One step pyrometallurgy process for PCB

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orvi said:
Maybe also publisher of the video do not know why he added urea :) maybe because it fizz nicely. Looking like it is doing something...

We do know why urea kinda works, we know what it can accomplish, but generally, I do not bother as it does not make sense in a way for me to use it in my setup. I pointed it in my reply in the stated article. I do not have resources or time to scientifically prove the assumed benefit of adding urea, but based on several papers regarding reactions of urea with various oxidants, few experiments I performed, and utter fact that urea does not react with nitric acid, I concluded what I concluded.

In original video, thing serving better than urea is high dilution of the liquid, minimizing redissolution of gold powder. Paired with urea, it can maybe serve well, but I would never do it like he does, because ammount of waste produced is just insane.
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orvi said:
Maybe also publisher of the video do not know why he added urea :) maybe because it fizz nicely. Looking like it is doing something...

We do know why urea kinda works, we know what it can accomplish, but generally, I do not bother as it does not make sense in a way for me to use it in my setup. I pointed it in my reply in the stated article. I do not have resources or time to scientifically prove the assumed benefit of adding urea, but based on several papers regarding reactions of urea with various oxidants, few experiments I performed, and utter fact that urea does not react with nitric acid, I concluded what I concluded.

In original video, thing serving better than urea is high dilution of the liquid, minimizing redissolution of gold powder. Paired with urea, it can maybe serve well, but I would never do it like he does, because ammount of waste produced is just insane.
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Urea does react with nitric acid. It is used to destroy nitric acid in aqua regia before gold is dropped. Other things are also used but urea is quite common in industrial settings because it is inexpensive.
 
kurtak said:
They are two completely different things

With the batteries you only have two things to deal with (1) burning off the plastic (2) recovery of the molten lead

With PCBs you have MANY things to deal with (as somewhat explained by 4metals - as well as by me)

The plastics have already been discussed & if they were the only concern would not be that big of a deal - but --------

Besides the PMs (silver gold & palladium) you have multiple base metals to deal with (copper, iron, aluminum, tin etc. etc.) most if not all of those - except the copper - you want/need to eliminate in the smelt (oxidize so they slag off - or remove before going to the smelt)

You also have things like ceramics, silica & silicon etc. that need to be slagged off (& for what it is worth - the silicon will alloy with your copper/PM dore - if not properly slagged off)

So simply put - smelting PCBs - is not as simple as smelting something like lead acid batteries because you have MANY more elements to deal with then just the plastic & lead found in lead acid batteries

Or as I said earlier - trying to smelt PCBs - in a one step process - will result in A BIG MESS !!!

Kurt
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If only lead acid batteries were so simple. Most of the lead is in the form of lead oxide and sulfate. They are reduced at red heat. The plastic is not burned in any process i know with the batteries. It is collected when the batteries go through the shredder to get the h2so4 out.
As I understand the pyrometallurgy of pcb recycling the boards are incinerated first in a kiln that can act as a retort. All of the polystyrene in the boards will depolymerize and then be distilled off with the condensate going for farther processing. The lower melting metals are reverbed off and collected solder, aluminum whatever else. But if it is not completely removed it is not a great concern as it will be later in the process anyway. As far as I know the charge is burnt to ash at this point and once cooled is run through a hammermill to fine powder. The powder is then run into the copper concentrates received at the refinery and is processed right along with no change to the refinery process that is used for just concentrates. All of your metals are recovered except for the iron oxidized in the first burn. The blister copper comes out of the smelter and right to electrolytic refining where the good stuff is left as anode slimes.
 
Ayham Hafez said:
In past, I worked in rotary lead smelting furnace, some times we were feed the rotary furnace with scrap acid batteries without dismantling I mean we feed the scrap batteries with their plastic container into the furnace, plastic container and plastic seperators in the acid batteries is about 10% from the whole battery weight, when start burning the scrap batteries in the rotary furnace we use low heat to incinerate the lead oxide then we start to increase the heat till we melt all lead with fluxes such as iron, when pouring the lead we get slags above the melted lead with no issues, from this my idea came of one step process, I mean using rotary furnace for incinerate then start melt without feed out the pcb batch
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That is not the way to get the lead out unless you don’t give a rats ass about the environment. What did you do with all the sulfuric acid? I know that the money to burn it off was not spent.
 
4metals said:
The unit I had used air for the O2 source and the flame entered from the rear. The feed was from the rear as well. It was a real workhorse.
View attachment 59878


But like I said I would never use it for anything that wasn't pyrolyzed first.Cutler stopped making these things a long while ago. I called them a few years back and they said they would sell the engineering if anyone
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It is a conventional rotary furnace, one of those used for non-ferrous scrap with hydraulic tilting. What load capacity does it have? I can't see the numbers and letters on the plan. It is true that TBRC furnace were used a lot for minerals and scrap. copper, nickel, lead and e-waste are very efficient and versatile, they can work at 1600°C with the load constantly stirring with variable speed of rotation, they do not need to cool the refractory because the rotation distributes the heat homogeneously and the possibility of drastically varying the oxide-reduction conditions allow "in situ" refining, they undoubtedly need an important gas purification system, especially for uncalcined PCBs, which is the issue that you rightly question based on your theoretical and practical experience, doing the math Boliden processes more than 400 tons per day and they assure that they comply with all environmental standards, it is also true that it has been just over 10 years since new large furnaces of this type have been installed in the world and that Boliden a few decades ago caused an environmental disaster in Chile, Spain and Sweden itself and that they imposed millions of dollars in fines that he never paid.
 
4metals said:
The unit I had used air for the O2 source and the flame entered from the rear. The feed was from the rear as well. It was a real workhorse.
View attachment 59878


But like I said I would never use it for anything that wasn't pyrolyzed first.Cutler stopped making these things a long while ago. I called them a few years back and they said they would sell the engineering if anyone wanted it.
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Remember the recovery percentages of different precious metals in the rotary kiln process?
 
FrugalRefiner said:
I'd like to see the scientific basis for that statement. Are you saying that every child who ever consumed lead could have been cured by drinking milk? Citations, please.

Dave
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The calcium in milk and other dairy foods also helps prevent lead from being absorbed into the body, you can Google it, and from my experience in lead smelting business I can ensure that, we were providing labors 200 ml of fresh milk on daily basis that save them from poisoning and make their 💪 stronger.
 
Ayham Hafez said:
The calcium in milk and other dairy foods also helps prevent lead from being absorbed into the body, you can Google it, and from my experience in lead smelting business I can ensure that, we were providing labors 200 ml of fresh milk on daily basis that save them from poisoning and make their 💪 stronger.
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if it's on google, it must be true. ;) but really, any scientific proof of that? i drink a lot of milk, and do think milk has its health advantages for those not allergic to it, so happy to hear that, but is it really true?

Is does save on preventive safety measures, and loss of health claims, i'm sure. I'm also sure I would never get it approved as a control measure in a health & safety plan for any project.
 
Martijn said:
if it's on google, it must be true. ;) but really, any scientific proof of that? i drink a lot of milk, and do think milk has its health advantages for those not allergic to it, so happy to hear that, but is it really true?

Is does save on preventive safety measures, and loss of health claims, i'm sure. I'm also sure I would never get it approved as a control measure in a health & safety plan for any project.
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Yes its true and self tested, another info, in past they were use milk to eliminate poisons from absorbed by human stomach.
 
Martijn said:
There seems to be some truth to your claim according to this article:
https://pubmed.ncbi.nlm.nih.gov/15474612/
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Yes, one day ago, I saw lead smelting furnace ran in village without any filter, children and everyone in the village inhale the air comes from the furnace, it ran for couple years, after government start to stop such black businesses, they made a health survey for children and old people in the village, they didn't record any lead toxic case, at the end they noticed that all the village drink fresh milk two times a day , at morning and at evening, in that time they understood that milk prevent any lead poisoning, so they obligated lead factories to provide milk to their labors.
 
Ayham Hafez said:
Yes, one day ago, I saw lead smelting furnace ran in village without any filter, children and everyone in the village inhale the air comes from the furnace, it ran for couple years, after government start to stop such black businesses, they made a health survey for children and old people in the village, they didn't record any lead toxic case, at the end they noticed that all the village drink fresh milk two times a day , at morning and at evening, in that time they understood that milk prevent any lead poisoning, so they obligated lead factories to provide milk to their labors.
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Milk does not prevent poisoning, they are placebos given by the factory manager to avoid the expense of a gas purification system, it is a serious crime. Chronic lead poisoning sets in slowly and many times when the poisoned person goes to the doctor for the first symptoms, there may be irreversible hematological, renal, neurological injuries that lead to lifelong disability or, in the worst case, death.
 

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