Journal of the Society of Powder Technology, Japan
Online ISSN : 1883-7239
Print ISSN : 0386-6157
ISSN-L : 0386-6157
Volume 24, Issue 12
Displaying 1-16 of 16 articles from this issue
  • Toshio INOUE
    1987 Volume 24 Issue 12 Pages 759
    Published: December 10, 1987
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
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  • Hirosuke OKAMOTO
    1987 Volume 24 Issue 12 Pages 760-764
    Published: December 10, 1987
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
    A thermodynamic derivation is given for the stress-strain representation of a medium having relaxation properties. This is done by means of the deviation ψij of the realxation tensor ψij appling Onsager's theorem to the thermodynamics of irreversible phenomena.
    The main calculations in this study are as follows:
    (1) In the general case of heating deformation, and in the plastic domatin, the kinetic equations are,
    ψij+1/τψijijT
    wheer εij is the strain tensor, ψij is the deviation tensor, T is the temperature, τ is the realxation time, and a dot represents the time differentiation.
    (2) For quasi-stationary processes, the formula for the stress tensor is,
    σik=KεeeKΔT+2η1ik-1/3εeeδik)+η2eeT)
    where K is the bulk modulus and η is the coefficfient of viscosity.
    (3) Mechanical stability posthulate is
    (∂2F/∂ψi2)>0
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  • Tatsushi MATSUYAMA, Hideo YAMAMOTO
    1987 Volume 24 Issue 12 Pages 765-770
    Published: December 10, 1987
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
    This paper describes an experimental investigation of the charge acquired by a single particle when striking a metal plate. The particle was projected from a pneumatic gun onto the metal plate. The initial charge carried on the particle before impact and the impact charge were measured under various conditions of impact velocity, v0 (7-18m/s) and angle, θ (0°-60°).
    The charge transfer is dependent not only upon the impact conditions but also upon the initial charge of the particle. The impact charge almost decreases proportionally to the increase in the initial charge. There is a particular value of this charge which results in no net transfer and which is independent of the impact conditions. This special point can be utilized to estimate the effective work function of insulating particles. While a larger impact velocity leads to a larger charge transfer because of the increase in the contact area, the data cannot be arranged with the maximum contact area derived from the normal component of the impact velocity, v0cosθ. A much larger enhancement of the charge transfer is caused by the tangential component of the velocity, v0sinθ. This fact is extremely different from the previous works (Refs. 2, 4) which describe that the tangential component had no effect on the charge transfer by collision.
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  • Tsuyoshi HIRAJIMA, Takakatsu TAKAMORI, Masami TSUNEKAWA, Masao TSURUI
    1987 Volume 24 Issue 12 Pages 771-776
    Published: December 10, 1987
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
    Agglomeration experiments were carried out using BaSO4 as model particles, sodium oleate (NaOl) as the surface active reagent and kerosene as the bridging liquid. The percentage of surface coverage of oleate on BaSO4 required to achieve 90% recovery with flotation and agglomeration was about 13% and about 95%, respectively. From the results of agglomeration, phase inversion and flotation experiments, it is concluded that the particle-particle cohesive force due to negative capillary force is a necessary condition for agglomerate formation. This is a reason why a high surface coverage of oleate on BaSO4 is required for agglomeration.
    Simulations of agglomerate growth were conducted using the population balance equations derived by the authors. The equations consist of a collision frequency function and a coalescence probability, formulated on the basis of Kolmogoroff's theory under isotropic turbulent flow conditions and the physical properties of agglomerates. Both the experimental and simulated results showed that agglomerate growth was restricted by a characteristic agglomerate diameter (CD) which increased with increasing γcos θ and φB and with decreasing NI and ε as expressed in Eq. (11).
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  • Masami TSUNEKAWA, Takakatsu TAKAMORI
    1987 Volume 24 Issue 12 Pages 777-782
    Published: December 10, 1987
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
    Studies were made on the chemical constituents of aqueous solutions containing both fluorite and calcite at various mixing ratios and on the effects of the chemical constituents on the flotation characteristics of each of the minerals. A special apparatus simulating the real flotation in plural minerals system was developed by the authors. All experiments were carried out without pH adjustments except in the single fluorite system where KOH was used for pH adjustments. The concentrations of the ionic species from both minerals were regulated by apparent solubility products and the ionic species adsorbed on each mineral surface. The flotation characteristics of liberated fluorite or calcite in the mixed system with both the minerals differed from that in the single systems. The difference was caused by the effect of the ionic species in the aqueous solution with both minerals. The effect was remarkable even with 0.7% calcite. The adsorption-washing-flotation method was effective in the separation of fluorite from calcite.
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  • Hiroshi TAKEZAKI, Hirofumi KIKKAWA, Yoshinori OTANI, Kazunori SATO, Ka ...
    1987 Volume 24 Issue 12 Pages 783-787
    Published: December 10, 1987
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
    The effect of fine particles on the storage stability of CWM has been investigated, and the method to improve the stability has also been studied. The stability of CWM is considered to depend upon the amount of fine particles present in the slurries, and it improves with an increase in the amount of fine particles. The characteristic parameters in the particle size distributions and slurry rheology are correlated with the stability of CWM.
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  • Yukio FUJIHARA, Yoshihide YOSHIMURA
    1987 Volume 24 Issue 12 Pages 788-791
    Published: December 10, 1987
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
    To investigate the method of estimating the degree of dispersion and stability of a dispersed system, the frequency responses of AC-impedance were measured using ground SiO2, TiO2 and Al2O3 powders.
    It was found that the electric equivalent circuit of the dispersed system was a parallel circuit made up of a resister and capacitor. Its AC-impedance was dominated by the concentration of the dissociation ion on the surface layer of the powders.
    From the measurement of the AC-impedance and of the concentration of the dissociation ions in the dispersed system with increasing specific surface area of grinding powders, it was found that for the SiO2-CH3OH and TiO2-CH3OH systems, the AC-impedance and the concentration of the dissociation ions, H+ showed an interesting tendency. For the Al2O3-CH3OH systems, the AC-impedance tended to decrease while the concentration of the dissociation ions, OH- showed an interesting tendency.
    The AC-impedance of the dispered system was closely related to the concentration of the dissociation ion on the surface layer of powders.
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  • Masao SUZUKI
    1987 Volume 24 Issue 12 Pages 792-797
    Published: December 10, 1987
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
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  • Shinnosuke USUI
    1987 Volume 24 Issue 12 Pages 798-804
    Published: December 10, 1987
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
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  • Mamoru SENNA
    1987 Volume 24 Issue 12 Pages 805-809
    Published: December 10, 1987
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
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  • Mitutaka KAWAMURA, Akihiro GOTO, Kunio UCHIDA, Kunio KAMIYA, Fumikazu ...
    1987 Volume 24 Issue 12 Pages 810-815
    Published: December 10, 1987
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
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  • Toshihiko OGUCHI
    1987 Volume 24 Issue 12 Pages 816-821
    Published: December 10, 1987
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
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  • Masatoshi CHIKAZAWA, Takashi TAKEI
    1987 Volume 24 Issue 12 Pages 822-830
    Published: December 10, 1987
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
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  • 1987 Volume 24 Issue 12 Pages 831-835
    Published: December 10, 1987
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
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  • 1987 Volume 24 Issue 12 Pages 836-837
    Published: December 10, 1987
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
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  • [in Japanese], [in Japanese]
    1987 Volume 24 Issue 12 Pages 838-849
    Published: December 10, 1987
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
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