In this study,we investigated the performance of a synthetic resin for the adsorption of Li from predesilicated solution which is the waste liquid produced by extracting aluminum from fly ash.The adsorption kinetics a...In this study,we investigated the performance of a synthetic resin for the adsorption of Li from predesilicated solution which is the waste liquid produced by extracting aluminum from fly ash.The adsorption kinetics and isotherms of the resin were obtained and analyzed.The saturated adsorption sites of the resin were in agreement with the quasi-second-order kinetic model.Then,the pore diffusion model(PDM)was applied to represent the lithium adsorption kinetics which confirming that the external mass is the limiting step.Moreover,we evaluated the adsorption properties of this resin in fixed-bed mode.We established a feasible extraction process for Li from strong alkaline solutions with low Li concentrations.The process parameters,such as the flow rate,initial adsorption solution concentration,water washing process,desorption agent concentration,and flow rate were studied.The desorption rate of the Li;ions was directly proportional with the concentration of the desorption agent.The time required to accumulate Li decreased as the hydrochloric acid concentration and flow rate increased.Time of the peak appeared increased from 0.5 bed volume(BV)to 2.5 BV as the concentration was increased from 1 to3 mol·L^(-1),and the peak increased from 231 to 394 mg·L^(-1).The resin presented good selectivity for Li;ions and could effectively separate impurity ions from the pre-desilication solution.展开更多
A combined acid–alkali hydrothermal method was used to prepare fly ash–derived SAPO-34 molecular sieves from a thermal power plant in Inner Mongolia(China).The specific surface area of the prepared fly-ash-derived S...A combined acid–alkali hydrothermal method was used to prepare fly ash–derived SAPO-34 molecular sieves from a thermal power plant in Inner Mongolia(China).The specific surface area of the prepared fly-ash-derived SAPO-34 molecular sieves was 579 m^2 g^-1,the total pore volume was about 0.27 cm^3 g^-1,and the pore size was 0.56 nm;the molar ratios of Al2O3:P2O5:SiO2 were 1:0.86:0.45.Cu/SAPO-34 catalysts were prepared by impregnation of low-cost fly-ash-derived SAPO-34 molecular sieves as a support and tested in selective catalytic reduction with NH3(NH3-SCR).Powder X-ray diffraction(XRD),N2 adsorption–desorption,X-ray photoelectron spectroscopy(XPS),H2 temperatureprogrammed reduction(H2-TPR),NH3 temperature-programmed desorption(NH3-TPD),electron paramagnetic resonance(EPR),nuclear magnetic resonance(NMR),X-ray fluorescence analysis(XRF)and scanning electron microscopy(SEM)were used for catalyst characterization and investigation of the relationships between the catalyst structure and the catalytic activity.The actual silica:alumina ratio of the molecular sieves did not increase with increasing Cu loading,indicating that increasing the Cu loading does not change the original structure of the SAPO-34 molecular sieves.The XRF and NMR results showed that replacement by Cu results in more Si islands.The molecular sieve acidity decreased because of the increased number of Si islands.The NH3-TPD results showed that for the Cu/SAPO-34 catalysts there was a low correlation between the low-temperature activity and the amount of acidic sites.SCR activity is closely related to the location of Cu.The 4.47 Cu/SAPO-34 catalyst has the highest isolated Cu2+showed the highest NH3-SCR activities(>90%)at 250–350℃.This work opens up new avenues for recycling fly ash formed in coal-fired power plants(reducing environmental pollution)and developing low-cost SCR catalysts for NOx pollution control.展开更多
In this paper, the fly-ash ceramics with prior physical properties was fabricated in a low sintering temperature range. XRD, SEM were used to study the microstructure and sintering mechanism. The results show that in ...In this paper, the fly-ash ceramics with prior physical properties was fabricated in a low sintering temperature range. XRD, SEM were used to study the microstructure and sintering mechanism. The results show that in this fly-ash ceramics,three kinds of matter form its structure frame such as the glass pearls from the fly-ash raw materials, quartz and mullite in which glass liquid phase was produced during sintering. And the sintering mechanism is that of liquid sintering.展开更多
Novel AZ91D Mg alloy/fly-ash cenospheres(AZ91D/FACs)composites were fabricated by melt stir technique.Fly-ash cenosphere particles with 4%,6%,8%,10%in mass fraction and 100μm in size were used.Hardness and compressiv...Novel AZ91D Mg alloy/fly-ash cenospheres(AZ91D/FACs)composites were fabricated by melt stir technique.Fly-ash cenosphere particles with 4%,6%,8%,10%in mass fraction and 100μm in size were used.Hardness and compressive strength of the composites were measured.The effects of mass fraction of cenospheres on the microstructure and compressive properties were characterized.The results show that the cenospheres are uniformly distributed in the matrix and there is no sign of cenosphere cluster or residual pore.The densities of the composites are 1.85-1.92 g/cm 3 .By comparing with matrix,the compressive yield strength of the composites is improved,and the cenospheres is filled with Mg matrix alloy.SEM,XRD and EDX results of the composites show clear evidence of reaction product at cenosphere/matrix interface.On the basis of XRD and EDX,composition, structure and thermodynamic analysis,the main interfacial phase between the cenosphere and AZ91D Mg alloy was identified to be MgAl2O4.展开更多
A thermal insulating material is synthesized via a non-steam-cured and non-fired route by using fly-ash, sorel cement and hydrogen peroxide solution as raw material. Properties such as apparent density, compressive st...A thermal insulating material is synthesized via a non-steam-cured and non-fired route by using fly-ash, sorel cement and hydrogen peroxide solution as raw material. Properties such as apparent density, compressive strength, bending strength, thermal conductivity, water resistance, and thermal tolerance of this matrial are studied, some influencing factors on its performance discussed. This material has an apparent density of 360 kg/m3, a compressive strength of 1.86 MPa, a thermal conduction coefficient of 0.072 W/(m·K), a softening coefficient of 0.55, and a thermal tolerant temperature of 300 °C. Test results show that this material is light in weight, of high strength, and good thermal insulation. In addition, neither steam-curing nor sintering is needed in producing it. Further more, large amount of fly ash is used in this material, making it a low cost and environment-friendly building material.展开更多
Three fresh China coals(lignitie,bituminite and anthracite) from different geo-logical origin and the corresponding fly and bottom ashes were studied by room tempera-ture(RT)M(?)ssbauer spectroscopy(MS).The iron-beari...Three fresh China coals(lignitie,bituminite and anthracite) from different geo-logical origin and the corresponding fly and bottom ashes were studied by room tempera-ture(RT)M(?)ssbauer spectroscopy(MS).The iron-bearing minerals were characterized tobe mainly pyrite in all coal samples by the hyperfine parameters.Suphate(FeSO_4.nH_2O)was found in bituminite and anthracite coal.The M(?)ssbauer spectra of the fly and bottomashes as a result of pulverised coal combustion(PCC) in Xiaolongtan,Shuicheng andLuohuang Power Plants are comprised of superimposed sextets and doulets of oxides in-cludes maghemite(γ-Fe_2O_3),magnitite(Fe_3O_4),haematite(α-Fe_2O_3),magnesioferite(MgFe_2O_4),Fe^(3+)/Fe^(2+)-mullite,Fe^(3+)-glass silicate and metallic iron.The studies also showthat iron-bearing minerals in coals are largely dependant on geological regions and coalrank,the composition of the corresponding fly and bottom ashes will not only depend onthe type and mineralogy of the feed coal but also on the local nature of combustion.展开更多
基金supported by National Key Research and Development Program of China(2017YFB0603104)Sponsored by Shanghai Pujiang Program(2019PJD011)the financial support from the State Key Laboratory of Green Chemistry Synthesis Technology(Zhejiang University of Technology,Hangzhou 310032)。
文摘In this study,we investigated the performance of a synthetic resin for the adsorption of Li from predesilicated solution which is the waste liquid produced by extracting aluminum from fly ash.The adsorption kinetics and isotherms of the resin were obtained and analyzed.The saturated adsorption sites of the resin were in agreement with the quasi-second-order kinetic model.Then,the pore diffusion model(PDM)was applied to represent the lithium adsorption kinetics which confirming that the external mass is the limiting step.Moreover,we evaluated the adsorption properties of this resin in fixed-bed mode.We established a feasible extraction process for Li from strong alkaline solutions with low Li concentrations.The process parameters,such as the flow rate,initial adsorption solution concentration,water washing process,desorption agent concentration,and flow rate were studied.The desorption rate of the Li;ions was directly proportional with the concentration of the desorption agent.The time required to accumulate Li decreased as the hydrochloric acid concentration and flow rate increased.Time of the peak appeared increased from 0.5 bed volume(BV)to 2.5 BV as the concentration was increased from 1 to3 mol·L^(-1),and the peak increased from 231 to 394 mg·L^(-1).The resin presented good selectivity for Li;ions and could effectively separate impurity ions from the pre-desilication solution.
基金support by the National High Technology Research and Development Program (“863” program) of China (2012AA06A115)China Postdoctoral Science Foundation (2017M610723)
文摘A combined acid–alkali hydrothermal method was used to prepare fly ash–derived SAPO-34 molecular sieves from a thermal power plant in Inner Mongolia(China).The specific surface area of the prepared fly-ash-derived SAPO-34 molecular sieves was 579 m^2 g^-1,the total pore volume was about 0.27 cm^3 g^-1,and the pore size was 0.56 nm;the molar ratios of Al2O3:P2O5:SiO2 were 1:0.86:0.45.Cu/SAPO-34 catalysts were prepared by impregnation of low-cost fly-ash-derived SAPO-34 molecular sieves as a support and tested in selective catalytic reduction with NH3(NH3-SCR).Powder X-ray diffraction(XRD),N2 adsorption–desorption,X-ray photoelectron spectroscopy(XPS),H2 temperatureprogrammed reduction(H2-TPR),NH3 temperature-programmed desorption(NH3-TPD),electron paramagnetic resonance(EPR),nuclear magnetic resonance(NMR),X-ray fluorescence analysis(XRF)and scanning electron microscopy(SEM)were used for catalyst characterization and investigation of the relationships between the catalyst structure and the catalytic activity.The actual silica:alumina ratio of the molecular sieves did not increase with increasing Cu loading,indicating that increasing the Cu loading does not change the original structure of the SAPO-34 molecular sieves.The XRF and NMR results showed that replacement by Cu results in more Si islands.The molecular sieve acidity decreased because of the increased number of Si islands.The NH3-TPD results showed that for the Cu/SAPO-34 catalysts there was a low correlation between the low-temperature activity and the amount of acidic sites.SCR activity is closely related to the location of Cu.The 4.47 Cu/SAPO-34 catalyst has the highest isolated Cu2+showed the highest NH3-SCR activities(>90%)at 250–350℃.This work opens up new avenues for recycling fly ash formed in coal-fired power plants(reducing environmental pollution)and developing low-cost SCR catalysts for NOx pollution control.
文摘In this paper, the fly-ash ceramics with prior physical properties was fabricated in a low sintering temperature range. XRD, SEM were used to study the microstructure and sintering mechanism. The results show that in this fly-ash ceramics,three kinds of matter form its structure frame such as the glass pearls from the fly-ash raw materials, quartz and mullite in which glass liquid phase was produced during sintering. And the sintering mechanism is that of liquid sintering.
基金Project(2007KZ07)supported by Plans for Science and Technology of Changchun City,ChinaProject supported by the Program for New Century Excellent Talents in University,ChinaProject supported by the 985 Project of Jilin University,China
文摘Novel AZ91D Mg alloy/fly-ash cenospheres(AZ91D/FACs)composites were fabricated by melt stir technique.Fly-ash cenosphere particles with 4%,6%,8%,10%in mass fraction and 100μm in size were used.Hardness and compressive strength of the composites were measured.The effects of mass fraction of cenospheres on the microstructure and compressive properties were characterized.The results show that the cenospheres are uniformly distributed in the matrix and there is no sign of cenosphere cluster or residual pore.The densities of the composites are 1.85-1.92 g/cm 3 .By comparing with matrix,the compressive yield strength of the composites is improved,and the cenospheres is filled with Mg matrix alloy.SEM,XRD and EDX results of the composites show clear evidence of reaction product at cenosphere/matrix interface.On the basis of XRD and EDX,composition, structure and thermodynamic analysis,the main interfacial phase between the cenosphere and AZ91D Mg alloy was identified to be MgAl2O4.
基金Project 20062147 supported by the Liaoning Province Natural Science Foundation of China
文摘A thermal insulating material is synthesized via a non-steam-cured and non-fired route by using fly-ash, sorel cement and hydrogen peroxide solution as raw material. Properties such as apparent density, compressive strength, bending strength, thermal conductivity, water resistance, and thermal tolerance of this matrial are studied, some influencing factors on its performance discussed. This material has an apparent density of 360 kg/m3, a compressive strength of 1.86 MPa, a thermal conduction coefficient of 0.072 W/(m·K), a softening coefficient of 0.55, and a thermal tolerant temperature of 300 °C. Test results show that this material is light in weight, of high strength, and good thermal insulation. In addition, neither steam-curing nor sintering is needed in producing it. Further more, large amount of fly ash is used in this material, making it a low cost and environment-friendly building material.
文摘Three fresh China coals(lignitie,bituminite and anthracite) from different geo-logical origin and the corresponding fly and bottom ashes were studied by room tempera-ture(RT)M(?)ssbauer spectroscopy(MS).The iron-bearing minerals were characterized tobe mainly pyrite in all coal samples by the hyperfine parameters.Suphate(FeSO_4.nH_2O)was found in bituminite and anthracite coal.The M(?)ssbauer spectra of the fly and bottomashes as a result of pulverised coal combustion(PCC) in Xiaolongtan,Shuicheng andLuohuang Power Plants are comprised of superimposed sextets and doulets of oxides in-cludes maghemite(γ-Fe_2O_3),magnitite(Fe_3O_4),haematite(α-Fe_2O_3),magnesioferite(MgFe_2O_4),Fe^(3+)/Fe^(2+)-mullite,Fe^(3+)-glass silicate and metallic iron.The studies also showthat iron-bearing minerals in coals are largely dependant on geological regions and coalrank,the composition of the corresponding fly and bottom ashes will not only depend onthe type and mineralogy of the feed coal but also on the local nature of combustion.
