Used as a flux in analytical chemistry for decomposing refractory minerals and oxides, especially in sample preparation for spectroscopic analysis. Facilitates the fusion of silicates, aluminosilicates, and other difficult-to-dissolve materials by lowering their melting points. Commonly employed in gravimetric and titrimetric methods to determine metal content in ores and ceramics. Also serves as a sulfating agent and catalyst support in certain industrial processes. Its strong oxidizing nature makes it useful in metal cleaning and surface treatment applications.