Papers by Keyword: Fe₂O₃

Abstract: The surface of α-Fe₂O₃ nanoparticles was successfully coated with mesostructured silica templated by surfactant assemblies using cetyltrimethylammonium ions. By repeating the coating operation, it was possible to control the thickness of the mesostructured silica phase. In the sample obtained with ten coatings, in particular, the aggregation and sintering of the α-Fe₂O₃ nanoparticles was suppressed, and the bright red before the heat treatment was maintained even after a heat treatment at 1300 °C.

Abstract: Palm oil fuel ash (POFA) is solid waste from palm oil industries discarded after burning of shell, fiber, kernel and empty fruit bunches to heat boiler and generate electricity. A standard porcelain consisting of clay, feldspar and quartz is produced by sintering at temperature between 1300 °C to 1400 °C for toughness and translucency. This research developed a prediction model for optimum physical and mechanical properties of porcelain by addition of Fe₂O₃ at 5 wt.%. Quartz was replaced with POFA powder at 15 wt.% and Fe₂O₃ was also added at 5 wt.% of POFA mixed with others porcelain composition. Then the powder was dry pressed into pellet at 91 MPa and the samples were sintered at 1150 °C. The bulk density, compressive strength and Vickers microhardness were found to increase by addition of Fe₂O₃ at 5 wt.%. Prediction model was developed and from the predicted values it is revealed that, the model is efficient and good for the purpose of this research.

Abstract: Tin mining business in Malaysia produce many types of by product such as xenotime, monazite, zircon and ilmenite. Ilmenite is one of the crucial materials that helps the growth of economy in Malaysia. Instead of that, ilmenite becomes an important material in the process of oxygen carrier where it shows a better compare to the other such as olivine, hematite, biotite and cuprite. Incredible mechanical resistance and good thermal properties are playing an important factor for the materials that been used for oxygen carrier and ilmenite is the most suitable material for oxygen carrier process. Instead of its suitable properties, ilmenite also one of the lowest price materials among natural minerals sources. Ilmenite composition can provide titanium dioxide (TiO₂) which can be used in many industries such as painting and iron oxide (Fe₂O₃ or Fe₃O₄) for catalytic and magnetic industries. TiO₂ can be found in three phases which are anatase, rutile and brookite. In order to obtain TiO₂, dissolution – precipitation mechanism where titanium arranges into different crystal structure depending on the reactant chemistry. These phase formations were obtained by using hydrothermal treatment at elevated temperatures with the appropriate reactants. The transition temperature and the mechanism of the structural transformation also can be largely influenced the iron oxide phase. Therefor in this study, extractive metallurgy method was used in order to obtain separate TiO₂ and Fe₂O₃.

Abstract: In this paper, the reaction kinetic mechanism of Fe₂O₃ powder containing carbon was studied by microwave magnetizing roast. Based on the temperature-rise curve and weight loss curve of Fe₂O₃ powder by microwave magnetizing roast, the kinetic parameters of Fe₂O₃ powder microwave magnetizing roast were calculated by non-isothermal methods. The controlling steps of different temperature-rising periods in microwave magnetizing roast process of Fe₂O₃ powder were calculated by the Achar-Brindley-Sharp-Wendworth method. The results indicated that the controlling step of microwave magnetizing roast was phase boundary reaction control of contracted cylinder in 250~450°C, and it was three-dimensional diffusion control of spherical symmetry in 450~650°C. The results showed that the starting temperature of reduction roasting of Fe₂O₃ powder was 250°C, which was lower than that under electrical heating, thereby, it proved in theory that microwave heating can enhance reaction rate.

Abstract: Abstract. Ashield of gamma radiation with a basic material of fly ash (FA) type C have been made by additional graphite (G) and Fe₂O₃ (F) using Retsch MM 400 for 30 minutes at the frequency 10 Hz. GF is added to the FA matrix with mass variations of 0%, 1%, 2%, and 3%. Samples were activated with alkali solution at 70°C. Density obtained by calculation of each sample FA_GF0, FA_GF1, FA_GF2, and FA_GF3 are 2.09 g/cm^-3, 2.111 g/cm^-3, 2.113 g/cm^{- 3}, and 2.115 g/cm^-3, respectively. For sample FA_GF3 the density is high but the attenuation coefficient is small. This is influenced by the presence of graphite content in the sample. Graphite also plays a role in forming pores caused the radiation more transmitting through the samples. It can be concluded that the very good composition of the additional of GF is 2% with half value layer (HVL) is 3.980 cm and mean free path (MFP) is 5.743 cm.

Abstract: In this work, Fe₂O₃ nanooval is successfully synthesized with variation of glycine composition of 9, 12, and 15 mmol at hydrothermal temperature of 160 °C. The Fe₂O₃ nanooval is indexed by XRD as α-Fe₂O₃. SEM and TEM images show that the 12 mmol of glycine has the largest diameter with the perfect nanooval form. Nyquist plot shows that the 12 mmol of glycine sample has the best conductivity value of 8.26x10^-5 S/m. The CV of sample 12 mmol delivers the best intercalate/de-intercalate with ΔV of 0.82 V. The 12 mmol sample shows the largest specific discharge capacity of 631.62 mAh/g. It is attributed to high conductivity and high kinetics reaction of Li ion during charge-discharge process. Therefore, Fe₂O₃ nanooval is a promising candidate as anode for lithium-ion battery.

Abstract: The aim of this work is to use a residue from shale gas production, known as retorted shale (RS), as an alternative material for processes of sulfur adsorptive desulfurization in liquid fuels such as gasoline or diesel. Therefore, retorted shale samples were chemically modified. Two methods were applied: acid leaching and impregnation. The first method (RS-HCl) was an acid treatment with HCl solution (3M) in proportion of 1.5: 10. The second method (RS-Fe) was a wet impregnation of 20%wt. of Fe followed by calcination at 700°C for 2 h. The adsorbents were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The adsorption tests were performed using a solution of n-heptane and thiophene to simulate a fuel with an initial concentration of 500 ppm of sulfur. The results showed that both methods significantly altered the structure of the retorted shale, mainly the amount of Fe₂O₃. The adsorption test results indicated that the adsorbents prepared can remove up to 90% of the sulfur present.

Abstract: Despite several advantages of phosphate glass systems, their hygroscopic tendency (absorbing or attracting moisture from the atmosphere) remain a major limiting factor for widespread industrial applications. Dedicated efforts are made to improve the hygroscopic nature of such glasses for making them chemically durable and greatly resistant towards moisture attack. Guided by this requirement, we prepared five phosphate glass samples of composition (70-x) P₂O₅–xFe₂O₃–25ZnO–5CaO with controlled manipulation of iron-oxide contents (Fe₂O₃: x = 0 to 20 mol %) using melt-quenching method. The influence of Fe₂O₃ (as modifier) contents variation on the improvement of structural and chemical strength is determined. As-synthesized glass samples are immersed in acidic solutions for corrosion test. In this test, glass samples are engrossed in the aqueous hydrochloric acid (HCl) media at 90 °C and soaked for a period of 4 h. The corrosion rate (CR) was calculated from the weight loss obtained after the test. The least number of CR indicates that the inclusion of Fe₂O₃ in the glass network improved the network rigidity and made the glass much stronger as well as more water resistant. However, it is also established that there is an optimum limit of Fe₂O₃ content beyond which the durability cannot be further improved. The AFM analysis of pre- and post- chemically treated glass samples informed the surface roughness and 3D topography. Present observation must be validated with other supporting experiments and model calculation which is underway. In this study, it revealed that the lowest corrosion rate was sample S3 (10% of Fe₂O₃) which have CR value of 1.02±0.12 ´ 10^-3gcm^-2h^-1 .

Abstract: Pure 8 mol% yttria stabilized zirconia (YSZ) and 3mol % of Fe-doped YSZ electrolyte from different source of Fe (p)in oxide form (pure iron oxide powders, Fe₂O₃) and Fe(s) source from salt (iron nitrate, Fe(NO₃)₃) were prepared and sintered at 1550°C for 2 hours. The effect of Fe dopant from different source of Fe to the crystal structure and ionic conductivity of 8YSZ samples were investigated. The addition of 3 mol % Fe from iron nitrate source (sample 3Fe(s)YSZ) greatly enhanced the growth of monoclinic phase as compared to 8YSZ sintered samples while the addition of 3 mol % Fe from pure iron oxide powder source (sample 3Fe(s)YSZ) enhanced the crystallization of cubic phase and decrease the monoclinic phase. The addition of Fe significantly enhanced the ionic conductivity of 8YSZ sample for both source of Fe. However, 3Fe(p)8YSZ has smaller grain resistivity and thus has higher conductivity compared to 3Fe(s)YSZ.

Abstract: The results of experimental investigations of combustion of the powder mixture of titanium, carbon, and ferrous oxide (III) are shown in this paper. Iron reduction by carbon is an endothermic reaction and proceeds in combustion wave of SHS due to the heat of high-exothermic reaction of TiC formation. It was found that it is impossible to initiate the combustion process with (Fe₂O₃+C) content of 50 wt. % or more of the initial charge composition. With not very high content of (Fe₂O₃+C), only Fe and TiC are found in the reaction products. When approaching its content to 50 wt. %, also С and FeO impurity phases are detected. The SHS product is a cake of separate granules of Fe-TiC with the granule size of 100-500 μm.