鉱粒の浮遊現象と濡れとの関連性について

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書誌事項

タイトル別名
  • On the Relation Between Wettability and Floating of Mineral Particles
  • コウリュウ ノ フユウ ゲンショウ ト ヌレ ト ノ カンレンセイ ニ ツイテ

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抄録

Though it is clear from the preceding report that the floating mineral must satisfy both the supporting force equation (i), and the Young equation (ii), these two do not join mathematically with each other in these states. In this report, the supporting force equation (iii) is substituted for the equation (i), where Tl is the air-water interfacial tension or energy, θ is the contact angle and a is the inclination angle of the mineral plane to the horizontal.<BR>f (per unit length) =Tl sin (θ-α)(iii)<BR>This f has the positive and the negative sign. +f is the force acting toward the mineral to float and-f is the force acting toward the mineral to sink.<BR>On the other hand, instead of the Young equation, the surface free energy change W (the work done by the system per unit area) when the mneal moves at the air-water interface, is given by the following equation. This energy change W is considered a measure of wettability, <BR><BR>W=Tl (cos θ-cos α)(viii)<BR>expressing all types of wetting of the floating mineral, and when W > 0, the wetting proceeds spontaneously<BR>(Ts →Tls) which means “wettable”, or “hydrophilic” and when W<0, the wetting recedes spontaneously (Tls→Ts) which means “nonwettable” or “hydrophobic”, and when W=0, the wetting stops.<BR>Combining these two equations (the dynamic and the thermodynamic condition), the following relations are obtained. These relations explain the fundamental principle of flotation that the wettable<BR>W=0...f<0 W=0...f>0 W=0...f=0<BR>mineral sinks and the nonwettable floats.<BR>When the contact angle is 0°<θ<180°, the mineral at the air-water interface has always both the hydrophilic (W > 0) and the hydrophobic surface area (W < 0), and neglecting the gravitational effect, the mineral are moved spontaneously by either the hydrophilic force (-f) on the hydrophobic force (+f) to the area of W=0. This is the reason why the mineral clings to the air-water interface by the hydrophilic and the hydrophobic force, and one can easily understand that the force supporting the mineral at the upper interface of bubble is the hydrophilic force. And the hydrophilic force plays important roles not only in making the mineral to sink into water, but in supporting it at the interface, and cooperates with the hydro phobic force to make up the characteristic of flotation.

収録刊行物

  • 日本鑛業會誌

    日本鑛業會誌 77 (874), 258-264, 1961

    一般社団法人 資源・素材学会

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