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Volume 25, Issue 9
Displaying 1-10 of 10 articles from this issue
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Haruo WATANABE1988 Volume 25 Issue 9 Pages 573
Published: September 10, 1988
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSDownload PDF (2212K) -
Yoshiaki KAWASHIMA, Hirofumi TAKEUCHI, Hideto SASAKI, Tetsurou HANDA, ...1988 Volume 25 Issue 9 Pages 574-578
Published: September 10, 1988
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSEmulsified vitamin E with surfactant and colloidal silica (Aerosil ®) in water was transformed into a powder dosage form by a spray-drying technique. The type and the concentration of surfactant in the formulation mainly determined the shape and the size of the dried particles and their redispersibility in water. Those results were closely related to the state of aggregation of colloidal silica caused by the adsorption of surfactant in the feed fluid.View full abstractDownload PDF (2156K) -
Masami TSUNEKAWA, Takakatsu TAKAMORI, Naoto SASAMOTO1988 Volume 25 Issue 9 Pages 579-584
Published: September 10, 1988
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSSome critical interfacial properties of talc and its behavior in aqueous suspension have been studied in relationship to mineral processing, where reagent talc and four kinds of talc ore were used.
The pH of talc suspension with time was measured, and the results showed that the equilibrium pH of talc suspension was 7.5-7.9, but the value was slightly higher with talc accompanying dolomite and magnesite. As the initial pH of the suspension was lowered, the amounts of dissolved calcium and magnesium increased. With ore accompanying dolomite and magnesite, the amounts became very large, 3×10-3kmol/m3, when initial pH was 2. The isoelectric point of talc was found to be a pH of about 2.8. The coagulation phenomena were closely related to the zeta potential value, and the coagulation occurred below 10-15mV of the absolute value. With sodium carboxymethyl cellulose (CMC), the zeta potential values became extremely more negative. Flotation recovery of talc with methyl isobutyl carbinol (MIBC) alone and din-butylamine alone was high over the whole pH region, respectively. The adsorption of dodecylammonium acetate (DAA) on the talc surface was mainly electrostatic, and below pH 8 the recovery of talc with DAA alone was high. By CMC addition the recovery with MIBC was reduced to 10% or lessView full abstractDownload PDF (716K) -
Masafumi ARAKAWA, Hideki KOBAYASHI, Keiichiro HIRADO, Keikichi INOUE1988 Volume 25 Issue 9 Pages 585-590
Published: September 10, 1988
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSGenerally a slip-casting process is closely related to the flocculation state of particles. The present investigation was undertaken in order to understand the relationship between the flocculation state of the particles and the packing structure on the surface of gypsum mold.
The flocculation state of particles in an Al2O3 -slurry was discussed on the basis of rheological and sedimentation behavior as a function of dispersant concentration. It was found that these properties could be classified into three modes.
On the slurries, the rate and pressure in the absorption of water, the increase in the packing layer thickness, and the porosity and permeability of the packing layer were measured in order to explain the packing structure on the surface of mold.
From these measurements, the relationship between the flocculation state of the particles and the packing structure could be modelled.View full abstractDownload PDF (2287K) -
Kiyoaki KOMATSUZAKI, Hirotoshi ITO, Yukio FUJIHARA, Yoshihide YOSHIMUR ...1988 Volume 25 Issue 9 Pages 591-596
Published: September 10, 1988
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSIn this paper, the total electric resistance of a planar binary system of particles is described. To clarify the relationship between Rk (strict value of total electric resistance of the system applying Kirchhoff's law) and Rs (approximate value of total electric resistance of the system), a combinatorial study related to the total number (ns) of different values of Rs is done.View full abstractDownload PDF (675K) -
Hirotaka HONDA, Masumi KOISHI, Nobuatsu WATANABE1988 Volume 25 Issue 9 Pages 597-602
Published: September 10, 1988
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSTwo different methods for the preparation of graphite fluoride-modified powders were studied in a dry treating system. Nylon 12, polyethylene, and epoxy resin microspheres were used as core materials.
Using the binary powders blending method (called the powder/powder system blending method) it was impossible to prepare the regular monoparticle layer of graphite fluoride on each core particle.
On the other hand, with another method utilizing a strong impact force (the high speed impact treatment method) it was possible to easily prepare the fine arrangement of graphite fluoride particles on each core particle. From the results observed on the powder dispersability in water and SEM observation, it is found that fine graphite fluoride particles are homogeneously fixed onto the surface of each core particle. This tendency did not depend on the triboelectronic series of the materials.View full abstractDownload PDF (4728K) -
Qian-Qin ZHAO, Genji JIMBO1988 Volume 25 Issue 9 Pages 603-608
Published: September 10, 1988
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSGrinding experiments on the sieved-size fraction of silica sand in a planetary mill are carried out. It is found that for large balls (≥∅4mm), the breakage of she fine size fraction can be described by first-order law, but when the particle size is larger than the ball size, the breakage is not of the first-order, but even for smaller balls, the breakage is completely non-first-order. Reasons for this non-first-order breakage are experimentally investigated and discussed. The specific rate of breakage of particles is described by the equation Si=a·xia·Q(z), where Q(z) is the probability function ranging from 1 to 0, which has been used by Austin for a tumbling ball mill. In this equation, S has a maximum value, and the particle size of the maximum is related to the ball diameter by xm=k1dB, where k1=0.05 irrespective of the specific gravity of the balls. In another words a 20:1 ball diameter/particle size ratio can give the optimum grinding condition for planetary milling, which is found to be the same as in stirred ball milling, but it is different from tumbling ball milling and vibration ball milling. The effect of the diameter and the specific gravity of balls can be expressed as a=k3(ρB/dB0.35).View full abstractDownload PDF (682K) -
The Mixing Effect of a Small Amount of Fine PowderMunetake SATOH, Takashi FUJIMOTO, Takashi SHIGEMURA, Fumiaki HAMANO, K ...1988 Volume 25 Issue 9 Pages 609-614
Published: September 10, 1988
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSA vibration type of tester for measuring the dynamic physical properties of powders has been developed and examined. The system of the tester consists of an electromagnetic vibrator with a controller for the frequency and acceleration, a detecting sphere body attached to a load transducer and a micro-computer.
It has been shown that the patterns of the characteristic curve measured as the relationship between the vertical transmitted force through the powder bed and the frequency varied sensitively with changes in the physical properties of the powders. The mixing effect of a small amount of fine powder on the change in the peeks at the characteristic frequency has been measured by using two different types of mixers.View full abstractDownload PDF (795K) -
Toshiharu SHIBATA, Shinji NAKAYAMA, Kenji YAMAGUCHI1988 Volume 25 Issue 9 Pages 615-620
Published: September 10, 1988
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSTwo thin layers of sands were sieved in a single stage giving attention to size separation, shape change and blinding. One of the sands, olivine, was of an irregular shape and had a smooth surface, but the other, siliceous sand, was rather regular and uneven. Mogensen's random pass model related to a sphere was modified with size parameters in a Feret's box. The sieve-blinding phenomena were revealed through elongation and surface smoothness, based on the Fourier transformation of the particle shapes.View full abstractDownload PDF (613K) -
Yutaka YOSHIDA, Masami TUSNEKAWA, Akira NISHITSUJI, Shigenori KINOSHIT ...1988 Volume 25 Issue 9 Pages 621-626
Published: September 10, 1988
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSA procedure and apparatus have been developed to determine the concentration and size of particles suspended in a liquid.
A He-Ne Laser, nine kinds of powder samples and four kinds of liquid were used in the experiments.
The values of attenuation caused by particles of suspension were proportional to the amount of particles existing on the optical pass of a Laser beam. The attenuation values calculated, according to calculation program developed by the authors, were agreed well with the experimental values. The attenuation values with suspension containing two kinds of powders corresponded to the sum of the product of the weight fraction and the attenuation values for the individual powder.
The particle concentration of suspension and the mixing ratio of binary powders were determined by measuring the attenuation values.
The measurement of attenuation for suspension at a fixed level was carried out during gravity settling, and the size distribution of the particles based on the number was determined by analyzing the change in the attenuation values over time.View full abstractDownload PDF (691K)
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