my last company is doing pyrolysis to create diesel and other fuels out of plastic. The process is done on a kiln, oxygen free. When the plastic is fed nitrogen is used to purge any oxygen from the feed. Plastic melts at around 300C and vaporizes at around 400C. The left over coke is around 3%. They don't do PCBs because of the increase residuals of fiber glass.
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Non-Chemical Pyrolize quads chips in assay furnace?
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TomVader
Well-known member
I have a question. Is chlorine gas one of the products of burning the type of plastic that the PCBs are made of, and if so, can this chlorine bond with the gold plating and then carry the gold off in the smoke? Thanks in advance.
Geo
Well-known member
im not a chemist and may be 100% wrong about this, but i think the hcl has to be formed in water. chlorine alone should not effect gold.
Pantherlikher
Well-known member
Just a quick thought on smoke as a problem. Have you ever barbaqued in winter?. I do it when I feel like the good taste of a burned burger or something.
Having a furnace disguised as an old charcol BBQ would fool the nosy neighbors. I'm just not sure of the smell. maybe BBQ some before hand to get the juices down inside might help.
That's been my thinking here since my wonderful neighbor has taken a major dislike for me and likes calling the code enforcement every now and again just for having stuff in my driveway. Like the seats from my van to make room for more scrap inside.
Any how, wood chips or Pellets would be perfect as you cut a hole for the blower attachment. Metal can assembly in the middle of it all. Fire wood up. I use a propane torch. I'd think a round BBQ lit on the edge of pellets would create a nice slow circular burn toward the center. You could even take some meat fat and let it sizzle on the lid of the BBQ for the meat smell.
Just disguised MGiver thought.
BS.
Having a furnace disguised as an old charcol BBQ would fool the nosy neighbors. I'm just not sure of the smell. maybe BBQ some before hand to get the juices down inside might help.
That's been my thinking here since my wonderful neighbor has taken a major dislike for me and likes calling the code enforcement every now and again just for having stuff in my driveway. Like the seats from my van to make room for more scrap inside.
Any how, wood chips or Pellets would be perfect as you cut a hole for the blower attachment. Metal can assembly in the middle of it all. Fire wood up. I use a propane torch. I'd think a round BBQ lit on the edge of pellets would create a nice slow circular burn toward the center. You could even take some meat fat and let it sizzle on the lid of the BBQ for the meat smell.
Just disguised MGiver thought.
BS.
Burning poly vinyl chloride plastic can release HCl gas,
HCl hydrogen chloride is a gas, when this gas hits moisture in air or your lungs, or bubbled into water will form HCl acid hydrochloric acid.
http://www.ehow.com/list_5926080_dangers-burning-plastic-bottles_.html
if incinerating gold with HCl or any chloride salt, chlorides in melt, can form chlorine gas and HCl gases, gold is volatile in chlorine gas at 800 degrees and will vapor off in fumes, so basically yes if burning poly vinyl chloride with gold or any chloride salt with gold will result in gold chloride gases in these fumes
http://www.google.com/#sclient=psy-ab&hl=en&tbo=d&rlz=1R2RNQN_enUS457&q=gold+volatility+in+chlorine+gas+at+high+temperatures&oq=gold+volatility+in+chlorine+gas+at+high+temperatures&gs_l=serp.12...531.26078.1.27953.30.18.0.0.0.1.2672.18858.0j1j5-1j2j3j2j4.13.0.les%3B..0.0...1c.1.InQ8myUcgzo&pbx=1&bav=on.2,or.r_gc.r_pw.&fp=e474f98c32051253&bpcl=39967673&biw=1024&bih=539
HCl hydrogen chloride is a gas, when this gas hits moisture in air or your lungs, or bubbled into water will form HCl acid hydrochloric acid.
http://www.ehow.com/list_5926080_dangers-burning-plastic-bottles_.html
if incinerating gold with HCl or any chloride salt, chlorides in melt, can form chlorine gas and HCl gases, gold is volatile in chlorine gas at 800 degrees and will vapor off in fumes, so basically yes if burning poly vinyl chloride with gold or any chloride salt with gold will result in gold chloride gases in these fumes
http://www.google.com/#sclient=psy-ab&hl=en&tbo=d&rlz=1R2RNQN_enUS457&q=gold+volatility+in+chlorine+gas+at+high+temperatures&oq=gold+volatility+in+chlorine+gas+at+high+temperatures&gs_l=serp.12...531.26078.1.27953.30.18.0.0.0.1.2672.18858.0j1j5-1j2j3j2j4.13.0.les%3B..0.0...1c.1.InQ8myUcgzo&pbx=1&bav=on.2,or.r_gc.r_pw.&fp=e474f98c32051253&bpcl=39967673&biw=1024&bih=539
In the book "Metallurgy of Gold" by M. Eissler is treating the subject of "Loss of Gold by Volatilization in Chloridizing Roasting." (pg. 216-227)TomVader said:
More or less it can be summarized in that the loss of gold can take place to a considerable extent during chloridizing roasting. The higher the temperature is the easier it is to lose gold.
A lot of the chlorine in the plastic (my guess is that the main source of chlorine is PVC) is turned into HCl (not chlorine gas, Cl2) when it burns and then carried away in the gases. This can be done at lower temperatures than the red heat used in roasting ore. But there are also other sources of chlorine in PCB:s, for example the electrolyte in capacitors. Some of that chlorine could easily stay in the material and become active at higher temperatures during incineration.
One way to catch that gold is to use particle filters on the gases from the incineration.
I don't know how big the losses are in reality, it probably depends on the way the burning is done and could be really individual.
Thanks for asking the question, I had a really interesting read while researching it.
For the book, see http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=54&t=14107
/Göran
I just remembered the Miller process where chlorine gas is blown through molten gold. Most other metals will form chlorides before the gold starts to form chloride. So as long as there are other metals present the gold on the PCB:s should be mostly protected.
Free gold particles in contact with chlorinated substances could be another story...
/Göran
Free gold particles in contact with chlorinated substances could be another story...
/Göran
I am not totally sure, but from what I can gather,
If we have a gold chloride AuCl3 at a little over 200 deg. the AuCl3 begins to decompose the chlorine can begin to leave the gold salt crystal as a gas, but at higher temperature over 300 deg. the gold can again form a chloride of gold, gold at high temperature (I have read 800deg.) or (close to red hot) gold can be dissolved in a stream of chlorine gas, and become volatile in this atmosphere of gas at high heat.
I think also the PVC plastics would break down with heat melting and then gassing off the vapors one of which is HCl, at a much lower temperature than where gold would become volatile, if all of the PVC was decomposed to ash, at these lower temperature, the gold probably would not become volatile (assuming all of the plastic decomposed to ash in the container, at these lower temperatures).
An acid and a metal form salts of that metal, Chloride salts or salts of chlorine gas and a metal, or salts of HCl and a metal, (NaCl, CuCl, PbCl2, AuCl3 and do so on) Chloride salts in powders of gold, in heating or fusion before a roast, can fuse with the gold powders before the metal chlorides decompose, and the chlorides fume off.
On heating the dry gold powders can then become wet again (fuse seeming to melt back to a liquid syrup) and form a syrup like substance (fused salts) in these salts during the fusion with the heat, this entraps the gases from leaving, and much of the chlorides at these temperatures can react with these metal powders, the chemical reaction under these conditions can dissolve metals that normally will not dissolve (like Rhodium being dissolved in a fusion of bisulfate where otherwise Rh is not attacked and is very resistant to acids).
Then on further heating of a period of time this fusion begins to dry out again and harden as the more volatile gases leave, if this lump of fused metals are not again crushed and exposed to heat and air then much of these gases are trapped in the crystal matrix of the lump, but if crushed and exposed to air these gases can more easily escape and vapor off or leave the crystal matrix, oxygen can also help to oxidize the more reactive metals, anions, Cations involved, most of the chlorides (or acids are driven out of the powders or crystals) as long as the crystals are powdered enough and the temperature is not raised to a higher temperature where gold can become volatile, the crystals can decompose, with minimum lose of gold.
but if the temperature was raised to a red heat before the chloride was decomposed, (like burning biscuits in a hot fire the outside of the crystal can burn, before the inside of the biscuit or crystal dried out), at red heat with chloride salts entrapped in the crystal matrix the loses would be much higher and you can have gold vapor off in the fumes.
Not having chlorides, or HCl, or chloride salts, and eliminating them as much as possible before burning, incineration or roasting, can just help to eliminate the possibility of vapor off some of your gold.
It is not only gold that forms volatile chlorides, silver and many base metals will also.
If we have a gold chloride AuCl3 at a little over 200 deg. the AuCl3 begins to decompose the chlorine can begin to leave the gold salt crystal as a gas, but at higher temperature over 300 deg. the gold can again form a chloride of gold, gold at high temperature (I have read 800deg.) or (close to red hot) gold can be dissolved in a stream of chlorine gas, and become volatile in this atmosphere of gas at high heat.
I think also the PVC plastics would break down with heat melting and then gassing off the vapors one of which is HCl, at a much lower temperature than where gold would become volatile, if all of the PVC was decomposed to ash, at these lower temperature, the gold probably would not become volatile (assuming all of the plastic decomposed to ash in the container, at these lower temperatures).
An acid and a metal form salts of that metal, Chloride salts or salts of chlorine gas and a metal, or salts of HCl and a metal, (NaCl, CuCl, PbCl2, AuCl3 and do so on) Chloride salts in powders of gold, in heating or fusion before a roast, can fuse with the gold powders before the metal chlorides decompose, and the chlorides fume off.
On heating the dry gold powders can then become wet again (fuse seeming to melt back to a liquid syrup) and form a syrup like substance (fused salts) in these salts during the fusion with the heat, this entraps the gases from leaving, and much of the chlorides at these temperatures can react with these metal powders, the chemical reaction under these conditions can dissolve metals that normally will not dissolve (like Rhodium being dissolved in a fusion of bisulfate where otherwise Rh is not attacked and is very resistant to acids).
Then on further heating of a period of time this fusion begins to dry out again and harden as the more volatile gases leave, if this lump of fused metals are not again crushed and exposed to heat and air then much of these gases are trapped in the crystal matrix of the lump, but if crushed and exposed to air these gases can more easily escape and vapor off or leave the crystal matrix, oxygen can also help to oxidize the more reactive metals, anions, Cations involved, most of the chlorides (or acids are driven out of the powders or crystals) as long as the crystals are powdered enough and the temperature is not raised to a higher temperature where gold can become volatile, the crystals can decompose, with minimum lose of gold.
but if the temperature was raised to a red heat before the chloride was decomposed, (like burning biscuits in a hot fire the outside of the crystal can burn, before the inside of the biscuit or crystal dried out), at red heat with chloride salts entrapped in the crystal matrix the loses would be much higher and you can have gold vapor off in the fumes.
Not having chlorides, or HCl, or chloride salts, and eliminating them as much as possible before burning, incineration or roasting, can just help to eliminate the possibility of vapor off some of your gold.
It is not only gold that forms volatile chlorides, silver and many base metals will also.
Geo
Well-known member
consider this. how much plastic are you going to have with gold in it. if the OP is concerned about a few slot connectors needing incinerated to get the pins out, i dont see a problem with it. i havent noticed that any of the pins i incinerate was missing gold when the acid hit it.
NoIdea
Well-known member
Hi All - top of the morning to you all. 
From what i recall, PVC was and may still be 25-30% by weight HCl, dependng on its use, so if you burn/pyrolyze PVC you will create or the potential to create 1lt of 25-30% HCl acid if absorbed in water.
I think i made have mention somewhere here, that it was cheeper for a company to ship waste PVC from one contry to another and convert it to HCl acid via a conversion plant than it was to transport the equivelent amount of HCl acid due to the cost in specialize equipment and transportation permits. Food for thought.
And DO NOT burn PVC around fruiting trees unless you want all of your produce to end up on the ground. :shock:
Deano
From what i recall, PVC was and may still be 25-30% by weight HCl, dependng on its use, so if you burn/pyrolyze PVC you will create or the potential to create 1lt of 25-30% HCl acid if absorbed in water.
I think i made have mention somewhere here, that it was cheeper for a company to ship waste PVC from one contry to another and convert it to HCl acid via a conversion plant than it was to transport the equivelent amount of HCl acid due to the cost in specialize equipment and transportation permits. Food for thought.
And DO NOT burn PVC around fruiting trees unless you want all of your produce to end up on the ground. :shock:
Deano
Good to know if we ever enter into urban warfare!NoIdea said:
bmgold2
Well-known member
NoIdea said:Hi All - top of the morning to you all.
From what i recall, PVC was and may still be 25-30% by weight HCl, dependng on its use, so if you burn/pyrolyze PVC you will create or the potential to create 1lt of 25-30% HCl acid if absorbed in water.
I think i made have mention somewhere here, that it was cheeper for a company to ship waste PVC from one contry to another and convert it to HCl acid via a conversion plant than it was to transport the equivelent amount of HCl acid due to the cost in specialize equipment and transportation permits. Food for thought.
And DO NOT burn PVC around fruiting trees unless you want all of your produce to end up on the ground. :shock:
Deano
After reading this, I did a quick Google search and came up with:
http://www.sciencemadness.org/talk/viewthread.php?tid=11274
and - couldn't figure out how to directly link to this:
http://lmgtfy.com/?q=Don't+ban+PVC:+Incinerate+and+recycle+it+instead!
You will have to research and decide for yourself if you can safely make your own HCl from recycled PCV plastic but it might --- Well, Don't try this at home --- A little knowledge can be a dangerous thing. It is something to think about though.
NoIdea
Well-known member
Good Morning, PVC pyrolysis is done in an oxygen free environment, hence the word "Pyrolysis", so no dioxins are produced. The only real difficulty i have encountered is the swelling of the PVC when heated, so make sure you leave a good head space in your reactor to allow for this. Remember 1kg PVC + Pyrolysis = HCl gas add 1lt H20 = 1lt 25-30% HCl acid
Cheers
Deano
Cheers
Deano
bmgold2
Well-known member
NoIdea said:
Now I'm really interested in this. It sounds like you actually did this before and not just repeating what you read or heard. Was this done in the unit you built from this post?
http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=38&t=16473&p=166282
I spent some time converting the metric weights and volumes to pounds and ounces only to realise that it is 1 to 1 by weight. I'm not much good with metric but figured out 1000 grams = 1000 liters of H2O or 1mL water weighs 1 gram.
That should mean 1 part PVC to 1 part water by weight to make HCL
Could this be done in steel (iron) pipe and fittings for a small test? Will the HCL gas destroy the pipe fast?
Maybe I'll never try it but I do have a contraption I built years ago out of pipe and pipe fittings to make wood gas (again small test) and PVC waste shouldn't be hard to come up with. Basically free HCL sounds pretty good to me.
bmgold2
Well-known member
bmgold2 said:
Some interest was expressed in a PM about how I made this contraption so I went out and took a couple pictures for anyone interested in what I did.
This isn't exactly how it was set up when I tried it. I converted it into a pestle to smash up rocks/I.C. chips or whatever I decided to break up. I used a fence post driver as the mortar.
Back to the wood gas generator idea. The pipe is, I think a 5 inch long piece of 2 inch diameter black iron pipe with threads on each end. On the bottom I brazed a pipe cap on to insure it was sealed. On the top I put a 2 inch to 3/4 inch adapter which was sealed with teflon tape. When I used it to try to make wood gas, there was a 90 degree elbow with a short piece of pipe at the adapter so it wasn't so high. The 3/4 inch pipe is about 24 inches long on the one I built.
How I used it was I put my wood (saw dust) in the 2 inch pipe maybe half filling it and screwed the adapter on. Then I shoved that end into a fire and that heated it up and a flammable gas came out the other end of the pipe. This was a small test so I put a balloon on that end to catch the gas which I intended to try running a propane burner with as a test.
The idea kind of worked but the problem was the device also produced a foul smelling tar like substance along with the wood gas. I should have built a filter to condense the tar and clean up the gas but never got around to finishing that part of it. I proved to myself that it did produce a flammable gas from the wood and also turned the sawdust into charcoal.
This device was what I was thinking about trying to make hydrochloric acid using scrap PVC in but so far I never even got any further than thinking about that idea. My though is that it probably will also produce some tar as well as flammable gas but I'm not sure that would happen. I'm guessing you would need some kind of trap to separate any tar or liquid and then bubble the gasses through water to capture the HCl gas. From there, I'm not sure if there would still be any flammable gas left so you might want to catch that or direct it back into the fire to burn it producing more heat to continue the process.
This is just my thoughts on how it might work and I very likely could be wrong. If anyone (especially NoIdea) cares to correct or confirm my thoughts please do. Since I still have store bought HCl and it is one of the cheaper and easier acids to get it probably isn't worth doing more than thinking about this idea but once it was set up and working it might help solve a couple problems. How to get hydrochloric acid and how to get rid of waste plastics. I was thinking (hoping) that maybe the plastic parts from the connectors I have been ripping apart might be able to be used for this but I don't even know what type of plastic they are made of. For a test I'm sure I could find some junk PVC or CPVC pipe laying around if needed.
