Ionic clays typically contain about 0.05–0.5 wt% of rare earth oxides (REO). In these clays, rare earth elements (REEs) are adsorbed onto the surfaces of aluminosilicate minerals such as kaolinite, illite, and smectite. The formation of ionic clay deposits is largely attributed to the in situ weathering of REE-containing rocks, like granitic or igneous rocks. This weathering process leads to the formation of aluminosilicate clays that capture solubilized REE ions. The primary method for extracting REEs from these ionic clays is through leaching with inorganic salt solutions that contain mono- or divalent cations. This leaching technique facilitates the desorption of physisorbed REEs, allowing these elements to be replaced by the cations in the leaching solution, and results in the REEs becoming soluble in the form of sulfates or chlorides. Some earlier studies have also employed pH adjustments to enhance REE extraction’s efficiency. In this specific study, a 20 g/L (NH4)2SO4 solution at a 1/3 g/mL solid to liquid ratio and a temperature of 25 °C is used to desorb REEs from an ionic clay sample. This study investigates the impact of varying agitation rates (from 150 to 700 rpm), pH levels (3–1), and particle size reduction (achieved through puck milling) on the extraction of REEs. The findings reveal that increasing the agitation to 350 rpm enhances REE extraction, while a decrease in pH marginally improves extraction efficiency. Additionally, reducing the particle size positively influences REE extraction, but it also raises the extraction of impurities like aluminum and thorium.