ABSTRACT

In this study, the effect of ultrasonic pretreatment on hydrophobic flocculation of fine coal was investigated and named as ultrasonic hydrophobic flocculation (USHF) technique. First, it was found that the ultrasonic power of 150 W and the ultrasonic pretreatment time of 180 sec was required to achieve for more combustible and good-quality coal. Then, the effects of ultrasound on the hydrophobic flocculation of coal with kerosene as bridging liquid were investigated and optimum kerosene concentration value was obtained 4 g/dm³ under the experimental conditions. Also, it was found that a stirring speed of 750 rpm was sufficient to achieve the maximum combustible recovery and minimum ash content values of fine coal particles. The effects of sodium silicate, sodium hexametaphosphate, and sodium pyrophosphate used as inorganic dispersants on the ultrasonic hydrophobic flocculation of coal were also studied. Sodium silicate was more effective than other dispersants in the presence of kerosene. Thus, it was concluded that the ultrasonic pretreatment is an effective method for the beneficiation of fine particle coal. Coal with an ash content of 17.63% was enriched and clean coal was recovered with an ash content of 9.75% with the efficiency of 94.35% by ultrasonic hydrophobic flocculation technique.

摘要

在本研究中，研究了超声预处理对粉煤疏水絮凝的影响，并将其命名为超声疏水絮凝（USHF）技术。首先，发现需要 150 W 的超声功率和 180 秒的超声预处理时间才能获得更多的可燃性和优质煤。然后，研究了超声对煤油作为架桥液疏水絮凝的影响，得到最佳煤油浓度值4 g/dm ³在实验条件下。此外，还发现 750 rpm 的搅拌速度足以实现细煤颗粒的最大可燃回收率和最小灰分含量值。还研究了硅酸钠、六偏磷酸钠和焦磷酸钠用作无机分散剂对煤的超声疏水絮凝的影响。在煤油存在下，硅酸钠比其他分散剂更有效。因此，可以得出结论，超声波预处理是细粒煤选矿的有效方法。采用超声疏水絮凝技术对灰分17.63%的煤进行富集，回收灰分9.75%的精煤，回收率为94.35%。