To carry out the fusion a glass former is required. Based on the relatively low melting point and low viscosity, borates are used.
Available flux at FLUXANA®:
· Pre-melted pure lithium tetraborate and not hygroscopic
· Mixtures of lithium tetraborate with lithium metaborate not hygroscopic, but highly soluble for samples containing high levels of silicon and zircon .
· Pure lithium metaborate, application for mainly for ICP fusions (more easily dissolved in acids)
· Lithium borates with halogen-containing anti-wetting agents such as LiBr , LiI , etc.
Lithium borates are available today in various forms and purities . All flux of FLUXANA are tested for their applicability and obtain a specification. For the automatic weighing in with the BORAMAT®, flux in glass ball form are used. For manual weighing powdered flux is preferred. Chemically, the two are composed the same way and the particle shape has no effect on the fusion. In the FLUXANA® laboratory both types are used in parallel.
Anti-wetting agents in
the flux such as LiBr , LiI or NH 4 I are required if the surface
tension of the melt falls below a critical
point. This is the case if a high proportion of metaborate is
used or if the sample contains elements such as Cr , Mn , Fe ,
Co, Ni, Cu in larger concentrations. Halogens such
as bromine or iodine, on the other hand,
increase the surface tension and usually help to compensate
for the problem.