Gold Foil coated parabolic reflectors for smelting

[stella polaris]

The earth receives just above 1000W per square meter from the sun, I believe that is what reaches the surface, I haven't really researched much.
And this would probably be at the equator so one have to deduct from there.

Edit to add:
Just popped into my head, I do not know if this is over the day or constant, so if it is 1000W per day then it would end up in just above 100W/h
Which increases the amount of mirrors by 8-10

That is based on 10 hour light/day. Then morning and evening the angle makes the reflectors getting less collecting area compared to mid-day. I stick to my 60w/h. Think you should take a look into it before start to make a project. Could be a little problematic if you later realise you have just 1/15:th of the energy needed.

 

[Yggdrasil]

I did a fast google on this and it seems that Stella Polaris is on track.
it is about 1000W per day per square meter in the latitude of the people discussing it.
So around 40 ish and 50 ish latitude I guess??
Not much left then

 

[stella polaris]

O yes. There is a lot left. This thread just made me thinking of doing one that can melt up to 5-10 gram. That´s doable. Next one will be to take a look on a smaller pyrolysis chamber.

Start small, learn then go BIG. Actually 7500 m2 is not that much (fotball field). Exists much larger than that. 1 ton batches is doable. Buy that not said its most efficient. Perhaps a continous smelting/melting is to prefere.

 

[Yggdrasil]

O yes. There is a lot left. This thread just made me thinking of doing one that can melt up to 5-10 gram. That´s doable. Next one will be to take a look on a smaller pyrolysis chamber.

Start small, learn then go BIG. Actually 7500 m2 is not that much (fotball field). Exists much larger than that. 1 ton batches is doable. Buy that not said its most efficient. Perhaps a continous smelting/melting is to prefere.

Not that much for a company maybe
I can see a need for very strict security protocols with all this concentrated light traveling through the air

 

[stella polaris]

Well, he stated he run around with the BIG ones. For the BIG ones 7500m2 is a pee in Mississippi. There are companies looking at 100 times that.

 

[stella polaris]

Goldshark, what is it exactly you want to smelt? Some kind of cleaning up operation as i understand.

 

[goldshark]

I/we do state wide clean up projects for the EPA. There are a lot of various size clean ups in the works, primarily based on size, and contamination threat. Primary work was done to control mine water discharges. After the largest water clean ups are done, the logistics dictate if the EPA finds another water project, or start cleaning highly toxic dumps. Threat assessment level, higher threat = higher priority to clean up.
So after number crunching to determine what size is needed for a certain production, we then have to determine what that energy can do as far as cleaning up these sites. If pyrolising just for the sulfides, so be it. The caveat is the potential for Au recovery. Dumps run from trace Au, to several dumps, 250,000 tons in size. Most would average .1 Au, from very extensive assay reports, and testing done through proper drilling of tailing, dump piles. We also could be selective in only doing dumps which pay, in going the full recovery route, verses sulphide recovery only. I am still crunching to determine if floatation is best, send cons to smelter, or pyrolyse sulfides only, with fume collector on site. other options of course include tapping into the grid and sucking power off of it. These mining towns have evolved from heavy mining for 100 years, to the new greenies looking for a place to nest cheaply, low prices due to the condition of the land. However, they are then realizing the potential health risks of living on, or near, a super fund site. Then comes the plea for help. In steps EPA. Kind of like buying under a major airport, then complaining about the noise. One solar array has already been built, about 1 acre in size. Much more to come.
So I am weighing all options, even if they do not make economic sense to the common person, as this could be a mandated government funded project. It has been on the horizon for at least 20 years. Trucking cons to smelter is around 1000 miles away (Texas).
Pvs are currently at 7% efficiency at current rate of conversion. That is why I am researching for optimal efficiency of reflectors. They may be more efficient at pyrolising sulfides, with scrubber or Sulphuric acid converter, than building Pvs, and using the energy for floatation.

 

[stoneware]

Totally Green, Mushrooms used for everything from petrochemical and heavey metal toxic waste remediation.

Mycoremediation of heavy metals, Google Scholar.​

 

[stella polaris]

I/we do state wide clean up projects for the EPA. There are a lot of various size clean ups in the works, primarily based on size, and contamination threat. Primary work was done to control mine water discharges. After the largest water clean ups are done, the logistics dictate if the EPA finds another water project, or start cleaning highly toxic dumps. Threat assessment level, higher threat = higher priority to clean up.
So after number crunching to determine what size is needed for a certain production, we then have to determine what that energy can do as far as cleaning up these sites. If pyrolising just for the sulfides, so be it. The caveat is the potential for Au recovery. Dumps run from trace Au, to several dumps, 250,000 tons in size. Most would average .1 Au, from very extensive assay reports, and testing done through proper drilling of tailing, dump piles. We also could be selective in only doing dumps which pay, in going the full recovery route, verses sulphide recovery only. I am still crunching to determine if floatation is best, send cons to smelter, or pyrolyse sulfides only, with fume collector on site. other options of course include tapping into the grid and sucking power off of it. These mining towns have evolved from heavy mining for 100 years, to the new greenies looking for a place to nest cheaply, low prices due to the condition of the land. However, they are then realizing the potential health risks of living on, or near, a super fund site. Then comes the plea for help. In steps EPA. Kind of like buying under a major airport, then complaining about the noise. One solar array has already been built, about 1 acre in size. Much more to come.
So I am weighing all options, even if they do not make economic sense to the common person, as this could be a mandated government funded project. It has been on the horizon for at least 20 years. Trucking cons to smelter is around 1000 miles away (Texas).
Pvs are currently at 7% efficiency at current rate of conversion. That is why I am researching for optimal efficiency of reflectors. They may be more efficient at pyrolising sulfides, with scrubber or Sulphuric acid converter, than building Pvs, and using the energy for floatation.

It seems you need a flexible and moveable system. The first that popped up was to have a sundriven steam machine for the generator. Heat a water pipe to get steam. Then you have electrisity on the spot and the life will be easier. You can also have a power axel to connect other machinery. The Diesel bill always have a tendency to get hefty. and the price will go up. (But its cheaper in US than in Europe).

Then i should make up my mind how i want to heat my smelting operation. Heat the oven or heat the material? two diffrent approaches.

Anyhow each site probably have its own optimum and if on a Northern slope perhaps not the best sun. Go flexible even if not 100% effective.

 

[goldshark]

There are many sites where an array could be permanently established. Quantity of material is virtually endless, though still finite. 20 year large program would make a sizable dent, but probably not all of it. Other part of logistics is processing as course of material as possible, to keep grinding/crushing costs to a minimum. Leaching only would remove the Au, but lots of other base metals involved, and still doesn't abate the sulphide component. This is only one application. There are a bunch of other smaller high grade propositions which may be able to fly, only on a smaller scale.

 

[goldshark]

It seems you need a flexible and moveable system. The first that popped up was to have a sundriven steam machine for the generator. Heat a water pipe to get steam. Then you have electrisity on the spot and the life will be easier. You can also have a power axel to connect other machinery. The Diesel bill always have a tendency to get hefty. and the price will go up. (But its cheaper in US than in Europe).

Then i should make up my mind how i want to heat my smelting operation. Heat the oven or heat the material? two diffrent approaches.

Anyhow each site probably have its own optimum and if on a Northern slope perhaps not the best sun. Go flexible even if not 100% effective.

Every time you do conversions from one energy form to another, you will always have an energy loss through either friction, or some other factor(s). That is why I am inquiring about the most Sun reflective material, for direct focus on heating. Small and portable for small operations, almost permanent for large operations. Just trying to nail down the most efficient system with same technology, just variable size systems.

 

[billgold]

That reflectance graph makes me wonder why Astronomers use gold coating on their mirrors for IR astronomy. They must have some reason that is not reflected in the graph lines.

 

[goldshark]

James Web has a shutter over lens if pointing in the Sun's direction. I don't think the JAW telescope has a Gold IR filter, but does have some inter changeable ones, for different wave lengths. 99.9999% of the time, shutter is open when facing away from the Sun, usually into deep space. I think a lot has to do with land or space telescope, and what they are looking at, as to what filters they are using.

 

[MicheleM]

JWT has gold coated berillyum segments composing the principal mirror

 

[Yggdrasil]

JWT has gold coated berillyum segments composing the principal mirror

Beryllium make sense for anything lifted into space since it is very light and very stiff.
SG at 1.85 it is barely heavier then Mg at 1.3

 

[stella polaris]

If you have wind in the area crushing and grinding are suitable for this type of energy.

A larger permanent solar site is doable as i see it. The technology are more or less already there. But as Yggdrasil pointed out. You handle very strong light and the risk for meltdowns are always present. The same for accidents were you get a little to good sun tan. On the other hand you do not need to focus all light on one spot. Preheating the material makes the whole thing easier compared to one super duper ecological multispectra laser, on one spot. Large sites is just a matter of engineer work and money as i see it.

Smaller, movable and flexible systems is more the solution of a old timer in the game. Those sitting at an office often have problem with understanding about how to work in the field. Interesting would be to se what can be done on 20 and 40 foots container system. (How many m2 reflectors can you pack in to a 40 foot container?) A pyrolyse chamber based on a 40 foot container and heated with sun energy is defently doable with simple means (no gold reflectors needed) Batch cheaper and continous feeding more expensive.

 

[olawlor]

I've melted a few grams of silver with fresnel-concentrated solar, but I wasn't able to melt a full ounce even with a freestanding fresnel lens about 3ft (1.0m) tall. Even here in Alaska, with the sun never higher than about 45 degrees above the horizon, the heating seems consistent with 1,000 watts / square meter of actual sunlight area. With a total collecting area of about 0.4 square meters, it's only a 400 watt heater, but it's concentrated into a spot about 10mm across, so it will promptly melt small amounts of powdered metals or even rocks, which melt to a neat black obsidian glass. Graphite makes a long-lasting crucible, but it does conduct heat away.

One issue with scaling up solar concentrators is there is an inherent spot size limit, minimum diameter about 1/200th the focal length, that applies whether you're lens or mirror based. In practice with a simple wood frame I can get a spot about 1/100th the focal length. This limits the peak heat, especially in air, but 1000 C is easy to obtain in small samples, and it will easily melt copper and silver. Good focus requires the lens to be aligned to within about 1 degree, since a misaligned spot spreads out rapidly.

 

[MicheleM]

I've melted a few grams of silver with fresnel-concentrated solar, but I wasn't able to melt a full ounce even with a freestanding fresnel lens about 3ft (1.0m) tall. Even here in Alaska, with the sun never higher than about 45 degrees above the horizon, the heating seems consistent with 1,000 watts / square meter of actual sunlight area. With a total collecting area of about 0.4 square meters, it's only a 400 watt heater, but it's concentrated into a spot about 10mm across, so it will promptly melt small amounts of powdered metals or even rocks, which melt to a neat black obsidian glass. Graphite makes a long-lasting crucible, but it does conduct heat away.

One issue with scaling up solar concentrators is there is an inherent spot size limit, minimum diameter about 1/200th the focal length, that applies whether you're lens or mirror based. In practice with a simple wood frame I can get a spot about 1/100th the focal length. This limits the peak heat, especially in air, but 1000 C is easy to obtain in small samples, and it will easily melt copper and silver. Good focus requires the lens to be aligned to within about 1 degree, since a misaligned spot spreads out rapidly.

Very nice!

 

[goldshark]

JWT has gold coated berillyum segments composing the principal mirror

Thanks M, I did not know that! I had heard the IR protection was the shield, with varying filters to measure different color wavelengths, then over lapped or blended to get a better picture of deep space, through gas clouds.

 

[goldshark]

I've melted a few grams of silver with fresnel-concentrated solar, but I wasn't able to melt a full ounce even with a freestanding fresnel lens about 3ft (1.0m) tall. Even here in Alaska, with the sun never higher than about 45 degrees above the horizon, the heating seems consistent with 1,000 watts / square meter of actual sunlight area. With a total collecting area of about 0.4 square meters, it's only a 400 watt heater, but it's concentrated into a spot about 10mm across, so it will promptly melt small amounts of powdered metals or even rocks, which melt to a neat black obsidian glass. Graphite makes a long-lasting crucible, but it does conduct heat away.

One issue with scaling up solar concentrators is there is an inherent spot size limit, minimum diameter about 1/200th the focal length, that applies whether you're lens or mirror based. In practice with a simple wood frame I can get a spot about 1/100th the focal length. This limits the peak heat, especially in air, but 1000 C is easy to obtain in small samples, and it will easily melt copper and silver. Good focus requires the lens to be aligned to within about 1 degree, since a misaligned spot spreads out rapidly.

One of the problems I am encountering, is the need for a SiO2 coating over the metal, to protect from dust and other contaminations. It seems like a solar reflector smelter may not be doable on the large scale, using Au as the reflector surface metal. Way too costly at the time. A PV farm would provide a much more versatile energy source, but they are really not a green product at this time either, or only a percent or 2 above our little buddy fossil fuels.
I haven't given up the ghost yet. I will be ever vigilant in my search for green energy alternatives, as technology and understandings of the Universe ever evolve.