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Topic: Why do we use more glass than quartz?  (Read 4822 times)

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Offline iScience

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Why do we use more glass than quartz?
« on: July 21, 2014, 02:37:31 PM »
If i understand correctly, slow cooling of SiO4 leads to a crystalline arrangement whereas (quartz) and quick cooling leads to an amorphous arrangement (glass). but because pure glass is so brittle we need to add stuff to it to make it stronger.

so why what's the purpose of cooling it quickly as opposed to slowly?

Offline Enthalpy

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Re: Why do we use more glass than quartz?
« Reply #1 on: July 23, 2014, 08:59:40 AM »
The amorphous form of quartz is silica. Glass contains other components, among others to help the production.
Silica is expensive. It's made of selected natural quartz crystals or, for even higher purity, by direct reaction between ultra-pure silane and oxygen.
I didn't notice silica being brittle. I used it at semiconductor manufacturing and on a satellite: nothing worse than glass.
Quick cooling for glass? Are you sure?

Offline Furanone

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Re: Why do we use more glass than quartz?
« Reply #2 on: July 24, 2014, 08:05:05 PM »
I did not know this but it makes sense since with very rapid cooling a disordered state can be preserved (amorphous) whereas with slow, controlled cooling favours a more ordered crystalline structure. There are other differences of course to that Quartz is very pure SiO4 while many things are often added to glass such as lead. As for why glass is more abundant, I would think is because the huge delta T between the 1500-2200 C used to melt and form glass to ambient temperature makes for a fast cooling rate while quartz I would imagine needs to be in a oven that has a slow programmed cool

I found this video on the manufacturing of synthetic quartz crystals on Youtube if you are interested. The video said it is a hydrothermal process where the crystal grows in a alkaline solution at higher pressure and 700 degrees Fahrenheit.

https://www.youtube.com/watch?v=oFH8_uLzano
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Offline Enthalpy

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Re: Why do we use more glass than quartz?
« Reply #3 on: July 25, 2014, 02:27:06 PM »
Are you kidding? Glass cooled quickly?

Offline billnotgatez

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Re: Why do we use more glass than quartz?
« Reply #4 on: July 25, 2014, 04:19:10 PM »
Quote
Are you kidding? Glass cooled quickly?
I am wondering as well - considering that glass blowers use an annealing process on their work.

From WIKI
http://en.wikipedia.org/wiki/Glassblowing
 
Quote
Annealing is usually done between 700 and 900 °F (371 and 482 °C)

Also (it seems to me) the general supposition implied by the original question misses the point as to the utility of glass.

Am I missing something?


Offline iScience

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Re: Why do we use more glass than quartz?
« Reply #5 on: August 03, 2014, 08:59:37 AM »
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Are you kidding? Glass cooled quickly?

would you care to state your case?

and btw i remember pure silica to be quite brittle, from when i did TLC plates.



Quote
Also (it seems to me) the general supposition implied by the original question misses the point as to the utility of glass.

Am I missing something?


yup! originally i was only wondering about the utility of glass. since a morphous configuration i figured, would result in higher structural integrity (correct me if i'm mistaken), i thought, why use glass when it involves wasting other resources trying to make it stronger?

Offline billnotgatez

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Re: Why do we use more glass than quartz?
« Reply #6 on: August 03, 2014, 09:13:52 AM »
I state again from the WIKI i posted

Quote
Annealing is usually done between 700 and 900 °F (371 and 482 °C)

Am I missing something?
I think the WIKI implies that slow cooling is required

Offline Enthalpy

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Re: Why do we use more glass than quartz?
« Reply #7 on: August 09, 2014, 04:33:42 AM »
Well, every statement in the original post is wrong, so instead of detailing what is wrong and how badly they articulate, the better strategy is to read Wikipedia for quartz, silica, and glass.

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