What is the role of the Lithium metaborate

What is the role of the Lithium metaborate? A lot of people are not familiar with this stuff, and here's the introduction to it:

Lithium metaborate is a kind of fused flux of sample preparation, purity: 99.995 + %, high density: > 1.4 g/cm3, appearance: 100% glass bead shape, particle size < 500 microns, features: melt homogenization, clean, high liquidity, including mold release agents, moisture absorption, water: water content < 0.05% for long wavelengths, dispersion XRF fluorescence spectrometer, such as AA aas and ICP sample preparation. Its role is largely and lithium tetraborate mixed in proportion to neutralize acid and alkaline of different oxide to achieve molten sample and thus can get corresponding melting glass sample or solution.