Me! Me! Me! Me! Me! Me! I can start.... Oh.. too slow...
I started off by collecting every scrap that had a hint of gold and to keep acid costs down the only thing I processed was fingers. The only way I knew to process then was dissolving base metal with nitric and collecting the gold. This was back in the pre-forum days.
At that time I didn't know of anyone buying electronic scrap so anything picked cleaned went to recycling. Soon I realized I got more scrap than I had time to fully process and I started to prioritize, only picking pieces with decent gold. I started to skip PCI and ISA connectors.
Later on I found out the local scrap dealers paid good money for iron, aluminum, cables, brass, copper, stainless steel, lead batteries and any circuit boards so naturally that was the fractions I sorted in, picking off any good gold on the boards and no one noticed.
When I found the forum I realized I had missed quite a lot of the gold. At the same time they lowered the price on circuit boards so today I sort the circuit boards in three parts :
- Low value boards like power supplies, TV-boards, power electronics... and so on. These I sell in 50 kg batches.
- Good value boards like mother boards, hard disk boards, boards with a lot of IC:s... and so on. I don't care to remove any gold at all from these boards, just any non-gold containing parts like cooling fins, large capacitors... Any components removed here goes to the low value bin.
The good value cards are stored for later processing or for sending off to a smelter where I can get paid on content. There are no good buyers in my area and I would get the same price for this as for power supply cards.
- Stuff to process. Here is a mix of different things. Anything large and gold plated like microwave components and connector housings is placed in a box waiting for the next run of the sulfuric cell. Memory SIMM, CPU:s and mobile phones also ends up here. Basically this is what I have time for in the foreseeable future and if I get too much the border between "Good value" and "Stuff to process" will move to produce a balance.
The rest of the scrap is still sorted in the lots the scrap yards buy things in. For example, my buyer doesn't sort zinc from aluminum so all white non-magnetic metal except for stainless ends up in the same bin.
Some complex scrap is processed slightly, I had a couple of server power supplies that had gold fingers, some logic boards and MLCC:s. The gold fingers were cut off, the logic boards broken off and put with the Good value cards and the MLCC:s I could reach easily enough was cut off before the bulk went into the low value box.
The iron is mostly an annoyance, I filled up the car today with old computer chassis and 250 kg made me $20. I needed the space more than the money, tomorrow I'm filling up the car with old printers and that will result in quite a lot of iron scrap again.
When it comes to refining I don't have a lot of rules I follow, usually I start with quite specific treatment of scrap depending on what it is. Then as I progress I can combine the lots unless I want to do some assays on specific components or refining for a client.
- If it is fully plated on thick metal and everything can be accessed by a liquid, cyanide or sulfuric acid cell.
- If it is plated on thin copper, copper chloride leach to extract the gold foils.
- If it contains gold bond wires in plastic, incinerate and pan.
- If it is ceramic and got iron pins, hydrochloric acid to remove iron and solder.
- If it is ceramic and most base metals are mostly gone, aqua regia.
- If there is tin or indium on it, hydrochloric to remove it, then sort it again.
- If the precious metals are covered in plastic material, incinerate (dipped MLCC:s with pins for example)
... and so on, sometimes it is possible to merge two lots into the next processing step, for example foils from fingers, panned bond wires and gold sludge from a sulfuric cell can easily be dissolved in AR together. But sometimes mixing two lots can produce strange results... that builds experience. :lol:
I have the following bins I sort small electronic things in. Bins is a bit vague and can go from a small jar to large boxes.
Gold :
- Bin 1. Metal pins fully or mostly gold plated, no plastics (Currently 30-40 kilos). Too much metal to economically dissolve the metal. First plan, melting and copper cell but scrapped that. Second plan sulfuric acid tumbler cell on hold. Third plan cyanide leaching and researching it currently, looking good.
- Bin 2. Good plating contacts, mostly leaving it on boards unless the rest of the board is low value. Pulling pins while watching TV and putting it in bin 1. Having 10-20 kilos of it in storage.
- Bin 3. DIL IC:s, sell or process myself. Only stockpiling at the moment.
- Bin 4. Surface mount IC:s. Stockpiling but will process with RAM when I have a couple of kilos for a decent batch. Processed according to Patnor method.
- Bin 5. plastic BGA, Processed according to Patnor method when I have a kilo or more. I keep this separate from Bin 4 since there is only gold and trace copper inside, no lead frame to mess with.
- Bin 6. RAM, In small batches I would depopulate in HCl, collect IC:s and MLCC:s separately, circuit boards goes to copper chloride bath.
- Bin 7. CPU:s, Sort and process according to model and sell to collectors if possible. Modern CPU:s might end up with Good boards in the end. This is a subject of it's own.
- Bin 8. Mobile phones and similar high end scrap. I'm collecting for processing via smelting. Not there yet. Might go with Good boards in the end.
- Bin 9. Large plated objects. Collect a couple of kilos then run through sulfuric cell.
- Bin 10. Other gold containing components, throw in a box and look at it some other time. Might go to smelting with the mobile phones. Anything I don't have enough of or don't know what to do with ends up here.
Silver :
- Bin 11. Keyboard mylars. Collect for incineration or other treatment.
- Bin 12. Silver contact points from relays and breakers, collect, dissolve in nitric and cemented on copper.
Palladium :
- Bin 13. MLCC:s, When convenient I pick off some MLCC:s and collect. Usually process when I have 2-3 hg or more. A long soak in HCl (months), then nitric acid, silver as chloride, denox, cement and collect PGM concentrate.
Other :
- Bin 14. Tantalum capacitors. When I feel for it and there are easy pick on boards I remove some other components I usually pick these off too for selling.
If I would be doing this for economic reasons I would sort in low value boards to sell locally and high value boards to send away... yeah, that's about it. I might keep some high end stuff just as some CPU:s or fingers might be faster to payout if I process it in house. Then I would have gold in my hand in a few days instead of money in a month or more.
The reason I sort in so many bins is that I want to try different methods and to get a first hand knowledge on how much values there are in different types of scrap. If I know how much I can expect from a DDR3 RAM then I can buy scrap, collect a larger batch and send out for processing. There is more money in refining, toll refining or collect larger batches than in ripping apart computers one at a time.
As has been said before, if you need to sort scrap component by component then you will never earn any decent money. Smelting can process tons of scrap at a time so for us there basically is only high grading and collecting left that we can do with mixed scrap.
The sole exception is when we get already sorted scrap that we can process straight away, like CPU:s or RAM.
So far I'm only a hobby refiner and have kept all metal I have refined. I'm getting closer to my first ton of good boards and is still collecting.
Being a hobby refiner, nothing I do needs to make economic reason...
A long post but when I started to write I couldn't stop. :mrgreen:
Göran