[billnotgatez]

Tinkering with Glass and Ceramics

It has been said that Apple computers began as a project at home in a garage. Well, we are working on a project not so earth shattering at home. We continually tinker with various projects, some of which involve chemistry. So, we could post this item in analytical or inorganic boards, but chose to post it here since it is a home tinkering project. This project is derived from my ceramic / glass making hobby and has some roots on glaze making / glass making.
Currently, we are mixing various combinations of chemicals together to achieve a final product that contains glass mixture. For instance, we might have silica, sodium, and aluminum in our final product. We know what chemicals we put into the process, but are unsure of the final glass composition due to whatever factors that may not allow for complete combination.
So we thought we would verify the final product. Well, glass is typically the holder of the item to be analyzed and not the item analyzed. So, our GOOGLE, WIKI and library search is in progress, but we thought we would do some brain storming as well.


One thought is to rig a spectrometer (maybe home built) to get the relative composition.

The other approach is to do some chemical analysis where we dissolve the glass and then precipitate out the various components. We could then weigh the various precipitates. Without hitting the books yet, we thought of using hydrofluoric acid for the dissolving. Well, I am not keen as my cohorts on having hydrofluoric acid around let alone acquiring it. But, we press on.

Now we have various pieces of equipment about like a kiln, glassware etc. I also have supplies and equipment that is use in various chemistry home making activities like soap making, bio diesel, brewing etc.
But, we do not have a glass furnace or high end spectrometers. No matter how devoted to citizen science, I have limits to my funds.

So while we are doing our book research, if anyone has suggestions as to an inexpensive or home built device, or other methods, off the top of your heads please post. Especially if you have another approach.

If you have an idea on how to dissolve the glass please post

If you have a suggestion on how to participate the sodium, aluminum or silicon separately please post

If you think we are dummies please post (be kind).

Our goal is not to get precise, just reasonably close.

By the way, we are trying to be safe as possible and adding to our practices and equipment as we proceed. Much of what we are doing is modified accepted ceramic processes typical of many home ceramic studios like I have.

Thanks
Bill

So many projects, so little time.

EDIT
I had to post again since I hit the button before I was done and did not notice

[curiouscat]

Way I see it, the recipe is most important for others to know. Like what to put in, how much, how hot to heat, how long etc.

The final composition, I don't know if that's very interesting. At least to a hobbyist. It may be too much trouble. Do you really need to find out?

[billnotgatez]

@curiouscat
Sorry for the changing the post
Actually I just added to it
I do not think it negated your answer
Thanks for your prompt response.

[billnotgatez]

Part of this is for our own piece of mind.

In addition, let us say we combined 60% silicon, 20% sodium and 20% aluminum in various compounds. We then process to remove the other parts of the compounds leaving only silicon, sodium and aluminum.
But, the processing produced a final glass product of 60% silicon, 30% sodium and 10% aluminum,
The melting and other properties could be very different.
We could review our preparation steps to correct any flaws

[408]

Break the glass and ball mill it with steel media..  This will give fine silica (I'd rather work with HF, I hate dust inhalation risks) This should dissolve in hot concentrated Na/KOH or in the fused salt giving silicates and aluminates that you can analyze.  Whatever the standard analysis for silicates and aluminates is can be used.  I imagine there is a selective precipitation somewhere. 

[billnotgatez]

hot concentrated Na/KOH

So I suppose, in the case were the glass is composed of silicon, aluminum, and sodium we could use hot concentrated Potassium hydroxide. Or, do we need a mixture of Sodium hydroxide and Potassium hydroxide.

[billnotgatez]

Just some background to understand why we are trying various mixtures

The glaze on pottery now days is basically a glass coating
Here is some glaze chemistry lore that we are basing our glass composition.
It is simplistic
Silicon Dioxide (Silica) (SiO₂) Glass Former
Aluminium Oxide (Alumina) (Al₂O₃) Stabilizer
Sodium Oxide (Soda) (Na₂O) Flux
Various combinations of the above will control the melting properties of the glaze (glass).

There are several other chemicals that are Glass Formers, Stabilizers, and Fluxes.
We are just looking at silicon, sodium and aluminum first.
Also we are looking at both glaze making and glass making.
We can use other compounds containing silicon, sodium and aluminum and process them to achieve glass with only silicon, sodium and aluminum.

[408]

the slash meant or, I forget whether the Na or K variety is more corrosive, I think K.  In any case, if you analyze for Si and Al, you have Na content by process of elimination, so using NaOH would not be a deal breaker.

[billnotgatez]

@408
What I thought == thanks

[TyPie]

I'm not sure how much it matters, but have you tried looking at phase diagrams of glass w/ various compositions.  You can probably compare specific physical properties of the glass w/ the phase diagrams at specific points. 

[billnotgatez]

@TyPie

As a mater of fact, what led us to manipulate the various concentrations of constituents of glass were the phase diagrams. We merely want to confirm that we have the right concentrations of the constituents. That way we can hope we got the glass with the properties we are looking to attain.

[TyPie]

Becareful with this idea.  Physical properties don't always translate out to the concentrations of the constituents in materials science, er at least with physical metal properties.  From watching Corning's glass manufacturing videos, they used gravity to make their glass uniform.  You can probably come up with a statistical calculation by using the atomic radii of the lattice structure, and comparing that to the glass' volume (This would give you your optimal values).

If you take some sort of weight and nitrogen gas, you can weight the change in the weight of the glass, to see if there are any semi-permeable pores in your glass.

I don't know too much about glass, sorry...
I am coming more of from an organic, metals, and medical background. 
       

[billnotgatez]

As mentioned earlier in this thread we are doing the GOOGLE and we found

http://pubs.usgs.gov/bul/1547/report.pdf

The Classical Chemical Analysis of Silicate Rocks- The Old and the New GEOLOGICAL SURVEY BULLETIN 1547 By HERBERT KIRSCHENBAUM UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1983

We think we can modify the process suggested to find our concentrations of Silicon, Aluminum, and Sodium.
We will try to keep you all posted.

@408
We will probably modify the above using your thoughts involving hot Sodium Hydroxide or hot Potassium hydroxide
as well as guidance from the paper above.
@TyPie and @curiouscat
Thank you for your input