摘要
泡沫浮选是目前国内外选矿领域应用最广的选矿方法，但该方法对微细粒和粗粒矿物的回收效率低下，已造成了巨大的金属流失。为了提高泡沫浮选对微细粒和粗粒矿物的回收效果，世界范围内开展了进100年的研究，由于泡沫浮选原理所致，至今仍然没有从根本上解决这一问题。充分弄清矿粒与气泡间相互作用的各种微观过程，是进行浮选设备和流程设计的重要基础。
在广泛查阅矿粒与气泡相互作用方面的文献资料的基础上，对矿物颗粒在泡沫层中的行为作了比较详细的理论分析，得出了矿粒与气泡接触前后的自由能变化ΔG，理论分析表明，ΔG不仅与接触角θ值有关，而且与气—液界面张力有关，即疏水性增加，矿粒与气泡接触过程的自由能变化ΔG的负值增加，矿粒与气泡的附着过程越容易进行。对矿粒在水中和泡沫层中与气泡附着和脱落的概率进行了分析，疏水性矿粒直接加入泡沫层，能稳定存在于泡沫层中，且其系统自由能在附着和脱落前后都没有发生变化，因此，气泡与矿粒在泡沫层中附着的可能性要远远大于矿粒在矿浆中附着于气泡的可能性，矿粒在泡沫层中从气泡上脱落的可能性远远小于在矿浆中矿粒从气泡上脱落的可能性。
对疏水性矿粒在水中的沉降未速公式和疏水性微细矿粒在水中的阻力进行了详细的探讨。得出了疏水性矿粒在水中的阻力为：由该式可知，微细颗粒表面与水的相互作用对其在水中的沉降阻力具有重要影响，而且颗粒越小，这种影响就越大。疏水性微细矿粒在水中的沉降未速公式为：微细矿粒在水中的自由沉降未速不仅决定于矿粒和水的性质，而且还受矿粒与水之间相互作用的影响。对疏水性粒群在水中的沉降速度也作了一定的探讨，得出了疏水性颗粒干涉沉降速度的对数与松散度的对数也基本保持直线关系，疏水性增加，粒群干涉沉降速度将加快。
昆明理工大学硕士学位论文
开展了不同粒级的单颗粒方铅矿、黄铁矿和石英粒群及钦铁矿粒群
疏水化前后在水中的沉降试验，试验结果表明，不论是方铅矿、黄铁矿，
还是石英和钦铁矿，疏水性矿物颗粒在水中的沉降速度受表面疏水性的
影响，表面疏水化后，沉降速度加快。这进一步证明了疏水性粒群的干
涉沉降速度的对数与松散度的对数基本保持直线关系，也证明了矿粒表
面疏水性增加，沉降速度加快的理论研究结果。
开展了不同粒级的方铅矿、黄铁矿和磁铁矿颗粒疏水化前后在泡沫
层中的沉降试验。掌握了不同疏水性，不同粒度颗粒在泡沫层中的运动
规律以及粒级大小对矿粒在泡沫层中的沉降速度的影响。结果表明，粒
级的大小对矿粒在泡沫层中的沉降速度的影响很大，粒级大的矿物颗粒
在泡沫层中的沉降速度比粒级小的矿物颗粒在泡沫层中的沉降速度要
快;疏水性的强弱对矿粒在泡沫层中的沉降速度也有显著的影响，疏水
性强的矿粒在泡沫层中的沉降速度比疏水性弱的矿粒在泡沫层中的沉降
速度要慢，这就成为在泡沫层中按疏水性分离矿物颗粒的基础和依靠。
进行了磁铁矿一黄铁矿人工混合矿在泡沫层中的分离试验。结果表
明，粒级大小对混合矿的分离效果有很大的影响，在适当的分离时间下，
不同粒级的混合矿均能得到良好的分离效果。而捕收剂用量是分离效果
好坏的决定性因素。对于一2.Omm+l .smm粒级的人工混合矿，在泡沫层
中分离时，获得黄铁矿回收率84.02%，黄铁矿品位70.49%的良好指标，
而对于一0.12mm+0.074mm的细粒级人工混合矿，黄铁矿品位高达
90.53%，此时的回收率也有56.1%。所以，特粗粒级的矿粒，在泡沫层
中能按疏水性有效的分离，这是常规的泡沫浮选难以做到的，而对于较
细粒级，在泡沫层中分离，也能得到跟泡沫浮选类似的结果。
Nowadays, froth flotation is a widely-used method at home and abroad in mineral processing, but this method is not effective in the separation of fine particles and large particles, which results in a lot of metal loss. In order to increase the effictiveness of fine particles and large particles flotation, people in the world have done a lot of research near 100 years. Because of the limitation in froth flotation principle, the problems are yet not completely solved. To do a clear investigation of the microscopic process of the particles interact with bubbles, is the momentous foundation of flotation equipment design and flow-sheet design.
On the basis of looking up the data about theory of bubbles interacting with mineral particles in detail, the analysis of mineral particles behaviour in bubble-bed have been made, the conclusion that the free energy varity AG of mineral particles and bubbles pre- and after touch has been drawn, according to the theory, AG is not only relative with touch angle 9, but also with the interface tension of air- liquid, i.e., the increase of hydrophobic nature, the negative AG increases, the touch procedure of mineral particles and bubbles is more easy. In this thesis the possibility of mineral particles touch and abjection with bubbles in water and bubble-bed are analyses. The hydrophobic nature particles are added in bubble-bed directly, the particles can exist in it stability, AG of the system aren't change. So, the possibility of mineral particles touch with bubbles in bubble-bed is greater than in water, and the possibility of mineral particles separate from bubbles in bubble-bed is lower than in water.
In the thesis, the settling latest-velocity and the resisting of the hydrophobic mineral particles in water have been studied, and the results are as follows:
From the formula, interaction between the surface of hydrophobic fine
particles and water leads a obvious effect to the resisting force when it settle in water, the particles is more finer, the effect is more obvious. And the settling latest-velocity formula of hydrophobic mineral particles is as follows:
The free settling latest-velocity of hydrophobic mineral, when it settles in water, is not only decided by the character of mineral and water, but also by the mutual interaction between mineral and water. The settle velocity of cluster mineral particles is studied in thesis, the results show that the logarithm of interference settle velocity keep straight line relation with the logarithm of 1-, that is, with the hydrophobic increase, the interference settle velocity of cluster mineral particle increases.
The results of the different size particles settling experiment in water pre- and after hydrophobic treatment have been described in the thesis. From the test results, no matter it is galena, pyrite, quartz or magnetite, the surface hydrophobic is also a factor of the settle velocity of the hydrophobic particles, when the mineral surface is more hydrophobic, the settle velocity is quicker in water. The results have certified that the logarithm of interference settle velocity keep straight line relation with the logarithm of 1-, as well certified the theoretical results that with the hydrophobic is increase, the interference settle velocity of cluster mineral particles increases.
The different size particle settling experiment in bubble-bed pre- and after hydrophobic treatment has been described. The kinesic regularity of particle which is different hydrophobic and different sizes, and the effect of size to the settle velocity when particle settle in bubble-bed have been gained. From the test results, the settling of large particle is quicker than the smaller, the hydrophobic also effects the settle velocity, the more hydrophobic of the mineral is, the slower the settle velocity is in the bubble-bed. This is the foundation and reference that mineral particle separate in bubble-bed according hydrophobic nature.
The separation experiment of magnetite-pyrite artificial mixed minerals in bubble-bed has been
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