In this study, the relationship between the physicochemical properties of kaolin slurries and their particles produced by spray drying to obtain FCC matrices was discussed. Eight aqueous slurries were prepared with 40 wt.% solids using two types of kaolin (K1 and K2) and sodium silicate solution as the dispersant. Additionally, nitric acid at 5.0 wt.% was used to adjust the pH in the range between 6 and 8. Both kaolin sources were characterized by X-ray diffraction and scanning electron microscopy. The K2 kaolin had a higher crystallinity of kaolinite and smaller particle size in comparison with K1. Likewise, while K2 showed 4 well defined bands of hydroxyl groups in the infrared spectrum at 3688, 3666, 3653 and 3620 cm⁻¹, the K1 IR spectrum consisted of two sharp signals at 3692 cm⁻¹ and 3620 cm⁻¹ and two poorly developed bands at 3666 cm⁻¹ and 3653 cm⁻¹. These features intimately related to their structure were shown to have an effect on the morphology of the particles obtained during the drying process; in the case of the K1 slurries, these led to the formation of microspheres, and on the contrary, from K2 slurries mushroom head shape particles were formed. Furthermore, the average diameter (D₅₀) of the particles increased with the increase of the amount of the binder in the slurry. Thus, the results show that a less crystalline kaolin favors the formation of microspherical particles during the spray drying process that allows a better control of the FCC matrix produced to be used in in-situ zeolite Y crystallization on kaolin particles.

在本研究中，讨论了高岭土浆料的理化性质与其通过喷雾干燥获得 FCC 基质产生的颗粒之间的关系。使用两种类型的高岭土（K1 和 K2）和硅酸钠溶液作为分散剂，制备了 8 种固体含量为 40%（重量）的水性浆液。此外，使用 5.0 wt.% 的硝酸将 pH 值调节在 6 到 8 之间的范围内。两种高岭土来源均通过 X 射线衍射和扫描电子显微镜进行表征。与K1相比，K2高岭土具有更高的高岭石结晶度和更小的粒度。同样，虽然 K2 在 3688、3666、3653 和 3620 cm ^-1的红外光谱中显示出 4 个明确定义的羟基带，但 K1 红外光谱由 3692 cm ^-1处的两个尖锐信号组成 和 3620 cm ^-1以及在 3666 cm ^-1和 3653 cm ^-1处的两条发育不良的带。这些与其结构密切相关的特征被证明对干燥过程中获得的颗粒的形态有影响；在 K1 浆料的情况下，这些导致了微球的形成，相反，K2 浆料形成了蘑菇头形状的颗粒。此外，平均直径 (D ₅₀)的颗粒随着浆料中粘合剂量的增加而增加。因此，结果表明结晶度较低的高岭土有利于在喷雾干燥过程中形成微球颗粒，这允许更好地控制所产生的用于高岭土颗粒上原位沸石 Y 结晶的 FCC 基质。