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Volume 53, Issue 3
Special Issue of 51st Summer Symposium
Displaying 1-6 of 6 articles from this issue
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Original Paper
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Junichi Tatami, Gaku Tsuchibuchi, Motoyuki Iijima2016 Volume 53 Issue 3 Pages 132-135
Published: March 10, 2016
Released on J-STAGE: March 30, 2016
JOURNAL FREE ACCESSOrganic binder is usually added to improve the strength of the green body of porous ceramics. However, it is sometimes difficult to maintain the shape of the green body after burning out. In this study, we fabricated porous alumina ceramics using basic aluminum lactate as an inorganic binder. The density of the porous alumina was independent of the quantity of basic aluminum lactate. The strength of green body not only before but also after dewaxing was improved by adding basic aluminum lactate. Addition of basic aluminum lactate as an inorganic binder was also effective in the improvement of the strength of sintered porous alumina, which resulted from neck growth by alumina formed from the basic aluminum lactate. Consequently, it was shown that basic aluminum lactate as an inorganic binder is effective for the improvement of the strength of the sintered body as well as green body.View full abstractDownload PDF (836K) -
Katsuyasu Sugawara, Kosuke Sakusabe, Takahiro Kato, Hirokazu Okawa2016 Volume 53 Issue 3 Pages 136-141
Published: March 10, 2016
Released on J-STAGE: March 30, 2016
JOURNAL FREE ACCESSIn a series of studies on the development of dry and selective recovery process of gold, release behavior of gold from an incinerated sewage sludge ash was investigated at the temperatures from 100 to 1000℃under a chlorine gas stream. Gold was released from the ash above 600℃ and all gold was released to gas phase at 1000℃. When carbon was added to the ash, the initial release temperature of gold was reduced to 400℃ and all gold was transferred to both gas and carbon phases by 700℃. To control the reactions for gold of volatilization from the ash and capture by carbon, the mixture of ash and carbon was heated first to the terminal temperatures of 700 or 800℃ under a nitrogen gas stream. When reaching this temperature, the gas was changed to the chlorine and the mixture held at the terminal temperature for 1 h. By using this procedure, all gold was captured successfully by the carbon. No appreciable effects of surface area and type of the carbon were observed on the capture of gold. Gold was captured selectively and dispersed in the carbon matrix.View full abstractDownload PDF (1269K) -
Tohru Yamamoto, Yoshihisa Tochihara, Naoki Noda, Hiroyuki Akiho, Mak ...2016 Volume 53 Issue 3 Pages 142-148
Published: March 10, 2016
Released on J-STAGE: March 30, 2016
JOURNAL FREE ACCESSX-ray absorption fine structure （XAFS） spectroscopy is one of the effective analytical methods to determine the chemical form of trace elements in the complex powder mixtures such as soil, coal ash, sludge, and so on. XAFS spectra with different oxidation state of selenium （Se） compounds were collected in order to estimate the chemical form such as an oxidation state and a mixing ratio from the near edge XAFS spectra of Se. X-ray absorption energy and shape of the near edge spectra were sensitively varied in the range from 12,656 to 12,667eV with increasing the oxidation number of Se. It was found that the chemical form of Se contained in coal ash was able to estimate by using a linear fitting analysis with the collected XAFS spectra of this study.View full abstractDownload PDF (1079K) -
Yuto Deki, Kazunori Kadota, Atsuko Shimosaka, Yoshiyuki Shirakawa2016 Volume 53 Issue 3 Pages 149-156
Published: March 10, 2016
Released on J-STAGE: March 30, 2016
JOURNAL FREE ACCESSIn composite particle production processes, simplification of process and composite morphology control are technical problems. In this study, NaCl-amino acid composite particles were prepared by atomizing crystallization method for the purpose of achievement of problems. The obtained composite particle had different composite morphology, such as distributed type and a surface-covering type for different combinations of solute materials. The morphology variation of the composite particles depends on the difference in crystallization rate and a habit modifier effect. As a result of calculating the solubility curve of pure solute into water, it turned out that the crystallization speed of sodium chloride was larger than amino acid. The distribution ratio of the water of sodium chloride is smaller than amino acid. It supports to be easy to dehydration.View full abstractDownload PDF (3639K) -
Atsushi Ikeda, P. N. van Esdonk, Satoshi Umemoto, Kenji Tanno, Shir ...2016 Volume 53 Issue 3 Pages 157-163
Published: March 10, 2016
Released on J-STAGE: March 30, 2016
JOURNAL FREE ACCESSGasification is a promising technology for the effective utilization of low-rank solid fuels such as lignite. Char gasification, a rate-limiting step, has been studied using several kinetic models, one of which is the random pore model （RPM）. Although catalytic gasification is an effective method to accelerate the char gasification rate, the RPM is sometimes not applicable to catalytic gasification due to rapid acceleration of the gasification rate with catalysts. Therefore, in our previous study, an extended RPM was applied for the CO2 gasification for catalyst-loaded char, and the model-predicted results were compared with the experimental results. The model prediction was in good agreement with the experimental results, and the applicability of the extended RPM for CO2 gasification with catalyst was thus established. In order to analyze the catalytic effect of calcium present in raw coal and the loaded calcium, CO2 gasification and steam gasification of raw coal char and calcium-loaded coal char were evaluated by dividing the extended RPM into a non-catalytic reaction term and a catalytic reaction term. It was clarified that the first term was constant regardless of the presence or absence of the loaded calcium. The second term successfully described the catalytic effect of calcium. Further unlike in the case of CO2 gasification, in steam gasification, deactivation of calcium present in raw coal was slower than that of the loaded calcium.View full abstractDownload PDF (1077K)
Review
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Yoshiyuki Shirakawa2016 Volume 53 Issue 3 Pages 164-173
Published: March 10, 2016
Released on J-STAGE: March 30, 2016
JOURNAL RESTRICTED ACCESSPowder and fine particles are commonly used in industrial applications such as the preparation of food, pharmaceutical products and materials of electronic devices. The physical and chemical properties of powder particles strongly influence the characteristics of products prepared in powder processes. Therefore, the control of particle morphology, shape and size distribution gives us significant advantages in adding a new function to the products.
Bottom-up technology such as crystallization and sol-gel methods is often used for controlling particle properties in such fabrication processes. Recently, particle synthesis in confined spaces has attracted attention like a micro-reactor because it has large interfacial area per unit volume, controllable residence time of the fluid by changing the channel length and operation at low Reynolds numbers. Then, the confined space becomes a reaction field with relative uniform and rapid changing from circumstance. In this paper, our works concerning particle synthesis in the confined space are introduced. Spherical amino acid and titanium oxide particles were fabricated in an atomization crystallization process based on liquid-liquid interfacial diffusion. Composite particle synthesis was performed in a coaxial tube reactor controlled the fluid pattern.View full abstractDownload PDF (2848K)
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