柱浮选精煤细泥污染形成机理及抑制研究

发布时间：2018-01-23 18:00

  本文关键词： 柱浮选 煤粒 细泥 污染机理 抑制　出处：《中国矿业大学》2016年博士论文　论文类型：学位论文

【摘要】：高灰细泥污染导致浮精灰分超标是煤泥浮选亟待解决的难题。本论文针对柱浮选过程中细泥污染问题,分析了工业浮选柱精煤中污染矿物特性,探究了细泥对疏水煤粒浮选行为的影响及细泥回收规律,研究了浮选柱内煤粒与细泥的分布规律和细泥污染精煤的机理,提出了减少细泥污染的措施。主要研究成果如下:阐明了工业浮选柱精煤中污染矿物的粒度特性、矿物组成。浮精中+0.045 mm粒级灰分一般达标,但-0.045 mm粒级灰分远不达标;浮精中细泥含量一般小于5%,却是导致浮精灰分超标的主要原因;细泥颗粒的平均粒径为10-20μm,其中-20μm粒级含量大于60%,且粒度越小越易污染精煤;细泥的矿物组成主要为亲水的粘土类矿物和石英矿物。研究了细泥对低灰煤粒浮选行为的影响及细泥的回收规律。细泥与不同粒级低灰煤粒混合浮选与低灰煤粒单独浮选相比,细泥质量比例小时能提高低灰煤粒的回收率,反之降低其回收率,且低灰煤粒的粒度越大,回收率降低越明显;细泥质量比例小时可提高0.5-0.25 mm粒级低灰煤粒的浮选速率常数,反之降低其浮选速率常数;不同质量比例下,细泥主要提高0.25-0.125 mm粒级低灰煤粒的浮选速率常数,但降低0.125-0.074mm粒级低灰煤粒的浮选速率常数。然而,同一粒级低灰煤粒的浮选速率常数均随细泥质量比例增大而减小,表明细泥质量比例增大将减小低灰煤粒的浮选速度。低灰煤粒的浮选速度符合一级矩阵分布模型,细泥颗粒的浮选速度符合二级矩阵分布模型。细泥颗粒与低灰煤粒混合浮选时,细泥颗粒的主要回收方式为水流夹带,细泥的回收率随细泥质量比例增大而增大。揭示了浮选柱内煤粒与细泥颗粒的分布规律。采用自制浮选柱研究了批处理与连续分选工况下低灰煤粒与细泥颗粒的轴向分布规律。批处理工况下,从泡沫区顶部至底部,低灰煤粒的浓度差异小,分布较均匀;细泥颗粒的浓度明显呈增大趋势。从矿浆区顶部至底部,低灰煤粒的浓度先增大后减小,但矿浆区底部浓度最大;细泥颗粒的浓度呈增大趋势。连续分选工况下,从泡沫区顶部至底部,低灰煤粒的浓度差异小,分布较均匀;细泥颗粒的浓度明显呈增大趋势。从矿浆区顶部至底部,低灰煤粒的浓度先增大后减小,细泥颗粒的浓度逐渐增大。对比批处理与连续分选工况下颗粒的分布规律,泡沫区内的低灰煤粒、细泥颗粒分布规律相同;矿浆区内低灰煤粒分布规律不同,但细泥颗粒分布规律相同。通过采集工业旋流微泡浮选柱轴向、径向不同点的物料,探究了样品灰分、细泥颗粒的分布规律。轴向上,从泡沫区到捕集区再到旋流矿化区,细泥颗粒的含量整体呈增大趋势,不同分选区域内细泥颗粒的含量差异明显,但捕集区内细泥颗粒的含量变化规律不明显;径向上,从中心至周边,泡沫区内细泥颗粒的含量明显呈减小趋势,捕集区内细泥颗粒的含量变化规律不明显,旋流矿化区内细泥颗粒的含量明显呈增大趋势。工业浮选柱内各点样品灰分分布规律与细泥含量分布规律具有相关性。工业浮选柱轴向细泥颗粒的分布规律与实验室浮选柱内细泥颗粒的分布规律一致。阐释了细泥污染精煤的机理。采用高速动态摄影仪、实时在线颗粒录影显微技术(PVM)、诱导时间测定仪证实了细泥的气泡尾涡夹带回收机制、气泡边界层粘附回收机制以及细泥罩盖回收机制,并提出了多气泡液流携带回收机制。气泡尾涡夹带回收机制不具有选择性,微细煤粒与矿物颗粒均可通过该机制回收;颗粒粒度越小,气泡尾涡夹带现象越明显。微细矿物颗粒与气泡的粘附时间与相同粒级疏水煤粒与气泡的粘附时间差异不大,表明微细矿物颗粒确实可以粘附在气泡表面而跟随气泡运动。然而,粒度大于0.125 mm的矿物颗粒与气泡的粘附时间大于5000 ms,表明粒度较粗的矿物颗粒不与气泡粘附。微细矿物颗粒粘附气泡的本质是进入气泡表面液膜而跟随气泡运动的行为,与疏水煤粒穿破气泡表面液膜真正粘附气泡的行为具有本质区别。在多气泡连续上浮体系中,细泥颗粒还可通过多个气泡的协同携带方式回收,定义为多气泡液流携带回收机制,其本质是水流夹带机制的一种具体形式。细泥颗粒可在块精煤表面形成罩盖现象,且高岭石颗粒最易形成罩盖,方解石颗粒在粗糙的块精煤表面也存在罩盖现象,而石英颗粒则很难罩盖在块精煤表面。提出了泡沫区内置倾斜板、多点组合充气、矿浆稀释和添加泡沫喷淋水4种减少柱浮选过程中细泥污染的措施。试验结果表明,上述4种措施均可有效降低浮精灰分,改善煤泥的浮选效果。
[Abstract]:High ash slime flotation concentrate ash pollution leads to exceed the standard problem of coal slime flotation to be solved. This thesis focuses on the problem of pollution of fine mud flotation process, analyzed the pollution characteristics of industrial minerals in coal flotation column, explores the effects of fine mud flotation behavior of hydrophobic coal particles and slime recovery law, study the mechanism of flotation column in the coal slime and the distribution and pollution of coal slime, proposed to reduce the fine mud pollution measures. The main results are as follows: to clarify the characteristics of grain size, mineral flotation column in coal industrial pollution. The mineral composition of +0.045 mm grade float ash general standard, but the -0.045 mm particles of ash far standard; float in fine silt content is generally less than 5%, is the main cause of float ash exceed the standard; the average particle size of 10-20 fine particles M, which -20 m particle content is more than 60%, and the smaller the particle size of the coal slime pollution; The main mineral composition of hydrophilic clay minerals and quartz minerals. The recovery law effects of fine mud on low ash coal particle flotation behavior and slime. Fine mud with different particle level low ash coal particle mixed flotation compared with low ash coal slime flotation particles alone, the proportion of hours can improve the recovery quality low ash coal particles rate, and reduce the recovery rate, particle size and particle low ash coal is bigger, the recovery rate decreased more obviously; the proportion of fine quality hours can improve the flotation rate constant 0.5-0.25 mm grade low ash coal particles, and reduce the flotation rate constant; different quality ratio, improve fine mud flotation rate constant 0.25-0.125 mm particle low ash coal particle level, but reduce the flotation rate constant of 0.125-0.074mm grade low ash coal particles. However, the flotation rate constant with the same grain size increased with the proportion of low ash coal particle slime quality increases, that the proportion of fine quality Increase will reduce the flotation rate low ash coal particles. The flotation rate low ash coal particle accords with the first-order matrix distribution model, the flotation rate fine mud particles with two stage matrix distribution model. Fine clay particles and low ash coal particle mixed flotation, the main way for the recovery of fine mud particles entrained flow, the recovery rate with fine mud the proportion of fine quality increases. The distribution of coal particles and fine particles flotation column. Using the self-made flotation column of batch and continuous separation under the condition of low ash coal slime particles and particle axial distribution. Batch processing conditions, from top to bottom foam area, low concentration difference ash particle is small, uniform distribution; concentration of fine mud particles significantly increased. From the top to the bottom area of pulp, low ash coal particle concentration increased firstly and then decreased, but the concentration of the maximum concentration area at the bottom of the pulp; fine mud particles increased. Continuous separation conditions, from the top to the bottom of the bubble zone, the concentration difference of low ash coal particle size, uniform distribution; concentration of slime particles obviously increased. From the top to the bottom area of pulp, low ash coal particle concentration increases and then decreases the concentration of fine mud particles increases gradually. Compared the distribution of particle number treatment with continuous separation conditions, the foam within the area of low ash coal slime particle, particle size distribution of the same area of low ash coal slurry; particle distribution is different, but the fine particle size distribution of the same industry. Through the acquisition of axial swirl micro bubble flotation column, the material of different points on the radial distribution of the ash samples. Fine clay particles. The axial direction from the bubble zone to the trapping zone to the cyclone mineralized area, content of fine mud particles showed an increasing trend, the difference of content of fine particles of different separation region is obvious, but the trapping zone containing fine mud particles The amount of variation is not obvious; the radial direction, from the center to the periphery, the content of fine particle bubble area was decreased, the changing rule of the contents in the trapping area of fine mud particles is not obvious, the content of fine particles in cyclone mineralization area was significantly increased. The industrial flotation column of each point in the distribution of ash samples law and fine silt content distribution is consistent correlation. Distribution of industrial flotation column axial fine mud particle distribution and laboratory flotation column in fine clay particles. The mechanism explains the slime coal pollution. Using high-speed dynamic camera, real-time video microscopy on line particle (PVM), confirmed the fine measuring instrument mud bubble wake entrainment recovery mechanism of induction time, recovery mechanism of bubble boundary layer and adhesion of fine mud cover recovery mechanism, and puts forward the multi bubble flow carrying recovery mechanism. Bubble wake entrainment mechanism has not recovered Selective, coal particle and mineral fine particles can be recovered through the mechanism; particle size is smaller, the bubble wake entrainment phenomenon is more obvious. The adhesion time of fine mineral particles and bubbles with the same size and hydrophobic coal particles bubble adhesion time difference, that fine mineral particles can adhere to the surface of the trailing bubble bubble sports. However, the adhesion time of mineral particles and bubble size is greater than 0.125 mm greater than 5000 ms, indicating that the mineral particle size of coarse and fine mineral particles. The essence of bubbleattachment adhesion bubble is into the bubble liquid film on the surface and follow the bubble movement behavior, has the essential difference with the hydrophobic coal particles through the bubble liquid film on the surface of real adhesion the behavior of bubbles. The bubbles floating in the continuous system, fine clay particles may also be carried through collaborative way to recycle multiple bubbles, as many articles back to the definition of bubble flow This mechanism, its essence is a specific form of water entrainment mechanism. Fine clay particles can be formed in blocks of coal surface cover, and kaolinite particles formed most easily cover, calcite grains also exist in the block coal surface roughness, and quartz particles are difficult to cover on the surface. The inclined coal block foam district built board, multi-point combination inflatable, slurry adding foam spray water dilution and fine mud pollution 4 reduction measures in the process of flotation column. The experimental results show that the above 4 measures can effectively reduce float ash, improve the effect of slime floatation.

【学位授予单位】：中国矿业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TD94;TD923
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本文编号：1457892