| Currently,fly ash is mainly used in construction projects,mine backfilling,road engineering,mineral extraction or agricultural applications.The main problem with these applications is that the added value is generally not high,and the enthusiasm of enterprises for the application of fly ash is limited.Even some enterprises rely on state subsidies to survive.High value-added utilization has always been a hot spot in the application of fly ash.On the one hand,the use of fly ash with high added value can bring high profits to enterprises,promote technological upgrading of enterprises and promote industrial development;on the other hand,the application of fly ash is expanded to replace relevant functional materials of different industries,reducing The demand for mineral resources also protects the environment.In this paper,in order to realize the conversion of fly ash to functional materials,with reference to the functional characteristics of traditional minerals,the functionalization of fly ash is studied from two aspects:(1)organic modified coating.The surface of the fly ash particles is first modified with a small molecule modifier,and then coated with functional groups,in order to obtain good dispersibility and bonding interface in the organic composite material;(2)inorganic modified loading.After the inorganic modification of the fly ash,such as pickling,the functional material is loaded on the surface to realize the functionalization of the fly ash.Research indicates:1.After the fly ash is organically modified and coated,it is added as a functional filler to the polymer matrix.The modified fly ash coated with sodium tripolyphosphate replaces the composite material prepared by adding calcium carbonate(CaCO3)to the polypropylene(PP)plastic matrix,and the tensile strength is 26.5 MPa,and the notched impact strength is 61.5 MPa.The length ratio is 945.7%,which is not much different from the mechanical properties of the plastic before replacement.The modified fly ash partially coated with the aluminate coupling agent replaces the carbon black added to the styrene-butadiene(SBR)rubber matrix,and the tensile strength is 18.1 MPa,and the tear strength is 38.8 MPa.The mechanical properties of the rubber before replacement are basically the same.When modified fly ash acts as a filler in polymer materials,it greatly reduces the cost while maintaining its performance,and has good applicability.2.Fly ash(FA),fly ash magnetic beads(FAB)and nickel powder(Ni)are organically modified,and as a core,polyaniline is coated on the surface of the particles by in-situ polymerization.When preparing polyaniline,when the doping acid DBSA:HCl=2:8(molar ratio),the minimum reflectance peak is-11.58dB,and the absorbing performance is best;the absorbing property of K-OFAB@K-ONi-PANI Excellent,the minimum reflectance peak reaches-49.35dB,and the lOdB bandwidth is 4.32GHz.The fly ash magnetic beads play a synergistic role in the composite absorbing material,and the prepared composite material achieves better absorbing performance and has a wider absorption frequency.3.After modification by wet grinding,the particle size of fly ash is reduced to below 7.3?m,and the specific surface area is increased.By acid washing and calcination,the optimum calcination process is 800?,the holding time is 150 min,and the fly ash whiteness is from 35.1.The whiteness is increased to 52.8%;the whiteness of the fly ash is increased to 70.7%by the surface phase transformation coating of zinc hydroxide(Zn(OH)2),and the process parameter is set to the zinc ion concentratioI c during the coating process(Zn2+)=0.3 mol·L-1,the dropping rate of hydroxide is v(OH-)=5×10-4 mol·min-1,and the phase transition temperature is T=65?.This result shows that the phase change coating is successful,and the degree of whiteness increase is similar to the whiteness obtained by the complicated method in the reference.4.After the fly ash is inorganically modified and loaded with zinc oxide(ZnO),the inhibition zone and antibacterial rate of the composite material are tested.The results showed that in the inhibition zone experiment,no obvious inhibition zone could be observed in both powder and tableting,in which the contact area of the powder was large and the inhibition zone was larger;the antibacterial rate of the modified fly ash was antibacterial in the experiment.The rate is up to 86.5%and the antibacterial effect is remarkable.Among the composite materials,the effective antibacterial component ZnO accounts for only 28.9%of the total mass,achieving effective antibacterial while greatly saving the cost of the antibacterial material.5.After the inorganic ash is modified by fly ash,TiO2 is supported on the surface of the granule by uniform precipitation method,and the fly ash photocatalytic composite material is obtained.The composite exhibits strong adsorption capacity in the dark reaction process,and its photocatalytic efficiency under ultraviolet light reaches about 95%,while the photocatalytic efficiency under visible light conditions is about 93%;this is due to the powder.The forbidden band width of the coal ash photocatalytic composite material is reduced to 2.82 eV,which can show a good photocatalytic effect under visible light.At the same time,the quality of the active component TiO2 in the composite material only accounts for 28.6%of the total mass,which greatly saves the cost of the photocatalytic material.In summary,the functional materials prepared by the organic modification and inorganic modification of fly ash can be well applied in different fields,because the functional functions of most functional materials are mainly at the surface and interface.Occurrence,through targeted treatment and resource utilization of fly ash,not only increased the added value of fly ash due to functionalization,but also expanded the application of fly ash.Figure:[59]Table:[30]Reference:[95]... |
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