I have seen this video many years ago, no pyrolysis is seen, they indicate that they are melting ore with gold and what is charged is the ore with flux, I do not think they have good recovery performances of precious metals, the slag looks very pasty, They don't have the right temperature or the right flux mix or both at the same time.
One step pyrometallurgy process for PCB
- Thread starter Ayham Hafez
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I have seen this video many years ago, no pyrolysis is seen, they indicate that they are melting ore with gold and what is charged is the ore with flux, I do not think they have good recovery performances of precious metals, the slag looks very pasty, They don't have the right temperature or the right flux mix or both at the same time.
Kind of. Depends on how you describe "reaction".
If you take urea and plain nitric acid, mix them together in solution and wait, you will obtain urea nitrate. This is ordinary salt. Urea is basic, nitric acid is acidic, thus you will create salt of the aforementioned two. Similarly as you mixed nitric acid and ammonia. Or nitric and sodium hydroxide.
This, in chemical terms does nothing interesting in terms of nitric removal from solution. It just transform free nitric to nitrate.
In AR solutions however, nitric acid is decomposed by reaction with hydrochloric acid to chlorine and nitrosyl chloride. And only these two can actually react in some redox reactions with urea to chlorinate it, nitrosate it, eventualy diazotize the urea nitrogen and be extruded as elemental nitrogen (this is that familiar fizzing).
This sequence of reactions is very complex, leading to very strange intermediates and products, such as formamide, chloramines/nitrogen chlorides (nasty stuff), carbon dioxide, in some scenarios even carbon monoxide...
And all in all, this just do not prevent active oxidizer - chlorine - to re-dissolve gold in most scenarios. As urea does not reduce gold from solution, this "theatre" of often questionable and non-plesant reactions do not stop active species of AR from re-dissolving gold. It just supress it.
Most of the times, diluting of the solution can actually prevent significant re-dissolution of gold, if paired with urea. But I do not like the wannabe chemistry (without replicable reliability) to be performed on larger scale.
Of course you will obtain gold powder in the end. But remember, analytical significance of stannous Au detection in heavy metal chloride solutions has quite some limitations. And fact that you cannot see stannous "positive" does not necessarily mean you have all of your gold dropped.
BTW, I opened links you posted, but this is just a general promo and product sortiment of the company (what I seen, maybe it is there somewhere). Does it somewhere say something about the process ? Or do you have this information from some insider ? I doubt that such company will publically disclose it´s secretive setup and procedures. Urea can be used as additive in some electroplating baths, so maybe that´s it.
Drinking milk to prevent lead poisoning is like curing yourself with herbal tea when you have pneumonia.
It won´t make things worse, there are maybe some benefits or even minor measurable good outcomes... But I really doubt that it will make significant difference. Maybe in persons with calcium deficiency, where lead could be more easily incorporated on the active sites for calcium.
Really. Lead is cumulative poison. Years and years unnoticed without obvious symptoms - as the decline in brain activity and other neurotoxic effects worsen only very slowly. But we now know for sure that lead is one of major causes of cognitive decline in humans (loss of IQ and brain functionality). From very low levels. Even ancient Romans noticed, and it was some 2000 years ago.
Any time you are heating/melting lead over 700 °C, the fumes arising from the melt contain very significant lead oxide outgas. Raise the temperature and it gets worse exponentially. During classic cupellation, few % of total lead is just volatilized away in the process. That is why colder parts of the furnance in proximity of molten stuff will turn yellow.
We used to have scrubber for pyro-hood mounted, and once during the melting of mixed alloy of base and precious metals containing lead (around 15-20% Pb, mass around 1kg, induction furnance - with natgas or similar it will only get worse as volume of circulated gas is magnitude higher), I placed thin mineral wool blanket piece to the intake of the scrubber. After just 15 minutes I removed it, and it clearly measured lead when zapped with handheld XRF (which LOD isn´t that good)... That was just clear warning sign not to underestimate this phenomenon.
I don't believe that. That study that was posted earlier stated that the workers were given 700 grams of milk every day - which would be roughly 700 ml. The study stated there may have been somewhat less neuropathy in the hands, but did not note any reduction for the feet.
In no way did the study hint that the milk would "solve any health issue caused by lead".
The only thing drinking milk can do, is to temporarily bind the Lead that is swallowed.
But that will be released when it gets into the bowels and the milk is broken down and taken up into the body.
I can do nothing for Lead that is inhaled or taken up from the skin.
Ayham Hafez
Well-known member
It not solves, it prevents.
It will not prevent anything Lead related.
Milk can under certain circumstances encapsulate ingested toxins and shield them for the body for a short time.
But you do not drink the Lead here.
You drink milk and it will be taken up in the body and converted into different biological substances that will exist in the blood for longer or shorter time.
It will never be able to interact with the inhaled Lead, since it is in the lungs and not the stomach.
Here is from an article in LARC, Lead Abatement Resource Center:
As one see here fatty foods are bad and Milk are fatty so it may even worsen the situation, for ingested Lead that is.
Calcium is good, and Fat is bad so net 0, maybe.
For Our purpose it may be considered a Placebo.
Not doing anything bad, but not anything good either with respect to Lead.
Ayham Hafez
Well-known member
Scientifically maybe you alright, but from my experience milk stopped any lead poisoning, believe me , more than 2 years work in lead factory that has very bad filtration system, automation not exist at all, all production done by labors, you can smell lead oxide gases every where, am talking about 10th world factory, in spite of that, we didn't record any poisoning case, we just obligated labors to drink milk everyday.
Lead is a sneaky accumulative poison, it may take years or decades until it manifest itself.
So you do not believe in science, if so why are you here asking help from scientific minded people??
People believe what they will, but in here we do not promote Alchemy, witchcraft, unproven medical treatments or similar.
So please let this go.
Ayham Hafez
Well-known member
I sent scientific article proof my experience, but none believe it, just google it you will find different articles talking about that.
Martijn sent a link, you did not if my memory serves me correct.
But the problem about that is that it can not do anything with what you breathe, only what you eat and what gets into your bloodstream as far as I understood it.
And in this one they only measure the peripheral nerve damage and they are drinking 700grams a day.
This is done in a presumably much better controlled environment than you are describing.
The Lead-Calcium interaction might reduce the Lead content in the bloodstream,
but most articles also urge the use of Vitamin B9, Iron and Zinc.
And this probably is just a help in delaying symptoms.
What is needed is a properly vented and scrubbed Lead free environment.
Not some cheap "here drink some milk" attitude.
It will help some, but will not solve the issue.
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So you concur that nitric acid and urea react. Great. I didn’t have to elaborate because I can’t debunk a false statement to any degree greater than its false. I rarely say anything about language but I must say that if you are going out of the way to say that my debunking was not technically correct into the minutia your language should be. I don’t believe its a good use of time for me to go line by line pointing out irregularities in your explanation. I will say that reaction is defined and aluminum is extruded. That is as much as I will succumb to pettiness.
Yes I have credentials as an organic chemist, I have had employment as a chemist to develop processes for enhanced recovery methods regarding most of the transition elements. Yes i have insider information. The links I posted were both from divisions of Mitsubishi materials. No they do not explain how it works in depth. They don’t need to, and if you are only going for the precious metals in your material you can not compete with them. Why can I be so sure in this statement? Because I know that they pay more for their feedstock than it contains in precious metals sometimes. How? Because tin is right up there as the most valuable metal in ewaste and it’s basically free to them.
BASF also has some ewaste expertise and they basically use iron as an extraction solvent and convert the material to a glass or flux or whatever you want to call it. They are better than any wet chemical processing methods but not quite so good as Mitsubishi is.
I will post this now because I keep loosing my writing because of my fingers being too big for the diminutive buttons on this site.
Nice coincidence, I am also organic chemist. I refined common precious metals as side-job for few years, and for more than 10 years on hobby level.
I don´t want to argue with you, there is no point in arguing here.
My experience with various de-NOx-ing agents is quite rich, as I tested various things on still active AR solutions. Urea simply wasn´t working as I wanted - completely and cleanly de-NOx-ing the solution.
I can agree with you in absolute terms that urea react with nitric acid. But not all reactions will give desired outcome, they just happen. This is one of the cases.
In nitric acid solutions (no HCl/chloride), it will form urea nitrate and there, reaction stops. Urea nitrate will maybe form in stronger solutions, but nothing will change the oxidation state of the nitrate nitrogen - and that is the important thing.
In AR, nitric must first react with HCl to liberate chlorine and reduce the nitrogen down to N(III). Only then urea react with it in redox fashion - and that is what matters there.
That is the point. Once chlorine is liberated, it can dissolve gold. And nothing will re-precipitate the dissolved gold, as urea do not precipitate gold. Addition of urea thus only supress this reaction by removing some of the chlorine and N(III) residues. These reactions all go in parallel with gold re-dissolution.
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Do you happen to use sulfamic acid now? I do agree that urea is not a clean way to denox ar before you precipitate your gold from solution.
Yes, I use sulfamic, but most of the times in combination with copper. I developed my own technique of simultaneous de-NOx-ing and precipitation on copper, which is effective also for ferrous base metals solutions, with benefit of mutual de-NOx-ing and first and complete gold drop. Another benefit is obviating stock-pot completely (if you do not have Pd and Pt in your plated scrap, which is rare in my case).
Sulfamic alone isn´t without issues, it is slow and oftentimes not very plesant in terms of time vs. efficacy.
I always try not to use excess of nitric, and if possible (or desired, if you still have active nitric in and you want to de-NOx in most cost/waste-effective way), I simply concentrate values by cementation on another portion of material added to still slightly active AR. Everything is then much nicer when you raise gold concentration - gold drops are heavy and easy settling, not that much unfilterable microparticles of Au will form etc.
OH! I have done that recently, by mistake. Was melting a bunch of aluminium heat sinks to recast and I grabbed a tiny capacitor in the mix. It explodes like popcorn, very dangerous since I was watching it all from close up. Luckily I had only 1 in there.
I melt my aluminum in a cast iron pipe with 1cm-thick walls. I toss the aluminum caps in there and listen to them pop, with a jet of flame shooting out the top of the pipe!
Oh, and I did my first full firing of my new brick furnace early this week, using just wood as the fuel.
The 'blast' of the air is so intense and focused with the directed air flow that it super-heated the cast iron and caused it to fail structurally! I estimate the temp reached at least 2200F, and went through hundreds of pounds of trash wood in an hour! (was mainly doing the fire to both test and get rid of a bunch of wood junk from house repairs.)
On the plus side, at that temp the inside of the pipe was strongly reducing with the carbon residue of the paper in the capacitors, and the aluminum recovery appeared to be almost total. Very little remained in the slag!
What do you do with the dangerous fumes from the caps?
The pipe is inside the furnace. The fumes combust completely, without even any smoke whatsoever. The heat is so intense you couldn't stand next to it if you wanted to. I have to wait for the fire to die down to poke down into the pipe and knock the slag loose. By then, everything is melted/burned off.
