Some alkaline earth metals will reduce the stability of the XRF fusion bead, making sample becomes brittle and fragile. Especially when these elements exist in a large number of samples, the XRF fusion bead can be made more stable by adding glass elements such as SiO2、Al2O3, etc..

Pay attention to elements that evaporate at high temperatures. For example, sulfur is easily volatilized by self-generating SO2 at high temperatures, resulting in deviation. Therefore, in the process of melting, maintaining a high oxidation atmosphere and appropriately reducing the melting temperature can keep a certain amount of sulfur in the XRF fusion beads.

Take care to prevent XRF fusion bead rupture. The bead breaks easily when it cools too fast. And when the bead cools slowly to generate crystallization, it is also easy to rupture.

In addition, dust can also cause bead break. So it is necessary to fully shake evenly in the melting process. Make sure the even XRF fusion bead interior and natural cooling.

Sometimes the XRF fusion bead prepared has bubbles, which are related to the sample composition, the flux used, and the dilution ratio. It can be rocked during the melting process so that the bubbles move to the edge of the melting sample and then removed. For the small bubbles that can not be removed, the melting flux can be added to reduce the decomposition temperature and reduce the viscosity of the melting sample.

Regarding the measurement of loss on ignition, burn sample and measure LOI before melting. Pay attention to the loss of certain components to be measured.

The participation of sulphides in the melting process should be avoided. When the sulphide directly contacts with the crucible, it will permanently corrode the crucible surface, causing the glass residue to stick more easily to the corroded part and remain in the crucible after each subsequent melting. In addition, sulfur in low valence state can easily be converted to SO2 at high temperatures and lost. For analyzing the total sulfur in the sample, a lower melting temperature is necessary, and an oxidant is used to convert sulfur in low valence to sulfate.

Melting aims to produce no-bubble transparent samples. Opaque samples indicate that the melting, decomposition, and chemical reaction are incomplete. And if the sample contains bubbles, the measure of removing bubbles is improper, or the melting temperature is too low to make the sample too sticky. At this time, the melting temperature can be increased to achieve complete melting with continuous heat until no bubbles come out. It shows that the chemical reaction is complete. Rocking crucible during the melting process is an effective means of fast homogenization and bubbles removal(commercial XRF fusion machines have automatic rocking function).