Getting silver from Galena

[cpt_squish]

Hi all,

I've just found a local mine which is stated to assay for silver at 900 oz/ton - or 3%. Ie every kilo of ore, contains an once of silver

This seems very economical to me for processing but I'm not sure how would be the best way.

What I'm thinking is first separating aragonite/calcite host rock by grinding,
Then using the latest method for producing low alpha lead (smelting);
This entails mixing the galena powder with sodium carbonate and salt, under an oxygen lance in a crucible.
This way any sulfur dioxide is absorbed by the carbonate.
This is a patented known process and would be much easier and safer than regular smelting. I think at around 900 C - I have a hobby furnace capable of upto 1200 C

The problem I then have is what to do with the lead bullion containing silver.
Is it possible to dissolve it all in Nitric acid or would it have to be a fine powder ?
Then using the previous posts process for refining silver by separating lead and copper, with ammonium hydroxide or hot water.

I have done 2nd Chem in uni so I know most of the safety concerns of using these chemicals and processes.

I know of both cupelation of the whole material (really dangerous given you accutually want to produce lead oxides) and of the parkes process ( which is just a derivative of cupelation, and much more difficult; remaining zinc can lead to frozen cupel)
I would much prefer a chemical means!

 

[Harold_V]

It is my opinion that you are wasting your time. The cost of operation, including labor, on a small scale, will be greater than the recovered values.

Harold

 

[cpt_squish]

I'm not looking for a business oportunity, nor an I seeking to make enough money to cover labor.


How do I get the silver out of the lead bullion!
Does anyone have an equation dissolution potential of lead in nitric acid.
I have also just found out that when lead nitrate is dropped with chlorides the nitric acid is regenerated, so I thinking it might be possible to reuse the same solution - depending on some factors.

I have plenty of time, 15kg of ore, therefore, (15oz silver - $300), a little bit of money. And I am seeking to extract a pure silver button!

 

[g_axelsson]

One possibility is to do like in the old times....
Crush, wash (ie panning), roast to get rid of the sulfur, reduce to lead with coal.
Then when you have metal lead, melt it in an iron vessel and keep it at just above melting point. At this temperature silver have a very low solubility in lead and will form crystals that will float to the surface and you can skim it off the top.
You will not get all the silver but a large part of it.

Personally I would try Parkes process.

/Göran

 

[Palladium]

This is some really dangerous stuff to do and are really dissapointed by the lack of safety prevailing the answers given in this forum.

Your answer was really dissapointing and uninformative.
This is supposed to be a forum where information is shared freely so I can make the final decision as to wether I will bother or not.

I will say it REALLY CLEARLY this time.

Some people make this to easy. Continue on jester, entertain us.

 

[Oz]

Seems all I do now days is waste my time!

Perhaps you may wish to consider that this is a free forum and not a paid consultant service. Seeing the above quotes Palladium has attributed to you does not seem like the kind of request or behavior that would cause members to go out of their way to help you.

Harold has played with more than an ounce or 2 of silver and he gave you his honest opinion based on your first post. He was trying to help you, you just did not like the help he gave.

 

[Harold_V]

I will say it REALLY CLEARLY this time.

So will I.

Stop wasting your time, and if you don't find that useful, stop wasting my time. I also advise you to keep your smart remarks to yourself. If you don't like the answers you get here, kindly move on to the other refining forum. We do not take kindly to folks that think they have free run of their mouths on this forum.

I gave you excellent advice---assuming you have no desire to spend more than $300 on $300 worth of silver. Some things simply don't work on a small scale. This is one of them.

Unless you are curious about a process, and don't care about the hazards to which you'll be exposed, and the hazardous materials you're going to set loose on the environment, or the good money you'll spend chasing a badly conceived idea, I strongly suggest you lose this one.

I grew up in a smelter town---one that processed sulfides. They dumped their gasses to the atmosphere until 1958. If you lived near me and attempted to process that ore by heat, I'd have you standing in front of a judge faster than you could turn off the burner.

Harold

 

[cpt_squish]

In that case I will appoligise to any people I have offended by this post.

I have thought that this process is possible in a cheap and moderately difficult process.
I have no intention of roasting the sulfides to get at the lead so this is the process I have put together based on information I have read:

Crush and sort the ore with gold pan thankyou to the person above suggestion - or heavy liquids.
Mix the ore with Sodium Carbonate and Sodium Chloride, I'll have to double check the ratio's (Sodium chloride is just a flux)
Heat in furnace to (temperature I also have to check), with oxygen lance.
This is based on a modern patent process:
PbS + NaCl + NaCO3 + O2 = Pb + SO2 + Na(Cl, CO3) = Pb + Na (Cl,SO4) + CO2
So the only gas leaving the system is CO2, SO2 produced is quickly absorbed by the NaCO3 = NaSO4 +O
I haven't balanced the equation but if requested I could

Now we have a lead silver bullion metal.

Hello,
I'm currently developping a simple process to make pure silver nitrate (or metal if you prefer) from Sterling silver. This should yield a product a least 99,9% pure. I'm not the inventor of the process in any ways, it's just ideas I gathered from ScienceMadness.org. Special thanks to Fleaker who helped me indirectly lol. If you think there are any flaws in my process, please let me know ! Any comments is also welcomed.

Cementation of silver with copper is a well know technique to produce silver metal of an acceptable purity, but you will always get some impurities from the Copper.

Method for producing 500 grams of photo grade AgNO3

-Start with incinerating you scrap silver to remove any dirt and oil residues. Do not melt the silver. More informations are available on this forum on how to do it properly.

-Let it cool then add your sterling (343,25 grams in this case) in a large beaker. 2000mL should suffice.

Following steps must be performed in a low light environnement.

-Add at least 1100mL of 30% nitric acid. When the reaction has stopped, add small amounts of HNO3 to dissolve the remaining pieces. Try not to add too much acid.

-Vacuum filter your solution to remove any insoluble particles. Use a fast to medium speed filter paper.

-Add NaCl (lab grade, food grade or equivalent) until no more precipitate forms. You now made Silver Chloride (AgCl) and Lead Chloride if there was any present.

-Decant your solution, you only want to keep the precipitate. Rinse the powder once in tap water.

-Then add enough HCl to cover it. Digest the powder in boiling HCl for one hour. This will dissolve any remaining metals. Use a magnetic stirrer if you have one. Keep your beaker covered with a watch glass. Decant the solution and rinse the powder two times with tap water. Not sure if this step is useful or not.

-Rinse you powder two times with boiling distilled water.

-Now dissolve your powder in Ammonium Hydroxide (lab grade, try not to use too much). Ammonia water will form a complex with silver but will not dissolve any lead chloride that may have still been present.

-Vacuum filter your solution using a medium to slow filter paper. Discart any precipitate.

-Add HCl to neutralize the ammonia and destroy the complex. This will form new AgCl. The amount of HCl used is not critical. Better too much than not enough. Add HCl until pH becomes acidic (under 7).

-Decant the solution and rinse your powder two times with tap water and two times with distilled water. This will remove the NH4Cl that formed during the neutralization.

-You can convert your Silver Chloride to Silver Oxide by the addition of an alkali solution like NaOH or KOH. Both are soluble in water in all proportions.

-Rinse your powder again with water a few times and heat to 300°C (590°F) to decompose your Oxide back to silver metal.

-At this time, your silver powder should be very pure, with only traces of other metals. You can either melt it to cast ingots or dissolve it back in Nitric acid (lab grade or higher) to make silver nitrate.


That's it !

Any comments ?

So ammonia hydroxide removes the silver from lead.
The trick is, how much nitric acid will it take to dissolve the lead?

 

[Platdigger]

I believe I would do some research into thiosulphate.

You may not have to roast the ore at all.
Or even disolve the lead.
Of course it will depend on what else is in the ore as to whether or no, this will work.

Juan may have some input.