Borate fusion is an extremely effective method of preparing cement, refractories, ceramics, rock, and similar materials for elemental analysis by XRF, AA, and ICP. The samples are mixed in powdered form with a flux, usually lithium tetraborate or a mixture of lithium tetraborate and lithium metaborate; this mixture is heated until the flux melts and the sample dissolves in it, yielding a homogeneous melt. The melt can be cast as a glass disc for XRF, or quickly dissolved in dilute nitric or hydrochloric acid for analysis in solution form. Recent advances in technique also allow borate fusion of troublesome samples containing sulfides, ferroalloys, etc.

One of the advantages of borate fusion is short preparation time, typically ten to fifteen minutes to make glass discs or solutions with automated fluxers. Another advantage specific to XRF is that fused glass discs are homogeneous at the atomic level, eliminating the particle size effects and mineralogical effects associated with pressedpowder discs. For samples prepared as liquids, borate fusion can be quicker overall than even microwave dissolution in pressure vessels,
and the use of hazardous acids (e.g. HF) is avoided.

SPEX SamplePrep offers two approaches to borate fusion: Katanax Automatic Electric Fluxers and platinumware for rapid, reproducible fusions, and graphite crucibles for smaller-scale operation with muffle furnaces. SPEX SamplePrep also offers the full range of our high quality fusion fluxes and additives.