Sciencemadness Discussion Board - Ruby synthesis with the help of the Sun

Ruby synthesis with the help of the Sun

Admagistr - 19-3-2023 at 22:41

I found a video,which demonstrates my long time dream and idea to produce rubies from Al2O3+Cr2O3 mixture with the help of the Sun.The author uses a 55 inch Fresnel lens.The price with shipping to Europe is not low.The question is is there a cheaper alternative? I can think of building a parabolic mirror of comparable size...Or I will save up for the Fresnel lens mentioned in the link...

https://www.youtube.com/watch?v=XVg4J8a3JzQ

https://greenpowerscience.com/FRESNELSHOP/55INCHSPOT.html

Parakeet - 20-3-2023 at 05:39

I've heard a method of making a concave mirror using a bowl/basin and an aluminum sheet. The method is to cover a big round bowl with an aluminum sheet and stick it on to create a nice dent by removing the air inside.
I have never made one, but it seems easy and powerful enough.

blogfast25 - 20-3-2023 at 05:53

Quote: Originally posted by Admagistr

I found a video,which demonstrates my long time dream and idea to produce rubies from Al2O3+Cr2O3 mixture with the help of the Sun.

Sorry but these are NOT rubies, totally opaque as they are. They have no commercial value.

Admagistr - 20-3-2023 at 13:47

@Parakeet Interesting idea, could you elaborate a bit or send me a link?I thought of making a parabolic "skeleton", according to the equation y=5/2 x² and completing it around this "skeleton". The best way to reflect IR radiation would be a gold foil, like the kind used to gild art objects.
@blogfast25 The question is,do you define ruby as just transparent alumina crystallizing in alpha modification,contaminated with trivalent chromium?Is the transparency to light a necessary condition that only then it is ruby?In my opinion ruby is defined by chemical composition and crystal modification.Yes,this ruby is very low grade,because it was formed quickly,also be cooled quickly and was contaminated by its precursor. So it doesn't form crystals and is opaque.I got better results when I precipitated mixed hydroxide from a solution of KAl(SO4)2+KCr(SO4)2 using K2CO3 and melted this gel using autogenous flame,then the transparency and overall appearance was much better.There was no powdered precursor in the ruby,only gas bubbles.

[Edited on 20-3-2023 by Admagistr]

Texium - 20-3-2023 at 17:54

If you can find an old projection TV, they had big Fresnel lenses like that right on the front! They’re very obsolete now, so you can sometimes find them thrown out on the street, or on Craigslist or Facebook Marketplace (or whatever your local version is, probably) for free or cheap.

https://www.instructables.com/Salvaging-the-Fresnel-Lens-fro...

mayko - 20-3-2023 at 18:43

Cool stuff! I was thinking about this sort of thing when I was experimenting with my satellite dish reflector:

https://www.sciencemadness.org/whisper/viewthread.php?tid=26...

Admagistr - 21-3-2023 at 02:15

Thank you Texium and Mayko for the information and advice,I will look into it...

Conversion of Al,Cr(OH)3 gel by autogenous flame to rubies.

[Edited on 21-3-2023 by Admagistr]

Parakeet - 21-3-2023 at 04:54

Quote: Originally posted by Admagistr

@Parakeet Interesting idea, could you elaborate a bit or send me a link?I thought of making a parabolic "skeleton", according to the equation y=5/2 x² and completing it around this "skeleton". The best way to reflect IR radiation would be a gold foil, like the kind used to gild art objects.

https://youtu.be/exWqdHBrg2M
This is what I was talking about. He is using the silver side, but as you mentioned, it might be better to use the gold side.

Sulaiman - 21-3-2023 at 06:27

The lens pointed to looks really useful
That area should capture about 1kW
and the short focal length could produce a very intense spot
but
1 it is (I believe) theoretically impossible to produce temperatures higher than the source
(the sun has an apparent temperature of 5700K from memory)
2 the black body radiation of the object(s) being heated will significantly reduce the maximum achievable working temperature.
Typically c1000C... maybe it could melt copper,
aluminium should be easy,
I would not expect it to be able to melt steel.

Admagistr - 21-3-2023 at 19:34

@Parakeet:

https://youtu.be/exWqdHBrg2M
This is what I was talking about. He is using the silver side, but as you mentioned, it might be better to use the gold side. [/rquote]

Thanks @Parakeet for the link and the information.I was surprised that it is a planar round mirror,although the name associated with Archimedes suggests it...

[Edited on 22-3-2023 by Admagistr]

Chemistryreacts - 17-4-2023 at 21:24

@Sulaiman

You would struggle to heat up anything reflective like a metal directly, if you had something else to absorb the light better (like some narrow band gap oxide) which then transfers the heat then it should be possible with a home setup on small scale.

For reference, I have made Fe2O3/Fe3O4 melt with just a small A4 sized plastic magnifying lens (>1500 C), it basically occurs immediately once focused.

Admagistr - 18-4-2023 at 07:54

Quote: Originally posted by Chemistryreacts

@Sulaiman

You would struggle to heat up anything reflective like a metal directly, if you had something else to absorb the light better (like some narrow band gap oxide) which then transfers the heat then it should be possible with a home setup on small scale.

For reference, I have made Fe2O3/Fe3O4 melt with just a small A4 sized plastic magnifying lens (>1500 C), it basically occurs immediately once focused.

Thank you for the interesting information!Did you make a video about it?Your YT channel is very interesting,I look forward to your next videos...

Chemistryreacts - 18-4-2023 at 20:20

Thank you, I will do it the next time there is a sunny day haha. I am currently procrastinating editing a video where I make small ceramic pieces pretty much the same way.

Admagistr - 19-4-2023 at 15:55

Quote: Originally posted by Chemistryreacts

Thank you, I will do it the next time there is a sunny day haha. I am currently procrastinating editing a video where I make small ceramic pieces pretty much the same way.

That's great news!Do you use a perfectly normal Fresnel lens, which is sold for reading, with a magnification of 5x, or do you have a special one?

Chemistryreacts - 20-4-2023 at 19:43

Yes, the ones I use are completely normal not anything special. I believe they are 3x magnification. I have tried 2 types, one which is more "floppy" with a black plastic border and one which is more rigid without the black border. Both do the same job but the rigid ones are easier to focus using just one hand.

Admagistr - 21-4-2023 at 06:21

Quote: Originally posted by Chemistryreacts

Yes, the ones I use are completely normal not anything special. I believe they are 3x magnification. I have tried 2 types, one which is more "floppy" with a black plastic border and one which is more rigid without the black border. Both do the same job but the rigid ones are easier to focus using just one hand.

Thanks for the information!You made me happy

,I will try to involve the Sun more in my chemical activities,not only to produce rubies,it is clean energy and does not pollute the reaction mixture!

Texium - 31-5-2023 at 07:37

Quote: Originally posted by Texium

If you can find an old projection TV, they had big Fresnel lenses like that right on the front! They’re very obsolete now, so you can sometimes find them thrown out on the street

And this morning, what do you know, a projection TV was sitting on the sidewalk just outside my house! Fresnel lens acquired. Sometimes it pays to live on a street that people like to dump their junk on.

Admagistr - 31-5-2023 at 08:46

Quote: Originally posted by Texium

If you can find an old projection TV, they had big Fresnel lenses like that right on the front! They’re very obsolete now, so you can sometimes find them thrown out on the street

You're very lucky Texium, I wish you luck!A good friend of mine, a Catholic priest, tried to help me get a projection TV, he went to a distant town to get it, but the person who promised him the TV told him he didn't have time and tried to keep raising the original low price, apparently he sold it to someone who paid him well and never heard message from him again...

Benj-NH2 - 31-5-2023 at 12:11

If you are up for some DIY projects, then I found some potentially useful links for you:
1. DIY Fresnel Lens from a Tube:
https://www.youtube.com/watch?v=SIMxPDa7Hc4&list=WL&...
2. Burning Mirrors:
https://www.youtube.com/watch?v=Ci6GiC-jQEA

Robert Murray Smith has made some interesting videos on this topic of DIY mirrors, and they might help you. I haven't had the time to test them out yet, but I hope to soon build some melting mirrors of my own and try to make some ruby, sapphire,... (or any sort of Al2O3 derived "gemstone") for myself.
Sadly, I'm not sure if these crude mirrors will reach the required temperature (the melting point of Al2O3 is 2.072 °C), but considering the cheap starting materials, it's definitely worth a try (and you can always scale your mirror up to gather more light)
When I get around to doing this experiment, I can give you more information. However, if any of you does it first, it would be nice if you could keep us updated on your progress.

Admagistr - 31-5-2023 at 14:07

@Benj-NH2
Thanks so much for the tips and information,of course,if I make it before you do,I'll let you know right away via U2U and post in the thread! In the case of the parabolic mirror,it would probably be best to place the Al2O3 mixture in a clear quartz test tube,ideally the reaction mixture will be as dark as possible,this will be most fulfilled with sapphire,where black FeO+TiO2 is used,but CO2 must be injected, or argon, or create a vacuum, to create a beautiful blue sapphire requires a reducing environment, without oxygen, the alternative can be Co2O3, but natural sapphire has its coloration from Ti3+ and Fe3+, Ti2O3+Fe2O3 as a result of the reaction between FeO and TiO2.