| Iron scale as a solid waste of ironmaking and steelmaking enterprise in the production processing,possesses valuable recycling for rich in iron element.Currently,the added value of the products obtained by the recycling technology of iron scale is relatively lower.Fe3O4 nanoparticle is a kind of ferrite with anti-spinel structure,and has the advantages of small particle size,narrow size distribution and excellent magnetic properties,stable surface properties and good bio-compatibility.It is widely used in the fields of heavy metal adsorption from wastewater,catalyst,angiography,targeted drug delivery,cell separation and so on.So it has important theoretical and practical value to explore the recycling technology of iron scale with higher value-added.The above topic has also attracted the attention of many researchers.Pure iron nitrate powders were obtained by using hydroxide precipitate method form iron scale of ironmaking and steelmaking plant,and ferric nitrate was used as iron source.The pure phase of Fe3O4 was prepared by reduction method and its magnetic property was investigated.The surface morphology of the final products was characterized by X-ray diffraction?XRD?and Fourier Transform Infrared Spectroscopy?FTIR?.The particles were characterized by Field Emission Transmission Electron Microscopy?HRTEM?.Furthermore,the magnetic properties were characterized by Vibrating Sample Magnetometer?VSM?.The conclusions indicate that:The preparation of iron nitrate powders from iron scale found that the amount of ferric nitrate was increasing with the increasing of the concentration of nitric acid.When the concentration of nitric acid is 10mol/L,the mass of Fe?NO3?3 in 20 g ironscale is 9.77 g,and the yield ratio of Fe?NO3?3 is 48.85%.The Fe3O4 nanoparticles were prepared by reduction method.Firstly,the amount of reactants and the reaction temperature were deduced by thermodynamic calculation,fuel ratio calculation and differential thermal analysis.The synthesis mechanism of the carbon reduction stage was studied.Then,the influence of the molar ratio of ferric nitrate and citric acid,reaction temperature and reaction time on the final product phase results showed that the single phase,particle dispersion,particle size in the 230nm Fe3O4 powder was formed when n [Fe?NO3?3 · 9H2O]: n [C6H8O7 · H2O] = 1: 1,carbon reduction temperature was 600 ? and holding time was 20 min.The preparation conditions of the xerogel were n [Fe?NO3?3 · 9H2O]: n [C6H8O7 · H2O] = 1:0.8,and the mass ratio of xerogel and picric acid was 12:1 when the explosive picric acid was added.When the temperatures were 500 ?,550 ?,600 ? respectively,the pure,particle size in the 1525nm Fe3O4 powder were formed.The morphology and magnetic properties of Fe3O4 nanoparticles prepared by different reaction devices and different reaction temperatures were studied.The results showed that the size of the Fe3O4 nanoparticles prepared in the autoclave is 220nm and the Fe3O4 nanoparticle size of preparing in the quartz tube is 1030nm.The saturation magnetization of the Fe3O4 nanoparticles prepared in the autoclave is Ms = 75.3emu·g-1,the saturation magnetization of the Fe3O4 nanoparticles prepared in the quartz tube is Ms = 96.84 emu·g-1.When the temperature was 500 ?,550 ?,600 ?,the saturation magnetization of the Fe3O4 nanoparticles was found to be 87.86 emu·g-1 at600 ?. |
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