Journal of the Society of Powder Technology, Japan

Wet Size Classification for Fine Particles in Centrifuges

Zennosuke TANAKA, Tadashi MIYA, Teruo TAKAHASI

1992 Volume 29 Issue 10 Pages 750-754
Published: October 10, 1992
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.4164/sptj.29.750

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The cut sizes in tubular and disk centrifuges have been discussed both experimentally and theoretically, and the theoretical maximum separation particle size has been underestimated in previous separation mechanisms. A new separation model is proposed here to consider the force balance acting on a particle. This model agrees better with experimental values than the estimated values proposed previously by other authors. Applying a proper correction factor, the calculated values agree well with the experimental results.

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Silica Coating at the Nano-meter Level on an α-Alumina Fine Powder

Mutsuo SANDO, Atsuya TOWATA, Akira TSUGE

1992 Volume 29 Issue 10 Pages 755-761
Published: October 10, 1992
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.4164/sptj.29.755

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Alumina fine powder which adsorbed a given amount of water was dispersed in a hydrophobic solution of n-hexane and ethyl silicate with a small amount of surfactant such as, fatty acid, alkyl amine or sorbitan monostearate (Span 60). Ultra-fine particles and a thin film of silica were formed on the alumina particles after being coated in the solution with stearic acid and stearylamine, respectively. The addition of Span 60 reduced the catalytic activity of stearic acid and stearylamine for the hydrolysis. The silica content of the powder after coating treatment in the presence of stearylamine was nearly equal to that calculated from the amount of water adsorbed on the alumina powder. The silica content was controllable up to 15wt.% by adjusting the amount of adsorbed water.

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Packing of Binary Particulate Mixture with a Continuous Composition Profile by Using a Filtration Method

Masashi IWATA, Won-Deok YI, Masaaki NAKAMURA, Shigeki TOYAMA

1992 Volume 29 Issue 10 Pages 762-768
Published: October 10, 1992
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.4164/sptj.29.762

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A packing technique which can smoothly vary the composition of a formed material is essential to develop a functionally gradient material. In this paper, a packing method based on semi-batchwise filtration operation of two slurries is investigated. One slurry of the light particles is put into a mixing tank, and then the other of the heavy particles is fed in continuously. A theoretical method predicting the composition profile of the functionally gradient material is presented on the basis of the mass balance combined with the filtration theory. Alumina and nickel particles are used in this study as an example of ceramics-metal composite. The experimental composition profiles are in good agreement with the calculated theoretical ones.

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Characteristics of Lamination Layer Formed by Uniaxial Compression of Ultrafine particles

Mitsukuni MIZUNO, Genji JIMBO

1992 Volume 29 Issue 10 Pages 769-771
Published: October 10, 1992
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.4164/sptj.29.769

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On Physico-Chemical Phase in Comminution

Fumikazu IKAZAKI

1992 Volume 29 Issue 10 Pages 772-781
Published: October 10, 1992
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.4164/sptj.29.772

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[title in Japanese]

Norio KIMURA

1992 Volume 29 Issue 10 Pages 791-795
Published: October 10, 1992
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.4164/sptj.29.791

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