Microwave Heating Applications in Mineral Processing

Koleini, S.M. Javad; Barani, Kianoush

doi:10.5772/45750

Cited by 9 publications

(4 citation statements)

References 43 publications

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“…Contrary to the case of Fe(III)2O3, Covalently bonding Fe(III)4O6 structures are verified to undergoes thermo-upconversion. On careful examination,Koleini and Barani reported that Fe2O3 heats up to 1000 ℃ at 6-min interval 4). Then we conclude that ferrite heat up accompanying structural change under MW irradiance.Fig.…”

mentioning

confidence: 59%

Quantum chemistry molecular modeling for radio-frequency and microwave- frequency thermo-upconversion heating of metal oxides of NiO and Fe2O3

Yanagida

Matsumura

2019

Proceedings 17th International Conference on Microwave and High Frequency Heating

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Under irradiance of 1kW-MW, nickel oxide (Ni(II)O, 25 gr)) can heat up to 1,300°C in 6 min, while ferric oxide (Fe(III)2O3, 25gr) up to 88°C in 30 min. Since Ni(II) and Fe(III) have unpaired electron (spin) of respective 2 and 5, the big difference in the MW heating speed must be explained by thermo-upconversion mechanism as recently verified for quick MW heating of water clusters.1) MW heating power by magnetic loss factor of magnetic metal oxides with unpaired electron, i.e., spin dcould not rationalize such heating-speed and temperature difference. Density functional theory-based molecular modeling(DFT/MM, B3LYP, 6-31G*) of NiO-tetramer of [(NiO)2]2 is successfully carried out with negative heat of formation, giving effective absorption in both FIR and IR regions, which verifies that Ni(II)O should be heated up through thermo-upconversion to the IR region via radio-, MW- and FIR-absorption, i.e., FIR/IR absorption and thermal IR dissipation

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mentioning

confidence: 59%

Quantum chemistry molecular modeling for radio-frequency and microwave- frequency thermo-upconversion heating of metal oxides of NiO and Fe2O3

Yanagida

Matsumura

2019

Proceedings 17th International Conference on Microwave and High Frequency Heating

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“…Microwave heat treatment is followed by low intensity (0.1-1.8 T) magnetic separation. This treatment has significantly faster reaction times and potentially lower energy consumption as compared to conventional heat treatment methods [115]. Some of the limitations of this technique include high costs of reductants, low grade iron recovery and scaling issues.…”

Section: Microwave Carbothermal Reductionmentioning

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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“…Em várias condições experimentais, solos argilosos, dotados de altos teores de ferro, têm apresentado um comportamento peculiar quando submetidos à radiação eletromagnética. Isso porque óxidos reagem de maneira diferente ao serem bombardeados por micro-ondas, com alguns óxidos com comportamento não linear de aquecimento (KOLEINI, BARANI, 2012). Enquanto as hematitas apresentam um aumento de temperatura linear, as goethitas exibem picos de aquecimento, dada a perda de água e sua transformação para uma nova composição mineralógica: hidrohematita.…”

Section: Introductionunclassified

Influência da textura e mineralogia na determinação da umidade de solos utilizando micro-ondas

Silva

Benevenute

Domingues

2021

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A umidade obtida pelo método da estufa apresenta como inconveniente o tempo necessário para sua obtenção. Como alternativa, tem sido sugerida a obtenção da umidade via forno micro-ondas. Entretanto, solos argilosos dotados de altos teores de óxidos têm apresentado comportamento peculiar, quando submetidos à radiação eletromagnética. Assim, o objetivo deste trabalho foi avaliar a utilização do forno micro-ondas na determinação da umidade de Latossolos de texturas contrastantes e variados teores de óxidos de ferro e alumínio. Foram utilizadas amostras deformadas do horizonte Bw de dez Latossolos. Em triplicata foram realizados ensaios para obtenção da umidade pelos métodos da estufa (105ºC/ 24 horas) e micro-ondas. Os ensaios em micro-ondas foram efetuados com o aparelho Turntable Microwave Oven, em potência calibrada de 800 W.J.s-1. Os dados obtidos foram submetidos ao teste de comparação de médias Tukey (5%). Apenas 6 minutos de secagem no micro-ondas foram suficientes para obtenção de resultados semelhantes ao da estufa. Latossolos argilosos e com maiores teores óxidos de ferro e alumínio permaneceram mais úmidos. Forno de micro-ondas é um método viável por fornecer resultados confiáveis da umidade do solo com o menor tempo.

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Microwave Heating Applications in Mineral Processing

Cited by 9 publications

References 43 publications

Quantum chemistry molecular modeling for radio-frequency and microwave- frequency thermo-upconversion heating of metal oxides of NiO and Fe2O3

Quantum chemistry molecular modeling for radio-frequency and microwave- frequency thermo-upconversion heating of metal oxides of NiO and Fe2O3

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

Influência da textura e mineralogia na determinação da umidade de solos utilizando micro-ondas

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