(中南大學(xué)資源加工與生物工程學(xué)院，長沙410083)
摘 要: 利用氣泡碰撞測試、接觸角測量、原子力顯微鏡(AFM)試驗研究了十二胺(DDA)對氣泡與疏水性滑石表面TPC形成的影響及作用機理。結(jié)果表明：滑石在去離子水及DDA溶液中均能形成TPC三相接觸線，且TPC形成時間(tTPC)隨著DDA濃度的升高而增加。氣泡與滑石表面三相接觸線形成時間(tTPC)為氣泡與滑石碰撞-反彈所需時間(tB)和氣泡與滑石間液膜排液時間(tD)之和。TPC形成的必要條件是氣泡與礦物之間液膜的破裂，液膜的穩(wěn)定性對TPC的形成至關(guān)重要，氣泡與礦物間液膜越穩(wěn)定，tD越長，tTPC也越長。氣泡與滑石間液膜的穩(wěn)定性是由滑石表面的疏水作用力和氣泡與滑石表面微納米氣泡之間的相互作用力等共同決定的。疏水作用力是引力，隨著DDA濃度的升高，滑石的疏水性增強，使得液膜的穩(wěn)定性趨向于減弱。氣泡和微納米氣泡之間是斥力，隨著DDA濃度的升高，液膜的穩(wěn)定性逐漸增強。
關(guān)鍵字: 三相接觸線；滑石；十二胺；浮選
（School of Resource Processing and Bioengineering,Central South University, Changsha 410083,China）
Abstract:Forming a three-phase contact line (TPC) by contacting and colliding between bubbles and mineral particles is a very important step in the flotation process. The bubble collision test, contact angle measurement and atomic force microscopy (AFM) test were used to study the effect of dodecylamine (DDA) on the formation of TPC on bubbles and hydrophobic talc and its mechanism. The results show that talc can form TPC in both deionized water and DDA solution, and the TPC formation time (tTPC) increases with the increase of DDA concentration. The formation time of three-phase contact line (tTPC) between bubbles and hydrophobic talc surface is the sum of the required time for the collision and rebound of the bubbles and talc (tB) and the liquid film drainage time (tD) between the bubble and talc. The rupture of the liquid film between bubbles and minerals is the necessary condition for the formation of TPC, so the stability of the liquid film is very important to the formation of TPC. The more stable the liquid film, the longer tD and longer tTPC. The stability of the liquid film between bubbles and talc is determined by the hydrophobic force on the talc surface and the interaction force between the bubbles and the nano-/micro-bubbles on the talc surface. The hydrophobic force is gravitational force. As the concentration of DDA increases, the hydrophobicity of talc increases, which tends to weaken the stability of the liquid film. There is a repulsive force between bubbles and nano-/micro-bubbles. As the concentration of DDA increases, the stability of the liquid film increases.
Key words: three-phase contact; talc; dodecylamine; flotation
