Sciencemadness Discussion Board - Literature on how Na2O2 fusion works


	Not logged in [Login ]

FAQ

Member List

Today's Posts Forum Stats

Stats

Back to:

Sciencemadness Discussion Board » Fundamentals » Chemistry in General » Literature on how Na2O2 fusion works

Printable Version

bolbol

Hazard to Others

Posts: 167
Registered: 3-1-2015
Member Is Offline

Mood: No Mood

posted on 2-4-2023 at 20:28

Literature on how Na2O2 fusion works

I am looking for literature on the reactions/mechanisms of sodium peroxide and sodium oxide fusion. All I seem to find highlights the procedures and not so much the underlying mechanism.

What I know is that these methods are use for rock analyses depending on mineral matrix and elements of interest when acid digestion is not sufficient.

This method can dissolve refractory silicate minerals which may be pretty resistant to aqua regia. Zircon being one example. I am very curious as to what the driving force is. The way I think of it is that Na2O2 somehow brakes the silica tetrahedra and whatever original cation was in the silicate remains at a high oxidation state and turns into an oxide. Sodium oxide definitely lowers the melting point pure SiO2 so I wonder if there is a Na-Si-O phase in the molten state that is thermodynamically favorable driving the silica away from the cations its bonded to and effectively breaking down the crystalline structures

Does this have something to do with how silicon and sodium bond together? IE would fusion work with LiO? CsO?

Does the peroxide have oxidizing properties? [SiO4]4- tetrahedra contain plenty of oxygen with Si being at 4+ so it seems unlikely that's the case.

Any pointers would be appreciated.

Osmiridium

Harmless

Posts: 26
Registered: 13-3-2023
Member Is Offline

Mood: excited

posted on 5-4-2023 at 02:01

There aren't many ways to dissolve silicates. One is with hydrofluoric acid to form SiF₄ the other with strong bases since SiO₂ respectively Si(OH)₄ is acidic.
Molten Na₂O₂, Na₂CO₃ or NaOH may be used for this. Unlike many other silicates the formed sodium silicate is soluble in water.
Other strongly alkaline oxides or hydroxides will work similarly. You mentioned Li₂O and Cs₂O where the first is a weaker and the latter a stronger base than the sodium analogue.
Sodium peroxide is actually a very strong base and oxidizer making it very suitable for such uses. As you already wrote it will not oxidize silicon any further since it is already +IV in silicates but it might oxidize other cations and ease their dissolution. It is for example used to oxidize platinum group metals.

Sciencemadness Discussion Board » Fundamentals » Chemistry in General » Literature on how Na2O2 fusion works