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Segawa, Tomoomi; Kawaguchi, Koichi; Ishii, Katsunori; Suzuki, Masahiro; Arimitsu, Naoki*; Yoshida, Hideto*; Fukui, Kunihiro*
Advanced Powder Technology, 26(3), p.983 - 990, 2015/05
Times Cited Count：8 Percentile：27.64(Engineering, Chemical)Denitration of the aqueous solution of nickel nitrate hexahydrate (Ni(NO
)
6HO) by a microwave heating method was investigated. Since Ni(NO)6HO aqueous solution cannot be heated to over 300 
C by microwave irradiation owing to the low microwave absorptivity of its intermediate, NiO could not previously be obtained by microwave heating. We propose a novel NiO synthesis method that uses microwave heating without the risk of chemical contamination. A NiO powder reagent was added to the solution as a microwave acceptor. The denitration efficiency to NiO could be improved by an adiabator around the reactor to increase the temperature homogeneity in the reactor. Numerical simulations also reveal that the use of the adiabator results in remarkable changes in the electromagnetic field distribution in the reactor, temperature inhomogeneity decreases.
Fukui, Kunihiro*; Igawa, Yusuke*; Arimitsu, Naoki*; Suzuki, Masahiro; Segawa, Tomoomi; Fujii, Kanichi*; Yamamoto, Tetsuya*; Yoshida, Hideto*
Chemical Engineering Journal, 211-212, p.1 - 8, 2012/11
Times Cited Count：13 Percentile：41.01(Engineering, Environmental)The process for synthesizing metallic oxide powders by the microwave denitration method was investigated using hexahydrated nickel nitrate and trihydrated copper nitrate aqueous solutions, and the electrical field and the temperature distributions in the reactor were numerically simulated. Although CuO powder can be obtained from a trihydrated copper nitrate aqueous solution by the microwave denitration method, a hexahydrated nickel nitrate aqueous solution cannot be heated up to over 270 C by microwave irradiation. It was also found that the reaction routes for microwave heating are the same as those for conventional external heating. This finding indicates that the success of producing oxide particles by microwave denitration depends not only on the microwave absorptivity of the intermediate and the metallic oxide, but also on the temperature difference.
Tamaru, Ayaka*; Nagakawa, Genta*; Segawa, Tomoomi; Fukasawa, Tomonori*; Ishigami, Toru*; Fukui, Kunihiro*
no journal, ,
This study aims to investigate the effect of hybrid heating on the denitration reaction of a nickel nitrate aqueous solution to evaluate the feasibility of hybrid heating method with an alumina jacket containing carbon nanotube (CNT) as a microwave heating medium. When an alumina jacket without CNT was used, the temperature decreased and the denitration reaction stopped due to the formation of an intermediate product Ni(NO)
(OH)
with low dielectric loss. Whereas, when an alumina jacket containing 0.2 mass% CNT was used, the denitration reaction was completed and nickel oxide particles were obtained. It is presumed that the denitration reaction proceeds by heat conduction from the CNT-containing alumina jacket because the jacket is selectively heated by microwaves more than the Ni(NO)(OH). It is clarified that hybrid heating can be realized by a CNT-containing alumina jacket.
