scholarly journals Changes in phase composition of soderites of the bakal deposit at heating

2018 ◽  
Vol 61 (11) ◽  
pp. 891-897
Author(s):  
O. Yu. Sheshukov ◽  
M. A. Mikheenkov ◽  
E. A. Vyaznikova ◽  
A. S. Bykov ◽  
L. B. Vedmid’
Keyword(s):  
Phase Composition ◽  
Iron Oxide ◽  
Iron Oxides ◽  
Inert Atmosphere ◽  
Degree Of Substitution ◽  
Oxide Content ◽  
Iron Oxide Content ◽  
Magnesium Ions ◽  
High Iron Content ◽  
Oxidizing Atmosphere

The article presents the results of a study of formation mechanism of magnesia-ferrite when heated siderites of the Bakal deposit with different iron oxide content in an inert and oxidizing atmosphere. It was established that in the case of firing in an inert atmosphere, the decomposition of siderite with high iron content begins at a lower temperature and the enthalpy of such decomposition is less. This effect can be explained by the different phase composition of the samples. The main phases formed under conditions of oxidative firing are hematite and magnesia-ferrite. The amount of hematite and magnesia-ferrite produced in the samples with different iron oxide content during firing in an oxidizing atmosphere is different. Siderite with high content of iron oxides contains more hematite in the firing products than magnesia-ferrite, and siderite with a low content of iron oxides contains more magnesia-ferrite in the firing products than hematite. Formed under conditions of oxidative firing magnesia-ferrites are solid solutions and differ in the degree of substitution of iron and magnesium ions. In siderites with high content of iron oxides, the degree of substitution of magnesium ions with iron ions is greater than in samples with a low content of iron oxides. Since the siderites of the Bakal deposit are poor ore formations, the considerable amount of magnesia-ferrite formed in them during firing makes it difficult to separate silicate and iron-oxide firing products by traditional enrichment methods. Wustite in the products of oxidative firing is not detected, because under these conditions it is in a metastable state and in the presence of a weakly oxidizing atmosphere is converted into magnetite. The scientific novelty is the explanation of the mechanism of siderite decomposition and the description of products of such decomposition. Understanding of the mechanism of decomposition of siderite from the Bakal deposit made it possible to develop the technology of reductive firing of siderite to facilitate separation of its products, and which consists in the regulation of the phase composition of silicate products of reductive firing, ensuring the collapse of magnesia-ferrite and output of iron oxide in a separate phase. The developed technology can be used to provide high-quality enrichment of siderite from the Bakal deposit.

scholarly journals On the Possible Significance of High Free Iron Oxide Content in Mabí Clay, a Vertisol from East-Central Puerto Rico

1969 ◽  
Vol 52 (1) ◽  
pp. 47-52
Author(s):  
Raul Pérez Escolar ◽  
M. A. Lugo-López
Keyword(s):  
Puerto Rico ◽  
Iron Oxide ◽  
Soil Structure ◽  
Mean Value ◽  
Oxide Content ◽  
Iron Oxide Content ◽  
High Iron Content ◽  
East Central ◽  
Free Iron ◽  
Genetic Process

Data are given here on the free iron oxide content of Mabí clay, an Aquic Chromudert montmorillonitic-isophyperthermic Vertisol from east-central Puerto Rico. A mean value of 14.4 percent was obtained with a high of 15.9 and a low of 12.6. These values are, as compared with the 13-percent average content of free iron oxides in Cialitos clay, those of a typical Ultisol. Probably the same genetic process was involved to some extent in the formation of these soils. There are definite indications that this high iron content can be of value in stabilizing mechanically created soil structure.

Coloring effect of iron oxide content on ceramic glazes and their comparison with the similar waste containing materials

2021 ◽  
Author(s):  
Fatma Gol ◽  
Zeynep Gizem Saritas ◽  
Selin Cıbuk ◽  
Cigdem Ture ◽  
Emre Kacar ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Oxide Content ◽  
Iron Oxide Content

scholarly journals Polymer-encapsulation of iron oxide clusters using macroRAFT block copolymers as stabilizers: tuning of the particle morphology and surface functionalization

2020 ◽  
Vol 8 (22) ◽  
pp. 4917-4929 ◽  
Author(s):  
Thiago Rodrigues Guimarães ◽  
Muriel Lansalot ◽  
Elodie Bourgeat-Lami
Keyword(s):  
Iron Oxide ◽  
Block Copolymers ◽  
Surface Functionalization ◽  
Particle Morphology ◽  
Amphiphilic Block Copolymers ◽  
Oxide Content ◽  
Iron Oxide Content ◽  
Polymer Encapsulation ◽  
Magnetic Carriers ◽  
Surface Functionalizations

We report a versatile platform for the preparation of magnetic carriers stabilized by macroRAFT amphiphilic block copolymers, exhibiting encapsulated morphologies, high iron oxide content and tailored surface functionalizations.

scholarly journals Iron oxide/titania composites for radar absorbing material (RAM) applications

Cerâmica ◽  
2019 ◽  
Vol 65 (375) ◽  
pp. 470-476 ◽  
Author(s):  
A. Fisli ◽  
D. S. Winatapura ◽  
E. Sukirman ◽  
S. Mustofa ◽  
W. A. Adi ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Pore Volume ◽  
Weight Ratio ◽  
Total Pore Volume ◽  
Precipitation Method ◽  
Oxide Content ◽  
Iron Oxide Content ◽  
Radar Absorbing Material ◽  
Radar Signature ◽  
Absorbing Material

Abstract Iron oxide/titania composites were synthesized by precipitation method. Amount of iron oxide was varied in the composites. The single phase (anatase) was obtained for the weight ratio of 0-20% and three phases (anatase, magnetite and hematite) were found for the weight ratio of 30% and 40% of iron oxide. The crystallite size of titania decreased with increasing of iron oxide content. The specific surface area, total pore volume and BJH pore volume of the sample increased with increasing iron oxide content in the composite. The composites possessed mesoporous characteristic (6.5-9.6 nm in pore diameter) and exhibited ferromagnetic properties. The measurement of the microwave absorption showed that the 40Fe/Ti composite had the best reflection loss of -14 dB at a frequency of 10.9 GHz. This meant that the electromagnetic wave was absorbed 80% in that frequency. Thus, the developed material can be a promising microwave absorbing agent in radar signature reduction.

Determination of the iron oxide content in bauxite: comparing ICP-OES with UV–VIS and volumetric analysis

2020 ◽  
Vol 75 (1) ◽  
pp. 389-396
Author(s):  
Gordana Ostojić ◽  
Dragica Lazić ◽  
Saša Zeljković
Keyword(s):  
Iron Oxide ◽  
Volumetric Analysis ◽  
Oxide Content ◽  
Iron Oxide Content ◽  
Icp Oes

scholarly journals Magnetic properties of glasses with high iron oxide content

2001 ◽  
Vol 36 (7-8) ◽  
pp. 1513-1520 ◽  
Author(s):  
Maximina Romero-Perez ◽  
Jesús Ma. Rincón ◽  
Carlos J.R.González Oliver ◽  
Claudio D’Ovidio ◽  
Daniel Esparza
Keyword(s):  
Magnetic Properties ◽  
Iron Oxide ◽  
Oxide Content ◽  
Iron Oxide Content ◽  
High Iron

Effect of Concentration of Iron Oxide on Crystallization Behavior in Leadless Iron Oxide Crystalline Glaze

2012 ◽  
Vol 554-556 ◽  
pp. 18-22
Author(s):  
Supakorn Silakate ◽  
Anucha Wannagon ◽  
Apinon Nuntiya
Keyword(s):  
Iron Oxide ◽  
Nepheline Syenite ◽  
Crystallization Behavior ◽  
Raw Materials ◽  
Average Particle Size ◽  
Average Particle ◽  
Oxide Content ◽  
Iron Oxide Content ◽  
X Ray Diffraction ◽  
X Ray

The objectives of this study were to prepare leadless crystalline glazes from iron oxide by using low temperature firing (1,100°C) and to study the effect of concentration of iron oxide on the phase composition of the glaze raw materials on phase transformation in leadless iron oxide crystalline glaze. The crystalline phases were investigated by using the DTA, X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The composition of the glaze raw materials compose of nepheline syenite, colemanite, pottery stone, bentonite, ZnO, Li2CO3, SiOSubscript text2 and 10, 15 and 20%(w/w) iron oxide (Fe2O3). The glaze raw materials were ground for homogeneous mixtures by ball milling for 24h. The average particle size of the mixture was 3.86 µm. The glaze bodies were carried to firing at 1,100°C at the heating rate of 2°C/min and soaking for 0.5h. Then, the glaze bodies were cooled at the cooling rate of 1°C/min and maintained at 1,080°C for 3h and then maintained at 980°C for 1h, respectively. From the experiment results, it was found that the crystallization temperatures (Tc) of franklinite (ZnFe2O4) and anorthite (CaAl2Si2O8) depend on the concentration of iron oxide content.

scholarly journals The chromite deposits of the Fiskenæsset region, West Greenland

1967 ◽  
Vol 12 ◽  
pp. 1-39
Author(s):  
M Ghisler ◽  
B.F Windley
Keyword(s):  
Iron Oxide ◽  
Total Iron ◽  
Oxide Content ◽  
Iron Oxide Content ◽  
X Ray ◽  
Average Value ◽  
Maximum Thickness ◽  
V2o5 Content ◽  
Cr2o3 Content ◽  
Almost All

The chromite deposits of the Fiskenæsset region occur in anorthosites, which together with intercalated pyribolites (hypersthene amphibolites) and subsidiary pyroxenites and peridotites occur in the gneisses as horizons belonging to a folded and metamorphosed stratiform complex which has a maximum thickness of 2 km. The chromite occurs in horizons which average 0.5 - 3 m in width, reaching a maximum of 20 m, and consist of alternating anorthosite and chromitite layers, usually between 0.5 and 10 cm wide. Chromite horizons occur in almost all of the anorthosite horizons in the region which have a minimum exposed length of 125 km. 175 X-ray fluorescence analyses show that the Cr2O3 content of the chromite varies between 26% and 36%, averaging 32.7%. The total iron oxide content varies between 28% and 42%, averaging 31. 8% (as FeO), with the result that the Cr:Fe ratio varies between 0.66 and 1.05, averaging 0.93. The chromite has a high V2O5 content varying from 0.2% to 0.5% with an average value of 0.3%. The chromite horizons occur along the shores of the fjords or only a few kilometres from the coast in easily accessible terrain that rarely exceeds 500 m in altitude. Fiskenæsset harbour is ice-free for the whole year.

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