Papers by Keyword: Iron

Abstract: The content of elements in the main mineral components of the ore, such as serpentine, talc, and chlorites, were determined. It was shown that, during heat treatment of the ore, in addition to the decomposition of hydrates and carbonates, serpentine decomposes and new phases (forsterite and enstatite) form. On the bases of analysis of the properties of the ore, patterns of phase transitions during heated in inert and reducing atmosphere were identified. It was found that the coal-thermal reduction of nickel and iron from oxides begins at temperatures above 800 °C, and from serpentines begins at temperatures above 1250 °C. It was found that, when heating the ore above 1200 °C in a mixture with a reducing agent, the metals reduce and form iron-nickel alloy. During electro-thermal smelting, the mode of which was determined by the melting points of slag (SiO₂ – MgO – FeO – CaO – Al₂O₃ system) and ferronickel, the ratio of Ni / Fe in the metallic phase was determined by the consumption of reducing agent (coal, coke).

Abstract: The reducibility of titanomagnetite iron ore materials (agglomerate, pellets) with various TiO₂ contents are studied. The mineralogical features of agglomerate and pellets before and after reduction are investigated. Calculations of technical and economic indicators of blast furnace smelting using iron ore materials with different TiO₂ contents are carried out. It is shown that an increase in the content of titanium dioxide in pellets and agglomerate (with an increase in the amount of concentrate introduced into them) does not change the quality of iron ore preparation for blast furnace smelting.

Abstract: Autoclave oxidative leaching is one of the most promising hydrometallurgical approaches for copper suplhide materials processing. In previous studies [2–4], the possibility of an efficient autoclave treatment of chalcopyrite concentrate was confirmed. The concentrate has the following chemical composition, %: 21.5 Cu, 0.1 Zn, 26.5 S, 24.5 Fe, 0.05 Pb, 0.04 Ni, 16.2 SiO₂ [1]. At high temperature conditions (190–200 °C; 4–6 bar) in sulfuric-acid media during 100–120 min about 98% Cu was extracted. A leaching residue after POX (POX-cake) contained the following compounds, %: 55 Fe₂O₃, 40 SiO₂, 4 MeS₂/MeS. Current paper presents the results on purification of POX-cakes from iron by autoclave treatment. Futher ways for by-products (SiO₂-cake and FeSO₄-solution) processing are sugested.

Abstract: The current state of the issue of the slag waste processing was considered, using the example of the Southern Urals Nickel Plant. The average analysis of the chemical composition of the slag was performed; the determined phases contained iron, cobalt, nickel and chromium. The maps of the distribution of these elements in the slag were obtained.

Abstract: The paper presents the results of the research for the reasons of the formation of a brownish bloom on a light clinker brick during its operation. In the work course, the clinker bricks, their mineralogical composition, the nature of the secondary brick coloring and the base materials were tested during bricklaying. It was established that 2 factors caused incrustation. Firstly, the site on which the clinker brick was laid was characterized by a level of alkali soil water close to the surface, and the surface evaporation prevailed over the soil absorption in the warm period of the year. That is all soil water-dissolved salts migrated to the surface of the brick along well-permeable sand joints between the bricks. Secondly, ferrous minerals, including hematite, which was subjected to hydration with the formation of iron hydroxides, and also reacted with sulphates of groundwater with the formation of iron sulphates, were found in the foundation under the brick. This confirms the higher sulfur content in incrustation areas and the presence of a film similar to crystalline hydrates. The analysis of the research allowed us to develop the recommendations for the performance of paving various types of sites with clinker bricks, to develop measures to eliminate an existing bloom, and also to defend the “honor and dignity” of light bricks.

Abstract: Based on aerosol chemical deposition, a method was developed and the process of simultaneous formation of a composite with a carbon matrix and iron oxide nanoparticles incorporated therein was developed. As the source of carbon, o-xylene is proposed, source of nanoscale iron oxide - stabilized and unstabilized magnetic fluid based on benzoic acid in dimethylformamide solution, where benzoic acid is addition source of carbon. The proposed method makes it possible to obtain composite materials of various types with several directions of growth.

Abstract: The morphology and structure of iron silicide nanorods formed on Si (111) vicinal surface by the SPE method at T = 630 °C were studied. Optimal Fe coverage and Fe deposition rate for the formation of a dense array of the nanorods (54-65% of the substrate area) on Si (111) surface with 3-4^o miscut angles were established. The aspect ratio of the nanorods is 1.9 – 3.3. Cross-sectional images of a high-resolution transmission electron microscopy (HRTEM) have shown that the nanorods have α-FeSi₂ crystal structure. They are strained along the “a” axis and stretched along the “c” axis, which increased the unit cell volume by 10.3%. According to HRTEM image analysis, the nanorods have the following epitaxial relationships: α-FeSi₂[01]//Si [10] and α-FeSi₂(112)//Si (111). All the data obtained have provided, for the first time, a direct evidence of α-FeSi₂ nanorods formation on Si (111) vicinal surface without noticeable penetration of Fe atoms into the Si substrate.

Abstract: Questions of melting of iron ore and raw materials with receipt of cast iron and slag are considered in vitro. The chemical composition of cast iron of slag is studied in vitro. The viscosity of slag is researched. Object of research - titaniferous ores with various contents of titan dioxide. The technical and economic indicators of a blast furnace melting an agglomerate and pellets (a consumption of coke and productivity, a chemical composition of cast iron and slag) received from a concentrate of the Kachkanarsky deposit are calculated. The technique of scientific research is used [1].

Abstract: Solids show the feature of internal friction and the feature of fatigue. As a cause for the both features we assume the migration of atomic items. The driving forces for the migration of the atomic items can be mechanical stress gradients and temperature gradients. In an earlier publication formulas have been derived for the internal friction and for the fatigue. From these formulas follows a relation between internal friction and fatigue. The mechanical stress gradients are the cause of the background of internal friction which shows a monotonous rise with temperature. Temperature gradients in the solid can be produced by total internal friction. In contrast to the background of internal friction the temperature dependence of the total internal friction shows maxima and minima. Because of the relations between internal friction and fatigue the temperature dependence of fatigue shows that the fatigue is caused by temperature gradients. The relation between internal friction and fatigue also shows the influence of the internal friction on the fatigue curve.

Abstract: The paper dwells upon the specifics of worn spots being formed on a silicon-carbide crystal in microscratching of iron, cobalt, and nickel. Analysis was done using a Versa 3D dual-beam electron microscope. The chemical composition of worn spots was studied by local X-ray microanalysis. It was found out that the amount of metal transferred to the silicon-carbide worn spot was associated with the electron structure of metal atoms.