ASTM D4503

Dissolution of Solid Waste by Lithium Metaborate Fusion

Applicability: Applies to solid wastes, including industrial sludges, mineral-matrix residues, and acid-resistant silicate-bearing samples requiring complete dissolution prior to multielement inorganic analysis. Validated for bauxite ore and neutralized metal treatment sludge; may be applicable to other matrices with analyst verification. Not suitable for samples where volatile metals such as cadmium or zinc may be lost during the 550°C ashing step, nor for matrices incompatible with fusion at 1000°C. Restricted to nonvolatile inorganic constituents and intended as a preparatory dissolution step for subsequent ICP-AES or AAS quantitation.

Purpose: Provides a standardized procedure for drying, ashing at 550°C, and fusing solid waste with lithium metaborate (LiBO₂) at 1000°C to completely solubilize silicate and acid-resistant matrices. The molten fusion bead is poured into stirred dilute nitric acid, filtered, and diluted to volume for analysis of aluminum, barium, calcium, chromium, copper, iron, magnesium, manganese, nickel, silicon, titanium, vanadium, and zinc by ICP-AES or atomic absorption spectroscopy. Results support regulatory characterization of wastes, selection of appropriate disposal methods, and compliance with environmental reporting requirements.