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Synthesis and Functionalization of Magnetic Particles
Published in Jeffrey N. Anker, O. Thompson Mefford, Biomedical Applications of Magnetic Particles, 2020
Erika C. Vreeland, Dale L. Huber
Hematite (gamma-Fe2O3) is a magnetic iron oxide where the iron is all present as Fe (III) but forming it by aqueous precipitation is not as simple as neutralizing a solution of Fe (III) ions. This reaction typically forms a complex mix of phases with some hematite and some magnetite as well. Hematite is not the thermodynamically preferred phase of iron oxide at ambient temperature and pressure, magnetite is, and this makes it difficult to form phase pure hematite using room temperature aqueous chemistry. Thermolysis of iron salts in water has been shown to form hematite more effectively, as have hydrothermal reaction conditions (discussed below).
Research Progress in Synthesization, Coating, and Characterization of Magnetic Nanoparticles
Published in Francisco Torrens, A. K. Haghi, Tanmoy Chakraborty, Chemical Nanoscience and Nanotechnology, 2019
Lavanya Tandon, Poonam Khullar
Nanoparticles synthesis has been motivated due to interest and applications. The magnetic metal oxide nanoparticles possess application in a large number of fields.41-45 One of the important oxides of iron is the hematite. It is non-toxic, stable, and resistant to corrosion. It possesses a wide band gap of 2.1 eV and is an n-type semiconductor. It is used in the non-linear optics, gas sensors, and catalyst. The properties of the nanoparticles intensely affect the morphology and structure. Hematite nanoparticle fabrication under controlled shape and size is the goal of the scientist. Hematite possess the trigonal crystal system and possess pseudo-cubic morphology and corundum type structure.41 it has been reported that cubic like nanoparticles of hematite can be synthesized in different ways. Pseudocubic particles are also obtained through the sol-gel method as reported by Sugimoto et al. and also the synthetic parameters influencing the shape have been studied extensively.42
Raw Materials: Characterization and Preparation
Published in Ram Pravesh Bhagat, Agglomeration of Iron Ores, 2019
Hematite is an iron oxide ( Fe2O3 ) mineral and widespread in the earth's crust. The mineral has the crystal structure similar to corundum. Hematite is colored black to steel or silver-gray, brown to reddish brown, or red. Huge deposits of hematite are found in banded iron formations. While the forms of hematite vary, they all have a rust-red streak.
Magnetization Roasting of Specularite Ore: Phase Transformation, Magnetism and Kinetics
Published in Mineral Processing and Extractive Metallurgy Review, 2023
Xinran Zhu, Yuexin Han, Yue Cao, Yongsheng Sun, Yanjun Li
Iron ore, an essential strategic resource, has been rapidly consumed in the past decade. Although global reserves of iron ore are large, rapid development of the iron and steel industry has greatly increased the demand for additional reserves. Hematite (α-Fe2O3) is a typical iron mineral in iron ore, characterized by high iron grade, low impurity, and easy beneficiation. Thus, hematite-rich ore is the most commonly used iron resource in the iron and steel industry worldwide. Common beneficiation methods for hematite-rich ore include gravity concentration, magnetic separation, and froth flotation (Liu et al. 2016, 2014; Tripathy et al. 2017; Zhu et al. 2022b). With unrestrained exploitation of iron ore resources, high-grade iron ore is gradually being exhausted; use of low-grade hematite ore has become more common (Li 2018). However, with its low iron grade, complex mineral composition, and fine granularity, low-grade hematite ore is difficult to process using conventional methods (Nunna et al. 2021; Quast 2018; Song, Lu and Lopez-Valdivieso 2002).
An experimental study on the effect of alumina nanocomposites on asphaltene precipitation
Published in Petroleum Science and Technology, 2023
Albert Brandt Mbouopda Poupi, Katia Nchimi, Ronald Nguele, Muhammad Iqbal, Vijo Poulose, Kyuro Sasaki, Hakim Saibi
In this research, we investigated the effect of alumina oxide (Al2O3)–iron oxide (Fe2O3) nanocomposites, hereinafter NCP, on asphaltene precipitation. The choice of this combination is justified by the fact that Al2O3 and Fe2O3 have, respectively, a catalytic activity and semiconductor property. Fe2O3 is a well-known n-type semiconductor and exists in various forms in nature (Zong and Li 2018; Khalid et al. 2021). Hematite is a particularly attractive substance because of its natural abundance, low cost, activity, thermodynamic stability, and non-toxicity under environmental conditions (Wu et al. 2010; Zhang, Boxall, and Kelsall 1993). On the other hand, studies revealed that Al2O3 has acid Brönsted sites of moderate strength playing an important role especially in the cracking of heavy gas or oils, during the 80 s by Exxon researchers (Cornell and Schwertmann 2006).
Geotechnical Properties and Microstructure of a Diesel Contaminated Lateritic Soil Treated with Lime
Published in Soil and Sediment Contamination: An International Journal, 2021
Fernando Henrique Martins Portelinha, Natalia De Souza Correia, Igor Santos Mendes, Jose Wilson Batista Da Silva
The SEM analysis was performed on compacted samples of natural and diesel-contaminated soils (4%, 8%, and 16% of diesel), as shown in Figure 5. Figure 5a shows the compacted natural soil microscopy, indicating a significant presence of agglomerates of iron and aluminum oxides and kaolinite, which is common in lateritic soils. In these aggregations, the oxides and kaolinite are strongly connected by natural cementation, and the compaction efforts were insufficient to break the aggregates. In terms of granular particles, results show a majority of quartz minerals. Iron oxides are essentially Hematite minerals. The aluminum oxide was identified as Goethite. Relatively high porosity of the natural soil due to particles aggregation was observed. In Figure 5b, which corresponds to the soil contaminated with 4% of diesel oil, the aggregation seems to be reduced, owing to the presence of the oil and compaction efforts. The dispersion effect given by the oil is significantly increased as percentages of oil increase (Figure 5c). When soil was polluted by diesel, the organic or inorganic colloid compounds, free oxide colloids, and soluble salts that connect fine soil particles can be dissolved by the diesel, leading to a reduction in the connectivity between soil grains. In Figure 5d, in which 16% of oil was added to the soil, a significant quantity of oil covering particles was observed. The oil coating associated with compaction stresses seems to provide a new orientation and dispersion of the fine particles, probably owing to relative sliding.