环形充气浮选机的研制

【作者】 杨琳琳；

【导师】 文书明；

【作者基本信息】 昆明理工大学 ， 矿物加工工程， 2008， 博士

【摘要】 矿物加工工业目前面临着资源、环境、经济等方面的挑战,其严峻形势越来越受到关注。数十年的理论研究和工业生产实践表明,浮选柱是行之有效的物料分选设备,具有结构简单、高效节能、对微细粒浮选优势明显等特点。在提高矿物加工的分选效率和资源综合利用率,降低分选成本的可行途径等方面,浮选柱有着良好的发展前景。本文总结了浮选柱研究和应用的历史和现状,讨论了浮选柱的发展趋势。对气泡与颗粒作用的理论及柱浮选方程进行研究发现,增加浮选柱的效率主要从以下几方面来考虑:增加颗粒与气泡的碰撞几率,尽量减小气泡尺寸,增加气泡数量,增加气泡表面积通量,提高浮选柱对粒度的适应性,进而提高回收率。同时,粗粒浮选时应缩短浮升距离,减小浮升过程中的扰动,减小脱附几率;细粒浮选则应增加脱附几率,提高选择性。传统的浮选柱要提高回收率则必须增加柱高,增加柱高则气泡尺寸增大,所以不能同时满足这两方面的要求。而且,由于粗粒易脱落,而微细颗粒则不易脱落,导致以往浮选柱的选择性差,应用的粒度范围小。因此,设计制造一种可以解决回收率与气泡直径的矛盾,同时又可以扩大粒度适应范围的浮选机是非常必要的。基于以上条件和要求,设计了环形充气浮选机。环形充气浮选机由分选柱、压入空气型气泡发生器、环形泡沫刮板机构、中矿提升管组成,多棵分选柱组合成圆环形,采用压入空气产生气泡。矿浆给入一棵分选柱的给矿口中,矿粒向下沉降,气泡向上浮升,具有疏水性的矿粒被浮选成为粗精矿,并进入精选分选柱中进行多次精选获得最终精矿。亲水性的矿粒随矿浆向下流动,通过中矿提升管,进入扫选分选柱中进行多次扫选得最终尾矿。本试验制造了实验室型环形充气浮选机,单柱采用有机玻璃管制成,采用空气压缩机供给气体,通过变频器控制刮板转速。论文对设备的浮选效率进行了理论研究,对矿粒在设备内的运动轨迹及矿粒在中矿提升管内的受力进行了分析,对设备的气泡特性及充气性能进行了研究,进行了矿物分选试验并与机械搅拌式浮选机的结果进行了对比。1.以往浮选柱过高带来很多问题,包括操作及维修不方便,加入矿浆时消耗太多的能量,气泡在底端生成需要较大的压力及气泡发生器更换不方便等。而本设备的实际高度远远低于以往浮选柱的高度,完全可以避免这些问题。2.通过理论研究得出,回收率随浮选柱的高度增加而增加,而气泡直径也随柱高增加而增大,所以传统浮选柱无法解决这种矛盾。而本设备在降低实际高度的同时增大了实际分选空间,所以在减小气泡的同时提高了回收率。以往的浮选柱对于处理粗粒及微细矿粒效果都不好,原因是粗粒易脱落,微细颗粒不易脱落。本设备的结构提高了粗粒与气泡的碰撞几率,微细颗粒则由于多次冲洗水的作用,提高了选择性。3.本文对所设计的浮选机的效率进行了理论研究,分选柱较低的高度避免了气泡的大量兼并,保持了微小气泡的数量,提高了微细粒矿粒的分选效率;捕集区较大的高度确保了较高的矿物回收率;多分选柱组合的方式在降低浮选柱高度的情况下,实现了低柱高回收率的目标。4.本文对矿粒在设备内和单个分选柱内的运动轨迹进行了分析,并对矿粒在中矿提升管内的受力进行了分析,并得出了计算公式。5.本文对设备气泡发生器产生的气泡直径进行了观测及计算。首先,采用摄像法观测气泡速度,计算气泡直径;其次,采用微孔成泡的理论公式进行估算气泡直径,估算结果与观察结果相吻合。6.表观充气速率、活化剂浓度、充气压力等对气泡发生器产生的气泡直径有很大影响,本文研究了在本设备的单棵分选柱中它们与气泡直径之间的关系。结果表明,气泡直径随着表观充气速率的增大而增大,随着起泡剂的浓度的增大而减小,随着充气压力的增大而减小,但在超过一定程度时不再明显。7.本文对设备的单个分选柱中的表观充气速率与充气率及气泡表面积通量的关系进行了研究,并在清水状态下,找到其最佳值。经过研究,得出了适合本设备的有关气泡表面积通量和充气率的关系式。8.对浮选机进行了浮选硫铁矿的参数试验,包括气泡发生器的表观充气速率、中矿提升管的充气压强、磨矿细度、矿浆浓度、矿浆流量、刮板速度等。同时,本文还做了每个分选柱的选别作用分析。分析认为设备的每个分选柱都具有富集精矿和回收尾矿的作用,符合设计的要求。9.论文对本设备和机械搅拌式浮选机浮选硫铁矿进行了比较。结果显示,本设备的浮选效果要远远高于机械搅拌式浮选机的浮选效果。在浮选低品位的硫铁矿时,环形充气浮选机一次粗选一次精选的效果比机械搅拌式浮选机三次粗选三次精选的S精矿品位要高了0.18个百分点,达到了52.06%;回收率提高了0.1个百分点,达到了99.15%;而尾矿品位则下降了0.05个百分点,为0.21%。更多还原

【Abstract】 Mineral industry is currently facing challenges associated with resources, economy, environment and other aspects, so increasingly importance has been attached to its grim situation. Several decades of theoretical study and industrial production practice show that flotation column is a very effective separation materials equipment, it has characteristics of simple structure, high efficiency, energy saving and obvious advantages of micro-fine flotation. In the ways of increase mineral separation efficiency and comprehensive utilization of recourses, reduce the cost of sorting, flotation column has good prospects for development.This paper summarized the history and current situation of flotation column research and application, discussed the development trend of flotation column. In the study of role of bubble and particle theory and flotation equation, found that to increase the efficiency of flotation column mainly contents as follows: increase collision probability of particle and bubble, minimize bubble size, increase bubble number, high bubble surface area flux, improve adaptability of granularity, thus increase recovery. On the other hands, coarse flotation should shortened distance, reduce disturbance in the floating and risk of desorption. Fine flotation should increase desorption probability and increase selectivity. Conventional flotation column to increase recovery must increase height, the height increase so the bubble size increased, can not satisfy these two requirements simultaneous. And, coarse off easy but fine not easy shedding, conduce the poor selectivity of flotation column at past, and the small particle size application. Therefore, design and produce a flotation machine to solve the bubble diameter and recovery, and expend the scope of particle size is very necessary.Based on the above conditions and requirements, designed ring-like inflatable flotation machine. This machine was made of separate columns, independent bubble generators of air pressure, ring scraper agencies and tailings lifting tube. Several separate columns arranged as a circular ring, and used pressurized air made bubble. Pulp feed into one column, mine tablets down and air bubble rise, hydrophobic ore became thick ore concentrates after flotation process, and into concentrate separate column made many times generation got finally concentrate. Affinity ore along with the pulp, through the tailings lifting tube entered sweeps elects to separate in the column to carry on sweeps many times and got finally tailings. This experiment made the laboratory ring-like inflatable flotation machine. The single column made of Perspex, used air compressor gas, through frequency changer control scraper rotational speed.This paper researched the flotation efficiency of this machine on the theoretical,analyzed the movement trajectory of particles and the force in tailings upgrade tube, researched the bubble speciality and the charge capability, made the mineral processing test and compared to the mechanical agitation-type flotation machine.1.The height of flotation column was high brought many issues, including inconvenient operation and maintenance, consumed too much energy to feed the mineral, needed more pressure of bubble generation in the bottom and replace the bubble generator inconvenient. The height of this machine was far lower than flotation column in the past, so the problems can be avoided completely.2. The theoretical studies showed that, the bubble size inversely to the height of flotation column, but the recovery proportional to the height, conventional flotation column can not solve this contradiction. This machine reduced the actual height and increased the separate room, so the machine reduced the bubble size and enhanced the recovery.The effect of previous flotation column was not good to deal with the coarse and fine particles, because of coarse off easy but fine not easy shedding. The structure of this machine enhanced the risk of collision of coarse with the bubble, and the fine particles increased selectivity because of washed many times.3. This paper researched the efficiency of flotation machine on the theoretical, the lower height avoid a large number of mergers of bubbles, maintained the quantity of small bubbles and improved the micro-fine ore particle separation efficiency. The higher trapping interval ensure that the higher mineral recovery. Multi-column sorting portfolio approach reduced flotation column height and improved the recovery.4. This paper analyzed the movement traiectory of particles in the machine and the single tube, analyzed the force in tailings upgrade tube and get the formulation.5. In this paper, the bubble diameter was made by bubble generator was measured and calculated. Firstly, observed the bubble speed used camera and calculated bubble diameter. Secondly, used the theoretical formulation of microcellular foam estimated the bubble diameter, the results is inosculated to the results of observed.6. Apparent inflatable rate, activator concentration and inflatable pressure have significant impacts to the bubble size, the connection of them in the single column of thie machine was studied in this paper. The bubble diameter increased with the apparent inflatable rate increased, induced with activator concentration increased, and induced with the inflatable pressure increased, but in more than a certain extent, the effect are no longer significant.7. In this paper, the relationships of apparent inflation rate and inflation rate and bubble surface area flux of ring-like flatable flotation machine was studied. And in the state of clean water, found the best value. And this paper studied and got the relatation of bubble surface area flux and inflation rate.8. Made the test parameters of pyrite used the flotation machine, including apparent inflation rate of bubble generator, the inflatable pressure of tailings ascend tube, grinding fineness, pulp concentration, pulp flow and scraper speed. And this paper analyzed the concentrate and tailings of each tube. The results showed that each tube has enriched concentrate and tailings recovery, accord with the design requirements.9. This paper compared the flotation to mechanical agitation-type flotation machine in flotation pyrite. The results showed that, the effect of this flotation machine is better than the effect of mechanical agitation-type flotation machine. In the low-grade pyrite flotation, the flow of ring-like inflatable flotation machine is one rough election and one choiceness and flow of the mechanical agitation-type flotation machine is three rough election and three choiceness. The concentrate grade of this machine is higher 0.18% and attained 52.06%, the recovery of this machine is higher 0.1% and attained 99.15% and the tailings grade is lower 0.05% attained 0.21%.更多还原