# Turning Soda Glass into Lead Glass and Fused Silica [closed]

What would be the method of turning Soda Lime Glass into:

B. Fused Silica

Soda Lime Glass is $\ce{SiO2}$ ~70%. Lead Glass is $\ce{SiO2}$ ~ 62.9%. Fused Silica is $\ce{SiO2}$ ~ 99.9%. Can one start with a batch of Soda Glass, chemically separate the $\ce{SiO2}$, and then use that to make Lead Glass/Fused Silica? I'm not expecting it to be cost effective, but I doubt it's physically impossible. Is it?

• Two completely different chemical compositions. So the only way to make a conversion is to sell the soda glass and use the money to buy lead glass. – MaxW May 22 '18 at 7:53
• Cannot be done. – Waylander May 22 '18 at 7:55
• @Johan88 I added your comment to the question. As your question previously stood it was violating the homework policy and would have been closed. Hope that's fine with you. – Avnish Kabaj May 22 '18 at 8:10
• @AvnishKabaj much appreciated. Thank you. Really don't understand the difference between a hw and a non-hw question but I'm sure you do. Grazie – Johan88 May 22 '18 at 8:17
• The policy is very badly titled. It's not limited to questions which are literally homeworkA "homework question" is any question whose value lies in helping you understand the method by which the question can be solved, rather than getting the answer itself. This includes not just questions from actual homework assignments, but also self-study problems, puzzles, etc. – Avnish Kabaj May 22 '18 at 8:25

Soda glass can be purified by high temperature. The sodium oxide will evaporate as the temperature becomes high, but we are talking on the upside of 1600 $^o$C perhaps even up to 2000 $^o$C. All the other alkali and many rare earth oxides will evaporate as well, so if you want any of those back, you'll have to add them. In addition, high temperature silica is a mess to work with when it is pure, viscous and prone to "boiling over" when releasing gases - so YMMV. So there you have pure silica. It'll never be "fused" silica though, the name derives from the process it was taken from - and it is usually in the form of micro-sized globes or spheres. You'll end up with a "lump" or "pile" of silica.