Gold Foil coated parabolic reflectors for smelting

[goldshark]

Since I may have hijacked the thread on Carbon free Gold, getting no responses, and it pertains to the concept, I think this question may still have some validity.
In an attempt to do solar smelting, has or does anybody have experience with coating a parabolic, or any shape reflector, with pure Au foil? I have tried to research the subject on line, but have not found any info on the performance of Au verses Ag or Al. I have found that Au is far superior to any other metals reflecting in the IR range. If the results are worth the investment, I would certainly invest in a solar smelter. I doubt you could go much "greener" than that. Any input would be greatly appreciated, I hope.

 

[stoneware]

Since I may have hijacked the thread on Carbon free Gold, getting no responses, and it pertains to the concept, I think this question may still have some validity.
In an attempt to do solar smelting, has or does anybody have experience with coating a parabolic, or any shape reflector, with pure Au foil? I have tried to research the subject on line, but have not found any info on the performance of Au verses Ag or Al. I have found that Au is far superior to any other metals reflecting in the IR range. If the results are worth the investment, I would certainly invest in a solar smelter. I doubt you could go much "greener" than that. Any input would be greatly appreciated, I hope.

Melting gold with solar.

 

[MicheleM]

Since I may have hijacked the thread on Carbon free Gold, getting no responses, and it pertains to the concept, I think this question may still have some validity.
In an attempt to do solar smelting, has or does anybody have experience with coating a parabolic, or any shape reflector, with pure Au foil? I have tried to research the subject on line, but have not found any info on the performance of Au verses Ag or Al. I have found that Au is far superior to any other metals reflecting in the IR range. If the results are worth the investment, I would certainly invest in a solar smelter. I doubt you could go much "greener" than that. Any input would be greatly appreciated, I hope.

 

[goldshark]

Stoneware, great way to start! Now lets figure out how to do 1 ton lots in a crucible, every 1/2 hour, for as long as the Sun allows.

 

[MicheleM]

Gold coating is used to reflect VIS/IR in high-end applications ( and for applications in harsh environments).
low end mirrors usually are made with dielectric multilayer or Al / Ag coatings.

 

[goldshark]

Thanks Michellem, from what I see in the graph Al would appear to have the best reflectance. Then I saw the dip in the 780nm-1.4 mm (Infrared zone). So am still seeing Au as the winner in the overall reflectance. What am I missing?

 

[goldshark]

Gold coating is used to reflect VIS/IR in high-end applications ( and for applications in harsh environments).
low end mirrors usually are made with dielectric multilayer or Al / Ag coatings.

I prefer to do the best way possible, even if it costs more. It would pay huge dividends in the long run, even with a slight improvement, for this application.

 

[MicheleM]

Thanks Michellem, from what I see in the graph Al would appear to have the best reflectance. Then I saw the dip in the 780nm-1.4 mm (Infrared zone). So am still seeing Au as the winner in the overall reflectance. What am I missing?

You should find the Blackbody emission spectrum of the sun and compare it with metal reflectance, only looking to the graph I think Silver and aluminum are also good but a preliminary computation of how much intensity you need to melt gold powder is necessary. I think the hardest part is to make a good coating on the metal/dielectric base. Pretty interesting subject, unfortunately i left the game a couple of years ago

 

[Golddigger76]

You might have better luck with a huge magnifying glass ???
I have seen mirrors set up to heat a house. The old guy was a litteral genius, he built these crazy wooden gears that were driven by a small electric motor and the mirrors would be repositioned by the wooden gears so the mirrors moved with the sun to keep the reflection on the wall of his house.
He melted his mini blinds before he got it working perfectly lol.

 

[Yggdrasil]

Since I may have hijacked the thread on Carbon free Gold, getting no responses, and it pertains to the concept, I think this question may still have some validity.
In an attempt to do solar smelting, has or does anybody have experience with coating a parabolic, or any shape reflector, with pure Au foil? I have tried to research the subject on line, but have not found any info on the performance of Au verses Ag or Al. I have found that Au is far superior to any other metals reflecting in the IR range. If the results are worth the investment, I would certainly invest in a solar smelter. I doubt you could go much "greener" than that. Any input would be greatly appreciated, I hope.

How about Rh plating?

 

[Yggdrasil]

Since I may have hijacked the thread on Carbon free Gold, getting no responses, and it pertains to the concept, I think this question may still have some validity.
In an attempt to do solar smelting, has or does anybody have experience with coating a parabolic, or any shape reflector, with pure Au foil? I have tried to research the subject on line, but have not found any info on the performance of Au verses Ag or Al. I have found that Au is far superior to any other metals reflecting in the IR range. If the results are worth the investment, I would certainly invest in a solar smelter. I doubt you could go much "greener" than that. Any input would be greatly appreciated, I hope.

Remember that the IR spectrum is the spectrum with the lowest energy level.
Another thing about that is, what the Gold reflects in the reflector is also what the Gold for melting is going the reflect.

I used to work a place with laser cutting machine and talked a lot to the operator.
Steel, Ceramic and what ever was easy to cut, but reflective metals like Copper, Bronze or Brass was risky due to reflections.
The reflections could backfire and damage the nozzle and mirror of the laser.

 

[MicheleM]

Remember that the IR spectrum is the spectrum with the lowest energy level.
Another thing about that is, what the Gold reflects in the reflector is also what the Gold for melting is going the reflect.

I used to work a place with laser cutting machine and talked a lot to the operator.
Steel, Ceramic and what ever was easy to cut, but reflective metals like Copper, Bronze or Brass was risky due to reflections.
The reflections could backfire and damage the nozzle and mirror of the laser.

What you said is true , especially for parallel plane metal surfaces, in this case the eventual retroreflected light depends from the convexity/concavity of molten gold, in this scenario i didn't expect problems except for very unlikely configurations. I.e. you can use your reflector/parabolic mirror with an angle respect to the surface of the dish that contains the powder and avoid the problem.

 

[goldshark]

What I am envisioning is either parabolic reflectors, Frannel (?) lens, either focused on a crucible, maybe Graphite for best IR acceptance, or possibly a crucible bathed in a molten salt solution via heat exchanger, for even heating of the crucible. I will have to explore the technique used by the large solar array in Mohave County,USA, where their solar panels are focussed for a similar operation. Still have to figure BTUs for smelting the amount needed per day. Also would have to figure either a scrubber, or sulphide catalyst to convert a large amount to Sulphuric. Hate to waste anything. We may have access to millions of tons from dump material, currently in a potential EPA clean up site. A cyanide mill project was shut down after going to almost start up, before regulators decided it necessary to have a secondary liner be installed under entire facility. Anyway, keep the thoughts coming. Thanks for all replies. Think big, semi portable, and "green".

 

[MicheleM]

*Fresnel

 

[goldshark]

What you said is true , especially for parallel plane metal surfaces, in this case the eventual retroreflected light depends from the convexity/concavity of molten gold, in this scenario i didn't expect problems except for very unlikely configurations. I.e. you can use your reflector/parabolic mirror with an angle respect to the surface of the dish that contains the powder and avoid the problem.

I wouldn't be focusing onto metal directly, but onto a graphite crucible. This would be for smelting sulphide cons. Like I said, 1 ton per 1/2 hour, as long as the Sun permits. No shortage of materials.

 

[goldshark]

*Fresnel

Thanks, had a brain fart, and couldn't remember the exact name, couldn't watch the video while in the middle of my post either.

 

[goldshark]

*Fresnel

Why is it every time I look at your Avatar, I see a cheeseburger, and not the Au in the pan?

 

[goldshark]

How about Rh plating?

I will look into Rh for performance.

 

[Yggdrasil]

What you said is true , especially for parallel plane metal surfaces, in this case the eventual retroreflected light depends from the convexity/concavity of molten gold, in this scenario i didn't expect problems except for very unlikely configurations. I.e. you can use your reflector/parabolic mirror with an angle respect to the surface of the dish that contains the powder and avoid the problem.

I was merely pointing at the efficiency.
The reflectiveness will reflect most of the energy directed at it and thus be less effective.
If you use a crucible or ore, that is a different story all together, but the initial proposal seemed to me to melt Gold metal directly.

 

[goldshark]

A bit of misunderstanding on all parts. My thread headline stated smelting, Stoneware posted the video melting some Au with a Fresnell lens, I tried to steer back to smelting, but the video put everyone's mind on a strictly metal melting vision. Lots of steps to getting to melting metal, but maybe have to start with smelting. I would like this to be a large scale project. It will require a fair amount of piling mounts, and Sun tracking devices. After a large clean up, the pilings and tracking equipment could then be utilized for a PV installation. A huge rage around here.
There are a multitude of heavy sulphide dumps around the state of Colorado. Colorado has 4 major rivers flowing from it. Even a solar roaster, to remove the sulfides, would be a winner for our state, and all states down stream. The current mitigation is put a cap of Limestone to neutralize the acid formation, heavy metals are still leaching into the ground. Maybe create a supergene deposit. Just trying to make lemonade out of lemons.