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ASHIDA Toshifumi


FacultyDepartment of Biotechnology and Chemistry / General Education Division / Graduate School of System Enginnering
Commentator Guide
Last Updated :2020/09/30

Education and Career

Academic & Professional Experience

  •   1989 ,  - 1990 , Faculty of Engineering, The University of Tokushima

Research Activities

Research Areas

  • Environmental science/Agricultural science, Environmental materials/recycling technology
  • Manufacturing technology (mechanical, electrical/electronic, chemical engineering), Chemical reaction and process system engineering
  • Nanotechnology/Materials, Inorganic compounds/materials chemistry
  • Natural sciences, Solid earth science

Published Papers

  • Briquette made from oyster shell powder and the properties, Toshiumi Ashida, 50, 15 - 19, Dec. 2016
  • Thermal analysis of formation of spinel from raw materials activated mechanochemically, Toshiumi Ashida, 47, 1 - 5, Dec. 2013
  • Mechanochemical synthesis of spinel powder using low-crystalline magnesia and transition alumina, 46, 25 - 30, Dec. 2012
  • New Approaches to Phase Analysis of Smelter Grade Aluminas, Light Metals 2004:Proceedings of the Technical Sessions, Light Metals 2004:Proceedings of the Technical Sessions, 93 - 97, Sep. 2004
  • Effect of texture and composition of microorganisms carrier for disposal of wastewater, Y Hirashima, T Moriga, T Ashida, E Kanezaki, K Murai, Nakabayashi, I, MATERIALS SCIENCE RESEARCH INTERNATIONAL, MATERIALS SCIENCE RESEARCH INTERNATIONAL, 9(4), 282 - 286, Dec. 2003 , Refereed
    Summary:For cleaning-up the water quality of artificial non-fecal drainage, surface-treated porous bodies made of glass beads were used as carriers for microorganisms which have biological activity for the mitigation of pollutants in the water. The influence of chemical species used for coating the bodies and also the texture of the treated surface on the effectiveness of the mitigation of pollution was examined. Coating with calcium silicate, iron oxide and calcium oxide decreased CODMn of the artificial drainage significantly, thus indicating effectiveness for the mitigation of the pollution. The size of cavities which were generated as voids in the three dimensional arrangement of the differently-sized glass beads also affected the effectiveness of the pollution mitigation though the effectiveness was limited. It was concluded that chemical composition of the surface was the most important factor in acting as the carrier of the microorganisms.
  • Performance of calcium silicate hydrate briquettes produced from fly ash and slaked lime in disposal of wastewater, Y Hirashima, T Moriga, T Ashida, E Kanezaki, Nakabayashi, I, MATERIALS SCIENCE RESEARCH INTERNATIONAL, MATERIALS SCIENCE RESEARCH INTERNATIONAL, 8(2), 68 - 73, Jun. 2002 , Refereed
    Summary:Hydrothermal reaction of fly ash and slaked lime produces a porous briquette which is composed of amorphous calcium silicate, a tobermorite-like compound and hydrogarnet. It is essential for the molar ratio (calcium oxide)/(silicon dioxide) of the briquette to be 0.3 to achieve high performance in the purification of wastewater through improved microorganism-carrying ability. The chemical oxygen demand (CODMn) index in artificial, non-fecal drainage decreases more rapidly with the use of the briquettes than that without the briquettes. The macroscopic configuration of the briquettes is an important factor in the water-purification ability, although the high specific surface area of the briquettes does not affect the performance. By increasing the circulation flow rate of the wastewater, the purification performance is improved considerably.
  • Pressure-induced stractural transition in intermetallic compounds MnRhP and MnRhAs, (307), 96 - 100, 2001 , Refereed

Conference Activities & Talks

  • Characterization of Smelter Grade Alumina by Rietveld Refinement,   2003 10


  • Synthesis of Vaterite by Carbonation Process in Aqueous System, MATSUSHITA Isao, HAMADA Yukitoshi, MORIGA Toshihiro, ASHIDA Toshifumi, NAKABAYASHI Ichiro, Journal of the Ceramic Society of Japan, 104, 1215, 1081, 1084,   1996 11 01 , 10.2109/jcersj.104.1081,
    Summary:The synthesis of vaterite was attempted by carbonation process (Ca(OH)_2+CO_2→CaCO_3+H_2O) in aqueous systems with addition of organic compounds having amino group or carboxyl group such as amine, carboxylic acid salt and amino acid salt. Sodium L-glutamate, sodium L-aspartate and ethylenediamine are effective for crystallization of vaterite from amorphous calcium carbonate (ACC), as an initial product. ACC gradually crystallized to vaterite while releasing the additive and H_2O contained in ACC, under the absence of OH^- species in the liquid phase. The existence of OH^- in the liquid phase prevented strongly the formation of vaterite from ACC.
  • Properties of calcium silicate briquette improved by pretreatment of raw materials of coal ash, Toshifumi Ashida, Ichiro Nakabayashi, Teruhiko Okamoto, Yasushi Hirashima, Zairyo/Journal of the Society of Materials Science, Japan, 45, 3, 286, 291,   1996 , 10.2472/jsms.45.286,
    Summary:Calcium silicate briquettes were hydrothermally made from the raw materials of waste coal ash which were activated by pretreating with 0.05 mol/l-HCl solution or 0.1 mol/l-NaOH solution at 80°C for 4 hours. After curing for 72 hours, the briquette consisted of hydrogarnet, C-S-H, and tobermorite. The briquette made from the pretreated coal ash had lower bending strength and lower bulk density than those made from untreated coal ash. To improve the strength, waste silica containing 85 wt% α-quartz was added with the pretreated coal ash. The pretreatment of coal ash indirectly improved the reactivity of waste silica, since hydrothermal solution easily invaded into the briquette through pore developed by the reaction of coal ash. The briquettes having bending strength of 18.7 MPa and bulk density of 1.42 Mg/m3 were obtained.
  • Improvement of Strength of Briquette Autoclaved from Fly Ash Containing Unburned Carbon by Addition of Waste Silica, Toshifumi Ashida, Kazuyuki Koshi, Ichiro Nakabayashi, Journal of the Society of Materials Science, Japan, 44, 497, 170, 174,   1995 , 10.2472/jsms.44.170,
    Summary:Calcium silicate briquettes were prepared from raw materials of fly ash and lime by autoclaving at 180°C. The fly ash was supplied from a fluidized bed boiler and contained 29 wt% unburned carbon. The briquette with the bending strength of 15 MPa and the bulk density of 1.44 Mg/m3 was obtained by autoclaving for the duration of 12 to 24hrs at Ca/Si = 1.0. The addition of NaOH lowered the crystallinity of hydrogarnet in the briquette and decreased the bending strength. To improve the strength, waste silica containing 85 wt% quartz was added to the fly ash in the ratio from 0.15 to 0.75 as SiO2. The bending strength increased to 25 MPa with the addition of waste silica until the ratio of 0.5 when 1N-NaOH was added. Without NaOH, the strength was not so much increased by the addition of waste silica below the ratio of 0.3. © 1995, The Society of Materials Science, Japan. All rights reserved.
  • Effect of atmosphere on the pyrolysis process of basic calcium carbonate, Isao Matsushita, Junichi Nakanishi, Toshio Kono, Toshikazu Sekita, Toshihiro Moriga, Toshifumi Ashida, Ichiro Nakabayashi, Nippon Seramikkusu Kyokai Gakujutsu Ronbunshi/Journal of the Ceramic Society of Japan, 103, 1195, 240, 244,   1995 , 10.2109/jcersj.103.240,
    Summary:The pyrolysis process of basic calcium carbonate (BCC) in air was studied by TG-DTA and high temperature X-ray diffractometry, and obtained results were compared with our previous results in a flowing N2 gas. The decomposition of Ca(OH)2 and calcite was observed at higher temperatures than those in a flowing N2 gas. An exothermic peak appeared in DTA around 370°C before the decomposition of Ca(OH)2. The difference between the results in air and in a flowing N2 gas was caused by carbonation of intermediate products by a slight amount of CO2 in air. The carbonation was promoted by H2O. The exothermic peak around 370°C was attributed to the crystallization of CaCO3.
  • Crystal Structure of Basic Calcium Carbonate and Its Decomposition Process in Water, MATSUSHITA Isao, HAMADA Yukitoshi, SUZUKI Takashi, NOMURA Yuji, MORIGA Toshihiro, ASHIDA Toshifumi, NAKABAYASHI Ichiro, Journal of the Ceramic Society of Japan, 101, 1180, 1335, 1339,   1993 12 01 , 10.2109/jcersj.101.1335,
    Summary:The crystal system of BCC (basic calcium carbonate) was determined by analyzing XRD patterns and SAED spot patterns. It was proved that the BCC was assigned to an orthorhombic system, having the lattice constants of a=7.094Å, b=8.627Å, and c=6.558Å. The decomposition process of BCC in water at 40-80°C was investigated by means of XRD, SEM, TEM, and SAED. XRD measurement showed that BCC decomposed to Ca(OH)2, calcite, and aragonite. Elevation of the slurry temperature resulted in an exponential increase of the decomposition rate and a decrease of the yield of aragonite. SEM, TEM observations and SAED measurement indicated that CaCO3 (calcite and aragonite) deposited on the surface of BCC particles resulting from the dissolution of Ca2+ ion from BCC in the early stage of decomposition. With progress of decomposition, the aragonite grew in the [001] direction and the number of calcite particles increased. Ca2+ ion dissolved into the liquid phase precipitated as Ca(OH)2 and grew to large single crystals with progress of the decomposition.
  • Pyrolysis Mechanism of Basic Calcium Carbonate, MATSUSHITA Isao, NAKANISHI Junichi, KONO Toshio, MORIGA Toshihiro, ASHIDA Toshifumi, NAKABAYASHI Ichiro, Journal of the Ceramic Society of Japan, 101, 1176, 895, 899,   1993 08 01 , 10.2109/jcersj.101.895,
    Summary:Pyrolysis of basic calcium carbonate (BCC) in inert gas flow was studied. Three endothermic peaks in the DTA curve and three weight losses corresponding to the DTA peaks in the TG curve were observed. The evolved gas was analyzed and the thermal decomposition process was investigated by high temperature X-ray diffractometry. The first endothermic process was found to correspond to the formation of BCC anhydride by dehydration of BCC crystals. The second one corresponded to the formation of calcite and Ca(OH)_2 by decomposition of BCC anhydride, and dehydration of the resulting Ca(OH)_2 into CaO. The third one was related to decarbonation of the calcite into CaO. Infrared absorption spectra of intermediate products support these results. Electron microscopic studies showed that, after the decomposition of plate-like BCC anhydride, calcite particles were produced inside the plate-like condensates. After decarbonation, single crystals of CaO were formed by disintegration of the condensates.
  • XPS Study on the Carbonation Process of Ca(OH)_2, MATSUSHITA Isao, SUZUKI Takashi, MORIGA Toshihiro, ASHIDA Toshifumi, NAKABAYASHI Ichiro, METSON James, Journal of the Ceramic Society of Japan, 101, 1174, 725, 727,   1993 06 01 , 10.2109/jcersj.101.725,
    Summary:Intermediates produced in the carbonation process of a Ca(OH)_2 slurry were analysed by X-ray photoelectron spectroscopy (XPS). The molar ratios of CO_3^<2-> to Ca^<2+> of the intermediates, determined from the peak areas of Ca_2p and Cls of XPS spectra, indicated that the rate of carbonation in the vicinity of the surface was comparable to that in the bulk. The binding energy of Ca2p_<3/2> was found to have shifted linearly toward higher binding energies with increasing formation of CaCO_3. These facts support the view that decrease in the Ca^<2+> concentration in the early stages of the process was caused by the formation of an amorphous phase with the formula Ca_<1+x>CO_3(OH)_<2x>・yH_2O(x>0.05,y=0.6-0.8).
  • Effects of Ca2+ and OH Ions on the Process of Calcium Carbonate Synthesis and its Crystallization, Isao Matsushita, Toshikazu Sekita, Takashi Suzuki, Toshihiro Moriga, Toshifumi Ashidaand, Ichiro Nakabayashi, Journal of the Society of Materials Science, Japan, 42, 473, 195, 201,   1993 , 10.2472/jsms.42.195,
    Summary:The effects of ionic concentrations of Ca2+ and OH- ions and crystallinity of Ca(OH)2 on its carbonation reaction were investigated. The process of carbonation was followed by the measurement of electrical conductivity in slurry. Calcite was produced via an intermediate amorphous product, whose composition was determined to be Ca1+xCO3(OH)2x ⋅ yH2O (x> 0.05, y=0.6~0.8) by means of DTA, TGA and GHN analysis. The particles of calcite obtained varied from a dispersed cubic shape to a needle-like or spindle-like condensed shape. This change was ascribed to the decrease in ionic concentration during the crystallization process from the intermediate amorphous phase to calcite. © 1993, The Society of Materials Science, Japan. All rights reserved.
  • Lightening of Calcium Silicate Briquette Synthesized from Waste Silica and Lime by Addition of Colloidal Silica, Toshifumi Ashidaand, Ichiro Nakabayashi, Toshihiro Moriga, Yasushi Hirashima, Journal of the Society of Materials Science, Japan, 42, 480, 1115, 1120,   1993 , 10.2472/jsms.42.1115,
    Summary:Calcium silicate briquette using waste silica was lightened by the addition of colloidal silica to the raw material. The ratio of SiO2 in the colloidal silica against that in waste silica, r, was varied from 0 to 1.2. With an increase of r until reaching 0.4, the bulk density decreased. Above 0.4 the bulk density remained in 1.1 to 1.2 Mg/m3. The bending strength dropped sharply with the small addition of colloidal silica and linearly decreased with an increase of r. The briquette of 13 MPa strength and 1.17 Mg/m3 bulk density was obtained at the optimum ratio, r = 0.4. © 1993, The Society of Materials Science, Japan. All rights reserved.
  • Hydrothermal Synthesis of Calcium Silicate Briquettes from Waste Silica and Lime, and their Properties (Effects of Alkali on Hydrothermal Synthesis and Properties), Yasushi Hirashima, Hiroki Kitayama, Akira Bando, Shinya Shiraiwa, Toshifumi Ashida, Ichiro Nakabayashi, Journal of the Society of Materials Science, Japan, 39, 444, 1304, 1310,   1990 , 10.2472/jsms.39.1304,
    Summary:Waste silica with 5.6μm mean particle diameter was mixed with lime and autoclaved in alkaline solutions at 180°C for several hours under saturated vapor pressure. The observation under a scanning electron microscope (SEM), DTA and X-ray analysis were performed to determine the microstructure, phase component and crystallinity of the reaction products. The additions of sodium and potassium hydroxides accelerated the hydrothermal reaction. On the contrary, lithium hydroxide served as an inhibitor, because of the formation of Li2SiO3 on the surface of silica. Glauconite (mica group), an impurity in waste silica, retarded the crystal growth of calcium silicate hydrate, because of the formation of analcite (zeolite group) by sodium hydroxide. The use of low concentration of NaOH or KOH resulted not only in a considerable reduction in autoclaving time, but also in increasing the bending strength of calcium silicate hydrate briquettes. The addition of 1 wt% potassium titanate whisker (K2O·6TiO2) into the waste silica and lime caused the bending strength of briquettes to increase by about 40%. © 1990, The Society of Materials Science, Japan. All rights reserved.