Experimental Investigation of Kaolinite–Zeolite Transformation: Insights from Al-Habala Area Saprolite, Abha, Saudi Arabia

This study investigates the synthesis of zeolite from kaolinite-rich saprolite from Al-Habala Area, Saudi Arabia, providing insights on kaolinite as an economically viable precursor for zeolite formation. This study was conducted using hydrothermal rectors with a 0.5 M Na₂CO₃ solution at temperatures of 150 °C, 200 °C, and 250 °C over a duration of 336 h. At 150 °C, the dissolution of the clay and feldspar grains began, forming amorphous silica, from which mordenite rods formed. Increased temperatures promoted the formation of cubic analcime crystals at 200 °C to well-developed trapezohedron aggregates at 250 °C. The mineralogical transformations were characterized using SEM, XRD, and ICP-OES analyses, revealing the role of temperature on the morphologies, compositional alteration, and decreasing Na concentrations correlating with the formation of analcime. The newly formed analcime closely matched the composition of natural analcime from different basins. The results confirm that saprolite can effectively serve as a medium for zeolite synthesis, highlighting its potential for cost-effective industrial applications and expanding the understanding of kaolinite-to-zeolite conversion pathways.