SiO2 melting
SiO2 melting
(OP)
I'm searching information about melting of high silica glasses in laboratory scale.
Any reference would be helpful.
Any reference would be helpful.
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RE: SiO2 melting
<nbucska@pcperipherals.com>
RE: SiO2 melting
RE: SiO2 melting
If you are starting with sand (with or without other materials) and are melting a tiny quantity, you can start with a ceramic crucible that is available from many lab supply catalogs. This can be heated in a high temperature oven or over a high temperature flame
If you are wanting to remelt and reform existing glass via 'lampworking' a glass rod, you can do that with a common lab burner.
RE: SiO2 melting
RE: SiO2 melting
the problem with Pt-crucible is that it melts above 1736°C!!!!!!!!
Meanwhile we tried some induction melting and that seems to work out quite good.
RE: SiO2 melting
RE: SiO2 melting
High Silica glass is not enough to have the understanding of what would be the best way to melt the glass. Do you have any compositional aspect in mind?
If it is in the range of 96% sio2 then the route is totally different. There is a type of glass called Vycor glass.This has 96 to 97% silica,1.5% Na2O and may be another 1.5% B2O3.
The normal way to produce this glass is to make a batch having more than 22% B2O3 content Na2O higher than 18%. The glass so formed is again leached out with Acid. The acid leaches out the soda and boron content of glass leaving back the high silica rich skeleton structure of the glass.The so leached glass is then fired in a MoSi2 fired furnace to fuse out the Silica structure to almost 97 to 96% SiO2 glass.
Hope that is a new option for you.
ERegards
shudipto
RE: SiO2 melting
I knew about the vicor process, but there is still too much sodium in the glass at the end.
I found some papers about preparing a glass in a hot press: Ceramics International, 23 (1997) 291-296.
RE: SiO2 melting
The guys above mentioned using H2-O2 or Moly elements. Just for curiosity, have you considered carbon arcs?
BTW, What size is "laboratory scale"? We art glass guys melt soda-lime glass at around 2300f in ceramic crucibles between 100-300 lbs. Science to us is mixing in metalic oxides to make pretty colors and adjusting the COE's to "fit" each other.
Good Luck,
Glenn
RE: SiO2 melting
If you need high purity and therefore do not want to melt in ceramic refracory crucibles, there is an option. A crucible of 80%Pt/20%Rh alloy is much more refractory than Pt itself (melting point 1900 C). Currently the price for Rhodium is quite close to Pt so there is no monetary penelty. Rhodium can impart a slight color to your glass however, so if color is a problem then Pt/Rh may not be your answer.
Hope this helps.
RE: SiO2 melting
RE: SiO2 melting
I don't really know any details. I do know steel mills use carbon electrodes which melt using an electric arc. I once visited a plate glass factory that had an electric furnace but I'm not positive that the elements were the arcing type, maybe they were "normal" heat radiating elements. They were submerged in the glass, I do know that.
RE: SiO2 melting
There might be thow an electric way to heat the glass, but don't know how expensive would be not only the "furnance", but also the electric power used.
This spring I'll start experimenting with the H2-O2 as I said before and I'll tell you the results. There is still one thing that bothers me with that: The heat accumulated in the "new born" glass might heat the gear of the H2-O2 torch (torch, hoses, etc.) over the saftey limit...
RE: SiO2 melting
If you are looking for high purity natural fused silica (99.8% SiO2), fused quartz (99.99%+ SiO2) or synthetic fused silica (99.9999%+ SiO2) you are better off buying a suitable commercially produced material.