Kinetics of hematite to magnetite transformation by gaseous reduction at low concentration of carbon monoxide

Ponomar, Vitalii; Brik, O.B.; Cherevko, Yu.I.; Ovsienko, V.

doi:10.1016/j.cherd.2019.06.019

Cited by 34 publications

(16 citation statements)

References 22 publications

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“…To investigate the reason for the reduction of Fe(III) into Fe(II) during pyrolysis, gas products during reaction were collected by using N 2 as carrier gas, and the detailed acquisition procedure is described in Text S1 . According to previous reports, CO and H 2 can effectively reduce trivalence hematite into mixed–valence magnetite [ 40 ]. Moreover, because CH 4 is the main pyrolysis gas from biomass decomposition, O 2 exists largely in air atmosphere.…”

Section: Resultsmentioning

confidence: 92%

Low-Temperature Reduction Synthesis of γ–Fe2O3−x@biochar Catalysts and Their Combining with Peroxymonosulfate for Quinclorac Degradation

Zhong

Tong

Merchant

et al. 2022

IJERPH

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Biochar loading mixed–phase iron oxide shows great advantages as a promising catalyst owing to its eco–friendliness and low cost. Here, γ–Fe2O3−x@biochar (E/Fe–N–BC) composite was successfully prepared by the sol–gel method combined with low–temperature (280 °C) reduction. The Scanning Electron Microscope (SEM) result indicated that γ–Fe2O3−x particles with the size of approximately 200 nm were well–dispersed on the surface of biochar. The CO derived from biomass pyrolysis is the main reducing component for the generation of Fe (II). The high content of Fe (II) contributed to the excellent catalytic performance of E/Fe–N–BC for quinclorac (QNC) degradation in the presence of peroxymonosulfate (PMS). The removal efficiency of 10 mg/L of QNC was 100% within 30 min using 0.3 g/L γ–Fe2O3−x@biochar catalyst and 0.8 mM PMS. The radical quenching experiments and electron paramagnetic resonance analysis confirmed that •OH and SO4•− were the main radicals during the degradation of QNC. The facile and easily mass–production of γ–Fe2O3−x@biochar with high catalytic activity make it a promising catalyst to activate PMS for the removal of organic pollutants.

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Section: Resultsmentioning

confidence: 92%

Low-Temperature Reduction Synthesis of γ–Fe2O3−x@biochar Catalysts and Their Combining with Peroxymonosulfate for Quinclorac Degradation

Zhong

Tong

Merchant

et al. 2022

IJERPH

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“…Besides, a minor peak of hematite disappeared at 1000 °C was believed to be transformed into magnetite at 600 °C, which leads to the beige color appearance of the geopolymer sample (Figure 3c). The occurrence of this conversion process was common under elevated temperature [33]. A new crystalline peak of albite appeared at 1000 °C.…”

Section: Phase Identificationmentioning

confidence: 94%

Evaluation of the Effect of Silica Fume on Amorphous Fly Ash Geopolymers Exposed to Elevated Temperature

Yun-Ming

Cheng-Yong

et al. 2021

Magnetochemistry

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The properties of amorphous geopolymer with silica fume addition after heat treatment was rarely reported in the geopolymer field. Geopolymer was prepared by mixing fly ash and alkali activator. The silica fume was added in 2% and 4% by weight. The geopolymer samples were cured at room temperature for 28 days before exposed to an elevated temperature up to 1000 °C. The incorporation of 2% silica fume did not cause significant improvement in the compressive strength of unexposed geopolymer. Higher silica fume content of 4% reduced the compressive strength of the unexposed geopolymer. When subjected to elevated temperature, geopolymer with 2% silica fume retained higher compressive strength at 1000 °C. The addition of silica fume in fly ash geopolymer caused a lower degree of shrinkage and expansion, as compared to geopolymer without the addition of silica fume. Crystalline phases of albite and magnetite were formed in the geopolymer at 1000 °C.

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“…Due to increase in demand of steel in recent years in countries such as China, India and Malaysia, gradual depletion of high-grade magnetite ores has been noticed leading to the exploitation of low-grade ores worldwide [1]. However, processing of low-grade magnetite ores is characterised by poor separation efficiencies due to poor liberation and complexity of the ore. Magnetite is strongly magnetic and magnetic separation is generally applied in the beneficiation process of magnetic ores [2]. Magnetic separation is one of the methods that has been used for almost 200 years in the concentration of iron ores and is still used extensively even today.…”

Section: Introductionmentioning

confidence: 99%

Upgrading the Fe Grade of Magnetite Concentrate Using a Magnetic Hydro-Sizer

Rissenga¹,

Nheta²

2021

World Congress on Mechanical, Chemical, and Material Engineering

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In this study, a magnetic hydro-sizer was used to upgrade the final Fe concentration grade of a magnetite ore. The impact of the magnetic field intensity and water flow rate on the concentration grade were investigated. The chemical composition, mineralogical phases and surface topography of the feed to the hydro-sizer were analysed using XRF, XRD and SEM respectively. The results revealed that the feed to the magnetic hydro-sizer contained 61.25% Fe. Major phases in the feed are magnetite, hongquiite, calcium magnesium catena-silicate and quartz. SEM results showed that the sample was well liberated. A concentrate containing 63.9% Fe was produced whilst operating at particle size distribution of 80% passing 180 µm, water flow rate of 290m 3 /hr and a magnetic intensity of 1350gauss. The higher the magnetic intensity, the lower the Fe grade of the concentrate. The higher the water flow rate, the higher the Fe grade of the concentrate. For a magnetic hydro-sizer, operating field should be between 1200 and 1350 gauss and a water flow rate above 260m3/hr for the final concentration of magnetite.

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Kinetics of hematite to magnetite transformation by gaseous reduction at low concentration of carbon monoxide

Cited by 34 publications

References 22 publications

Low-Temperature Reduction Synthesis of γ–Fe2O3−x@biochar Catalysts and Their Combining with Peroxymonosulfate for Quinclorac Degradation

Low-Temperature Reduction Synthesis of γ–Fe2O3−x@biochar Catalysts and Their Combining with Peroxymonosulfate for Quinclorac Degradation

Evaluation of the Effect of Silica Fume on Amorphous Fly Ash Geopolymers Exposed to Elevated Temperature

Upgrading the Fe Grade of Magnetite Concentrate Using a Magnetic Hydro-Sizer

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