Used in water treatment to remove phosphate from wastewater, helping prevent eutrophication in natural water bodies. Effective in flue gas purification by capturing sulfur dioxide and hydrogen sulfide due to its alkaline nature. Employed in the production of specialty glasses and optical materials for its high refractive index and thermal stability. Serves as a precursor in synthesizing other lanthanum-based compounds used in catalysts and electronic ceramics. Also investigated for use in medical applications, such as phosphate binders in dialysis treatments for kidney disease patients.