نتایج جستجو برای: hematite and magnetite
تعداد نتایج: 16829021 فیلتر نتایج به سال:
It has been discovered that magnetite ( Fe304 ) is rapidly oxidized to hematite (o<-Fe 0 ), upon illumination ( X<.310p1 ) in an 02-bear~ni atmosphere. A laboratory investigation has been carried out to determine the kinetics and mechanism of this rapid oxidation process. It has been found that the process consists of a series of constituent reactions which are common to most oxidation mechanis...
Undoped hematite nanowire arrays grown using plasma oxidation of iron foils show significant photoactivity (~0.38 mA cm(-2) at 1.5 V versus reversible hydrogen electrode in 1 M KOH). In contrast, thermally oxidized nanowire arrays grown on iron exhibit no photoactivity due to the formation of a thick (>7 μm Fe(1-x)O) interfacial layer. An atmospheric plasma oxidation process required only a few...
Using laboratory methods, we investigate the effect of the presence and mineralogic form of iron on measured proton nuclear magnetic resonance NMR relaxation rates. Five samples of quartz sand were coated with ferrihydrite, goethite, hematite, lepidocrocite, and magnetite. The relaxation rates for these iron-oxide-coated sands saturated with water were measured and compared to the relaxation ra...
In the present study, the potential for the alkali–silica reaction (ASR) in radiation shielding concrete containing special aggregates is presented. The tests were performed on two kinds of aggregate: (1) high-density aggregate to absorb the gamma radiation (barite, magnetite, and hematite) and (2) mineral with high bound water content to attenuate the neutron flux (serpentinite). The optical m...
Different phases of iron oxide were obtained by hydrothermal treatment of ferric solution at 200°C with the addition of either KOH, ethylenediamine (EDA), or KOH and EDA into the reaction system. As usually observed, the α-Fe2O3 hexagonal plates and hexagonal bipyramids were obtained for reaction with KOH and EDA, respectively. When both KOH and EDA were added into the reaction system, we obser...
[1] The Mössbauer spectrometer on Spirit measured the oxidation state of Fe, identified Fe-bearing phases, and measured relative abundances of Fe among those phases for surface materials on the plains and in the Columbia Hills of Gusev crater. Eight Fe-bearing phases were identified: olivine, pyroxene, ilmenite, magnetite, nanophase ferric oxide (npOx), hematite, goethite, and a Fe-sulfate. Adi...
Abstract The aim of the research is to study mineral analysis and oxides ratios in two cultivated uncultivated soils governorates Qadisiyah, Babylon Najaf. And determination proportions hematite magnetite oxide minerals, following results showed that there a great predominance minerals (quartz calcite) all middle Euphrates, were diagnosed Al-Qadisiyah Governorate, calcite 32.8%, which came firs...
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