There have been increasing efforts to utilize energy by-products （EBP） all over the world. In the Czech Re- public fly ash is usually used in ceramic technology, es- pecially in brick manufacturing and for ceramic t...There have been increasing efforts to utilize energy by-products （EBP） all over the world. In the Czech Re- public fly ash is usually used in ceramic technology, es- pecially in brick manufacturing and for ceramic tiles. The average production of EBP is about Ig million tons per year. The range of potential products, where EBP could be used, is very wide and energy by-products have become an important raw material source. In this paper the attention was focused on class C fly ash and its usage in field of refractory materials. Experimental works were carried out on mixtures with fly ash and clay. There were also tested batches for lightweight fireclay bricks. The maximal amount of CFA should be up to 50%.展开更多
The feasibility of utilization of flue gas desulfurization （FGD） gypsum and Class-C fly ash （CFA） to prepare CFA-based geopolymer were studied. The results showed that geopolymer made from 90% CFA and 10% FGD gyps...The feasibility of utilization of flue gas desulfurization （FGD） gypsum and Class-C fly ash （CFA） to prepare CFA-based geopolymer were studied. The results showed that geopolymer made from 90% CFA and 10% FGD gypsum （FGDG） which was thermally treated at 800 ℃ for 1 h obtained the better compressive strength of 37.0 MPa. The micro characteristics and structures of the geopolymer samples of CFA and CFA-FGDG were tested by XRD, FT-IR, and SEM-EDXA after these samples cured at 75 ℃ for 8 h followed by 23 ℃ for 28 d. Both the geopolymer samples of CFA and CFA-FGDG have significant asymmetric stretching of A1-O/Si-O bonds and Si-O-Si / Si-O-A1 bending band. In geopolymer sample of CFA-FGDG, a small quantity of lathy products probably being the ettringite wrapped over the spherical fly ash particle, and the concentration of sulfur is much more than that in geopolymer sample of CFA. It is indicated that FGD gypsum may react during alkali-activated and geopolymeric process.展开更多
Fly ash particles are usually spherical and based on their chemical composition;they are categorized into two classes: C and F. This study compares the microstructural, mechanical and thermal properties of extruded ri...Fly ash particles are usually spherical and based on their chemical composition;they are categorized into two classes: C and F. This study compares the microstructural, mechanical and thermal properties of extruded rigid PVC foam composites reinforced with class C and class F fly ash. The mechanical properties: such as tensile and flexural strength of composites containing class C fly ash were superior to the composites containing class F fly ash particles. Composites containing 6 phr class C fly ash showed a 24% improvement in the tensile strength in comparison to a mere 0.5% increase in composites reinforced with class F fly ash. Similarly, the addition of 6 phr of class F fly ash to the PVC foam matrix resulted in a 5.74% decrease in the flexural strength, while incorporating the same amount of class C fly ash led to a 95% increase in flexural strength. The impact strength of the composites decreased as the amount of either type of fly ash increased in the composites indicating that fly ash particles improve the rigidity of the PVC foam composites. No significant changes were observed in the thermal properties of the composites containing either type of fly ash particles. However, the thermo-mechanical properties measured by DMA indicated a steep increase in the viscoelastic properties of composites reinforced with class C flyash. The microstructural properties studied by Scanning Electron Microscopy (SEM) confirmed that fly ash particles were mechanically interlocked in the PVC matrix with good interfacial interaction with the matrix. However, particle agglomeration and debonding was observed in composites reinforced with higher amounts of fly ash.展开更多
Zeolite P was synthesized through hydrothermal method based on a kind of Class C fly ash(FA). X-ray diffraction(XRD), scanning electron microscopy(SEM), and Brunauer–Emmett–Teller(BET) were used to analyze and chara...Zeolite P was synthesized through hydrothermal method based on a kind of Class C fly ash(FA). X-ray diffraction(XRD), scanning electron microscopy(SEM), and Brunauer–Emmett–Teller(BET) were used to analyze and characterize the synthetic sample. The kinetics and thermodynamics of copper and nickel ions removed by the zeolite samples were experimentally explored in detail. The results of kinetic treatment showed the second-order exchange second-order saturation model(SESSM) can well describe the removal process of copper ions, while the first-order empirical kinetic model(FEKM) is the best kinetic model for nickel ions. Langmuir and Freundlich isotherms were used to fit the equilibrium concentration of Cu(Ⅱ) or Ni(Ⅱ) under certain conditions. Whether for copper or nickel ion, the Langmuir model is in good agreement with the experimental equilibrium concentration.The apparent theoretical removal capacities for Cu(Ⅱ) and Ni(Ⅱ) can reach to 138.1 mg·g^(-1) and 77.0 mg·g^(-1),respectively.展开更多
文摘There have been increasing efforts to utilize energy by-products （EBP） all over the world. In the Czech Re- public fly ash is usually used in ceramic technology, es- pecially in brick manufacturing and for ceramic tiles. The average production of EBP is about Ig million tons per year. The range of potential products, where EBP could be used, is very wide and energy by-products have become an important raw material source. In this paper the attention was focused on class C fly ash and its usage in field of refractory materials. Experimental works were carried out on mixtures with fly ash and clay. There were also tested batches for lightweight fireclay bricks. The maximal amount of CFA should be up to 50%.
基金Funded by the National Natural Science Foundation of China(Nos.51208370,51172164)the Specialized Research Fund for the Doctoral Program of Higher Education(Nos.20110072120046,20090072110010)of China
文摘The feasibility of utilization of flue gas desulfurization （FGD） gypsum and Class-C fly ash （CFA） to prepare CFA-based geopolymer were studied. The results showed that geopolymer made from 90% CFA and 10% FGD gypsum （FGDG） which was thermally treated at 800 ℃ for 1 h obtained the better compressive strength of 37.0 MPa. The micro characteristics and structures of the geopolymer samples of CFA and CFA-FGDG were tested by XRD, FT-IR, and SEM-EDXA after these samples cured at 75 ℃ for 8 h followed by 23 ℃ for 28 d. Both the geopolymer samples of CFA and CFA-FGDG have significant asymmetric stretching of A1-O/Si-O bonds and Si-O-Si / Si-O-A1 bending band. In geopolymer sample of CFA-FGDG, a small quantity of lathy products probably being the ettringite wrapped over the spherical fly ash particle, and the concentration of sulfur is much more than that in geopolymer sample of CFA. It is indicated that FGD gypsum may react during alkali-activated and geopolymeric process.
文摘Fly ash particles are usually spherical and based on their chemical composition;they are categorized into two classes: C and F. This study compares the microstructural, mechanical and thermal properties of extruded rigid PVC foam composites reinforced with class C and class F fly ash. The mechanical properties: such as tensile and flexural strength of composites containing class C fly ash were superior to the composites containing class F fly ash particles. Composites containing 6 phr class C fly ash showed a 24% improvement in the tensile strength in comparison to a mere 0.5% increase in composites reinforced with class F fly ash. Similarly, the addition of 6 phr of class F fly ash to the PVC foam matrix resulted in a 5.74% decrease in the flexural strength, while incorporating the same amount of class C fly ash led to a 95% increase in flexural strength. The impact strength of the composites decreased as the amount of either type of fly ash increased in the composites indicating that fly ash particles improve the rigidity of the PVC foam composites. No significant changes were observed in the thermal properties of the composites containing either type of fly ash particles. However, the thermo-mechanical properties measured by DMA indicated a steep increase in the viscoelastic properties of composites reinforced with class C flyash. The microstructural properties studied by Scanning Electron Microscopy (SEM) confirmed that fly ash particles were mechanically interlocked in the PVC matrix with good interfacial interaction with the matrix. However, particle agglomeration and debonding was observed in composites reinforced with higher amounts of fly ash.
基金Supported by the National Natural Science Foundation of China(51478308)the Scientific Research Special Fund of Marine Public Welfare Industry(201405008)the Natural Science Foundation of Tianjin(14JCYBJC23300)
文摘Zeolite P was synthesized through hydrothermal method based on a kind of Class C fly ash(FA). X-ray diffraction(XRD), scanning electron microscopy(SEM), and Brunauer–Emmett–Teller(BET) were used to analyze and characterize the synthetic sample. The kinetics and thermodynamics of copper and nickel ions removed by the zeolite samples were experimentally explored in detail. The results of kinetic treatment showed the second-order exchange second-order saturation model(SESSM) can well describe the removal process of copper ions, while the first-order empirical kinetic model(FEKM) is the best kinetic model for nickel ions. Langmuir and Freundlich isotherms were used to fit the equilibrium concentration of Cu(Ⅱ) or Ni(Ⅱ) under certain conditions. Whether for copper or nickel ion, the Langmuir model is in good agreement with the experimental equilibrium concentration.The apparent theoretical removal capacities for Cu(Ⅱ) and Ni(Ⅱ) can reach to 138.1 mg·g^(-1) and 77.0 mg·g^(-1),respectively.
