煅烧煤系高岭土吸油性能与颗粒形貌关系研究

以山西朔州煤系高岭土为原料,利用三水氟化铝(AlF₃·3H₂O)添加剂能够促进莫来石晶须生长的特性,结合超声破碎处理制备高吸油值煅烧煤系高岭土,随后分析了颗粒形貌对粉体吸油值的影响。通过扫描电子显微镜、X射线衍射仪和比表面积分析仪等表征手段分析了AlF₃·3H₂O提高煅烧煤系高岭土吸油值的作用机理。结果表明:AlF₃·3H₂O的添加能够使煅烧煤系高岭土的颗粒表面产生大量莫来石晶须,颗粒表面产生的亚微米级莫来石晶须可显著提高样品的吸油值;此外对样品进行超声处理可以进一步提高其吸油值,当超声处理时间为45 min时,其吸油值可达到86.14 g/100 g;颗粒的圆形度对粉体的吸油值影响较大,高吸油值煅烧煤系高岭土的圆形度整体比普通煅烧煤系高岭土的圆形度低,且圆形度分布更集中。

Relationship Between Oil Absorption Properties and Particle Morphology of Calcined Coal Series Kaolin

In this study, calcined coal series kaolin with high oil absorption value was prepared from coal series kaolin (Shuozhou, Shanxi province) by using aluminum fluoride trihydrate (AlF₃·3H₂O) additive which promotes the growth of mullite whiskers and subsequent ultrasonic crushing treatment. The effect of particle morphology on the oil absorption value of the powder was subsequently analyzed. The mechanism of AlF₃·3H₂O increasing the oil absorption value of calcined coal series kaolin was analyzed by scanning electron microscopy, X-ray diffraction and specific surface area analyser. The results show that the addition of AlF₃·3H₂O produces a large amount of mullite whiskers on the particle surface of the calcined coal series kaolin, and the submicron mullite whiskers on the particle surface significantly increase the oil absorption value of the samples. In addition, ultrasonic treatment of the samples can further increase their oil absorption values. When the ultrasonic treatment time is 45 min, the oil absorption value reaches 86.14 g/100 g. The circularity of the particles has a great influence on the oil absorption values of the powders. The circularity of the calcined coal series kaolin with high oil absorption values is generally lower than that of the ordinary calcined coal series kaolin, and the distribution of circularity is more concentrated.