振动重介质流化床流化特性及分选细粒高岭土的试验研究

发布时间：2018-07-17 20:31

【摘要】：煤系高岭土作为世界上特有的矿产资源,近年来,对硬质煤系高岭土的深入提纯开发利用逐渐成为各国学者的研究重点。煤系高岭土经过提纯、锻烧、超细粉碎等深加工可生产物理和化学性能稳定的高档次填料和颜料级产品,广泛应用于造纸、化工、电器、塑料、橡胶复合材料等工业领域。本文利用振动重介质流化床对河北灵寿6-3mm和3-1mm粒度级煤系高岭土进行干法分选脱炭研究,以0.074-0.4mm粒级硅铁粉作为加重质,实现细粒煤系高岭土的气固流态化分选。原矿的密度主要分布在1.9-2.7g/cm3,6-3mm和3-1mm原矿的烧失量分别为23.18%和24.98%。从原矿的XRF数据可以看出,主要组成元素为Si和Al,其中杂质元素Fe的含量较高,Ti的元素含量较少。对普通重介质流化床与振动重介质流化床的床层流化特性进行了研究,可以得出,振动能量可以显著降低流化床的床层压降ΔP、最小流化气速Umf和床层膨胀率ε。随着振动频率的增大,床层压降和床层流化密度先减小后增大;随着振幅的增大,床层压降和床层流化密度一直减小,不同静床高之间的流化床密度差随着静床高(Hs)的增大而减小。振动能量的引入活化了床层中颗粒的随机运动,增强了气相和固相之间的摩擦作用,有效抑制了床层中气泡的生成和长大,床层中颗粒的附壁现象减少,流化床三维空间中的床层压降分布均匀,形成了均匀稳定的分选环境。分别对6-3mm和3-1mm粒度级煤系高岭土进行分选试验,研究入料重量、振动频率(f)、振幅(A)和流化数(N)等操作因素对分选效果的影响规律,确定各单因素适用于分选的最佳取值范围。采用中心复合设计响应曲面法,以精矿烧失量、烧失比和总烧余量来评价6-3mm和3-1mm煤系高岭土的正交分选效果,研究了操作因素之间的交互作用。最终,确定两种粒级最适用的评价指标分别为精矿总烧余量和精矿烧失量,同时建立了评价指标对应的二次多项式预测模型。分选试验表明:对于6-3mm粒度级煤系高岭土,当Hs=100mm、f=15Hz、A=2.0mm和N=1.7时,精矿和尾矿的产率分别为23.42%和23.39%,烧失量分别为21.91%和28.93%,精尾矿的烧失量差值ΔX为7.02%,精矿回收率达到23.69%。精矿的产率较高,烧失量较小,总烧余量高达42.76%,取得较理想分选效果。对于3-1mm粒度级煤系高岭土,当Hs=100mm、f=15Hz、A=2.0mm和N=1.7时,精矿和尾矿的产率分别为10.73%和25.92%,烧失量分别为18.72%和30.52%,精矿回收率为11.65%,精尾矿的烧失量差值为11.80%。精矿的产率较高,烧失量较小,取得较理想分选效果。
[Abstract]:As a unique mineral resource in the world, the deep purification and utilization of hard coal kaolin has gradually become the research focus of scholars all over the world in recent years. Through deep processing, such as purification, calcination, ultrafine grinding and so on, coal measures kaolin can produce high grade packing and pigment grade products with stable physical and chemical properties. They are widely used in papermaking, chemical industry, electrical appliances, plastics, rubber composite materials and other industrial fields. In this paper, the dry separation and decarbonization of coal series kaolin with 6-3mm and 3-1mm granularity in Hebei Province were studied by vibratory heavy medium fluidized bed. The fine coal measure kaolin was separated by gas-solid fluidization with 0.074-0.4mm grained iron silicate powder as the weighting material. The densities of raw ore are mainly distributed in 1.9-2.7g / cm ~ (-3) mm and 3-1mm ore's burning loss is 23.18% and 24.98% respectively. It can be seen from the XRF data of the ore that the main elements are Si and Al, among which the content of impurity Fe is higher than that of Ti. The fluidization characteristics of fluidized bed in ordinary and vibrational heavy medium fluidized beds are studied. It can be concluded that the vibrational energy can significantly reduce the bed pressure drop 螖 P, the minimum fluidized gas velocity UMF and the bed expansion rate 蔚 of the fluidized bed. With the increase of vibration frequency, the pressure drop and fluidization density of the bed first decrease and then increase, and the pressure drop and the fluidization density of the bed decrease with the increase of the amplitude. The difference of fluidized bed density between different static bed heights decreases with the increase of static bed height (HS). The introduction of vibration energy activates the random movement of the particles in the bed, enhances the friction between the gas phase and the solid phase, effectively inhibits the formation and growth of bubbles in the bed, and reduces the phenomenon of the particles attached to the wall in the bed. The bed pressure drop in three dimensional fluidized bed is uniformly distributed, and a uniform and stable separation environment is formed. The separation experiments of coal series kaolin with 6-3mm and 3-1mm granularity were carried out to study the influence of loading weight, vibration frequency, (f), amplitude (A) and fluidization number (N) on the separation effect, and to determine the optimum value range of each single factor for separation. The central composite design response surface method was used to evaluate the orthogonal separation effect of 6-3mm and 3-1mm coal measures kaolin by using the concentration loss ratio and total burning allowance. The interaction between operational factors was studied. Finally, the two most suitable evaluation indexes of grain level were determined as the total combustion allowance of concentrate and the loss of concentrate, respectively, and the quadratic polynomial prediction model corresponding to the evaluation index was established at the same time. The separation test shows that for 6-3mm granularity grade coal series kaolin, the yield of concentrate and tailings are 23.42% and 23.3995%, respectively, the difference of burning loss 螖 X is 7.02, and the recovery ratio of concentrate is 23.699.The recovery of concentrate and tailings is 23.6995% and 7.02respectively, and the recovery ratio of concentrate is 23.699.When the coal measure kaolin is of 6-3mm granularity grade, the yield of concentrate is 23.42% and that of tailings is 23.69% and 28.93% respectively, the difference of burning loss of fine tailings is 7.02, and the recovery of concentrate is 23.69%. The concentrate yield is higher, the burning loss is small, and the total burning allowance is as high as 42.76. The ideal separation effect is obtained. For 3-1mm granularity coal series kaolin, the yields of concentrate and tailings are 10.73% and 25.92 respectively, the recovery rate of concentrate is 11.65%, and the difference of burning loss of refined tailings is 11.80%. The concentrate yield is high and the burning loss is small, and the ideal separation effect is obtained.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD97;TD455.7

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