起泡剂的加入使得煤泥浮选过程中产生稳定性强、黏度高、难以破灭的泡沫,大量泡沫的堆积严重制约了浮选精煤的压滤脱水效果。为探明气泡对浮选精煤的压滤压力及脱水性能的影响机理,使用新型加压脱水装置研究气泡对浮选精煤压滤压力、滤饼位移、滤液质量及滤饼水分的影响规律,并通过ImageJ图像处理、流变特性测试、FBRM试验和SEM表征等一系列方法对脱水机理进行探究。压滤结果表明,充气量为0.3m3/h时,浮选精煤压滤所需压力由451.2kg增至540.7kg,滤饼水分增加10.7个百分点。ImageJ图像处理表明小直径气泡分布占比随充气量的增大而增大,流变性测试表明随充气量增加,浮选精煤黏度增大且动切力τ0由0.9947mPa增至1.1703mPa,说明颗粒定向重排作用增强;FBRM试验表明气泡的存在使浮选精煤粒径增大,发生凝聚现象,颗粒间相互作用力增大;SEM结果表明气泡使浮选精煤颗粒聚集现象明显。气泡的存在导致浮选精煤颗粒排列更加紧密,颗粒间毛细半径减小,过滤所需压力增大,同时滤饼孔隙变小,水分迁移路径更复杂,不利于水分脱除。

The addition of frothing agent makes the coal slurry flotation process produce stable, large viscosity value and difficult to breakbubbles, and the accumulation of large amount of bubbles seriously restricts the pressurization and dewatering effect of flotationconcentrate coal. In order to investigate the influence mechanism of bubbles on the filtering pressure and dewatering performance of flotation concentrate, the influence law of bubbles on the filtering pressure, cake displacement, filtrate quality and cake moisture of flotation concentrate using a new pressurized dewatering device was investigated, the dewatering mechanism by a series of methods such as ImageJ image processing, rheological characteristics test, FBRM test and SEM characterization was explored. The results show that the pressure required to press filter the flotation concentrate increase from 451. 2 kg to 540. 7 kg at an aeration rate of 0. 3 m3 / h, and thefilter cake moisture increas by 10.7 percentage points. ImageJ image processing shows that the distribution proportion of small diameterbubbles increases with the increase of air volume, rheological test shows that with the increase of air volume, and the viscosity offlotation cleaned coal increases and the dynamic shear τ0 increases from 0.994 7 mPa to 1.170 3 mPa, indicating that the directional rearrangement of particles is enhanced. The FBRM test show that the presence of air bubbles increase the particle size of flotationconcentrate, coalescence occurred, and the interaction force between particles increase. SEM results show that air bubbles make the flotation concentrate particles agglomerate. The presence of air bubbles make the flotation concentrate particles more closely arranged, the inter-particle capillary radius decrease, the pressure required for filtration increase, and the pore space of the filter cake become smaller,the water migration path is more complicated, which is not conducive to the removal of water.

0 引言

1 煤样、药剂与仪器

   1.1 试验样品

   1.2 煤样粒度分析

   1.3 煤样XRD分析

   1.4 试验药剂与仪器

2 试验方法

   2.1 加压脱水试验

   2.2 浮选精煤泡沫分析

   2.3 浮选精煤流变性测试

   2.4 浮选精煤颗粒体系FBRM测试

   2.5 扫描电子显微镜SEM分析

3 试验结果与讨论

   3.1 加压过滤试验结果

   3.2 煤泥泡沫尺寸分析

   3.3 浮选精煤流变性测试结果

   3.4 煤泥水颗粒体系FBRM测试

   3.5 扫描电子显微镜SEM分析结果

   3.6 讨论

4 结论