Preparation Of α-Fe2O3 Research Articles

Separation of iron from converter dust by superconducting HGMS: A simulation analysis and experimental study

Converter dust (LT dust) is an important solid waste from steelmaking, in which iron oxides are the preferred raw material for preparing high value-added α-Fe2O3. Since LT dust contains many impurities, the iron oxides in the LT dust must be enriched and purified before the preparation of α-Fe2O3. Particle trapping behaviors of the matrices as well as the magnetic flocculation of LT dust particles in superconducting high gradient magnetic separation (S-HGMS) were investigated with numerical simulations and experiments. The geometric shape, aspect ratio a:b, and angle α between the axis and the magnetic field direction of the matrices affected the maximum magnetic field intensity (Hmax) and effective capture area (Seca). Diamond matrices had better particle-capture capacity than elliptic and circular matrices because the diamond matrices produced a tip effect and increased the magnetic field force. When the cross section of the matrices was parallel to the direction of the particle velocity, magnetic/weakly magnetic particles were more easily captured by the upper and lower ends of the matrices compared with that of two sides because the particle velocity at the upper and lower ends of the matrices was smaller than that of two sides, making the magnetic force greater than the drag force. Fe2MgO4 and Fe2O3 particles were more prone to magnetic flocculation than other particles because of their higher magnetic susceptibility. The dispersant changed the pH of the solution and the charges on the surface of LT dust particles, and the particles were effectively dispersed because of the action of electrostatic forces. When the magnetic induction was 1.8 T, the dispersant dosage was 20 mg/L, the pulp concentration was 1.5%, and the total Fe content increased by 8.72%, corresponding to an Fe recovery of 91.65%. Finally, a method was developed for extracting iron oxides from LT dust using S-HGMS, to prepare high value-added α-Fe2O3.

Preparation of α-Fe2O3@TA@GO composite material and its anticorrosion performance in epoxy modified acrylic resin coatings

Adding organic-inorganic composite materials is a common way to improve the anti-corrosion performance of organic coatings. In this study, tannic acid as a bridge was first modified with the mica iron oxide, and then reacted with the carboxyl group on the surface of graphene oxide. Mica iron oxide @ tannic acid @ graphene oxide (α-Fe2O3@TA@GO) composite materials were prepared and characterized by infrared spectroscopy, x-ray diffractometer, x-ray photoelectron spectrometer, and scanning electron microscope. The modified products showed good dispersion stability in water, and the sedimentation time was increased from 3 h to 24 h. Composite materials were doped in waterborne epoxy modified acrylic to manufactured coatings. The electrochemical workstation was used to evaluate the corrosion performance of coatings. It was found that the corrosion resistance of the paint film could be greatly improved by adding composite materials characterized by Potentiodynamic polarization curves and EIS analysis. The optimal corrosion resistance can be obtained by adding 5wt% α-Fe2O3@TA@GO fillers. The corrosion current density (icorr) was 1.459 μA/cm2 and the charged transfer resistance (Rct) was up to 14350 Ω cm2, which was shown good potential as anti-corrosive fillers in coatings.

Preparation of α-Fe2O3/(IPDI-HTPB) Composite Nanoparticles and Their Catalytic Performance

Preparation of <i>α</i>-Fe₂O₃/(IPDI-HTPB) Composite Nanoparticles and Their Catalytic Performance

Photocatalytic degradation of indigo carmine dye using α-Fe2O3/bentonite nanocomposite prepared by mechanochemical synthesis

Preparation of α-Fe2O3/bentonite nanocomposite has been successfully conducted by mechanochemical synthesis using iron sand from Syiah Kuala Beach, Banda Aceh and bentonite from Kuala Dewa, North Aceh as raw materials. The α-Fe2O3 was extracted using hydrochloric acid and precipitated using ammonium hydroxide as precipitation agent at pH 6 followed by calcination at high temperature in order to obtained α-Fe2O3. The α-Fe2O3/bentonite nanocomposite was prepared by milling the mixture of α-Fe2O3 and bentonite at 4:1 ratio in a planetary mill for 2 hours without any solvent. The XRD results showed that the main component of iron sand was magnetite (Fe3O4), while in α-Fe2O3/bentonite nanocomposite the main component was α-Fe2O3 and SiO2. The photocatalytic activity of α-Fe2O3/bentonite nanocomposite was investigated on degradation of indigo carmine (IC) dye at various conditions of pH, photocatalyst mass, initial dye concentration and irradiation time. The results showed that the highest photocatalytic activity of α-Fe2O3/bentonite nanocomposite was obtained at the initial pH value of IC solution 1, 250 mg photocatalyst mass and initial concentration of IC 10 mg/L after irradiated for 90 minutes under ultra violet and solar light, respectively. The photocatalytic activity of α-Fe2O3/bentonite nanocomposite using UV light was almost the same as that of by solar light.

Electronically-Coupled Phase Boundaries in α-Fe2O3/Fe3O4 Nanocomposite Photoanodes for Enhanced Water Oxidation

Photoelectrochemical (PEC) water splitting reactions are promising for sustainable hydrogen production from renewable sources. We report here, the preparation of α-Fe2O3/Fe3O4 composite films via a single-step chemical vapor deposition of [Fe(OtBu)3]2 and their use as efficient photoanode materials in PEC setups. Film thickness and phase segregation was controlled by varying the deposition time and corroborated through cross-section Raman spectroscopy and scanning electron microscopy. The highest water oxidation activity (0.48 mA/cm2 at 1.23 V vs RHE) using intermittent AM 1.5 G (100 mW/cm2) standard illumination was found for hybrid films with a thickness of 11 μm. This phenomenon is attributed to an improved electron transport resulting from a higher magnetite content toward the substrate interface and an increased light absorption due to the hematite layer mainly located at the top surface of the film. The observed high efficiency of α-Fe2O3/Fe3O4 nanocomposite photoanodes is attributed to the close pr...

Preparation of α-Fe2O3/rGO composites toward supercapacitor applications.

Reduced graphene oxide (rGO) integrated with iron oxide nanoparticles (α-Fe2O3/rGO) composites with different morphologies were successfully obtained through the in situ synthesis and mechanical agitation methods. It was found that the α-Fe2O3 was densely and freely dispersed on the rGO layer. By comparing electrochemical properties, the sheet-like α-Fe2O3/rGO composites demonstrate excellent electrochemical performance: the highest specific capacitance, and excellent cycling stability and rate capacity. The specific capacitance is 970 F g−1 at a current density of 1 A g−1 and the capacitance retention is 75% after 2000 cycles with the current density reaching 5 A g−1. It is mainly due to the synergistic effect between the α-Fe2O3 and rGO, and the high conductivity of the rGO offers a fast channel for the movement of electrons.

Synthesis, Characterization and Photocatalytic Activity of α-Fe2O3/Bentonite Composite Prepared by Mechanical Milling

Preparation of α-Fe2O3/bentonite composite has been carried out by solid state reaction method by using iron ore from Aceh Besar district, Aceh as hematite source and bentonite from Kuala Dewa, North Aceh. The α-Fe2O3 was extracted from iron ore using hydrochloric acid and precipitated using ammonium hydroxide. The α-Fe2O3/bentonite composite was prepared by mixing α-Fe2O3 and bentonite at 4: 1 ratio using ball mill for 2 h. The XRD results showed that the dominant phase of iron ore was magnetite (Fe2O3) and was converted to α-Fe2O3 after extracting and calcined at 700 °C. The photocatalytic activity of α-Fe2O3/bentonit composite was evaluated on degradation of indigo carmine (IC) dye at various condition of pH, photocatalyst mass, initial dye concentration and irradiation time. The results showed that the highest photocatalytic activity of α-Fe2O3/bentonite composite was obtained at an initial pH of 1, a photocatalyst mass of 250 mg and an initial dye concentration of 5 mg/L with UV irradiation time for 2 h. The photocatalytic activity of α-Fe2O3/bentonite composite using solar light was higher than that of UV light.

Chemistry of Methanol and Ethanol on Ozone-Prepared α-Fe2O3(0001)

The preparation of α-Fe2O3(0001) single-crystal surface by argon ion sputtering followed by ozone annealing is demonstrated to achieve a stoichiometric surface termination not attainable with molecular oxygen. Both methanol and ethanol thermally react on the stoichiometric α-Fe2O3(0001), and three different desorption states were found. At temperatures above 600 K a dehydrogenative disproportionation pathway to yield the respective aldehyde was found, while two peaks at lower temperatures were observed. The peak at 380 K is assigned as dissociative adsorption and recombination, while the less strongly bound peak at 285 K is attributed to molecular adsorption. The mechanism is attributed to a dissociative adsorption mediated by extra atomic oxygen species on top of iron surface sites from the ozone preparation. The absence of photochemical reaction for neither methanol nor ethanol shows that no hole-driven chemistry occurs on stoichiometric α-Fe2O3(0001).

The Recycling of Ferric Salt in Steel Pickling Liquors: Preparation of Nano-sized Iron Oxide

A novel process of recycling ferric salt in Steel Spent Pickling Liquors (SPL) is reported in this paper which refers to the combination of vacuum evaporation and preparation of nano-sized iron oxide (α-Fe2O3) by precipitation method. This study investigates the effect of ammonia concentration, Fe2+ concentration, reaction temperature, stirring speed and calcine temperature on the preparation of α-Fe2O3 by single factor experiment and the optimal preparation conditions of preparing α-Fe2O3 by orthogonal experiment. The results show that the concentration of Fe2O3 in product is up to 98.87%, and the average crystal diameter is about 31.3nm under optimized technological conditions, which realized the highest recycling rate of Fe at 85.6%.

Preparation of α-Fe2O3–TiO2/fly ash cenospheres photocatalyst and its mechanism of photocatalytic degradation

Abstract An α-Fe2O3–TiO2/fly ash cenospheres (FAC) composite photocatalyst was prepared by depositing α-Fe2O3 onto floating TiO2/FAC, which was synthesized via a simple sol–gel method. Scanning electron microscopy, X-ray diffraction analysis, Fourier transform infrared spectroscopy, and UV–vis diffuse reflectance spectroscopy were used to determine the structure and optical property of α-Fe2O3–TiO2/FAC. Rhodamine B was selected as the model substance for photocatalytic reactions to evaluate catalytic ability. Results showed that the degradation efficiency was close to 100% within 1 h. Active species measurements indicated that OH served as the dominating active species that played a key function in the reaction. A possible photocatalytic degradation mechanism of α-Fe2O3–TiO2/FAC was also discussed based on experimental results.

Facile preparation of α-Fe2O3/carbon and polyhydroxy iron cation/polyaniline hollow particles

By virtue of a smartly designed strategy, we successfully prepared the α-Fe2O3/carbon and electromagnetic polyhydroxy iron cation/polyaniline (PIC/PANi) hollow particles. First, poly(styrene-butyl acrylate)/polyhydroxy iron cation (P(S-BA)/PIC) composite particles were prepared based on electrostatic attraction between the P(S-BA) and PIC. Second, the coating of P(S-BA)/PIC composite particles with PANi was achieved by the “Swelling–Diffusion–Interfacial-Polymerization Method”. Finally, α-Fe2O3/carbon and PIC/PANi hollow particles were obtained by calcination or solvent extraction of the P(S-BA)/PIC/PANi composite particles, respectively. The whole preparation process was monitored by transmission electron microscope, scanning electron microscope, Fourier transform infrared, and X-ray diffraction. The synthesized α-Fe2O3/carbon and PIC/PANi hollow particles possessed of a narrow size distribution and well-defined morphology.

Chemical Precipitation Synthesis and Magnetic Properties of Hematite Nanorods

One-dimensional (1D) hematite (α-Fe2O3) nanorods have been successfully prepared using a chemical precipitation method. The sample was characterized by using a variety of techniques, such as X-ray diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometry (VSM). The results showed that the nanorods obtained were monocrystalline, with an average diameter of about 60nm and a length of up to 800nm. In the preparation of α-Fe2O3, the length of α-Fe2O3 seemed to increase with the addition of polyethylene glycol (PEG), and the diameter seemed to decrease with the addition of Zn2+. Nanorods of α-Fe2O3 with a smaller diameter and superior slenderness ratio were prepared by adding both PEG and Zn2+. A possible growth mechanism effect of PEG and Zn2+ upon the morphology of α-Fe2O3 was as follows: α-FeOOH grew in a one-dimensioned orientation upon the surface of a polyethylene glycol template. In the meantime, the Fe3+ position in the α-FeOOH crystal was substituted by Zn2+; resulting in point defects in α-FeOOH crystal due to the radius discrepancy between Zn2+ and Fe3+. The growth-step energy was then reduced as a result of the point defects in the α-FeOOH crystal. The results of magnetic measurements of the hematite nanorods revealed a weak ferromagnetic property which might be related to the shape anisotropy.

Preparation of α-Fe2O3 on Stainless Steel as Anodes for Li-Ion Thin Film Battery by Electrochemical Method

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Preparation of α-Fe2O3 (hematite) by oxidation precipitation of aqueous solutions of iron(II) sulphate

The oxidation precipitation of aqueous solutions of iron(II) sulphate by oxygen gas was studied; the effect of pH, temperature, and presence of α-FeOOH and α-Fe2O3 crystal nuclei was examined and the conditions for the preparation of phase-pure α-Fe2O3 (hematite) were sought. The hematite prepared contained 3-5% structurally bonded water. The effect of the bonded water on the properties of the product is described and the way of the bonding in the structure is discussed.