New feedstock question

[kurtak]

I don't know why the process you use on the boards (CN and electrowinning) cannot be used to strip the coils of gold plated material as well.

I have the same question

Anyway let some of our members who specialize in circuitry chime in after you post some photos.

Agreed - sound like the OP has a process that is working for his current feed stock but we need more info concerning the new feed stock

Kurt

 

[Golden]

Pictures can tell us a lot but I completely understand your discretion. Like I said you will receive a lot of valuable information here to help you that you will not get anywhere else.

Forgive the dirty workbench, but here is a front and back photo of the stock. May be hard to see in the photo but all traces are gold plated even under the solder mask.

 

[Golden]

You can't make that claim if you do this!

So your basic CN strip circuit you strip in either a proprietary strip or basic KCN and then run it through something like this?
View attachment 58660
When the copper cathodes load up you dissolve them in AR?
That seems to be an effective method as long as you don't have to account for small lots routinely.

KI doesn't bother me, I use to strip drums of hybrid thick film ceramics in KI. Great process, easy recovery.

I don't know why the process you use on the boards (CN and electrowinning) cannot be used to strip the coils of gold plated material as well.

Anyway let some of our members who specialize in circuitry chime in after you post some photos.

Very nice setup. Doing pretty much the same thing, we process about 30 gallons at a time so we have longer troughs, but thats about it. Again, yes we use AR only for refining our electrode drops.

I totally wish we could use the same process for both feedstocks we currently process. However, like most things regulations and permits control what I do. We simply could not expand the amount of KCN onsite and had to go down the KI path. I am currently limited to having a total of 50 lbs KCN ... and I push that limit every day with 1 single line. We have considered moving, but its ironic, the increase in the transportation fees negates the cost savings of processing in a single line.

 

[Golden]

Brett - Per the bold print - this process may well work (or work well) for the back yard hobby refiner that is dealing with smaller amounts of boards (10 - 20 - 50 pounds of boards) that does not care how long it takes to get their gold out of the feed stock (boards)

Hobby refiners generally don't care if they make a profit (or not) &/or how long the process takes --- it's a hobby

But it most certainly won't work for a larger scale commercial refiner that is taking in larger amounts of boards & doing so on a regular/continuing basis

Large scale operators (actual businesses) need to see their returns in a timely manner (ASAP) not only so they can pay their supplier/client in a timely manner but also see a consistent & dependable cash flow that pays for cost of operations

There is a reason that the BIG BOYS don't use your suggested process - they would go broke in short order

The OP of this thread is not a hobby refiner --- he is a commercial business so needs methods that will process continuing large amount of boards in a timely manner --- AP is not that process

Kurt

Forgive me for really just now understanding the AP process. But this is correct, I cannot have a line that takes weeks to process. Nor can I spend more money on labor to brush individual boards.

and just so Brett understands I have about 30 days from when a truck shows up to put a check back in the hand of my client. Sometimes thats hard to do. My refiner that I use takes about 7 of those days, from the date I ship to them to get a deposit. 23 days goes quick. I frequently have a 5-10 day backlog. So I have a window of 13 days. We don't process over the weekends ... etc etc you get the point. Things have to work well and quickly in order to keep everyone happy. I will say this though, thank you very much for your suggestion and I'm pleased it works for you.

 

[Golden]

The reason you get loaded with nickel is because cyanide will preferentially dissolve nickel over the gold once exposed the same is true of copper, you can reduce this problem by having less free cyanide in your solution which of course slows down the processing, as was pointed out by a very wise processor there’s always a trade off with processing .
You could try pumping your solution around the product so the solution is covering all the product with fresh solution all the time this should reduce the stripping time , the other alternative is to load the product into a rotating drum and move the product again exposing all the product to the solution.
With cyanide processing it’s almost impossible to recover all the values so I hope your end refiner pays on any gold as well.

I'm sorry I guess what I said wasn't totally clear. Totally correct on the Ni with KCN but what I was saying is sometimes our KI will just go to town on the Ni. We normally control it very will with very specific immersion times etc, but sometimes for whatever reason it does not work as intended.

You know what they say. You don't know what you don't know. So maybe I don't know. Math-wise though we do recover 99%+ of gold in the circuit, Ni and Cu .. not sure we have ever done that math. The electrowinning is wicked effective at pulling gold out. We then just drop everything else out, add it to the initial feedstock and send that out the door to the refinery for the few bucks of nickel and copper. We are very lucky that our current feedstocks are so simple, gold nickel copper thats it.

 

[kurtak]

Forgive the dirty workbench, but here is a front and back photo of the stock. May be hard to see in the photo but all traces are gold plated even under the solder mask.

NICE boards - I will post more info on the processing of these boards as well as some questions when I get more time (likely tomorrow)

First question - roughly volume of in take & is it one time deal or weekly/monthly

Kurt

 

[4metals]

I am currently limited to having a total of 50 lbs KCN ... and I push that limit every day with 1 single line.

I have clients who have a 10 pound limit for KCN in house set by the fire department. They can build out separate special storage areas for additional 10 pound increments but it gets crazy.

There are proprietary gold strips which are inhibited for copper and nickel and quite effective on gold. Technic in Rhode Island supplies a good one 9025 Gold Stripper. Since it is a proprietary product it may get you past that 50 pound limit. Worth calling them and having a discussion. The Technic strip yields it's gold which is recovered in an electrowinning cell by adding Glyoxal.

 

[Golden]

NICE boards - I will post more info on the processing of these boards as well as some questions when I get more time (likely tomorrow)

First question - roughly volume of in take & is it one time deal or weekly/monthly

Kurt

They have a little over 2 tons stockpiled now and anticipate generating about 250-300 lbs a week. So it's enough to consider, maybe not life changing, my biggest issue really is just keeping the customer happy.

My understanding is they have a contract to cycle out whatever hardware this is across the entire US. Apparently there are a lot of these things ...

 

[Golden]

I have clients who have a 10 pound limit for KCN in house set by the fire department. They can build out separate special storage areas for additional 10 pound increments but it gets crazy.

There are proprietary gold strips which are inhibited for copper and nickel and quite effective on gold. Technic in Rhode Island supplies a good one 9025 Gold Stripper. Since it is a proprietary product it may get you past that 50 pound limit. Worth calling them and having a discussion. The Technic strip yields it's gold which is recovered in an electrowinning cell by adding Glyoxal.

That's very interesting. I never even considered looking for something like that. They have been added to my call list for the day!! thank you

What really gets me is, I've been doing this forever (it seems) but really how many more people could I kill with 500 lbs vs 50 lbs ... I mean if you wanted to be a horrible horrible person 50 lbs is enough. You know what I mean? I just don't get it. We have gone to city council meetings and talked about how many more jobs we could create. They just don't care once you say CN. Ugh, sorry for the rant.

 

[4metals]

Technic also has strippers for solder by immersion. On populated boards it may be useful. Metal Strippers for Industrial Finishing | Technic Inc..

 

[4metals]

An interesting thought could be stripping the solder and (easily hopefully) removing the IC’s. You had mentioned they may contain Palladium, if they do an ability to break the feed into Gold only and Gold Palladium streams will simplify recovery.

 

[Golden]

An interesting thought could be stripping the solder and (easily hopefully) removing the IC’s. You had mentioned they may contain Palladium, if they do an ability to break the feed into Gold only and Gold Palladium streams will simplify recovery.

I don't have answers yet, but I have someone doing a complete breakdown of a board maybe another day and I'll know total contents of a board and will share that info. He did confirm that most of the plastic chips are palladium plated on die but I do not know quantities yet. He says the worst part is there is just enough silver in the solder to be a problem. Again no quantities, this is just me harassing him for feedback. Also learned this is a 3 layer board, but the middle layer is entirely copper.

oh and all of the leads for all of the chips are tinned steel, just one more nightmare.

 

[nickvc]

When I mentioned checking any remaining gold in your circuit I was referring to your stripped product , you rarely if ever recover all the gold so are possibly losing gold when you move the product on that’s why I suggested taking samples and melting them to get it tested , you already have a 1% loss apparently from your circuit if there is gold still on the product you are stripping then that number could increase to 2-5% at least and in a large volume throughput that could be a very serious amount of money you are losing.
My bad I didn’t read your post properly and missed the KI part and I’m afraid that I know little about that but assuming it has similar properties to cyanide it makes sense that it can and will attack the nickel, one thought is could it be possible you get different thicknesses of plating so the thinner plating dissolves quicker leaving the nickel to be attacked .
I will stress the one point again stripping gold rarely if ever gets all the gold so you could be losing considerable amounts of values …. if you ship 100 kilos of scrap to refiners and it contains 1% Au that’s 1 kilo of gold !
Do that check.

 

[Golden]

When I mentioned checking any remaining gold in your circuit I was referring to your stripped product , you rarely if ever recover all the gold so are possibly losing gold when you move the product on that’s why I suggested taking samples and melting them to get it tested , you already have a 1% loss apparently from your circuit if there is gold still on the product you are stripping then that number could increase to 2-5% at least and in a large volume throughput that could be a very serious amount of money you are losing.
My bad I didn’t read your post properly and missed the KI part and I’m afraid that I know little about that but assuming it has similar properties to cyanide it makes sense that it can and will attack the nickel, one thought is could it be possible you get different thicknesses of plating so the thinner plating dissolves quicker leaving the nickel to be attacked .
I will stress the one point again stripping gold rarely if ever gets all the gold so you could be losing considerable amounts of values …. if you ship 100 kilos of scrap to refiners and it contains 1% Au that’s 1 kilo of gold !
Do that check.

See my reading comprehension is low. You are completely correct. I thought you meant getting gold out of the KCN circuit, which we are really good at. But yes, feedstock wise that is not always the case. We test, we should probably test more, but the refiner seems to be fair and the numbers work well.

Is there an easier way to test than to take a piece of scrap (post procesS) and do a full AR dissolution on it and hit it with AAS?

 

[nickvc]

Yes just take a sample melt it , I would also check your waste from your AR circuit, and get an xrf reading or an assay which will cost you money in the US.
An xrf gun may well be a good thing for you to look at acquiring as it can be used for testing incoming product as well as outgoing material.
Does your refiner pay on the gold content or just nickel and copper ?
Thats a really important question.

 

[4metals]

Is there an easier way to test than to take a piece of scrap (post procesS) and do a full AR dissolution on it and hit it with AAS?

Atomic Absorption gets my vote. A valuable tool in the refinery lab. Be careful as the base material you are dissolving may contain enough weight to cement whatever minute quantities of gold remained on the wire. Filter it first and look for insolubles on the paper. They could be cemented gold. But if it's in solution the Atomic Absorption will pick up even tiny quantities.

 

[Golden]

Yes just take a sample melt it , I would also check your waste from your AR circuit, and get an xrf reading or an assay which will cost you money in the US.
An xrf gun may well be a good thing for you to look at acquiring as it can be used for testing incoming product as well as outgoing material.
Does your refiner pay on the gold content or just nickel and copper ?
Thats a really important question.

We do get paid on gold. but it is a very low percent because of the mix, like I'd have to look to be 100% but I think its about 75% of whatever they report. Versus the 99% I get paid when I send them my gold extract.

 

[Golden]

Atomic Absorption gets my vote. A valuable tool in the refinery lab. Be careful as the base material you are dissolving may contain enough weight to cement whatever minute quantities of gold remained on the wire. Filter it first and look for insolubles on the paper. They could be cemented gold. But if it's in solution the Atomic Absorption will pick up even tiny quantities.

Another good point. I should probably send out more samples for testing. If we have a flaw in our testing, we wouldn't know.

I gotta say, you guys are really opening my eyes. It's clear I know even less than I thought.

 

[nickvc]

Well at least you get some payment back for any gold but I’d be sure to do some checking to be sure they are playing fair , what percentage are they reporting for gold content and do your tests that I hope you are going to do say that may be interesting.
With your AR circuit waste it may pay to neutralise the waste and then run it in a low percentage cyanide solution which will be much more selective for the gold the same may be true for your other product lines, as I said it’s slow but the pay off could be worth it only testing will show that one way or the other.

 

[Golden]

Well at least you get some payment back for any gold but I’d be sure to do some checking to be sure they are playing fair , what percentage are they reporting for gold content and do your tests that I hope you are going to do say that may be interesting.
With your AR circuit waste it may pay to neutralise the waste and then run it in a low percentage cyanide solution which will be much more selective for the gold the same may be true for your other product lines, as I said it’s slow but the pay off could be worth it only testing will show that one way or the other.

Reporting-wise it is always less than a point.

But I'm not sure what you mean regarding the AR waste. Our refining circuit we weigh pre and post. Of course there is evaporation etc but it is also pumped through a resin circuit with activated charcoal at the end. I'm willing to bet for as many mistakes as we might be making, there are none in our AR circuit. As I said before, in over 5 years I have never recovered a single gram from the AC.