silver fixer

[markbooth]

Hello,
I am new to recovery/refining of metals. I have another member here helping me with a fixer solution problem I have encountered. Basically I have 700 gallons of spent solution that has set untouched since 1972. I have separated the sludge from the brown liquid. I have the sludge and have safely stored the barrels and liquid.There was a considerable amount of sludge in each barrel. Most barrels contained sludge that was extremely silvery, it looked basically like silver fingernail polish. Some barrels contained a mostly black sludge. All the barrels have the reddish brown solution in them and have formed crystals on the walls(some more than others). I am currently debating a fire assay or a spectral analysis. While I decide, I have done a few experiments on small samples. I tried drying the silver sludge and using the karo syrup method. It produced silver, but was only in minute amounts. I add sodium sulfide to to the brown liquid and it turned black like ink but had no precipitant. I added sodium sulphide to the silvery sludge and it turned greenish brown and gave off chlorine smell. All this was done outside and in extremely small batches. I have tried adding copper to brown solution, it had no effect. I put a clean copper wire in the brown solution and the silvery sludge, it did not plate either, but I just read that ph level affects this and I will determine it and adjust accordingly. What others that are helping, and I think, is the metals in the solution precipitated themselves due to the fact they were sitting so long exposed to the elements.(almost 40 years) If that is the case, then I cannot find any research dealing with this particular problem. I know that the fire assay will(should) tell me how much silver is there, but I am wondering if a complete analysis would be more prudent and possibly help in determining what method is best economically and efficiently. There is a member that mentioned sodium sulphide turning the liquid black and I have messaged him on the subject.
Again, I am on a fact finding mission and if I do anything wrong or dangerous I hope someone (and I know they will) will step up and say STOP! The quest for knowledge and the journey getting there is what I enjoy. To be successful in recovering the silver the safest best way possible is my goal. The money from the silver, if there is any, is just a wonderful bonus that allows me to devote more time and energy to learning. I will post pics of the various solutions and sludges, so others may give their advice. Thanks in advance for all your help.and to the ones that have been helping already.

P.S. there have been previous posts on this exact material. For reasons I'd rather not go into and have no bearing on the outcome, some of these posts have been removed, by their author, with good reason. Suffice it to say that all previous and future help from him or any other member of the forum is appreciated. I have read Hoke's book, and have copies of Lazersteve's videos and GSP's also. It's a lot of info and I am still sorting through it and trying to understand it all. In regards to previous posts on this subject, I am the one that encountered the lady who had it originally, it took about a month of talks and getting to know her before she would tell me all the story and the location of the barrels. She was generous in her price for the product ,and I believe, genuine in here belief of the value of the product. Whether that belief is true or false has no bearing on her good intentions or on the value of the knowledge and friends I have gained on this quest. As I said, I will post pics and what knowledge I have about the subject hopefully in the next few days. Until then, Thanks
Sincerely,
Mark Booth

 

[Juan Manuel Arcos Frank]

Mark:

Iron reduces silver compounds...if an iron slab is dipped on the spent fixer then a silver mud is formed,besides,if barrel is iron maden then the same reaction takes place on the barrel´s walls.

The silver should be somewhere...

1.-If it is in the liquid then the copper wire gets silvered.
2.-If it is in the mud then melting it with saltpeter or nitric acid process will lead you to metallic silver.
3.-If silver is in the barrel´s walls then treat the crust with saltpeter or nitric acid process
4.-None of above,finally we have found the silver: silver has taken away by the seller,the silver is in her/his pockets and sold you a worthless material,try to find a refund.

Please,write me to my e mail because my pm box is not working: [email protected]

Regards.

Manuel

 

[markbooth]

Here are the pics I said I would post. I don't know if this helps or not, but I figure a visual couldn't hurt. Thanks

 

[Harold_V]

While I processed a generous amount of silver, it was, primarily, from inquartation, so it was of a known quality. I have no experience with silver from film aside from one large lot that had been harvested from an electrical recovery unit.

Ok, having said that, I do have a little experience in working with sulfides, and I can't help but wonder if that's what you have. If so, it's possible you could effect a good recovery from the material you showed by melting in a furnace with a borax and soda ash flux, along with some scrap steel, so any sulfides that may be present will yield the silver. It's worth a try. Once everything is molten, allow the material to soak, and monitor the piece of inserted scrap. As silver gives up the sulfur, steel is dissolved. When you see no further dissolution of the added steel, you can expect the conversion to be complete. Remove the piece of steel (I used to use lengths of rebar), and pour the material to a cone mold. If you have silver, it will be at the bottom, with a layer of iron sulfide in the middle, then a layer of slag on top of the sulfide. This is one of the rare cases where you can separate by stratification.

If you have any doubts about the full recovery of silver, try running the sulfide layer once again, using steel. If you find no more silver, you can rely on a given period of time in the furnace to recover the silver.

Be advised that the flux in question is rather aggressive towards crucibles, so experiment with a small sample before committing to a large lot.



Harold

 

[markbooth]

Thanks Harold and Manuel. I'll try the re-bar method with a small sample and see. I'm waiting on nitric to do other tests and drying out samples for Harold's suggestion, as we speak. (at least I think they need to be mostly dry) I do not have a cone crucible, but may be able to borrow or make a temporary one for a small sample. If it works at all, I will invest in a proper one. There seems to be many options and possibilities. Before I commit the whole lot of several hundred pounds to one method, I am gonna create a homogenous blend of all sludge's and scrapings from the original barrel walls and send for fire assay. The cost associated with recovering silver from an amount this large can vary widely from process to process. I think it will be prudent to determine possible silver content first. Again, that's my thinking, and I've been wrong enough that I welcome anyone to play the devil's advocate. It'll make me research harder to prove to myself I'm right or wrong. Thanks

 

[Harold_V]

You will never be sorry for having an assay, so you'll understand what you face. The only possible reason I can think of to not combine all the lots is that one or more may be barren. Not suggesting that be the case----but if you have a valueless lot (or more), discarding would be preferred over paying to process the additional weight, all for no gain. You most likely could conduct the minor tests I proposed on each lot to determine the presence of values, or not.

If you are concerned about making a determination of content, dry and weigh representative samples of each lot before processing by furnace. You can process a small sample (a few ounces) in assay crucibles and a simple furnace made of fire brick, if necessary. You can even use a propane torch, assuming you can retain the heat. A Turbo torch (fed by a large bottle, such as used on a BBQ), should provide enough heat, although only with the aid of a furnace of sorts. All depends on how much effort you care to expend. In any case, be certain to use scrap steel, to liberate any silver that may be bound as a sulfate.

Note that the cone I spoke of is not a crucible, but a mold. It serves to make separation of the values from the slag very easy. If one is not at your disposal, consider pouring to a piece of angle iron with an end plate welded. Tip the angle so you end up with a three sided button, taking advantage of the corner of the mold.

Harold

 

[clint s]

hi all I have a similar thing going on, i have hypo solution that was ran through 5 gallon buckets of steel wool it had sat for 15 years or so it is dry and looks like dirt some of it is black and some has red color to it, i dissolved it in 50/50 nitric then turn it to silver cloride then used iron and sulfuric to change it to metallic silver , but what i am finding is that the nitric did not dissolve all the silver .i used heat as well , how i know is i have took the left over sludge i have filtered off, and took my torch and melted it and am get silver out of it still , any ideas way the first time it did not dissolve all the silver ? i have even added more nitric to make sure i got it all on the first time it just wont dissolve it all ,not sure way ? i am going to melt all the left over sludge to see, but shouldn't it dissolve the first time around with nitric and h2o?

 

[butcher]

You have made it harder to get your silver, you may have silver chloride mixed with silver sulfide, nitric will not dissolve these.

If I have silver nitrate and mixed with a sulfide the silver would become a sulfide, the nitric would not dissolve this silver sulfide.

If I had silver nitrate and added a chloride the silver would become a chloride.

There is an order of which acids will take the metal from another acid (I do not know what they call this in chemistry but I have seen this order, it is similar to the reaction series for metals, but I have never seen a reaction series for acids in print)


I believe the only silver you were able to dissolve with your nitric was elemental silver that was converted to metal silver by Iron wool, the method Harold posted above will convert silver sulfide, I would neutralize the nitric and was it first with caustic soda (sodium hydroxide) this may help to convert some of silver chloride if it is in this mix, if you try and melt the silver chloride it will most likely be lost.

Manuel and GSP have made many posts dealing with what you are facing, including on others who have made the same mistake you have made reading them would help better than my advice, they have much, much more experience with this than I do.

 

[clint s]

i think you are right ,there must be sulfides in the mix or chloride i would guess sulfides i am gonna try Harold's advice to heat with furnace first with soda ash borax and iron i had it assayed when i started the assayer said it was 40 % by weight but i am only getting less than 1.5 percent with the nitric and h2o method, i have kept all the sludge i have filtered so i hope i have not lost any silver in the nitrate solution,that i have filtered and drop with hci to silver cloride i kept most of the left over solution but there shouldn't be any values in the solution i hope, i added more hci just to check and no more silver clorides are droping the left over sludge from the one bucket is kinda green the other bucket is tan colored like mustard powder ok lets say we have sulfides is the furnace the best way to convert ? like Harold said .

 

[butcher]

The silver sulfide would need Iron in melt as Harold suggested, but if you had silver chloride in the mix it would be difficult to melt the chloride portion.

Juan Manuel Arcos Frank, just gave some very good advise recently to another member that done something very similar, I believe he was working with xray film.