could effectively separate the residual carbon and ash components, and greatly improve the separation and recovery rate of residual carbon. Therefore, the airflow crushing and classification has a good application prospect in the separation and enrichment of residual carbon of gasification fine slag.

Effect of Coal Water Slurry Gasification Slag on Soil Water Physical Characteristics and Properties in Saline-Alkali Soil Improvement

To explore the effect of coal water slurry (CWS) gasification slag on the soil water physical characteristics of saline-alkali soil in the Yellow River Basin of Inner Mongolia, CWS gasification coarse slag (GCS) and gasification fine slag (GFS) were used as improvement materials and mixed with saline-alkali soil in different proportions. The influence mechanism of GCS and GFS on saline-alkali soil water holding capacity was investigated by measuring particle size composition, water holding capacity, and the change in the soil water characteristic curve after mixing. The results showed that adding gasification slag improved the particle size composition of saline-alkali soil, with sand content increased by -3.79%~217.31% and clay and silt content decreased by 5.77%~56.50% and -0.38%~41.53%, respectively. Soil bulk density decreased significantly ( P < 0.05 ), with a decrease range of 15.17%~45.1%. The soil texture changed from silty loam to sandy loam, and the water retention performance improved, affecting the soil saturated water content, capillary water holding capacity, and field water holding capacity ( P < 0.05 ), with increases ranging from 20.75%~86.15%, 7.84%~27.81%, and -1.89%~34.56%, respectively. After adding GCS and GFS, the VG model fit the soil water characteristic curve of saline-alkali soil well, indicating that the addition of gasification slag enhanced soil water retention significantly. In conclusion, CWS gasification slag effectively improved the water physical properties of saline-alkali soil and significantly enhanced the water retention and water holding capabilities.

Study of the synthesis, adsorption property, and photocatalytic activity of TiO2/coal gasification fine slag mesoporous silica glass microsphere composite.

In this study, TiO2/MSGM composite material with adsorption-photocatalytic properties was prepared by extracting mesoporous silica glass microsphere (MSGM) from coal gasification fine slag (CGFS) as a novel TiO2 carrier. The results of characterization and properties of the composite showed that MSGM could improve the adsorption capacity and photocatalytic activity of the composite by improving the pore structure of the composite, hindering the growth of TiO2 particles, increasing the phase transition temperature of TiO2, enhancing the dispersion of TiO2 particles. The sample 1:3-TiO2/MSGM-2-500 prepared under the optimized conditions possesses satisfactory morphology characteristics, high adsorption capacity, and photocatalytic activity to rhodamine B (RhB). The synergistic effects of adsorption and photocatalytic significantly increase the total removal rate of RhB. This study not only provides a new direction for high-value-added resource utilization of CGFS but also gives a new kind of low-cost carrier material with adsorption property for TiO2 loading to remove organic dye pollutants.

Synthesis and adsorption performance of ultra-low silica-to-alumina ratio and hierarchical porous ZSM-5 zeolites prepared from coal gasification fine slag.

Since the human consumption of coal is increasingly growing and coal-based solid wastes are discharged in large quantities, the resource utilization of coal-based solid wastes has been paid more attention. In the present work, for the first time, the coal gasification fine slag is subjected to prepare ZSM-5 zeolites with ultra-low n(SiO2)/n(Al2O3) ratios (less than 20) and hierarchical pore structures. The increase in the concentration of the alkaline extract leads to the decrease of the crystallinity, the irregularity of the microscopic morphology, and the decrease of the specific surface area, resulting in the in-situ generation of mesopores within ZSM-5. Moreover, adsorption experiments demonstrate that ZSM-5-2M exhibits the best methylene blue adsorption performance at the pH of 9 with a removal rate of up to 82.07%, and it also has good adsorption performance in simulated real water samples. Furthermore, the adsorption performance of ZSM-5-2M on the malachite green, Rhodamine B, Congo red, and methyl orange has been investigated and it is found to be very effective for the adsorption of cationic dyes, and its adsorption performance for methylene blue and malachite green is reduced in the presence of anions.

Synthesis and characterization of silver nanoparticle-decorated coal gasification fine slag porous microbeads and their application in antistatic polypropylene composites

A conductive powder of coal gasification fine slag porous microbeads (CMs) coated with silver (Ag) nanoparticles was synthesized by a simplified electroless plating method. CMs were coated with uniform and dense Ag nanoparticles ([email protected]) to form a conductive structure consisting of internal conductive channels and a surface coating layer. The powder volume resistivity of [email protected] reached 1.47 Ω·cm. Subsequently, [email protected] were mixed with polypropylene (PP) to prepare an [email protected]@PP composite with a volume resistivity of 3.35 × 105 Ω·cm, a tensile strength of 26.06 MPa, and an elongation at break of 43.09%. Due to the high specific surface area (65.41 m2/g), small particle size (8.13 μm), and low density (1.51 g/cm3) of [email protected], the [email protected]@PP composite had better volume resistivity and mechanical properties than the PP composite filling with commercial silver-plated glass beads. The findings of this research could provide a theoretical foundation for future applications of [email protected]

ZnFe2O4 nanospheres decorated residual carbon from coal gasification fine slag as an ultra-thin microwave absorber

Microwave absorbers are commonly utilized in radar stealth and anti-stealth to improve battlefield penetration rates and equipment safety. The ZnFe2O4/residual carbon (ZFO/RC) nanocomposites were fabricated via a hydrothermal synthesis method. The RC was extracted by acid treatment of coal gasification fine slag (CGFS) to eliminate inorganic minerals. The crystal structure, micro-morphology, chemical compositions, and corresponding electromagnetic characteristics of the as-fabricated ZFO/RC composites were investigated. The synthesized nano-micro size ZFO/RC demonstrated excellent electromagnetic wave absorption (EMWA) property. The ZFO/RC-3 composites had exceptional EMWA performance with a minimum reflection loss (RLmin) of −46.33 dB at 13.04 GHz and a maximum effective absorption bandwidth (EAB, RL ≤ -10 dB) that reached 2.96 GHz (11.76–14.72 GHz) at a thickness of 1.48 mm. The EMWA ability of ZFO/RC can be adjusted by controlling the filler loading composites. Benefit from interface polarization, superb impedance matching of the special heterostructure, and conductive loss, the ZFO/RC composites can absorb 99 % of the waves passing through it under ideal conditions. The CST simulation evidently demonstrated that the ZFO/RC-3 composites can notably reduce the radar cross section reduction value under the actual conditions. These composites can serve as possible ultra-thin microwave absorbers with excellent EMWA capability, thus advancing solid waste utilization of residual carbon from entrained-flow CGFS.