Optimization of Magnetizing Reduction and Magnetic Separation of Iron Ores by Experimental Design.

Nasr, M. I.; Youssef, Mervat

doi:10.2355/isijinternational.36.631

Cited by 10 publications

(14 citation statements)

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“…For experiments using coal as the reductant, a lower limit temperature of 500uC has been reported for magnetising reduction. 8,14 For gaseous reductant, [5][6][7] a low reduction potential is commonly used to ensure product uniformity, and thus, high temperature is employed to enhance the reaction rate. However, the temperature should not be too high to avoid over reduction and excessive energy consumption.…”

Section: Effect Of Reduction Temperaturementioning

confidence: 99%

“…The study of this technology has a very long history, and different processes and operating systems have been developed. [1][2][3][4][5] Few of them, however, are so far operated at the commercial scale owing to economic considerations. In recent years, the magnetising roasting method has attracted much attention in China due to the price fluctuation in the international iron ore market.…”

Section: Introductionmentioning

confidence: 99%

“…Hence, a fluidised bed or circulating fluidised bed is commonly utilised as the reactor in recent studies. [5][6][7] In magnetising roasting of low grade haematite, feebly magnetic haematite is converted to strongly magnetic magnetite or maghemite (c-Fe 2 O 3 ). The resulting products can then be recovered by low intensity magnetic separation.…”

Section: Introductionmentioning

confidence: 99%

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Recovery of low grade haematite via fluidised bed magnetising roasting: investigation of magnetic properties and liberation characteristics

Zhu

2012

Ironmaking & Steelmaking

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The separability of low grade haematite from Tangshan was investigated experimentally via fluidised bed magnetising roasting. To better understand the separation mechanisms, the magnetic properties of the products (magnetite or maghemite) made from reduction roasting or reduction-oxidation process were investigated. The liberation behaviour was analysed through beneficiation results and theoretical models. It was found that several parameters such as temperature and roasting time would influence the reduction process; however, the magnetic susceptibility of the reduced sample is mainly determined by the content of the magnetic component. The beneficiation results are mainly influenced by the magnetic properties, magnetic field and grinding size. For the reduction products, i.e. low grade magnetite, the best results occurred when the applied magnetic field was 119?4 kA m 21 and the particle size was 20?048 mm, with the iron grade of the concentrate being 62?5% and the recovery rate being 91?1%. The produced magnetite can be reoxidised to maghemite at temperatures below 300uC, and the concentrate grade is improved when the reduced samples are reoxidised at 200uC. For the reoxidised samples, a preferential breakage effect appeared during the grinding process, and Hsih's model with a detachment factor of 0?3 was observed to provide a good fit for their liberation characteristics.

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Section: Effect Of Reduction Temperaturementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Recovery of low grade haematite via fluidised bed magnetising roasting: investigation of magnetic properties and liberation characteristics

Zhu

2012

Ironmaking & Steelmaking

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“…Reduction by the proper amount of carbon can convert toxic Cr 6+ into nontoxic chromium oxides, such as CrO and Cr 2 O 3 ; meanwhile, the iron oxide can be reduced partly to metallic iron [ 16 , 17 , 18 ]. After the reduction treatment, the metallic iron can be separated from the chromium slag by the melting separation method or magnetic separation method because of the magnetic difference between the metal and slag [ 19 , 20 , 21 , 22 ]. According to extensive experimental research and productive practices, the higher the ratio of chromium to iron (Cr/Fe) in slag, the higher the economic value of the slag.…”

Section: Introductionmentioning

confidence: 99%

Enrichment Characteristics of Cr in Chromium Slag after Pre-Reduction and Melting/Magnetic Separation Treatment

Wang

et al. 2021

Materials

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Concentrating the chromium in chromium slag and improving the chromium–iron ratio is beneficial for the further utilization of chromium slag. In this paper, chromium slag obtained from a chromite lime-free roasting plant was used as the raw material. Pellets made of the chromium slag and pulverized coal were reduced at different pre-reduction temperatures and then separated by a melting separation process or magnetic separation process, respectively. The mass and composition of the metallized pellets before separation, along with the alloy and tail slag after separation, were comprehensively analyzed. The experimental results showed that the output yield of alloy, iron recovery rate, and chromium content in the alloy were all higher when using melting separation than when using magnetic separation, because of the further reduction during the melting stage. More importantly, a relatively low pre-reduction temperature and selection of magnetic separation process were found to be more beneficial for chromium enrichment in slag; the highest chromium–iron ratio in tail slag can reach 2.88.

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“…Limonite ore is a common refractory iron oxide ore with low grade, weak magnetic property and high gangue content. Although limonite ore is poorly responsive to conventional beneficiation techniques, magnetizing roasting-magnetic separation approach has been proved a promising solution for such refractory iron oxide ore beneficiation [1,[6][7][8][9]. The limonite ore becomes porous, easy-to-be-reduced and the iron grade can be naturally enriched by the removal of crystal water which was banded with iron oxide after roasting process, then qualified iron concentrate can be obtained by the sequential magnetic separation [10].…”

Section: Introductionmentioning

confidence: 99%

Deposits in Gas-fired Rotary Kiln for Limonite Magnetization-Reduction Roasting: Characteristics and Formation Mechanism

Ze-zong

et al. 2019

Metals

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The formation mechanism of deposits in commercial gas-fired magnetization-reduction roasting rotary kiln was studied. The deposits ring adhered on the kiln wall based on the bonding of low melting point eutectic liquid phase, and the deposit adhered on the air duct head by impact deposition. The chemical composition and microstructure of the deposits sampled at different locations varied slightly. Besides a small amount of quartz and limonite, main phases in the deposits are fayalite, glass phase and magnetite. The formation of the deposits can be attributed to the derivation of low melting point eutectic of fine limonite and coal ash, and the solid state reaction between them. Coal ash, originated from the reduction coal, combining together with fine limonite particles, results in the accumulation of deposits on the kiln wall and air duct. Fayalite, the binder phase, was a key factor for deposit formation. The residual carbon in limonite may cause an over-reduction of limonite and produce FeO. Amid the roasting process, SiO2, originated from limonite and coal ash, may combine with FeO and reduce the liquefaction temperature, therewith liquid phase generates at high temperature zone, which can significantly promote the growth of deposits.

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Optimization of Magnetizing Reduction and Magnetic Separation of Iron Ores by Experimental Design.

Cited by 10 publications

References 0 publications

Recovery of low grade haematite via fluidised bed magnetising roasting: investigation of magnetic properties and liberation characteristics

Recovery of low grade haematite via fluidised bed magnetising roasting: investigation of magnetic properties and liberation characteristics

Enrichment Characteristics of Cr in Chromium Slag after Pre-Reduction and Melting/Magnetic Separation Treatment

Deposits in Gas-fired Rotary Kiln for Limonite Magnetization-Reduction Roasting: Characteristics and Formation Mechanism

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