Papers by Keyword: Iron Oxides

Abstract: The article provides information about the initial elements in the waste and tailings of the copper processing plant of the Almalyk Mining and Metallurgical Combine and theoretical solutions for the extraction of metals. According to chemical data, the amount of iron in the waste is high (52.6%), and the most effective solution for extracting iron from the waste is the reduction process. An increase in the amount of iron to 88.9% was formed using coal and lime as reducing agents.

Abstract: Nowadays, the excessive and uncontrolled discharge of chemicals are imposing major health threats. The demands for clean and safe water amplifies the need to develop improved technologies for environmental contaminant removal. Considering the limitations of conventional methods for contaminants removal, we have prepared magnetic iron oxide nanoparticles functionalised with reduced graphene oxide as a potential material for environmental pollutants removal. The magnetic properties in potential adsorbent materials are highly desirable due to several advantages. Among which are their large adsorptive surface area, low diffusion resistance, high adsorption capacity and fast separation in large volumes of solution. The surface functionalised magnetic iron oxide nanoparticles (MNP) were fabricated using a one-pot hydrothermal method by adding reduced graphene oxide (rGO) into the reaction system. The graphene oxide were reduced prior to the addition in the hydrothemal decomposition step. The resultant rGO-MNP nanocomposites were characterised using FT-IR, SEM and VSM to investigate the functional groups, morphology and magnetic properties, resepectively. We also demonstrated the potential of the hybridised magnetic material with hydrophobic reduced graphene oxide for environmental pollutant removal.

Abstract: Granulated iron oxide particles were incompletely reduced to structured particles comprised metallic iron and residual iron oxides. Structured particles were pressed into prismatic compacts and sintered. Some of sintered specimens were subsequently phosphatized and calcined. Specimens with an iron phosphate coating were found stiffer than specimens without coating. In Hanks' solution, a galvanic corrosion was induced by more noble iron oxides coupled to a less noble metallic iron. This could explain higher corrosion potentials and higher rates of iron dissolution in comparison with a pure iron. The coating of specimens with iron phosphates shifted corrosion potentials towards more negative values and slowed down the dissolution of iron. This was most likely caused by a reduction in oxygen flow through the coating to iron-oxide cathodes, which has enhanced the influence of diffusion control on the kinetics of reduction reaction.

Abstract: The optimization of the Copper ions (Cu ions) adsorption from aqueous solution for inclusion in prolonged the milling time of the extracted iron oxides from waste mill scales has been investigated. Different milling times were used to reduce the size of the raw mill scale which are 24, 48 and 72 h. The three adsorbents were characterized using XRD, FESEM and VSM. Adsorbents that milled for 72 hours gave pure magnetite from the XRD results. FESEM images revealed that prolonged the milling time might reduced the particle sizes. Magnetic hysteresis revealed that all the samples having ferromagnetic behavior. Batch adsorption experiment had been carried out with the three adsorbents and as the results, adsorbents that milled with 72 hours shown highest removal of Cu ions with 95% removal efficiency.

Abstract: The influence of the concentration of the initial solution on the size and composition of the particles obtained by the method of ultrasonic spray pyrolysis (USP) was investigated. An aqueous solution of Fe (NО₃)₃·9Н₂О, the concentration of which varied in the range of 0,0025–0,03 mol/l, was used as the starting material. As a result of the process, iron oxide particles were obtained, the average size of which varied from 123 to 292 nm. Based on FTIR and XRD, powders consist of several phases and have crystalline inclusions α-Fe₂O₃, β-Fe₂O₃, and γ-Fe₂O₃.

Abstract: Studies on the thermal reduction of iron oxide by using reducing agents have been carried out. Carbon-containing components and aluminum were used as reducing agent. The reduction conditions were determined.

Abstract: Iron oxides-doped carbon microspheres composites were synthesized by one-pot hydrothermal methods using Fe (NO₃)₃·9H₂O as the iron source and glucose as the carbon source. The morphology, particle size and crystal structure can be controlled flexibly by altering the concentration of ferric salts and glucose. The SEM and XRD were used to characterize the physicochemical properties of materials. The SEM images indicated that the composites were microspheres, and as the salts concentration increase, adhesion occurred between microspheres. The XRD results showed that the composites were composed of Fe₃O₄ and amorphous carbon. The materials were applied to photocatalytic degradation of dye wastewater and possessed high performance.

Abstract: The objective of this research work was to study the influence of the iron oxide phase resulted during steam oxidation of the sintered steels specimens obtained by powder metallurgy (P/M) route. Steam oxidation is a surface treatment applied to sintered iron parts, as an economic way to reduce the interconnected pores. In powder metallurgy products, the networks of pores are specific, who can be stress concentraions and can produce cracks in material. By steam oxidation treatment the interconnected porosity is closed by sealing them with iron oxides phases. Also, other properties of sintered PM steels are improved. The specimens analyzed in this paper were produced from atomised iron powders, compacted at room temperature at pressures of 600 MPa, sintered for 120 minutes at 1150o C in a laboratory furnace and then subjected to a continuous steam oxidation at 550o C for 60 minutes. Investigations on the structural, mechanical and abrasive wear properties were performed. The microstructure and the pore morphology of the sintered and steam oxidation samples were studied on using optical microscope.

Abstract: Specimens were prepared by using iron-rich magnesia and high-pure magnesia as the main starting materials, and introducing fused corundum of 3%(in mass), 6%, 9%, 12%, 15% respectively and sintered at 1420°C.The samples were characterized by XRD and SEM. The results show that in-situ synthesized composite spinel solid solution were formed in the reaction between iron-rich magnesia and fused corundum. Iron oxides play a key role on the formation of spinel solid solution. When fused corundum was added in a certain particle size, the material showed core-shell structure. Outer layer of core-shell structure were spinel solid solution and the inside were corundum. These core-shell structure make the synthesis of spinel solid solution bonded periclase material at low temperature happen.

Abstract: The scientific process was used to explain characterization and physical properties of the clay sample close to the ancient Nan kiln site. These samples were obtained from JQA, FQB, PQC and NQD. X-ray diffraction (XRD) and X-ray fluorescence (XRF) technique were used to determine the chemical composition and phase transformation before and after fired at 800-1250 °C. XRF result was confirmed that all clay samples mainly contained SiO₂ (>80 wt. %) XRD pattern indicated that quartz was the majority of phase in the all of them. High amount of Fe₂O₃ (>1.6 wt. %) was related to the red-brown tone color. The clay sample could be fired up to 1280 °C without wrapping behavior; it was found that FQB clay had the highest firing resistance due to the maximum quartz content.