Silver Powder with lead using NaOH or straight with hno3?

[Krystianes]

Hello!

I have some silver powder that contains 70% lead and 20% silver the rest is zinc. My first refining I have made with NaOH, to get rid of lead, it went very well, and the solution colour turned to red/brown, then I have taken out the soulution, whille silver was still in the bottom, but I really don't like working with NaOH, and waiting like 24 hours to let everything settle to the bottom, and getting correct PH, to let lead go into solution. My question is If i Would skipp using NaOH, and start with HNO3 instead of trying the get rid of lead, can it affect my silver % containt in the end? I know that I can wash the silver chloride with hot water and lite hcl to say good bye to lead in the finish, but Im wondering if my silver % containt will be still the same.

Thanks for any answers!

 

[snoman701]

Melt & cupel


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[Lino1406]

Silver chloride can be safely washed with hot water. Loss is negligible

 

[snoman701]

Silver chloride can be safely washed with hot water. Loss is negligible

If they are dissolving in nitric...

Isn’t the precipitation of lead with sulphuric easier? I just don’t think I’d want to try to rinse silver nitrate from that much lead sulphate. But either one would regenerate the nitric.




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[Lino1406]

Evidently a good alternative, works vice versa (leaving silver in solution)

 

[g_axelsson]

Wouldn't the low solubility of silver sulfate be a problem?

I know that silver were dissolved in sulfuric acid historically when refining silver, but I think it was in boiling concentrated sulfuric acid.

I found this article when googling, it concerns parting of gold doré bars in sulfuric acid.

Göran

 

[Lino1406]

Naturally, the solubility changes with temperature but if using a fitting volume you can manage this. Personally I would prefer the chloride way

 

[kurtak]

I have some silver powder that contains 70% lead and 20% silver the rest is zinc.

No - what you have here is some lead powder (not silver powder) that contains a little bit of silver

in other words - for every 100 grams of powder you have 20 grams of silver which equals "about" $11.50

By the time you factor in cost of chems to process - the time to process - & the HUGE amount of TOXIC waste you then need to deal with --- I would not even consider processing this product as the cost is likely to be more then the value recovered & certainly not worth while by way of a wet chem leaching process

factor in the fact that you are going to get less then spot price for the recovered silver & the recovered value is even less --- not worth it in my opinion

About the only thing I would consider this powder worth while would be to use it as a collector metal in a smelting process to collect other PMs (gold, silver &/or PGMs) & then cupel the lead dore to recover the "added" value of PMs from the smelt

Even if you have LOTS of this powder it's not worth it (IMO) - the more you have - the more TOXIC waste you are going to create - & you have to deal with that TOXIC waste

Any "real" refinery would "charge" you to take this powder (due to the lead) if they would even take it at all - they would consider it "hazardous waste

Kurt

 

[goldenchild]

I agree with kurtak. The material isn't valuable enough to process for the home refiner. This material would probably be more valuable for doing something like casting bullets.

 

[snoman701]

Make bullets out of something with a value of $45/lb?

If I had just a couple pounds, I'd heat up the lead pot and pour it in to the assay cone mould to cupel. Cupels are cheap, and absorb half their weight in lead. Yes, the cupels have to be properly disposed of. Cost is reasonable. On a small amount, you can grind and dispose of with your hydroxides.

Is this an item you are paying 90% spot on...no, but it still has significant value. Hardly garbage.

In quantity, anyone who takes e-scrap will buy it.

 

[Krystianes]

Thank you for the answers. Kurtaks answer made me start to think about it if it is even worth it. And he is right about what he has said. I can only add that I’m getting a little bit over spot price
I’m getting 105% of spot price and it’s normal in my country that you usually sell gold and silver over spot prices. For example gold between 101% to 102% and silver from 100% to 105%. I can also add that chemicals are very cheap in my country for example hno3 55% costs only 2,70 $ per liter if bought minimum 20 liters.
I will spend my time learning how to get other metals
out of it. Now I can only refine silver, and save the filters while filtering agno3, the rest is mystery for me. One more time Kurtak, you have looked on that from an other angle that I wouldn’t do and I really appreciate you answer. Thank you.

@kurtak

I have some silver powder that contains 70% lead and 20% silver the rest is zinc.

No - what you have here is some lead powder (not silver powder) that contains a little bit of silver

in other words - for every 100 grams of powder you have 20 grams of silver which equals "about" $11.50

By the time you factor in cost of chems to process - the time to process - & the HUGE amount of TOXIC waste you then need to deal with --- I would not even consider processing this product as the cost is likely to be more then the value recovered & certainly not worth while by way of a wet chem leaching process

factor in the fact that you are going to get less then spot price for the recovered silver & the recovered value is even less --- not worth it in my opinion

About the only thing I would consider this powder worth while would be to use it as a collector metal in a smelting process to collect other PMs (gold, silver &/or PGMs) & then cupel the lead dore to recover the "added" value of PMs from the smelt

Even if you have LOTS of this powder it's not worth it (IMO) - the more you have - the more TOXIC waste you are going to create - & you have to deal with that TOXIC waste

Any "real" refinery would "charge" you to take this powder (due to the lead) if they would even take it at all - they would consider it "hazardous waste

Kurt

 

[g_axelsson]

Time to go back to basics... Question, how do you remove silver from lead ore? Lead ores usually contain about 1-3% silver so this is a well known problem.

1. In the old days people used large iron kettles where they melted the lead. If you keep it just about molten for 20 hours then the silver starts to crystallize on the surface (it's lighter than lead) and can be skimmed off. This will produce a lead metal with less than a percent silver alloyed and solid silver.

This process were common from medieval times up until Parkes process were invented in 1850.

2. If you add zinc to molten lead it will not mix, but silver prefer to dissolve into zinc over lead with a factor of about 3000 times. This means you can do liquid liquid extraction of silver from lead. Then it's an easy thing to recover the silver from the zinc. Industrially the zinc is distilled off and reused, producing almost pure silver. And the lead is also a product you can sell and not a toxic nightmare.

So if I had enough of this silver lead mixture I would set up a smelting operation and extracting the silver with molten zinc. But with everything it's also a question of scale. If I had a couple of kilos it would be a problem not worth pursuing. If I had a ton it would pay off to learn a new skill.

* https://en.wikipedia.org/wiki/Parkes_process
* https://en.wikipedia.org/wiki/Pattison's_Process

Göran

 

[Krystianes]

Time to go back to basics... Question, how do you remove silver from lead ore? Lead ores usually contain about 1-3% silver so this is a well known problem.

1. In the old days people used large iron kettles where they melted the lead. If you keep it just about molten for 20 hours then the silver starts to crystallize on the surface (it's lighter than lead) and can be skimmed off. This will produce a lead metal with less than a percent silver alloyed and solid silver.

This process were common from medieval times up until Parkes process were invented in 1850.

2. If you add zinc to molten lead it will not mix, but silver prefer to dissolve into zinc over lead with a factor of about 3000 times. This means you can do liquid liquid extraction of silver from lead. Then it's an easy thing to recover the silver from the zinc. Industrially the zinc is distilled off and reused, producing almost pure silver. And the lead is also a product you can sell and not a toxic nightmare.

So if I had enough of this silver lead mixture I would set up a smelting operation and extracting the silver with molten zinc. But with everything it's also a question of scale. If I had a couple of kilos it would be a problem not worth pursuing. If I had a ton it would pay off to learn a new skill.

* https://en.wikipedia.org/wiki/Parkes_process
* https://en.wikipedia.org/wiki/Pattison's_Process

Göran

Tack för svaret. Jag tänkte skriva det här på svenska för att jag kikade på din profil och såg att du var från Sverige och jag bodde där i 5 år och jag tyckte det var rätt kul och träffa en svensk här.

I remove silver from lead by NaOH, when solutions color is turning into brown, then I wait a couple of hours to let everything to settle to the bottom and I have a small one liter cup which I use to taking out the solution when I’m coming to the bottom or when I see that some of powder from the bottom has gotten into my little cup then I add 20 liters of water and wait again and I repeat the process until I see color of solution changes into little brighter. Then HNO3 into the cauldron, the total capacity of my cauldron is 65l, once I’m refining I take 10 kg of this powder. When the bath with hno3 is end then I filtering everything and make silver chloride, then hcl + aluminum and the happy end.
I will now read about the alternative you have written. Never heard about that.

Thank you.