Comparison of microwave and conventional carbothermal reduction of red mud for recovery of iron values

Agrawal, Shrey; Rayapudi, Veeranjaneyulu; Dhawan, Nikhil

doi:10.1016/j.mineng.2018.12.012

Cited by 75 publications

(9 citation statements)

References 22 publications

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“…The results indicated that higher values of the degree of reduction of the self-reducing samples were obtained for high microwave power levels regardless of reaction time. In line with the increase in the degree of iron oxides reduction obtained, Agarwal et al 18 compared the red mud carbothermal reduction when applying conventional and microwave heating techniques. They found that the microwave route provided a significant improvement in the degree of iron reduction at lower levels of time and coal amount, as well as faster reduction rate, cleaner processing and savings when compared to conventional roasting.…”

Section: Degree Of Reduction Of the Mixtures As A Function Of The Variation In Power And Time Of Contact With Microwave Energymentioning

confidence: 99%

Evaluation of the Use of Microwave Energy on The Reduction of Iron Ore and Steelmaking Mill Scale Composite Self-Reducing Mixtures

et al. 2022

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With the growing industrialization, there is a constant increase in the world demand for steel, causing an increase on extraction of low-grade iron ores, which bear high levels of impurities. A feasible alternative is the use of residues from steel rolling processes (steelmaking mill scale) generated in the steel industry, which are composed of iron oxides consisting mainly of wustite (FeO), hematite (Fe 2 O 3 ) and magnetite (Fe 3 O 4 ). In line with the recycling of wastes, the application of heating by microwave energy in ironmaking processes consists in a promising new method developed in recent decades and is considered a cleaner technique. Therefore, this study aims to evaluate the self-reduction of mixtures composed of iron ore and steelmaking mill scale as iron source, together with coke fines as carbon source, heated using microwave energy. Through the rotational central composite design technique, it was possible to evaluate the best conditions for the use of steelmaking scale residue as well as the effect of the applied microwave energy power. The results indicated that the developed process has relevant utility with up to 41.48% of reduction obtained. The outcomes contribute to a better understanding of iron recovery from steelmaking residues in reduction processes using microwave energy for heating, providing significant insight for the development of new clean technologies.

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Section: Degree Of Reduction Of the Mixtures As A Function Of The Variation In Power And Time Of Contact With Microwave Energymentioning

confidence: 99%

Evaluation of the Use of Microwave Energy on The Reduction of Iron Ore and Steelmaking Mill Scale Composite Self-Reducing Mixtures

et al. 2022

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“…This technique uses isothermal/non-isothermal reduction using microwave heating followed by magnetic separation [113,114]. Microwave heating has several advantages over conventional heating, such as the instantaneous generation of heat inside moderately absorptive materials rather than relatively slow heat transfer from the outside surface.…”

Section: Microwave Carbothermal Reductionmentioning

confidence: 99%

“…In this study, the red mud was sourced from NALCO India; Bauxite type used was Laterite [114]. The chemical composition of RM is given in Table 2.…”

Section: Case Studymentioning

confidence: 99%

Red Mud as a Secondary Resource of Low-Grade Iron: A Global Perspective

et al. 2022

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Managing red mud (RM), a solid waste byproduct of the alumina recovery process, is a serious ecological and environmental issue. With ~150 million tons/year of RM being generated globally, nearly 4.6 billion tons of RM are presently stored in vast waste reserves. RM can be a valuable resource of metals, minor elements, and rare earth elements. The suitability of RM as a low-grade iron resource was assessed in this study. The utilization of RM as a material resource in several commercial, industrial operations was briefly reviewed. Key features of iron recovery techniques, such as magnetic separation, carbothermal reduction, smelting reduction, acid leaching, and hydrothermal techniques were presented. RMs from different parts of the globe including India, China, Greece, Italy, France, and Russia were examined for their iron recovery potential. Data on RM composition, iron recovery, techniques, and yields was presented. The composition range of RMs examined were: Fe2O3: 28.3–63.2 wt.%; Al2O3: 6.9–26.53 wt.%; SiO2: 2.3–22.0 wt.%; Na2O: 0.27–13.44 wt.%; CaO: 0.26–23.8 wt.%; Al2O3/SiO2: 0.3–4.6. Even with a high alumina content and high Al2O3/SiO2 ratios, it was possible to recover iron in all cases, showing the significant potential of RM as a secondary resource of low-grade iron.

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“…Smelting. Solid state reduction can be conducted as  Carbothermic reduction using a certain type of carbon source [6], conventional process for pig iron making  Reduction roasting, using certain additive(s) in addition to a carbon source [7][8][9][10][11][12][13]  Gaseous reduction using H2 and/or CO or certain gas mixtures [14][15][16][17]  Microwave heating applications [18][19][20] Keskinkilic et al [21] reviewed those examples, so more details can be found in the related literature. The authors have performed a laboratory-scale project dealing with stepwise recovery of valuable elements from red mud.…”

Section: Introductionmentioning

confidence: 99%

Reduction behavior of iron in the red mud

Eray

Keskinkilic

Topkaya

et al. 2021

J min metall B Metall

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Red mud or bauxite residue contains significant quantities of industrial metals such as Fe, Al and Ti, and rare earths such as Sc, Ce, and La. The authors performed a laboratory-scale project work dealing with stepwise recovery of valuable elements from two bauxite residues, namely Iranian red mud (IRM) and Turkish red mud (TRM). In the first stage, it was tried to recover iron which is present in large quantities in red mud. Two different methods have been investigated for this purpose: 1) solid state reduction followed by wet magnetic separation, 2) smelting. In the scope of this paper, some results of pyrometallurgical part of this project are presented. According to solid-state reduction experiments, it was found that more excess coal was needed for IRM (35%) than TRM (15%) to maximize iron reduction. Temperature had significant effect on the reduction process and metallization increased from about 70% to about 95% when the temperature was raised from 1000 to 1200?C. Metallization degree was reported to be slightly higher for IRM (96.2%) than TRM (94.1%). The results demonstrated that a high degree of iron metallization can be achieved regardless of the chemical and mineralogical composition of the bauxite residue sample.

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Comparison of microwave and conventional carbothermal reduction of red mud for recovery of iron values

Cited by 75 publications

References 22 publications

Evaluation of the Use of Microwave Energy on The Reduction of Iron Ore and Steelmaking Mill Scale Composite Self-Reducing Mixtures

Evaluation of the Use of Microwave Energy on The Reduction of Iron Ore and Steelmaking Mill Scale Composite Self-Reducing Mixtures

Red Mud as a Secondary Resource of Low-Grade Iron: A Global Perspective

Reduction behavior of iron in the red mud

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