Recycling e-waste for gold

Came across some videos about recycling electronics waste to extract gold. While using dangerous chemicals, the process itself did not appear difficult. India has relatively few such recycling facilities and a mounting pile of e-waste.

For example:

Occurs to me that in a country rife with poverty, this is something that could be turned into a professional skill. Do we take up projects of this sort? I don’t mean just the refining, but refining well enough to be able to teach it to people in order to empower them.

There are already wholesalers dealing in electronics gold scraps for recovery. For eg, results on IndiaMart: RAM Scrap at Best Price in India

It could be an interesting project combining recycling with chemistry, metal working and employment generation/social welfare. There are several marginalized communities that would already have the traditional knowhow to do the parts involving working with a forge or handling the materials carefully - for eg. blacksmiths.

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Someone should show that this is feasible in a frugal way. This can be a challenge for those who are interested. One thing for sure, this would require a highly interdisciplinary skillset.

Well, frugal to some extent. A forge can be built rather cheaply with little more than a bucket filled with plaster of paris and a solar concentrator or large fresnel lens (which can apparently be scrounged from the ancient color TVs). However, specific equipment will need to be sourced - whether frugally or purchased outright - glassware to work with acids, the acids themselves, a graphite or similar forge friendly “utensil” / mould…

(sorry for multiple edits. Thought I’d add the videos here itself)

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Something like this could be broken into parts to build capacity. Before we get into the acids and glassware and actual scraps etc - we could build the forge - it can be used for all kinds of other forge work also - from baking earthen pots to heating your lunch. Heck, if we have a good forge, we can make our own earthen cooler designs or a clay version of @jtd’s aeroponics tower also - from my other thread :stuck_out_tongue: It is like having a power tool. Many uses.

Once we have that working confidently, we can then focus on nailing the chemistry part. Some existing glassware and tools - like tongs, etc may be usable, others may need to be found, made or purchased. I bet the lab itself can provide scraps for experimental quantities :smiley:

Sequentially in the process, the chemistry comes first and the forge last, but storing chemicals is a dangerous business, particularly in a lab that is accessible to many, so they should be obtained only when we are ready to use them. Additionally, it may be necessary to create an area that is under lock and key for storing chemicals - not so much to limit access, as to ensure they aren’t used unsupervised.

At least that is how I would go about doing something like this.

If we make a solar forge, I’d recommend leaving out automatic solar tracking in non-production stages. An unattended solar forge going out of focus is a feature, not bug when figuring things out. Don’t need the forge setting things on fire during the lunch break.

A forge doing work all day is a different matter. Needs a solar tracker. But for most uses, that kind of power will not be needed for long durations - for that matter, even for making the gold bars/coins/whatever. Those short durations can easily be managed by focusing manually.

“Highly interdisciplinary” is my middle name. I just need co-conspirators, due to my own limitations because of kid, etc. I would be happy to get involved. Plus no electronics involved. I should be okay. :rofl:

However, automatic solar tracking could make the kiln suitable for pottery projects as well. Put in kiln, let it run through the day, take out lens in evening, remove pottery when cool…

Earthenware is one area I think needs to be explored more. It is poroous, effective at evaporative cooling, and if one has a furnace, could be used to fabricate all kinds of useful things for use directly or in other projects. @jtd’s aeroponics tower made of terracotta could be a highly decorative item in addition to functional and would be very beneficial to keeping roots cool in our climate. Even if not touchy highland plants, regular vegetables do better with cool roots (they naturally grow in wet soil, after all) - for eg, try growing lettuce with hot roots. If you can get it to live beyond germination, it will bolt and lose taste if the sun heats its black tower. For that matter, many food crops prefer cool roots - capsicum family, cucumbers, tomatoes… If we have the kiln, and the ground has all the clay we need… literally free production except for labour once an initial design is made and cast in plaster of paris. Such a design would also add resilience and give breathing room before plant damage/death in case of a power cut or electronics failure, etc.

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We wanted to do this on a large scale for the above reason AND localise grow towers to reduce costs. It is on my todo list.

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Here is what I know how to do and am willing to be involved to whatever capacity you find useful.

  • Some art background, some experience working with clay - not a lot.
  • Some plants background - mostly vegetables and carnivorous plants.
  • Have researched this considerably over the years and understood the tech involved, so that how it works is clear in my head along with most other ways it is done and why I prefer a certain one. For eg, to use as a kiln, would be better to do a sandwich between parabolic solar cooker and fresnel lens. High heat and long durations needed. Redundancy will allow us to reach the temperatures well, making for stronger towers + “fire” the material from both sides giving an even “bake” and reducing chances of cracking from uneven heat as well.

Edit: That said, my idea of a “parabolic cooker” is an upside down umbrella covered with reflecting foil (and excess handle cut off or it will heat/melt/get in the way)

Edit2: In case we scavenge for the Fresnel lens instead of buying it (of course. Where’s the fun in buying), this video may come in handy…

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You will see me soon collecting old TV lenses! I already have one.

Meanwhile we will also source potters clay in sufficient quantity to bake grow towers.

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Nice.

We can then try VKs geodesic structure with rammed earth hexagon brick.

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So I did some more research and while a fresnel is used to melt metal, etc, I didn’t find any references for firing kilns. Makes me think it has something to do with the relatively small focus area. Uniform firing may be hard. Because hard to think that someone who melts metal with a Fresnel for keeda didn’t try baking clay at some point.

So, the parabolic mirror in the experimental design in my head has been replaced with a “tank” type structure made of brick. And we may possibly need a hybrid kiln, with the fresnel providing the temperatures, but some way to distribute them. This is a design challenge. Some ideas I am toying with:

  • A brick enclosure with a raised platform for placing pottery (this is standard kiln stuff) and some kind of wood/kindling to create an overall fire? Might as well use a wood kiln.
  • A brick enclosure with a raised platform with some kind of cover that gets heated by the fresnel and fires the contents by raising the temperature of the whole area covered by it.
  • A brick enclosure with the ceramics buried in sand and heated with a slightly out of focus Fresnel covering a larger area. This could work, but the temperatures will need watching. Last thing we need is to fuse the sand and um… surround our greenware (unfired) ceramics in it. lol. Small broken pottery pieces may be a better idea but will probably not be as efficient unless quite small.
  • Brick enclosure with out of focus Fresnel warming the whole thing, and a small amount of wood/paper/cowdung/whatever-is-handy-and-will-burn added in the end to “finish off” (we can evaluate if this is needed with experimentation)

I don’t have a clear answer yet, but a brick enclosure or some kind of structure that holds in the heat sounds essential if we are to use a fresnel (as opposed to say… chucking the greenware onto the coals of a campfire).

Doable hack. Instead of one large Fresnel lens, we use an array of smaller ones - each will have its own focal point (don’t think Fresnel lens can converge focal points, given that same source of light), so heat will be distributed. Make them all slightly off focus so they project squares rather than points of light, and we should be in business.

A good material to line the brick enclosure could be “ceramic fiber” - apparently it is used for insulation in indoor kilns. Though not sure we need an insulation beyond the bricks outdoors. Or heck, we can simply pile up mud into a box-like shape and it can fire itself in its own time from use :stuck_out_tongue:

Thought of using some reflecting material for the heat on the inside, but it will likely melt so no point.

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