Process to convert silver sulphide into metalic silver

Here is my process to convert silver sulphide to metalic silver.

Originally I wrote it in WORD format,but it was 30 MB so I changed it to PDF,but I am such an idiot working with computers so the pics move a little bit,so I offer an apology.

This process is dedicated to GSP,My Dear Friend.

I hope this process will be useful to all the Members of the Forum.

Kindest regards.

Manuel

Nice job Manuel.

I know silver nitrate
silver chloride
How do I get silver suplhide

Rhodium:

You are welcome,it is my pleasure.One day,I will learn how to make better post with PDF,I hope.

Have a nice day

Manuel

Golddie:

It is very easy...when you have silver in solution (i.e.silver nitrate in water/acid solution,silver complex cyanide solution or silver thiosulfate complex which is common fixer) just add some sodium sulphide (hydrosulphide acid will work too,but it has a strong oddor of rotten eggs) and you will see that a black mud is formed...this black mud is silver sulphide.

If you find a silver mine,you will see some black powder line between rocks...this is silver sulphide.

Best regards

Manuel

In the process of removing excess silver chloride when digesting karat jewelery containing diamonds I generate a waste solution of sodium thiosulphate which is loaded with silver. (the thiosulfate dissolves the silver chloride and a very small percentage of the gold) Generally we just evaporate off the water and dry the powder and incinerate to make a sweep. Converting it to silver sulphide with sodium sulphide may be stinky but worth a try. Then the silver can be extracted from the muds directly.

Plus the rotten egg smell is most likely a water scrubbable fume. Worth playing with.

Thanks Manuel

4metals:

You are right,but you can avoid nasty rotten eggs odor controling sodium sulphide adittion.The trick is just adding the exactly quantity that you have of silver...I mean,if you check your silver content then add exactly the same weight of sodium sulphide...here is why I think it happens:

Sodium sulphide reacts with the silver thiosulfate complex to form silver sulphide and regenerates the sodium thiosulfate.

The bad reaction is that sodium sulphide reacts with water to form hydrogen sulphide that smells like hell,so do not add more than needed.

You can check the silver content using a copper wire.

4metals,a pleasure talking with you.

Have a a nice day.

Manuel

Manuel,
That's a good tip, the copper wire is coated by any silver in solution so just adding sodium sulfide slowly and checking with copper can minimize the stink.

I've already used your method to convert some silver sulphide, did it in an incinerator to control the heat, 20 pounds of damp sludge reduced in a refractory cement tray. Skimmed off the slag and let it cool, too awkward to pour out of the tray, the silver was sitting as a slab on the bottom.

Already thinking of a tray with a sloped bottom and a trough so the silver collects in an easier to remelt bar.

some great information manuel, very nice job, are those melting dish's homade or made locally?

I have been working on your challenge to come up with some caveman chemical, for gold refining.

4metals:

I am glad that this process is useful for you.

Kindest regards.

Manuel

Butcher:

Those dishes are called "copelas" (in Spanish),they are handmade and made of clay.In these dishes are melted gold and silver here in Mexico and they are very cheap,one like the pics cost me 8 pesos (0.60 USD).The trick is to treat it with borax,otherwise it breaks in a few minutes.Here is the way I do it:

Heat with the torch at medium heat level,front and behind.

Add borax and melt it,once that it is liquid cover all the dish letting the metled borax to fluid.

The dish seems like having some kind of glass film which protects it.

Butcher,I am waitting for your process to manufacture some banned chemcial substance.

Have a nice day.

Manuel

Manuel

I would like to say thankyou for taking the time to post this process.

I am a hobbyist (ie small amounts) and used your process today for the first time with great success. It is so easy and quick!!

For those of us processing small amounts (mine was 1oz of silver) a MAPP torch works fine for this process.

Many thanks
Marcus

Marcus:

It is my pleasure...try to find the biggest bottle of whisky,run,cognac,brandy,vodka,gin,wine or beer and say CHEERS!!!!! to me.

As you can see I live in Pachuca,Mexico,where do you live?

Kindest Regards.

Manuel

Interesting process. Thanks!.

One thing I will say: H2S (rotten egg smelling gas) is about the most poisonous gas known to man. Very small % concentrations are lethal. Be VERY careful!.

Hi Manuel

A toast of cognac to you!!

I am far far away from you, in Brisbane Australia.

I did not notice any smell of H2S, although it was a windy day and the process was done outside.

I am not sure what the gas is but I did not expect H2S with the reagents being Ag2S and KNO3. I expected either NOx or SOx or a mix of these and some kind of K compound going into the flux. If I am lucky someone knowledgable will know the reaction products.

This process done in medium sized batches can generate enough H2S to kill the operator, if the fumes aren't properly handled. H2S in higher concentrations will not give you the chance to smell it!. Highly dangerous!.

edit: Any process that can generate H2S should be treated with the same care as a process that can generate HCN. They are about as toxic.

Hi HAuCl4

Noted to always be aware of the fumes.

I am a novice in this field and am interested in the chemistry behind the processes.

Can you tell me where the H comes from to make the H2S? Is it from any residual water? Perhaps that in hydrated borax? Unburnt gas from the torch?

Thanks
Marcus

Marcus: There are a couple of posts above where 4metals and Manuel discuss a variation of the process that generates H2S as a by-product. The original process does not, except if any acid or maybe water gets in there somehow by accident you can have the extra hydrogen you need to get killed. :shock:

Marcus:

HAuCl4 is right about H2S,it is very toxic and atrophy the sense of smell,you are told not to generate it,the trick is using just Na2S as needed.H2S is formed with water + Na2S so try to avoid any excess.

I send you a big hug to Brisbane.

Regards.

Manuel

Excellent write-up, Manuel. I plan on using it.