Refining a huge chunk of lead and gold

[goldshark]

Cupeling requires a relatively calm environment, with just a touch of Oxygen , to convert the Lead to Lead Oxide.This is very hard to do in a propane fired, top loading furnace. I have a ceramic "cubicle " inside my front loading propane fired furnace. Placement is critical, and I feel , would be difficult for a first timer to get right. The electric furnace, as used by Jason at MBMM ,would be something much more in line for your needs. You can do both smelting and cupeling with this furnace. The only draw back to electric is that a high CO2 environment seems to consume the resistance wires quickly. If you are serious about your hobby, a gas for smelting, electric for cupeling, is your best option.Front loading doors are almost a must. Top doors, you have to lift out the crucible with 1 tool, then pick up with another tool for pouring. If not done quickly enough, your crucible contents can freeze prematurely. All the big assay houses have front doors for this reason. Much more efficient.
The rest of your post is pretty close, but not quite there. The respirator does not say what the filtering media is. Some filters will deplete by simply exposing to the atmosphere. I would call the manufacturer, tell them your use, and see if they still recommend that model.
Once you cupel, or slag off the Zinc, depending on which process you decide upon, you will have an Au/Ag prill or button. To get to high Au content, you will then need to either in quart with Ag, or take through AR, or one of several other refining processes. Something you should have done in the beginning. But what the hell, you are going to learn a lot.

 

[Martijn]

I was going to use this through out the whole process Mask

We've said it before:

Please be aware that masks only protect for a short time and are meant to clean up a spill, IF the concentration is not too high, and then you need an overpressure mask.
The capacity of the filter cartridges are limited and once you've opened them, they will protect you only for one day max, since the active carbon inside and other possible scrubbing compounds will deteriorate in normal air. So life span of one cartridge is limited.
then you do not know what concentration you're in, so you don't know when your mask is full and does not protect anymore.

Most tools and PPE are only applicable under certain circumstances, read the manual!
Working with a mask on that does not protect(anymore), and you thinking it still does, is a death trap.

Stay away from the fumes, and scrub them if possible, keep in mind that at a certain distance the fumes are still toxic, and the will get less in time.
Anyone around your workspace? Neighbors, kids, animals? at what distance will they need protection from your hobby?
Having a tall stack to vent it off can help dispersing the fumes to below 'acceptable levels', but the whole "acceptable emission levels" might be done with in a couple of years and you may not be allowed to expel anything that can be scrubbed or prevented.
I think covering the melt in a good flux can prevent a lot of fumes going up in the air. There surely are a lot of other pro-active ways to prevent the fumes from escaping.

You don't have to control what you don't expel. Think prevention in stead of correction and protection.

Martijn.

 

[Darkthirty]

We've said it before:

Please be aware that masks only protect for a short time and are meant to clean up a spill, IF the concentration is not too high, and then you need an overpressure mask.
The capacity of the filter cartridges are limited and once you've opened them, they will protect you only for one day max, since the active carbon inside and other possible scrubbing compounds will deteriorate in normal air. So life span of one cartridge is limited.
then you do not know what concentration you're in, so you don't know when your mask is full and does not protect anymore.

Most tools and PPE are only applicable under certain circumstances, read the manual!
Working with a mask on that does not protect(anymore), and you thinking it still does, is a death trap.

Stay away from the fumes, and scrub them if possible, keep in mind that at a certain distance the fumes are still toxic, and the will get less in time.
Anyone around your workspace? Neighbors, kids, animals? at what distance will they need protection from your hobby?
Having a tall stack to vent it off can help dispersing the fumes to below 'acceptable levels', but the whole "acceptable emission levels" might be done with in a couple of years and you may not be allowed to expel anything that can be scrubbed or prevented.
I think covering the melt in a good flux can prevent a lot of fumes going up in the air. There surely are a lot of other pro-active ways to prevent the fumes from escaping.

You don't have to control what you don't expel. Think prevention in stead of correction and protection.

Martijn.

https://multimedia.3m.com/mws/media/639110O/3m-respirator-selection-guide.pdf

 

[Martijn]

https://multimedia.3m.com/mws/media/639110O/3m-respirator-selection-guide.pdf

I don't know what you're trying to say or point out by sharing this link, but the first warning sentence says it all:

 

[Hbartamian]

Cupeling requires a relatively calm environment, with just a touch of Oxygen , to convert the Lead to Lead Oxide.This is very hard to do in a propane fired, top loading furnace. I have a ceramic "cubicle " inside my front loading propane fired furnace. Placement is critical, and I feel , would be difficult for a first timer to get right. The electric furnace, as used by Jason at MBMM ,would be something much more in line for your needs. You can do both smelting and cupeling with this furnace. The only draw back to electric is that a high CO2 environment seems to consume the resistance wires quickly. If you are serious about your hobby, a gas for smelting, electric for cupeling, is your best option.Front loading doors are almost a must. Top doors, you have to lift out the crucible with 1 tool, then pick up with another tool for pouring. If not done quickly enough, your crucible contents can freeze prematurely. All the big assay houses have front doors for this reason. Much more efficient.
The rest of your post is pretty close, but not quite there. The respirator does not say what the filtering media is. Some filters will deplete by simply exposing to the atmosphere. I would call the manufacturer, tell them your use, and see if they still recommend that model.
Once you cupel, or slag off the Zinc, depending on which process you decide upon, you will have an Au/Ag prill or button. To get to high Au content, you will then need to either in quart with Ag, or take through AR, or one of several other refining processes. Something you should have done in the beginning. But what the hell, you are going to learn a lot.

Thanks for the advice! now ill wait for everything to arrive well see

 

[Hbartamian]

We've said it before:

Please be aware that masks only protect for a short time and are meant to clean up a spill, IF the concentration is not too high, and then you need an overpressure mask.
The capacity of the filter cartridges are limited and once you've opened them, they will protect you only for one day max, since the active carbon inside and other possible scrubbing compounds will deteriorate in normal air. So life span of one cartridge is limited.
then you do not know what concentration you're in, so you don't know when your mask is full and does not protect anymore.

Most tools and PPE are only applicable under certain circumstances, read the manual!
Working with a mask on that does not protect(anymore), and you thinking it still does, is a death trap.

Stay away from the fumes, and scrub them if possible, keep in mind that at a certain distance the fumes are still toxic, and the will get less in time.
Anyone around your workspace? Neighbors, kids, animals? at what distance will they need protection from your hobby?
Having a tall stack to vent it off can help dispersing the fumes to below 'acceptable levels', but the whole "acceptable emission levels" might be done with in a couple of years and you may not be allowed to expel anything that can be scrubbed or prevented.
I think covering the melt in a good flux can prevent a lot of fumes going up in the air. There surely are a lot of other pro-active ways to prevent the fumes from escaping.

You don't have to control what you don't expel. Think prevention in stead of correction and protection.

Martijn.

Thank you for the warning and advice, I will be mindful of my surroundings for sure.

 

[Hbartamian]

filter looks correct for this Filter

 

[Hbartamian]

Alright doing this in a warehouse district tomorrow! Potassium nitrate didn’t arrive yet so only doing slag part

 

[Hbartamian]

Nevermind just arrived

 

[Hbartamian]

Alright, so it looks like I ended up with purified zinc and gold.
I did my first melt and that was intesnse.

you can see the red slag there, might of not let that fully oxidize. Led went down to 960 grams. Then threw in 3% zinc, got the crust all out into a jar. Purified that with the second charge.
you can see little gold bits in the final shot

 

[Hbartamian]

Jason oxidizes the zinc with soda and potassium nitrate and absorbs the oxides in the slag. I'm sure there are zinc fumes to watch out for, but most goes in the slag as i understand it.

I did this and oxidized the zinc crust and ended up with the final alloy at 360 grams. If I put 50 grams of zinc to the 960 gram alloy to extract 50 grams of gold, then the other 260 grams must be still be lead? I’m not sure where to go from here. Do I try to Cuppel this Now?

 

[Hbartamian]

I am assuming you melted the Iron skillet, at least partially. Scrape all you can free, wash the Portland off well, place in a crucible, place crucible in a furnace which will attain a heat of 2000 F. When Lead and Gold alloy are liquid, pour into a cone mold, decanting the Pb/Au alloy, leaving what still solid Iron is left in the crucible. Chip off any remaining slag. 1000 grams is a lot to cupel all at once. I would think you could also pour into other molds around 100 grams in size. My bigger store bought cupels, only absorb 165 grams of Lead ,maximum, and they are the biggest I could find. So dividing into 100 gram lots would be much easier. If you go the compressed Portland hack, you will need a cupel roughly 2 1/2"x 3" high, with enough depression to hold 100 Grams when melted flat, with perimeter space to allow for PbO to start absorbing into the cupel. Mind you, the entire cupel needs to attain 1850 F to work properly. Surface heating with a propane torch does not work. An electric cupeling furnace is probably the best for a beginner. Remember to crack the door very slightly to allow for a little Oxygen. That size slug may take 45 minutes to an hour to cupel at a constant 1850F heat, cupel pre heated to temperature of 1850. Make sure slug is completely dry, before placing in hot cupel. Remember all safety protocols, especially for the Lead fumes. Hacks shown on Youtube, do not work very well. For professional results, use professional equipment and supplies. I would find a professional assayer, and see if they will do what you want. The proper equipment and supplies will cost you 1000's. Invest in it if you continue to find interest in this. Otherwise, cut your losses while you are even. An assayer will probably charge you a couple hundred dollars for his service, just a heads up.

well I got up to where my skills can take me at this point, do you have a recommendation where I can have this refined Or exchanged?

 

[goldshark]

I do not know. I do not wish to get involved with potentially a he said/ she said scenario. There are many professional refiners located through out the country ( USA ). I do not know where Clearwater is, so cannot recommend one close by. A google search may help you find a suitable refiner. Read threads on toll refining fees.

 

[Shark]

Lead can be refined through an electrolytic cell. It may be a possibility.

 

[Martijn]

I did this and oxidized the zinc crust and ended up with the final alloy at 360 grams. If I put 50 grams of zinc to the 960 gram alloy to extract 50 grams of gold, then the other 260 grams must be still be lead? I’m not sure where to go from here. Do I try to Cuppel this Now?

I can't follow your math here. After zinc oxidization the final alloy is 360 grams, but then you add 50 grams to 960 alloy to get 50 grams of gold and are left with?
Maybe cupel 10 grams of lead and see what you can recover before cupelling the whole thing.
If you had 260 grams of lead left after oxidizing the zinc, something went wrong and should be done again?

 

[Hbartamian]

I can't follow your math here. After zinc oxidization the final alloy is 360 grams, but then you add 50 grams to 960 alloy to get 50 grams of gold and are left with?
Maybe cupel 10 grams of lead and see what you can recover before cupelling the whole thing.
If you had 260 grams of lead left after oxidizing the zinc, something went wrong and should be done again?

Yah, it’s impossible. I added the 3% and took out the zinc crust twice from the melted lead mixture. The I think the second process of melting the potassium nitrate and borax oxidized the zinc and left me with lead and gold, but in a higher concentration I can cupel. that’s the next step I‘m willing to take.

A note, there was definitely zinc fumes coming off while it was bubbling with the potassium nitrate and borax. Then it stopped bubbling and began swirling, then I poured it into a bar mold. The bar mold had a half inch of pure black oxidized slag (0.5 inch) and bott layer metal with gold shining through. I broke it all off and was left with the 360 grams.

 

[Yggdrasil]

Yah, it’s impossible. I added the 3% and took out the zinc crust twice from the melted lead mixture. The I think the second process of melting the potassium nitrate and borax oxidized the zinc and left me with lead and gold, but in a higher concentration I can cupel. that’s the next step I‘m willing to take.

A note, there was definitely zinc fumes coming off while it was bubbling with the potassium nitrate and borax. Then it stopped bubbling and began swirling, then I poured it into a bar mold. The bar mold had a half inch of pure black oxidized slag (0.5 inch) and bott layer metal with gold shining through. I broke it all off and was left with the 360 grams.

Upon revisiting the Parkes process, I do not think it is suited to separated the Gold from Lead, only Silver.
So what you now have, if you have done all correct, is one part Zinc/Silver alloy and one part Lead/Gold alloy.
Which means you are more or less back to square one.
Maybe Cupelling or electrolytic separation is the easiest/best way?

 

[goldshark]

Upon revisiting the Parkes process, I do not think it is suited to separated the Gold from Lead, only Silver.
So what you now have, if you have done all correct, is one part Zinc/Silver alloy and one part Lead/Gold alloy.
Which means you are more or less back to square one.
Maybe Cupelling or electrolytic separation is the easiest/best way?

Zinc will collect the Au, as well as the Ag. There is a paper online explaining the process, particularly the temperature gradient, which allows for the affinity to collect the Au better at a certain temperature. I do not have the link, or I would post it.

 

[Yggdrasil]

Zinc will collect the Au, as well as the Ag. There is a paper online explaining the process, particularly the temperature gradient, which allows for the affinity to collect the Au better at a certain temperature. I do not have the link, or I would post it.

Thanks Goldshark, I hope you can find and post the link later some time.
I'll do some more research as this may be an interesting angle for later processes.

 

[kurtak]

A note, there was definitely zinc fumes coming off while it was bubbling with the potassium nitrate

I hope you are doing this in away that keeps those fumes well away from you (preferably a good fume hood)

If not - you are likely to end up with heavy metal poisoning - if you breath enough of those fumes you may experience what is known as metal fume fever

From Wiki ----------

Metal fume fever, also known as brass founders' ague, brass shakes,[1] zinc shakes, galvie flu, galvo poisoning, metal dust fever, welding shivers, or Monday morning fever,[2] is an illness primarily caused by exposure to chemicals such as zinc oxide (ZnO), aluminium oxide (Al2O3), or magnesium oxide (MgO) which are produced as byproducts in the fumes that result when certain metals are heated. Other common sources are fuming silver, gold, platinum,[3] chromium[4] (from stainless steel), nickel, arsenic, manganese, beryllium, cadmium, cobalt, lead, selenium, and zinc.[5]

Welders are routinely exposed to the substances that cause metal fume fever from the base metal, plating, or filler. The most common form of exposure among welders occurs when welding galvanized steel, of which zinc is the primary component of the galvanization process. Galvanized metal must be thoroughly cleaned using an angle grinder or other abrasive means to remove the galvanized coating before welding or burning. Brazing and soldering can also cause metal poisoning due to exposure to lead, zinc, copper, or cadmium.[5] In extreme cases, cadmium[6] (present in some older silver solder alloys) can cause loss of consciousness.

Exposure usually arises through hot metalworking processes, such as smelting and casting of zinc alloys,

If I were you & you are not using VERY GOOD fume control while doing this - I would go & get a blood test done looking specifically for lead & zinc poisoning

You may need to go through chelating treatments to remove the lead & zinc from your body - if these metals are not removed from your body they will result in heath issues which you will not be aware of untill years later - heath issues including but not limited to a shorter life

These fumes (lead & zinc) are VERY TOXIC !!!!

Kurt