Kiln components for melted glass at 1700ºC ( 3092ºF)

You might check out Cotronics:

They have machinable alumina and silica materials good out to 3000F.

Dear Charles,

The compatibility of glass and refractory depends on the chemical composition of the glass and of the refractory. Some oxides are considered basic and some are considered acidic, and there is a formula which you can use to find where any particular refractory composition falls on the acid-base axis. You do the same for the particular type of glass you have, and choose a refractory that is compatible with that glass. (E.g., an acid glass or slag will quickly corrode a basic refractory.)

Sorry, but I cannot find a good on-line source for this. You might consider buying a refractory handbook.

You should definitely get in contact with a refractory manufacturer. They can advise you on this. (Harbison-Walker, A. P. Green, North American Refractories Company, etc.)

You might want to attend the Glass Problems Conference at Ohio State in October. There are usually a lot of glass industry vendors there and they have hospitality suites. (Although the industry is in financial trouble, and the hospitality may not be as lavish as it once was.) Olin Perry Norton

Thanks, I'll check their materials properties.

Regards

Charles

Thanks Olin, I know that glass/refractory compatibility is the point but I am starting for the scratch so I have to investigate first the refractory market in that field of temperature. Products which could work in that temperature zone are not a lot. and further researches will be necessary to perform tests with samples of available candidates. I spoke with people from Saint-Gobain SEFPRO and it seems that THTZ materials could be also on the line. Anyway, I will contact kiln manufacturers and Engineering firms which specialize on that field. Sorry for the conference in Ohio, I am living in Europe and I am afraid I'll be a little busy in October.

Best regards

Charles

Dear Charles,

Sorry, I didn't notice you were from Europe. The Glassman Europe meeting would be good, but it is held every other year, so you would have to wait until 2011 for the next meeting. On the other hand, you might enjoy Sao Paulo if you went to the Glassman South America meeting in March

2010.

I repeat my suggestion that you contact refractory suppliers. The ones that supply the glass industry know which types of refractory are best for which applications.

Also, a good refractory handbook will have useful information about corrosion compatibility.

What type of glass are you dealing with? Regular soda-lime glass?

Olin Perry Norton

It is about Investigation on glass-ceramics (LAS + nanocrystallization) I am afraid that a Handbook wouldn't address properly refractory materials to that zone of working temperatures in glass manufacture. In addition, specific elements of the glass composition (alone or combined) introduce specific refractory behaviouring concerning reaction/corrosion. Moreover, glass surface quality must be insured with processing elements in contact.

Actually, according with refr. manufacturers that I already contacted (RHI, Saint-Gobain SEFPRO R&D...) we are on the borderline of capability for existing materials. Thus, some lab experiments must be done to select the more suitable ones to a potential use on a production line by starting probably with very High Zicronia Content kinds (HZ) like RHI Monofrax® Zs Brands if I can't find better.

Charles.

TNO (Netherlands) has a division which provides consulting services to the glass industry.

OPN

>

Thanks, I add TNO to my agenda.

In the past the usual way to work at such temperatures was to use a metal like molybdenum and a reducing atmosphere. It's a bit OTT for the precious metals, like Pt60/Rh40. The fused silica people have some relevant experience. Iso-statically pressed Chromic Oxide and related refractories are the only ones that might work at the limit in air or oxidising conditions.

However there can be complications if you have Arsenic or Lead in the glass. Both cause trouble with corrosion of the Molybdenum.

According with the information collected form manufacturers, high Zirconia content electro-fused ref are suitable to such temperature.

Further tests are needed but RHI Monofrax® Zs Brands and Saint-Gobain SCIMOS Z are privilegied candidates for the melting zones.

Now, I am investigating to find materials suitable for the forming zone with a pasty glass at 1450ºC. The aim is to produce 1 m x 1 m plates. Max thickness 20 mm with tolerance of 0.1 mm