Shifting to pyrometallurgy process

[Ayham Hafez]

I think you may need to hit the metallic ingots with an XRF, to determine what you have. My suspicion is Al. Not really amendable to a Nitric bath, if in large enough quantity.

No its not aluminum, I make sure I removed all aluminum parts, I think its because of silicon, I didn't use any silica, I did another test with adding silica and I got a usual nitric reaction with the metallic shots.

Do you know any cons for using tiny amount of sulphur inside my fluxes recipe to put iron and other base metals in sulphur slags? So I don't need to make magnetic separation?

 

[goldshark]

No its not aluminum, I make sure I removed all aluminum parts, I think its because of silicon, I didn't use any silica, I did another test with adding silica and I got a usual nitric reaction with the metallic shots.

Do you know any cons for using tiny amount of sulphur inside my fluxes recipe to put iron and other base metals in sulphur slags? So I don't need to make magnetic separation?

Not really sure what you mean by "any Cons". Do you mean flux?

 

[Ayham Hafez]

Not really sure what you mean by "any Cons". Do you mean flux?

I mean is it a good idea to use sulphur powder as a flux when smelt E-waste, so we make sure iron and other base metals will be pushed into slags as sulphates, small amount of sulphur to avoid sulphurizing copper.

Cause I noticed if we use nitrates to oxidize base metals we should add big quantities of nitrates which will eat refractories or crucibles quickly, why we need a lot of nitrates? Simply because we will have a lot of carbon inside our pyrolized E-waste which will react with nitrates before iron or other base metals, also sulphur much faster with reaction with iron than oxygen

 

[goldshark]

I am not the authority on smelting. From what I have read and done for assaying, I have never used the addition of Sulphur as a flux, to my assays/smelts. Nor have I ever seen Sulphur as a flux in an assayers book of necessary reagents. Almost every sample I assay, has Sulphur in the sample. So I have learned of Sulphur effects on the bead/matte inter face, and how to deal with it by the addition of nitrates, or Iron. I have not done any assaying on e-waste, with the Silicon portion of the smelt.
Additions of Nitrates generally do not lead to excess Silica dissolution of the crucible. This is generally eroded by an excess of Soda Ash, Borax, or other basic ingredients.
Are you pouring the bulk metal into a cone mold, letting it freeze, knocking off all slag, remelting, then pour to shot, or pouring from furnace directly into water, thereby skipping a step?

 

[Ayham Hafez]

I am not the authority on smelting. From what I have read and done for assaying, I have never used the addition of Sulphur as a flux, to my assays/smelts. Nor have I ever seen Sulphur as a flux in an assayers book of necessary reagents. Almost every sample I assay, has Sulphur in the sample. So I have learned of Sulphur effects on the bead/matte inter face, and how to deal with it by the addition of nitrates, or Iron. I have not done any assaying on e-waste, with the Silicon portion of the smelt.
Additions of Nitrates generally do not lead to excess Silica dissolution of the crucible. This is generally eroded by an excess of Soda Ash, Borax, or other basic ingredients.
Are you pouring the bulk metal into a cone mold, letting it freeze, knocking off all slag, remelting, then pour to shot, or pouring from furnace directly into water, thereby skipping a step?

I use cone mold then melt again and make shots.

I think sulphur is the best option to push base metals into slag, even we can reduce the copper content in the molten metal in case its very high, I did a test on different network coax gold plated connectors, they have very high content of copper and since I use nitric to part the copper I added 10% sulphur to the connectors, used small amount of soda ash,borax and fluoride since most of the connectors is metallic part, after pouring the cone I got 50% of the main connectors weights, I believe if I increased the content of sulphur to double will push all copper into slag, but in this case I have to add some silver to make sure I collect all gold beads, theory,if I want to recover the copper I can remelt the slag with adding some iron or I can just mill and roast the slags to get rid off sulphur.


Using sulphur from my test is much faster and cheaper than using copper electrolysis cell or nitric parting, I got same amount of gold that usually got from same type of connectors using hydrometallurgy process.

I want to get some advices before use sulphur in large batches, now I'm planning to first smelt pyrolized connectors without sulphur in the flux so I will have wide molten metals space into my flat crucible ( its a customized furnace), then I will add the sulphur to ic chips and mlcc's ash and feed them above the molten connectors, so I can make sure the molten connectors will collect the metallic parts of the ic chips, then the sulphur will start to sulphurize the base metals, then pour into the cone mold.

Sulphur makes the smelting and gold recovering very easy and controllable, this make me confused if I make something wrong, hope I will get some advices about it.

 

[Ayham Hafez]

I got the idea of using sulphur from my friend, I think he got the idea from this video




So I think its effective way, but the video shows that tin not react with sulphur, I don't know how, I make some research and found that tin displace copper in copper sulphate ore, he only did two tests, one with 5% sulphur and other with 100% sulphur, maybe if he increased sulphur to 10 or 20% he will get tin sulphate.

 

[Yggdrasil]

I use cone mold then melt again and make shots.

I think sulphur is the best option to push base metals into slag, even we can reduce the copper content in the molten metal in case its very high, I did a test on different network coax gold plated connectors, they have very high content of copper and since I use nitric to part the copper I added 10% sulphur to the connectors, used small amount of soda ash,borax and fluoride since most of the connectors is metallic part, after pouring the cone I got 50% of the main connectors weights, I believe if I increased the content of sulphur to double will push all copper into slag, but in this case I have to add some silver to make sure I collect all gold beads, theory,if I want to recover the copper I can remelt the slag with adding some iron or I can just mill and roast the slags to get rid off sulphur.


Using sulphur from my test is much faster and cheaper than using copper electrolysis cell or nitric parting, I got same amount of gold that usually got from same type of connectors using hydrometallurgy process.

I want to get some advices before use sulphur in large batches, now I'm planning to first smelt pyrolized connectors without sulphur in the flux so I will have wide molten metals space into my flat crucible ( its a customized furnace), then I will add the sulphur to ic chips and mlcc's ash and feed them above the molten connectors, so I can make sure the molten connectors will collect the metallic parts of the ic chips, then the sulphur will start to sulphurize the base metals, then pour into the cone mold.

Sulphur makes the smelting and gold recovering very easy and controllable, this make me confused if I make something wrong, hope I will get some advices about it.

To me adding Sulfur seems strange.
It melts at 112C and boils off at less than 500C.
As it vaporizes it will burn with a blue flame and create SO₂
Maybe it can react with some substances, but most will be too cold to react much, before the Sulfur is vaporized and gone.

 

[Ayham Hafez]

To me adding Sulfur seems strange.
It melts at 112C and boils off at less than 500C.
As it vaporizes it will burn with a blue flame and create SO₂
Maybe it can react with some substances, but most will be too cold to react much, before the Sulfur is vaporized and gone.

That a good point, usually roasting evaporate the sulphur as an element with low temperature as you mentioned, but how its not depends on my experiment and Jason video?

When I added 10% sulphur I added it depends on small calculation, sulphur density is about 25% of copper density, so I added 10% only and I lost 50% of copper content into sulphide so I think all added sulphur contaminated with copper

 

[offtrailhiker]

best place to make the output smoke hole in the lid,is it better to make it above the lid or from Infront of it?

I'd vent from the top and install a simple afterburner to catch initial fumes before your furnace gets to operating temperature. Great work, by the way.
Edit for clarity: when pyrolyzing.

 

[RichardSukhoi]

I'd vent from the top and install a simple afterburner to catch initial fumes before your furnace gets to operating temperature. Great work, by the way.
Edit for clarity: when pyrolyzing.

I have wondered if a good way to clean fumes from a pyro decomposing vessel (I mean any chamber which organic matter is decomposed by heat) is to afterburner such as feeding the gas into a swirl flame propane torch? Is it necessary to make sure the vapour in the chamber is not combustible for example by adding a CO2 purge into it? Or is a platinum catalytic cleaner such as off a European motorcycle better? Just idle thoughts and questions.

 

[FrugalRefiner]

It's best to feed the fumes from pyrolyzing back into the combustion flames being used to heat the vessel. It serves double duty. Because the fumes are usually combustible, they support the heating allowing the use of less outside fuel. As they are fed into the flames, they are further decomposed in the heat of the fire.

Dave

 

[offtrailhiker]

This shows a method for separating parts from boards using hot liquid and separation.
like in a washing machine

Good idea. You may want to wear a respirator, though

 

[slsmp40]

BASF treats the boards as a liquid liquid extraction with the solvent being liquid iron. Any flux that is used is minimal and proprietary. The glass from the boards and components composes most of the flux. Iron is used as at it’s melting point is higher than almost anything else in the boards so it is more efficient and less waste is produced. It is probably the highest efficiency recovery going dollar for dollar. Copper refinery pulls are probably the next where low expense is concerned. Wet chemistry is about the worst way to go to recover the metals and is only used for its low barrier of entry.

 

[RichardSukhoi]

BASF treats the boards as a liquid liquid extraction with the solvent being liquid iron. Any flux that is used is minimal and proprietary. The glass from the boards and components composes most of the flux. Iron is used as at it’s melting point is higher than almost anything else in the boards so it is more efficient and less waste is produced. It is probably the highest efficiency recovery going dollar for dollar. Copper refinery pulls are probably the next where low expense is concerned. Wet chemistry is about the worst way to go to recover the metals and is only used for its low barrier of entry.

I guess it’s not easy to set up a small scale molten iron solvent bath
Long ago I was given a demonstration of a small ozone ashing rig. On the order of $2000 it consisted of a pressure swing oxygen concentrator (easiest way to obtain is to buy a used home medical unit - I see these for $100), then an ozone generator (this company held patents on high efficiency units which I assume are expired so can be bought from China now), a stainless steel box that sealed with a metal gasket, a small heater, then a charcoal ozone destroyer at outlet. A plastic encapsulated microcircuit was placed inside, unit turned on, and although I can really remember let’s say 72 hours later what remained was the ceramic wafer, the galvanized copper frame, the silicone chip with the gold wire and ball bonds exposed for examination with microscope. All that remained of the epoxy resin was the glass powder filler.
All the organic material was annhilated.
I wonder if such a rig makes sense for small scale circuit board metal recovery? Slow, but safe and clean.

 

[TheDoode]

Sounds like a lab setup for preparation of microscope samples, more than a PM recovery production setup.

But I have a dummy question. Pyroprocesses are outside my expertise. Why not just melt the stuff down with some carrier copper (if not enough in the feed stock)?
By stirring you can get the iron pins and other high melting coated stuff in contact with the copper melt. The copper melt will dissolve the gold plating off the high melting components. Skim the dross off the melt and cast the pregnant copper into the form you like. Does this not work?

Maybe blow air on the melt to burn off Zinc. Because getting Zinc out of the electrolyte is a bit of a hassle. So less is good.

I don't consider wet chemistry to be inferior, when properly done. When you know how to do it and recover reagents and metals from the "waste" streams. A good thing economically AND ecologically.