Carbothermic Reduction of MgO by Microwave Irradiation

Yoshikawa, Takeshi; Morita, Kazuki

doi:10.2320/matertrans.44.722

Cited by 26 publications

(22 citation statements)

References 6 publications

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“…Carbothermal reactions are thermal reactions that use carbon as the reducing agent at high temperature [29][30][31] , in which most metal oxide could be reduced into metal and metal carbide accompanying with the carbon atom leaving in the form of carbon monoxide and carbon dioxide 32 . The most prominent example is that of iron ore smelting, which is used in the production of iron or steel.…”

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confidence: 99%

A general and scalable synthesis approach to porous graphene

et al. 2014

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Porous graphene, which features nano-scaled pores on the sheets, is mostly investigated by computational studies. The pores on the graphene sheets may contribute to the improved mass transfer and may show potential applications in many fields. To date, the preparation of porous graphene includes chemical bottom-up approach via the aryl-aryl coupling reaction and physical preparation by high-energy techniques, and is generally conducted on substrates with limited yields. Here we show a general and scalable synthesis method for porous graphene that is developed through the carbothermal reaction between graphene and metal oxide nanoparticles produced from oxometalates or polyoxometalates. The pore formation process is observed in situ with the assistance of an electron beam. Pore engineering on graphene is conducted by controlling the pore size and/or the nitrogen doping on the porous graphene sheets by varying the amount of the oxometalates or polyoxometalates, or using ammonium-containing oxometalates or polyoxometalates.

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confidence: 99%

A general and scalable synthesis approach to porous graphene

et al. 2014

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“…3. Morita extended his application studies to carbo-thermal reduction of magnesia refractory 27) and blast furnace slag processing.…”

Section: Mw Application To Steel Industry and Environmental Techniquesmentioning

confidence: 99%

Brief Review on Microwave (MW) Heating, Its Application to Iron & Steel Industry and to the Relevant Environmental Techniques

et al. 2007

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Microwave (MW) was utilized for radar tele-communication during the World War II. In 1946, Percy Spencer found a candy bar in his pocket was melting during his experiments on the MW generation tube, thus he discovered MW heating.1) Since then, MW heating has been applied to various fields.2,3) At first, it was used in food production areas, such as drying of potato, roasting of coffee beans. It was in '70s, when the MW oven has become popular in house kitchens for cooking. And it was also in '70s when the oil shock or natural gas crisis occurred, which promoted the researches on MW heating in the western countries, because of their political necessity to be dependent on electric heating methods. 3,4) Application of MW heating to the energy and the environmental fields has also been attempted and realized. Their application extends to broad areas, 4) such as incineration of medical wastes, devulcanization of rubber tire, treatment of sewage sludges, regeneration of spent activated carbon and chemical residues of petrol industries. In the nuclear engineering, MW de-nitration for producing MOX (Mixed OXide) nuclear fuels by re-disposal of the used plutonium.5) Vitrification of radioactive wastes by MW heating had been proposed in early '90. 6) In the area of materials processing, MW application to polymer has started earlier. There are bunch of research reports, curing of thermosets 7) is one of the examples. During MW drying of Al 2 O 3 castable, it was recognized that they can be heated well by MW. 8) MW heating of the ceramic powders above 1 400°C made it possible to perform the sintering of ceramics. 9) Later, it was reported that MW sintering enhances the diffusion rate, and so-called non-thermal effect 10) has been pointed out, though its origin has been a long debate. In this field, milli-wave techniques have been developed and applied to new processing of ceramics.2) On the other hand, studies on MW heating of metals are far behind comparing with them. Generally, it is known that a bulk metal reflects MW, however, the metal particles can be heated, and also known that ferro-magnetic metals can be heated more, 11) indicating magnetism is related to the heating mechanism. Roy reported full sintering of metallic materials in 1999.12) MW heating of metals is a new technique and could be applied to synthesis of chemical regents 13) and new functional materials, MW rapid heating of catalysis 14) for the cold start of motor vehicles and so on. The MW heating research history is schematically shown in Fig. 1. Classification of Microwave Heating Application and MW CharacteristicsAmong the broad applications of MW heating in various fields, it is possible to classify their application into two major classes. 1) Graduate School of Environmental Studies, Tohoku University, 6-6-02, Aza Aoba, Aramaki, Aoba-ku, Sendai 980-8579 Japan.2) Formerly Graduate Student, Tohoku University. Now at Sharp Co. Ltd.3) Graduate Student, Tohoku University, 6-6-02, Aza Aoba, Aramaki, Aoba-ku, Sendai 980-8579 Japan. 4) Formerly Graduate S...

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“…In previous studies, we focused on the application of microwave irradiation to the treatment of waste slags and refractories. [6][7][8][9] Hydrothermal reactions involve water as a catalyst at elevated temperatures. In addition, microwaves are absorbed directly by water, and the use of microwaves yields a higher heating rate than that achieved by using a conventional heating system.…”

Section: Introductionmentioning

confidence: 99%