Energies
·
2024
·Vol. 17
·期 13
·3172
·
IF 3
Maierhaba Abudoureheman,Lanzhen He,Kunpeng Liu,Bo Wei,Jia Lv,Jianjiang Wang,Quan Zhu
The contents of alkali and alkaline earth metals are higher in Zhundong coal, and there are serious problems of slagging and fouling during the combustion process. Therefore, it is of great significance to reveal the mechanism of slagging and fouling in the boiler of Zhundong coal. In this paper, first-principle calculations based on density functional theory are used to study the competition mechanism of alkaline metal oxides during the combustion process in Zhundong coal by establishing the Na2O(110)/CaO(100)-SiO2(100) double-layer interface model. The results show that the bond lengths of the surface of Na2O(110) and CaO(100) with SiO2(100) after adsorption were generally lengthened and the value of bond population became smaller, which formed a stable binding energy during the reaction. The electron loss of Na is 0.05 e, the electron loss of Ca is 0.03 e, and the electron loss of Na2O is greater than that of CaO. The charge transfer on the surface of Na2O with SiO2is obviously higher than that of CaO and the orbital hybridization on the surface of CaO with SiO2is weaker than that on the surfaces of Na2O with SiO2. Na2O is easier to react with SiO2than CaO. The adsorption energies on the surface of Na2O and CaO with SiO2are −5.56 eV and −0.72 eV, respectively. The adsorption energy of Na2O is higher than that of CaO, indicating that Na2O is more prone to adsorption reactions and formation of Na-containing minerals and other minerals, resulting in more serious slagging. In addition, the XRD analyses at different temperatures showed that Na-containing compounds appeared before Ca-containing ones, and the reaction activity of Na2O is stronger than that of CaO in the reaction process. The experimental results have good agreement with the calculation results. This provides strong evidence to reveal the slagging and fouling of Zhundong coal.
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DOI
高影响因子
FUEL
·
2024
·
IF 6.7
Yaqi Duan,Conghao Ku,Yuping Lv,Yantao Wang,Weiran Yang
Due to its unique physical and chemical properties, applying activated carbon nanomaterials as catalysts gradually become a hot research topic. Herein, the synergistic catalytic effect of activated carbon nanoparticles and CaO for highly selective oxidation of levulinic acid to citramalic acid was first reported. Among various activated carbons tested (commercially available and biomass-derived), the one obtained from Nanjing Chemical Reagent Co., Ltd. exhibits the best catalytic activity due to its large surface area, suitable pore structure, abundant active sites, and excellent O 2 activation ability. The levulinic acid conversion and citramalic acid selectivity respectively reached 100 % and 82.8 % at 90 °C for 0.5 h under 0.5 Mpa O 2 . Further, the 3D flower-like CaO/carbon composite (CaO/CF) was developed, which also showed excellent catalytic activity for the selective oxidation of levulinic acid to citramalic acid, with 91 % levulinic acid conversion and 81.8 % citramalic acid selectivity under otherwise the same reaction condition. The mechanistic study indicated that superoxide anion radical ( O 2 – ), Ca 2+ and OH – all play a crucial role in levulinic acid oxidation. This work may promote the application of activated carbon nanomaterial as an effective catalyst for selective oxidation reactions.
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高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2025
·
IF 9
Hongru Rao,Junyi Xiang,Lu Qiao,Xu Zhang,Wei Lv,Qingyun Huang,Xuewei Lv
The calcium‑magnesium composite roasting – acid leaching process represents a sustainable alternative for vanadium extraction from vanadium slag, yet its underlying mechanism remains insufficiently understood. This study systematically investigates the phase transformation and dissolution behavior within the FeV 2 O 4 –CaO–MgO system to clarify the role of MgO. Results reveal its critical dual role: it promotes the formation of acid-soluble calcium‑magnesium vanadate (Ca 5 Mg 4 V 6 O 24 ), yet concurrently facilitates the formation of insoluble magnesium‑iron vanadates (e.g., Mg 2 FeV 3 O 11 ), thereby severely compromising leaching efficiency. The formation of the low-melting-point compound CaMgV 2 O 7 can also inhibit extraction via phase encapsulation. As a result, vanadium recovery demonstrates a pronounced non-monotonic dependence on MgO content, with a well-defined efficiency maximum under optimal conditions. These findings elucidate the phase-transformation mechanism governing leaching performance and establish a fundamental basis for the rational design of efficient vanadium recovery processes.
研究领域:
冶金学
·
湿法冶金
·
材料科学
·
无机化学
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Ziheng Han,Tuo Guo,Yuhai Liu,Yuzhe Lu,Jingjing Ma,Xiude Hu,Qingjie Guo
The limited reactivity of single transition metal nitrogen carrier (NC) is a significant factor contributing to the suboptimal performance of chemical looping ammonia production (CLAP). This research proposes a strategy of loading alkaline earth metal oxides to construct a vanadium-based NC loading CaO (VN/CaO composite NC) with enhanced reactivity. The results demonstrate that the incorporation of CaO increases the lattice nitrogen conversion rate of VN from 4 % to 21 % and reduces the ammonia production temperature. The ammonia production rate of VN/CaO composite NC reaches 481.25 μmol·g −1 ·h −1 at 800 °C. In contrast, the electron-donating ability of MgO is weaker than that of CaO, and the ammonia production rate of the VN/MgO is 350 μmol·g −1 ·h −1 . Theoretical calculations and experimental characterizations reveal that CaO maintains the surface basicity of the NC, creating an electron-rich surface that weakens the V N bond strength, promotes H 2 adsorption and dissociation, and enhances the reactivity of vanadium-based NC. The reaction mechanism of VN/CaO composite NC follows the Mars-van Krevelen mechanism, with the hydrogenation of NH 3 intermediates identified as the rate-determining step. This study provides theoretical support for the development of multi-component composite NC.
研究领域:
化学工程
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催化
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材料科学
·
能源技术
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高影响因子
REFRACTORIES AND INDUSTRIAL CERAMICS
·
2023
·
IF 0.5
Ding Donghai,Guan Yue,Xiao Guoqing,Mao Zhaoyuan,Shi Xiaoqi,Gao Kaiqiang,Chong Xiaochuan,Luo Jiyuan,Lei Changkun
The alumina ceramics with high compressive strength were prepared by pressureless sintering, and the kaolinite and calcium carbonate were added as Al 2 O 3 –SiO 2 –CaO sintering aids. The effects of sintering temperature on the volume shrinkage, bulk density, water absorption and compressive strength of the alumina ceramics were studied. The phase composition, crystal cell parameters, average grain size and microstructure of the ceramic were analyzed by XRD, SEM and EDS. The results show that the lattice tends to packed with the increase of sintering temperature. The bonding between grains is the most compact after sintering at 1700°C. The volume shrinkage increases with the increase of sintering temperature. The water absorption of alumina ceramics after sintering at 1700°C reaches the minimum value of 0.06%. The bulk density and compressive strength increase first and then decrease with the increase of sintering temperature. At 1700°C, optimized mechanical properties of alumina ceramics is obtained, with a bulk density of 3.80 g/cm 3 and a compressive strength of 1323 MPa.
研究领域:
材料科学
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陶瓷工程
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2026
·
IF 12.5
Hongchuan Jiang,Xiang Li,Guodong Zhang,Cai Liang
Solar-driven calcium-looping offers a promising pathway for efficient storage and utilization of concentrated solar energy. However, the large-scale application of calcium-based heat carriers is hindered by low solar absorptance, poor sintering resistance, and slow reaction kinetics. Moreover, the energy conversion characteristics and particle behavior under direct irradiation remain poorly understood. In this study, Mn-Zr co-doped CaO composite particles were synthesized via an extrusion-spheronization method, achieving high absorptance, strong sintering resistance, and rapid reaction kinetics. Specifically, the co-doping of Mn and Zr significantly enhances absorptance to 67.7% while effectively reduces cracking. The stable framework of CaMnO 3 and CaZrO 3 maintains abundant mesoporous channels and suppresses sintering. The composite particles exhibit outstanding cycling stability, maintaining an energy storage density of 1148 kJ/kg after 40 cycles with only 22.9% degradation, far outperforming pure CaO materials (64.9% degradation after 20 cycles). Direct irradiation experiments confirm their high solar-thermal conversion efficiency, with particle temperature within the light spot reaching 1600 °C in 3 s. The irradiation-induced particle inhomogeneous sintering mechanism was preliminary proposed. Meanwhile, the effect of non-uniform irradiation on energy storage characteristics and particle behavior is revealed. Non-uniform irradiation led to localized hotspots and increased thermal stress, which aggravated particle breakage and sintering within the light spot.
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高影响因子
METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE
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2026
·
IF 3.1
An Zhuoqing,Liang Weiwen,Gao Yuan,Chen Jiajing
The viscosity of the CaO–MgO–Al 2 O 3 –SiO 2 system containing La 2 O 3 and Fe 2 O 3 was measured by rotation, hot-stage microscopy and hot-stage load methods to investigate the rheological behavior across multiple temperature ranges. In-situ high temperature Raman spectroscopy was employed to quantitatively analyze the microstructure. The results show that with the La 2 O 3 /Fe 2 O 3 ratio varying from 2/0 to 0/2, the viscosity decreases gradually through the multiple temperature ranges, and the viscous flow activation energy also gradually decreases. As the ratio of La 2 O 3 /Fe 2 O 3 decreases, the relative contents of Q 0 , Q 1 and Q 2 increase gradually, and the relative contents of Q 3 and Q 4 decrease significantly. This indicates that both La 2 O 3 and Fe 2 O 3 act as network modifiers and simplify the glass network structure, resulting in a decrease in the degree of network polymerization and viscosity over the multiple temperature range. Compared to La 2 O 3 , Fe 2 O 3 is a more effective network modifier, as it breaks up the silicate network more efficiently and results in a lower overall viscosity. In addition, the microstructure of the melts was quantitatively analyzed by NBO/ T , and a quantified relationship among viscosity, microstructure and temperature was given.
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高影响因子
CERAMICS INTERNATIONAL
·
2026
·
IF 6
Xin Wang,Yao Luo,Chen Zhang,Xin Li,Qi Li,Jianliang Xie
To meet the need for ultrathin high-temperature radar-stealth coatings with effective X-band absorption, a metasurface-regulated FeSiCr/CaO-B 2 O 3 -SiO 2 (FSC/CBS) composite coating was designed. FSC/CBS coatings with different FSC contents were fabricated by atmospheric plasma spraying to examine the effects of absorber loading on particle state, microstructure, electromagnetic parameters, and high-temperature absorption. Increasing FSC content raised the in-flight particle temperature and promoted FSC spreading and flattening, causing the absorbing phase to evolve from isolated particles to lamellar structures and locally connected conductive networks. These structural features enhanced interfacial polarization and conduction loss, whereas excessive FSC aggregation suppressed the effective magnetic response through demagnetization and skin-effect shielding, degrading impedance matching. The 1-mm-thick 40FSC/CBS coating showed stable Ku-band absorption at 600 °C, with reflection loss below −5 dB over 11.7-18.0 GHz. After metasurface loading, its effective absorption band was regulated to 8.0-13.78 GHz, covering the entire X band, and the cavity radar cross section was reduced by 12.17 dBsm.
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高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2026
·
IF 9.1
Youhao Zhang,Jingjing Dai,Zhiyuan Chu,Chenglong Yang,Fengnian Wang,Xiangyu Han,Yingjie Li
Calcium looping (CaL) is a promising technology for CO 2 capture from coal-fired power plants, but it suffers from rapid activity loss of calcium-based materials. The hydration-CO 2 capture-calcination (CaHCL) process can reactivate the pore structure of calcium-based materials, yet the intrinsic reactivity of conventional CaO materials remains insufficient, leading to low hydration and carbonation conversions and high system energy consumption. Herein, a CaMn 2 O 4 -modified CaO composite with a paper fiber structure was synthesized via a sacrificial template method. Fixed-bed experiments showed that the optimized CaO composite, designated Mn 0.75 CaAP, maintained a hydration conversion above 0.92 and an effective CO 2 capture conversion of 0.77 over 20 CaHCL cycles. These values represent substantial improvements over unmodified CaO and over materials modified by either templating or Mn doping alone. Characterization results revealed that the hollow tubular framework not only preserves a stable mesoporous network by accommodating the volume expansion during hydration, but also exposed the active sites and promoted the formation of CaMn 2 O 4 . The CaMn 2 O 4 spinel introduced abundant oxygen vacancies, which accelerated the chemisorption of H 2 O and CO 2 . Process simulation showed that at a Ca/C ratio of 1.25, the system achieved over 90% CO 2 capture efficiency with an energy consumption of only 857.84 MJ/(ton·CO 2 ), which is 38.1% and 23.5% lower than those of the CaHCL with conventional CaO and the CaL process, respectively. These results demonstrate promising laboratory-scale performance of Mn 0.75 CaAP and favorable simulated process behavior, supporting further investigation of Mn 0.75 CaAP for potential application in CaHCL-based CO 2 capture and thermochemical energy storage.
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DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Wentao Guo,Xi Lan,Yongli Jin,Ziqi Ding,Jintao Gao,Zhancheng Guo,Zengwu Zhao
The irreplaceability role of rare earths in high-performance materials, such as ceramics, highlighting the significance of rare earth extraction. Strengthening the crystallization growth of the rare earth phase in rare earth slag is crucial for ensuring effective subsequent rare earth enrichment and separation. However, viscosity plays a major role in the characteristics of high-temperature melts and the crystallization process. In this study, an internal column rotation method was used to measure the viscosity of CaO-SiO 2 -CaF 2 -Ce 2 O 3 slag melts. The effect of shear rate on the rheological behavior of CaO-SiO 2 -CaF 2 -Ce 2 O 3 slag with varying Ce 2 O 3 and CaF 2 contents, and CaO/SiO 2 ratio was investigated by examining the viscosity evolution during the rare earth crystallization growth process. The rheological behavior of the CaO-SiO 2 -CaF 2 -Ce 2 O 3 slag was elucidated in regions of liquid phase, low solid phase, and high solid phase, providing insight into the viscosity changes of non-Newtonian flowing melts. Based on this, the effect of shear rate on the crystallization behavior of rare earth phases was investigated to provide a basis for improving the subsequent separation of rare earth phases.
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Yaling Zhang,Shuai Chao,Xi Zhang,Junguo Li,Yiming Duan,Chunhui Gu,Jiale He
The iron and steel industry is facing two urgent needs of comprehensive utilization of bulk solid waste and CO 2 emission reduction. Using LF refining slag as raw material to prepare efficient calcium-based CO 2 adsorbents can achieve the goals of waste-to-resource conversion and cleaner production. In this study, LF refining slag-derived CaO/C 12 A 7 high-temperature calcium-based CO 2 adsorbent materials with abundant pore defects were synthesized by the co-precipitation method, which showed the optimal high-temperature adsorption performance at 700 °C and pure CO 2 atmosphere, with an adsorption capacity of up to 0.681 g/g, which is 1.58 times that of the adsorption capacity of commercial CaO. C 12 A 7 , as an inert skeleton of adsorbent material, can inhibiting the agglomeration of CaO particles and slowing down the sintering deactivation process. After 20 cycles of calcination-carbonation, the adsorption capacity degradation rate was 32.5 %, lower than that of commercial CaO at 37.8 %. The related research effectively enhances the added value of resource utilization from LF refining slag and holds the potential to achieve a balance among environmental, economic, and social benefits in the steel industry.
研究领域:
材料科学
·
环境科学
·
冶金工程
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DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Mengchuan Li,You Zhou,Tongsheng Zhang,Rensheng Li
The sluggish advancement in technology for the recovery of rare earth elements from secondary resources can be largely attributed to an inadequate understanding of the thermodynamic properties of cerium oxide-based slag systems. This study systematically investigates the phase equilibrium of the Ce 2 O 3 -CaO-SiO 2 -5 wt% MgO quaternary system at 1500 °C and 1600 °C. High-temperature equilibrium experiments followed by rapid quenching were conducted, and phase assemblages were characterized by XRD, SEM and EPMA. For the first time, the results accurately determined the isothermal liquidus lines for the first time and identified the stable regions of key phases such as SiO 2 , Ce 2 Si 2 O 7 , CaO·2Ce 2 O 3 ·3SiO 2 , CaO·Ce 2 O 3 ·2SiO 2 , the Ce-doped dicalcium silicate (i.e., (Ca, Ce) 2 SiO 4 ), and the monticellite (i.e., CaMgSiO 4 ), as well as their coexistence relationships. Furthermore, the isothermal sections at 1500 °C and 1600 °C were constructed based on experimental data and fundamental thermodynamic principles. This study not only fills a critical gap in the thermodynamic database for rare-earth slag systems but also provides a theoretical basis for optimizing slag design and enhancing cerium recovery from waste slags.
研究领域:
冶金物理化学
·
无机非金属材料
·
高温过程热力学
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资源回收
·
稀土冶金
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）