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首页> 外文会议>XXI International Mineral Processing Congress >THE ROLE OF SURFACE FORCES IN FLOTATION KINETICS
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THE ROLE OF SURFACE FORCES IN FLOTATION KINETICS

机译：表面力在浮选动力学中的作用

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Mineral separation by flotation is based on controlling the hydrophobicity of the particulate materials to be separated. The most widely used measure of hydrophobicity is the water contact angles, θ, which are usually measured on polished mineral surfaces using either the sessile drop or captive bubble technique. It is well known qualitatively that the larger the θ of a mineral, the faster it floats. It has also been recognized that flotation rate is significantly affected by the ζ potentials of the particles. However, most of the flotation models reported in the literature failed to predict the flotation rates (or recoveries) from the values of such parameters. A new approach has, therefore, been taken to develop a flotation model, which incorporates various surface chemistry parameters. It is based on utilizing the results of the surface force measurements conducted in recent years using the surface force apparatus (SFA), atomic force microscope (AFM) and thin film balance (TFB) techniques. They can provide information on the changes in surface forces across the boundary layers surrounding air bubbles and mineral particles in aqueous media. In the present work, surface force profiles were constructed from the knowledge of three component surface forces (i.e., electrostatic, dispersion and hydrophobic forces), assuming that they are additive. The force profiles were then used to determine the force barriers for bubble-particle interactions, which can be readily converted to energy barriers using the Derijaguin approximation. By relating the energy barriers to the kinetic energies of the bubble-particle interactions, it is possible to predict flotation rates starting from various surface chemistry parameters such as contact angle, ζ potential, Hamaker constant, and surface tension.
机译：通过浮选的矿物分离基于控制待分离的颗粒材料的疏水性。疏水性最广泛使用的度量是水接触角θ，通常使用无滴或俘获气泡技术在抛光的矿物表面上进行测量。定性地知道，矿物的θ越大，其漂浮的速度就越快。还已经认识到，浮选速率受颗粒的ζ电势显着影响。但是，文献中报道的大多数浮选模型都无法根据此类参数的值预测浮选率（或回收率）。因此，采用了一种新方法来开发一种浮选模型，该模型结合了各种表面化学参数。它是基于利用近年来使用表面力设备（SFA），原子力显微镜（AFM）和薄膜天平（TFB）技术进行的表面力测量结果而得出的。它们可以提供有关水介质中气泡和矿物颗粒周围边界层表面力变化的信息。在目前的工作中，假设三个表面力（静电力，分散力和疏水力）是相加的，则根据它们的知识来构造表面力曲线。然后使用力分布图确定气泡-粒子相互作用的力垒，可以使用Derijaguin近似将其轻松转换为能垒。通过将能垒与气泡-颗粒相互作用的动能相关联，可以从各种表面化学参数（例如接触角，ζ电势，Hamaker常数和表面张力）开始预测浮选速率。

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