Step by step instructions for AP processing circuit boards

[FrugalRefiner]

Yes.

Dave

 

[4metals]

Ok then to proceed we have chosen cut fingers as the easiest it will be a good, (and relatively easy scrap-type to accumulate) scrap to start our AP learning process with.

Lets start with an assumption that we have collected 2 pounds of closely trimmed fingers and we are ready to proceed.

Start by describing how to mix up our starting batch of AP, what we do this reaction in, and what precautions are needed to follow. Also is it best with an aquarium air bubbler?

 

[FrugalRefiner]

I started my first AP with no gold. I put some copper wire in a container, covered it with HCl, then added about a capful of 3% hydrogen peroxide. I let it sit quietly for several days, just stirring it a bit a couple of times a day. That creates the CuCl₂ leach with no excess peroxide to dissolve the gold.

It was a tiny batch. I used a couple of 24 oz. sour cream containers. One had holes drilled in the bottom, and that one sat in another container with no holes.

I then added some fingers. I did not have an aquarium pump at the time, so a couple of times a day I would lift the inner container up, allowing the leach to drain out. Then I set it back in and allowed it to sink.

After a couple of days, foils start to come loose. As circuit boards became free of foils, I'd remove them with plastic tweezers and rinse them with a spray bottle into another container.

Once all the boards were finished, I filtered the solution and saved the foils.

Dave

 

[4metals]

Great, progress. From a refiners perspective we all know that hood space in your refinery is precious. So we don't want to fill it with reactions that do not absolutely require the ventilation.

I then added some fingers. I did not have an aquarium pump at the time, so a couple of times a day I would lift the inner container up, allowing the leach to drain out. Then I set it back in and allowed it to sink.

Did you ever notice any fumes coming off the reaction? Is it something that could be kept on a countertop or would you place it outdoors in a covered pail set so some critter (I know you have obnoxious squirrels in Ohio Dave) cannot push it over.

What I am trying to get at is how much exhaust is required if any for this process. Is this something that someone new to refining could get into just to collect the foils for now and do so with minimal investment in hoods and exhaust? Obviously to process the foils later on into fine gold a hood is desirable but while a collection of foils is building up can a newbie do without a hood for the AP alone?

 

[FrugalRefiner]

Again, my was a tiny batch; an acquaintance experiment size. At the time, I had a deck above a walk out basement area. I had the area covered with clear, corrugated plastic covering attached to the underside of the deck so I could store firewood there without having to deal with tarps. I put my sour cream containers into a larger plastic container (I believe it was a dishwasher soap container that had a lid). I put a hole in the lid so it could vent and put a brick on top. I never noticed any fumes and could do my daily "stirring" without any problems.

At that house, racoons were a bigger problem than the squirrels, but they never showed any interest in my tiny experiments. I expect they smelled awful to their sensitive noses.

I don't know how much fume comes from bigger batches like 5 gallon buckets of 55 gallon drums. I never processed so much ewaste that I had to scale up to that level. Shark?

Dave

 

[ssmontecarlo]

I would think that close cut fingers are the easiest for the AP process.

I agree. I started processing ram card, sound, and graphic card gold fingers using AP and a fish aquarium bubbler. When I filtered the gold foils, I would roast them until red.

 

[4metals]

When I filtered the gold foils, I would roast them until red.

And what did the roasting accomplish for you? Other than assuring they were dry.

 

[ssmontecarlo]

To help in the removal of tin/solder that may have remained. The person who instructed me on this doesn't respond on this group anymore. Anyhow...regardless of the method of removing the gold foils from ram card fingers, I roasted/ heated them until red. May just be a useless step in the process but I took his advice. His advice was always correct.

 

[Shark]

Small lots such as a 1L or 2L beaker wasn’t much trouble. I liked doing it in glass early on for the visual aspect. A small aquarium pump noticeably sped up the reaction. At that time, I started much the same as Dave did. A piece of green copper in some water and HCl and a tiny splash peroxide, 3%. When done, I dumped it into a five gallon bucket to try the waste treatment process but then got my hands on about 50 cdrom drives to dismantle and process.
At this point I picked up a two gallon bucket, drilled the bottom full of holes, just small enough so typical cut fingers wouldn’t slide through them. I would suspend this two gallon bucket inside the five gallon with around 3 to 31/2 gallons of AP. This is also when I started trying to add more air and bubbles spread over a larger area. 1/2 inch pvc formed in and H shape large enough to wedge in the bottom worked well. Drilled with a lot of tiny holes it spread out the bubbles pretty well. I used this for a long time and it worked well for larger boards as well. The holes were drilled only in the pipe and not the fittings, and turned to the bottom of the bucket to further aid in spreading the bubbles apart. This way the holes didn’t clog up as bad as they did on the top by allowing space for trash and some foils to settle below the air supply. I ran two of these at one point and couldn’t keep up so started looking into a larger barrel. I also noticed an increase in fumes based on the distance I started noticing things rusting further away.
At this time I was getting around 50-75 full mother boards and a few other large boards as well averaging about 100 or so smaller parts like cdroms and dvdroms, and large amounts of floppy drives. This is when I started looking into larger drums.

 

[4metals]

This is when I started looking into larger drums.

Is this scale (large drums of AP) where an exhaust would be beneficial? Also would a plastic drum with removable top that seals tightly be OK with a pipe running up high enough to dissipate any corrosive fume? I guess this depends on where you live and how close the houses are.

 

[Shark]

With the larger drums a lid helped a lot to control fumes. A wooden post, former basketball hoop, was used to aid as stand pipe that worked much like a chimney using 4 inch pvc pipe. I chose the 4 inch strictly based on cost and availability. It was strapped to the post and routed to a barrel lid. Nothing fancy, just enough to stop things from rusting. Two 8 foot sections formed the whole pipe system, with a couple of elbows. The lid was always just loosely laid on top of the barrel. It was around 50-60 feet away from anything of value on the edge of an asphalt slab.
The barrel started life as a large scale version of the five gallon bucket system mentioned above. For a short while before ending the processing of ewaste, I ran a system nearly identical to Dave’s cementing system. I learned about air lift pumps and used a similar system and to force air bubbles through a pipe made of 2 five gallon buckets, and eventually a 30 gallon drum. I had a used aquarium(?) pump from a friend that used to raise tilapia (fish) that could keep 50 fifty gallon aquariums oxygenated at a time with 4-6 one and half pound fish in each tank. It was impressive and worked great.

Once going past five gallon buckets, I stopped trying to remove solder masks, and stopped cutting boards. The AP was used as a long term system for extra money. So I only cleaned them out when things slowed down a bit, or I needed cash for larger purchases or pricey equipment. The boards were trimmed of fingers, and still ran on smaller scale AP or direct in AR. The boards were then very crudely, the rougher the better, broken into smaller pieces and warped as much as possible, and straight to AP. If they weren’t crooked enough I would scratch them to expose the metals under the mask and run them in smaller batch’s. These were left until the metals were gone and removed the mask as well. This also was about the time the copper cell posts came along and why I had such an interest in that thread.

 

[4metals]

I never ran AP but I did do a lot of cementation on different streams of waste. I never wanted to put all of those drums in a walk in hood because I felt it was a waste of premium ventilation space. I ran lengths of 1" PVC pipe up a wall and out through a roof penetration as mini stacks, about 3 feet off the roof. The pipe ended about 6 feet off the floor and connected to a piece of flexible PVC pipe (amazing stuff) which is also called spa piping. It was flexible enough to remove the lid without disconnecting it and was connected to a bulkhead fitting in the tight fitting lid of a 55 gallon open top drum. On the wall of the drum, close to the top, a small 1/2" bulkhead fitting acted as a penetration for the air hose from a pond aeration pump, which ran to the bottom into a pipe arrangement on the bottom to distribute the air.

The pressure from the air pump caused enough airflow up the pipe to vent the tank and remove any odors or corrosive fumes. The drums need to be fitted with fittings so the air pressure had only one place to go, up. Every time I was on the roof, which happens enough when actively running a refinery, I went over to those 1" pipes and felt the airflow coming out. Never smelled any odor from those pipes and never found any corrosion on equipment on the roof.

Surely the same setup would work for AP with a pipe running up and out of an outbuilding like a shed or a garage.

Edit to add; always keep the air pump above the liquid level of the drums, because if the power goes off, as it eventually will, the lower pumps will be ruined by siphoning the liquid and ruining the pump.

 

[ssmontecarlo]

With the larger drums a lid helped a lot to control fumes. A wooden post, former basketball hoop, was used to aid as stand pipe that worked much like a chimney using 4 inch pvc pipe. I chose the 4 inch strictly based on cost and availability. It was strapped to the post and routed to a barrel lid. Nothing fancy, just enough to stop things from rusting. Two 8 foot sections formed the whole pipe system, with a couple of elbows. The lid was always just loosely laid on top of the barrel. It was around 50-60 feet away from anything of value on the edge of an asphalt slab.
The barrel started life as a large scale version of the five gallon bucket system mentioned above. For a short while before ending the processing of ewaste, I ran a system nearly identical to Dave’s cementing system. I learned about air lift pumps and used a similar system and to force air bubbles through a pipe made of 2 five gallon buckets, and eventually a 30 gallon drum. I had a used aquarium(?) pump from a friend that used to raise tilapia (fish) that could keep 50 fifty gallon aquariums oxygenated at a time with 4-6 one and half pound fish in each tank. It was impressive and worked great.

Once going past five gallon buckets, I stopped trying to remove solder masks, and stopped cutting boards. The AP was used as a long term system for extra money. So I only cleaned them out when things slowed down a bit, or I needed cash for larger purchases or pricey equipment. The boards were trimmed of fingers, and still ran on smaller scale AP or direct in AR. The boards were then very crudely, the rougher the better, broken into smaller pieces and warped as much as possible, and straight to AP. If they weren’t crooked enough I would scratch them to expose the metals under the mask and run them in smaller batch’s. These were left until the metals were gone and removed the mask as well. This also was about the time the copper cell posts came along and why I had such an interest in that thread.

Holy moly...

 

[Shark]

“Surely the same setup would work for AP with a pipe running up and out of an outbuilding like a shed or a garage.“

It sounds like it would work pretty well. Smaller pipe and flexible sections should be cheaper and less intrusive as well.

 

[4metals]

Let's wait to see if more AP users want to contribute here before we move on to questions about how long the solution lasts and regenerating the solution.

 

[Shark]

Holy moly...

 

[malphorian1973]

I see pins ( older)?.. what the difference. Some are magnetic some are not.

Magnetic or non-magnetic, that doesn't matter. Older - newer pins, the difference is generally the older ones have thicker plating.

 

[4metals]

Magnetic or non-magnetic, that doesn't matter. Older - newer pins, the difference is generally the older ones have thicker plating.

While this is true, if you have any concerns about re-using your AP solutions processing them separately can make a difference. This was pointed out in this thread.

I am hoping this thread will continue on to re-using and recovery of AP wastes.

 

[Shark]

I only run smallish lots of pins in AP, and then only non kovar pins. Kovar seemed to break down better in hot ferric chloride for me and it doesn’t affect my AP. I always wanted my AP to stay copper based as much as possible except when testing it on various items early on. AP can be a very useful tool, but primarily on copper based items.

 

[ssmontecarlo]

While this is true, if you have any concerns about re-using your AP solutions processing them separately can make a difference. This was pointed out in this thread.

I am hoping this thread will continue on to re-using and recovery of AP wastes.

I read that, and I understand, when using AP on magnetic pins, you have magnetic base metals in your AP solution. And probably shouldn't use the solution on non- magnetic pins.