# thiosulphate / electrowinning low garde wastes



## Gold Trail (Nov 14, 2009)

After months of failed non sense attempting to process low grade wastes (such as eproms, memory after finger removal, low grade pins, fiber processors, BGA chips, flat packs, ect)

I have been looking into Thiosulphate recovery of the PM's .

Questions i cant seem to find answers for (yes i have looked outside this site as well)

all lowgrade electronic scrap will contain mostly copper as the base metal. With nitric acid pushing 100.00 a gollon delivered, and a gallon disolving / holding about 2 lbs of copper, just isnt practical. period. YOU WILL NEVER RECOVER YOUR MONEY FROM DOING THIS.

so.... I have researched the hell out of this Thiosulphate leaching, and its looking good. heres some problems ive been experiancing / learning about that no one seems to be talking about.

I understand that copper will plate silver as well as gold from the thiosulphate.

and thats the problem. the PM's are plating right back out onto my shreaded materials. Is there a solution for this? my tests as of now are nothing more than a bucket. is the agitaion / continuous movment of the solution required to prevent this? (seems most commercial units pump the solution around)

assuming the agitation would prevent the premature plating of PM's, would it make sense to have two tanks, one as a leach tank and the other as the electrowinning tank, with the thiosulphate being slowly pumped between the two? kinda like a continuous feed process.

the only question i have with electrowinning is the anode (i think) recovery. i dont see how plating gold onto steel wool is a good idea by any means. Copper will work, but were right back at the original problem of the high content of copper in the boards to start with.

I dont understand (havent came accross decent info yet) the further processes for the coconut or carbon 

i look forward to any insight on this. I think we can all benifit from this

Ryan


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## Anonymous (Nov 14, 2009)

Hi there,
I have some information that may help you. I use a grinder and punch press to cut the centers out of IC's, quak pak, and other plain black chip type (this is were I have found the vast majority of anything worth while to be) and cuts the volume of material by 70 - 90 percent.

I then process the ground pulp from this with HCL and peroxide, used hcl/peroxide from fingers processing these are my two starting points to save money. I like the used hcl/peroxide with air bubbling this will remove copper, aluminum, and convert silver plating to silver chloride and stir the pulp I use more water so the solution can be fluid. Rinse away the copper and other base metals with water then I remove the gold with hcl and chlorox. 
I have not removed the silver yet but I think it is soluble in ammonium chloride and when I think there is enough I will do a leach.

This may not get 100 percent of the values, but, is fairly cheap and works pretty good.

Jim

As an after thaught, you could use copper sulfate to remove base metals first, then the used HCL/peroxide to remove the copper, then do the gold and silver processes.


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## Gold Trail (Nov 14, 2009)

james122964 said:


> As an after thaught, you could use copper sulfate to remove base metals first, then the used HCL/peroxide to remove the copper, then do the gold and silver processes.



Now I think were getting some where. this would additionally allow for copper recovery as well. off to continue copper sulfate research thank you for your reply

Ryan


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## Anonymous (Nov 14, 2009)

Ryan,
The one thing to think about is the actual amount of metals in the IC chip mess. I use a lot more water than chemicals and time and more time. Let it sit and bubble.

One of the man mistakes I feel I made when first starting was straight acid and lots of chemicals when there was only a few grams of metals to be dissolved. Like if you grind up the whole ic chip, there will be much more bulk and more base metals, but if you cover this entire mess in enough acid to make a fluid solution so you can stir it and enough nitrate or water chemical to dissolve the gold there will in fact be so much extra chemicals that you will have a tremendously hard time getting your precious metals out.

jim


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## Gold Trail (Nov 14, 2009)

that definatly seems to be the main issue with other methods ive been trying. way too much solution and too little PM's, If any, recovered from the GALLONS of muratic and nitric ive burned through lately. (i'm not saying no PM's were recovered, either there wasnt enough to show results, or the excess of dilute solutions led me to never wanting to filter another damn thing in my life ever!!)

I have pins, fingers and ceramic chips down to a science. I could do them in my sleep

i an gonna give the low grades a few more tries, and if theres no plausable results ill sell them to the refiner as i used to do'

Assuming i acheive results, I will be certian to share them here.

Ryan


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## Anonymous (Nov 14, 2009)

I have been experimenting with the low grades for quite some time and have got results with the long skinny ic chips but the square quad paks would not run through my homemade center cutting machine. I am currently redesigning one specifically for them. I think the only way to make it is automation or incineration. I also am working on a super fine sluice box type thing to run the ground chip centers through to try and cut the plastics down so low that I can incinerate and melt without all the fumes.

Jim


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## Gold Trail (Nov 14, 2009)

I have a large amount of new header pins that are encapseulated in plastic. i tried grinding them coarsly, and didnt have much luck floating or even paning for that mater the plastics off. what i did notice, though is the plastics and the pins seemed to seperate in the water with some swishing around, but remained settled . 

either were fools for even messing with this low grade waste, or every one else just hits the honey on the high end goods and passes the buck on the low grade. 

I would love to have a way for processing this type of material as its available all day at dirt cheap prices. 

This will get interesting. Ill be interested to see what the pro's have to say about all this.. ....

Ryan


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## Anonymous (Nov 14, 2009)

Low grade stuff is all I have available to me since I live in a low populas area and aways get outbid for the good stuff when I go to auctions and rarely does the good stuff even get to auction hear since everyone knows everyone and everyone else is connected.
Me I am just a plain old refrigeration, HVAC, electrician, so I am out of luck when it comes to high grade.

Jim


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## nickvc (Nov 15, 2009)

Im enjoying these posts its good to see members trying to take on the major players.I think using chemicals is a total waste of time and money and would suggest you look to the mining members to help with a way to seperate the metals from the rest of the material ,if you can get it into small enough pieces,maybe a settlement system where the heavier metals are retained and the plastics resins and other lighter material would be washed away.If this is possible a magnet could be used to remove steel and other magnetic elements leaving a much greater concentation of the metals you actually want which could then either be melted( in my opinion the best option) or refined, but again the cost of doing this may well be too high.If your melted metals contained a high 90% + copper content a copper cell could be used to remove the copper and the sludges left would be where your values will be.Im sure there are members with greater insights into the mehods that ive suggested and look forward to reading their advice. Good luck with this, as i said i love the members having a go at taking on the big boys.


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## qst42know (Nov 15, 2009)

A magnetic separation of e-scrap is a bit of a mixed bag as much of the PMs sought are applied to magnetic materials.

However this separation of base metals may have some benefit. Copper based components could be digested in HCL/peroxide, while parts that contain iron could be digested in dilute sulfuric.


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## Gold Trail (Nov 15, 2009)

I most certainly dont wanna come across as "challenging the big boys" on this. I am looking more less for explanations on where the values are.

for example, I know as a fact, that 486 / 386 ceramic procesors will yeild 3 plus grams of AU per pound of chips, and i understand why why the refiners are paying 82.00 a pound for those materials. 

but, last june I was in a bind and sold 400 pounds of memery @ 8.00 per pound and 100 pounds of cell phone boards at close to 9.00 per pound to a refiner specializing in e-scrap

I, personally, through 20 plus failed small scale tests cant find 3.00 / pound worth of any thing in memory or cell phone boards. 

Keypad boards are another example. again, I have several hundred pounds of these. 

Lasersteve mentioned about using a toothbrush and acid peroxide to "scrub off" the gold from the cell phone and keypad boards. Thats a fine idea if you only have a few. I moved over 38,000 lbs of computer mother boards alone from my recycling facility. with all those towers, came cell phones by the bucket load.

To get back on topic here, I also know some of the chips on memeory hold value for the refurb of memory.. ok. Ill buy that. But where the hell is 9.00 a pound worth of what on these thinly plated cell pone boards? the more i mess with this the more it looks like selling the material out right may be the better option and get on with life.

Ryan


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## Anonymous (Nov 15, 2009)

The refiners are getting all of the values, copper, silver, palladium, tin, (platinum?)gold. I was making a profit on boards when I was able to get 3.00 a lb for copper. I am not able to do that now, even though last I checked copper was getting up there again, local guys know that everyone is hurting and just will not pay higher prices, since they still get the copper anyways.

Jim


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## nickvc (Nov 15, 2009)

Goldtrails dont take offence but thats what your doing in trying to extract values from low grade wastes taking on the big boys.If all you want, is to know where the values are, take samples and have assays done ,i think that GSP might be able to advise and help you on that, but the real challenge in this thread is to extract the values economically and with safe methods, dont give up, someone will get the answer sooner or later the big refining operations dont do it for nothing, and we all know they only just about make a living!!! :shock:


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## LeftyTheBandit (Nov 15, 2009)

Grind

Classify to mesh 200 (just like mining)
> Regrind feed that is > 200 mesh
> Classifying material is extremely important.

Cyanide leach
> Consider eDust as a mining ore (cyanide is cheap and used diluted)
> Spend time learning how to use cyanide safely. (cost=cheap)

Incinerate
> Destroys cyanide 
> Spend time on learning how to treat the exhaust.
> It is the most economical and effective way to reduce volume.

Melt

Sell copper alloy to smelter.
> Specialize in one aspect pass on the rest to another expert.


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## goldsilverpro (Nov 15, 2009)

Gold Trail,

Sodium thiosulfate is used as fixer in the photo industry to dissolve silver halides. The silver is then plated out in special electrolytic units. The cathodes in these units are usually stainless steel drums which rotate. The purpose of this rotation is to provide fresh silver ions directly to the cathode surface. The silver in this matrix is in the form of a negative complex thiosulfate ion. This *negative* ion is actually repelled by the *negativ*e cathode - this is important to understand. To break down and deposit silver, these ions have to virtually be next to the cathode surface. If the cathode surface is depleted of these silver ions, the cathode will instead deposit a black sulfide deposit, created from a breakdown of the thiosulfate. This is the reason for the rotating cathode - to keep the cathode film (an extremely thin layer of solution right next to the cathode) full of silver ions and prevent sulfide formation. It most probably works the same with gold in this system.

In this silver system, the black sulfide also forms when the silver concentration gets low. Same reason - there's not enough fresh silver ions next to the cathode.

I don't think that normal agitation would work, unless it were extreme. I think the rotating drums agitate the cathode film, whereas normal agitation would primarily agitate the solution. The cathode film is actually a separate entity from the body of solution. To replenish the cathode film with *negative* ions, you might be able to use ultrasonic agitation. I've also thought that the solution, circulating through under-the-solution spray nozzles, which impinge directly on a sheet cathode, might work.

This cathode film thing is a complicated subject, which I don't understand thoroughly.


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## Gold Trail (Nov 15, 2009)

LeftyTheBandit said:


> Grind
> 
> Classify to mesh 200 (just like mining)
> > Regrind feed that is > 200 mesh
> ...



will the cyanide leach PM's? or just gold

I had the understanding that cyanide was no longer available in the USA?

I still have alot of research to do on this, now that I have some others ideas / opinions to consider in all this. The guy that sugested this route stated thio and electrowinning were easy! 

Looks like another round of tests is in order.

Thanks for the insight and I look forward to some sort of results from all this

Ryan


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## Gold Trail (Nov 16, 2009)

heres some interesting reading from the chem books link in Palladium's sig line. (I think it links to aflacglobal's up loads) 

read "Thiosulfate leaching as an alternative to Cyanidation" One you get past all the chemistry formulas, thio leaching actually made some sense, particularly in regards to how it actually done, and the premature cementing onto the copper left in the boards issue. 

It was a quickie read of 20 or pages, worth checking out

Ryan

PS Thanks to Palladium for the links and Aflac for taking the time to scan all that


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## goldsilverpro (Nov 16, 2009)

> Thanks to Palladium for the links and Aflac for taking the time to scan all that



Same guy. His name is Ralph.


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## Palladium (Nov 16, 2009)

Chris, How's the setup of the assay lab going ?


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## goldsilverpro (Nov 17, 2009)

> Chris, How's the setup of the assay lab going ?



Everything is completely ready to go, except for making up a price list. I hope to finish that today. The price list takes a lot of thought. I couldn't find another lab on the internet that's assaying electronic components. Therefore, I have nothing to compare. I'll just try to keep the prices as low as possible, yet leave a little room for profit. About 15 years ago, there was a lab in CA that charged $100, and up, for electronic components. I'll be much, much lower than that. I'm thinking of starting at around $35. Bullion will be less.


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## Gold Trail (Nov 24, 2009)

we have some results, however i am reluctant to post them untill assay comes back. 

looks like a viable, yet so overly simple yet still complicated process with alot to learn. 

seems that silver will predominate the precipitation , so we poured dore bars (i think they are called? or is it refiners bars?) 

we'll see what the assay says and ill then post what went into it. 

as well as the over all process

Ryan


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## Anonymous (Jan 25, 2010)

Hi Ryan, did you find anything out yet? :roll:


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## Gold Trail (Jan 30, 2010)

its honestly looking good but again untill i perfect this crazey process I am reluctant to post any further info. I dont want anyone going down the wrong path with this. 

And right now, as much as id like to spend every available second in the lab working on this, a little thing called life keeps getting in the way.......

so much to do so little time, and its freaking cold in PA right now. 

Ill get this, and make sure all whos interested can make it work the first time. 

Ryan


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## Anonymous (Jan 30, 2010)

Hi Ryan,
I processed 8 lb of the square IC chips and gold a decent yield of gold, they had gold bonding wires quite a few and gold solder holding the wafer down.

I have a recipe for thiosulfate leach if you want it. I have not got to try it yet, just my digging around in old gold/metal refining books.

Jim


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## Scott2357 (Jan 30, 2010)

I find this thread very interesting. I too have been looking at an economical way to recover of all the metals.

James, About how much Au per pound for 8 lbs. of those chips?


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## Anonymous (Jan 31, 2010)

Scott,
I have not refined the material so I do not have an exact gold content.
I have a test tube with a pile of gold wires in the bottom, chunks of gold solder, and globes of gold/silver pieces that most likely contain some copper.

I have a process that does not include grinding up the whole chip and only concentrates on the center where the silicon chip is, this is also were the gold bonding wires are. 

I ran the 8 lb and gold about 4 oz of the centers above, ashed these with a propane torch to red heat for about 5 min, then quenced in water. I ground this stuff of as find as I could with a mortar an pestal. Then panned the material an got a good portion of gold wires and solder. then treated the rest with nitric acid for 4 hours to remove as many base metals as possible, then panned agian. thies seperated out the globes of gold/silver materials which I am sure have some copper content.

I am only interested in recovery, not refining since no one will pay me for spot price anyways. This material also, does not belong to me, it belongs to another forum member that sent me material to run to test my chip processing machine.

After I send the material to the person it belongs to, it would be up to them to refine and decide if they want to post actual metal contents.

I can tell you this, if you can process the chips quickly, without having to dissolve all of the base metals in the chips, with metals at or better than current prices, there is money to be made.

I am now working on a electrostatic sorter to allow even faster processing of the bulk material and need to make a grinder that will grind the concentrated material more uniformly and to a much smaller size.


Jim


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## Gold Trail (Feb 1, 2010)

goldsilverpro said:


> Gold Trail,
> 
> Sodium thiosulfate is used as fixer in the photo industry to dissolve silver halides. The silver is then plated out in special electrolytic units. The cathodes in these units are usually stainless steel drums which rotate. The purpose of this rotation is to provide fresh silver ions directly to the cathode surface. The silver in this matrix is in the form of a negative complex thiosulfate ion. This *negative* ion is actually repelled by the *negativ*e cathode - this is important to understand. To break down and deposit silver, these ions have to virtually be next to the cathode surface. If the cathode surface is depleted of these silver ions, the cathode will instead deposit a black sulfide deposit, created from a breakdown of the thiosulfate. This is the reason for the rotating cathode - to keep the cathode film (an extremely thin layer of solution right next to the cathode) full of silver ions and prevent sulfide formation. It most probably works the same with gold in this system.
> 
> ...




So this must be the "Black Plauge" Ive been finghting? its a gooey mess, that luckly goes away in warm dilute nitric, but has my silver bound up in the nitric......

I think the trick in my case is going to be to dump the fish tank bubler and step it up to an air compressor to get more of an agitaion. ( im exprimenting with a 55 gallon set up.) 

right now its just too cold out in the lab, especially when there projects to do in the nice warm house. ;-)


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## Gold Trail (Feb 22, 2010)

All right, almost ready to post results on this contraption

My gold yield was really low, and after some investigations i found out that IT IS POSSIBLE to leach too long. (thank you Action Mining Supply) 

So, after re-visiting my discard barrels, i noticed a black fim on the pins and copper traces on the boards.

so, I'm off to deal with this, now, and when exact results are available they will be posted along with pics of the set up. 

When I was getting started in all this I was fed so much Bull Sh*t and I refuse to mis lead anyone

If this process is a joke Ill say so and be done with it

Ryan


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## Anonymous (Feb 22, 2010)

Ryan,
I can tell you this, I have recovered .20 -.25 grams of gold per lb on the square chips and .10 -.15 grams from rectangular IC chips both these are actual yields from various chips in a wide mix, not seperated by chip number, only by shape square or rectangular.

If your yield is off from that then I would suspect a proplem, with the thio you should also be getting the silver from the chips.

Jim


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## Gold Trail (Aug 14, 2010)

Any one having some luck on this? I had to tear down my set up for cleaning last February and never set it up again. hoping to get back into this soon. I did have some luck flash striping mil spec pins with granulated pool chlorine and HCL, but the fumes were horrendous.


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