Entire RAM sticks in Cu(II)Cl

[AndrewSuperD]

Please forgive if this question has already been posted and commented on. That request is pretty common I know, but I couldn’t find this exact question anywhere. I’m happy to be pointed to an existing thread, if one exists. I have just purchased 9 pounds of RAM sticks from a friend for $225. I am planning on taking all those ram sticks and putting them in copper two chloride with an air bubbler for two weeks. What are some pitfalls that I’m going to run into? Tin in solution? If that’s my only pitfall, can’t I just boil filtered solution’s filter papers in hydrochloric acid to ensure no copper and no Tin and no steel? I have processed Ram sticks before by snipping the gold fingers, removing the IC chips, and processing separately, but I’m wondering if that’s even necessary. I know it’s the standard practice for Backyard Refiners, but I’m wondering why it’s necessary. I am assuming that pulling off the chips and the fingers and then discarding the board, I am missing out on gold in the solder, gold on the board, and any precious metals in smaller components. These sticks are 5% DDR, 5% RD, 90% DDR2 and DDR3. Any thoughts and recommendations are welcome, but as a newbie, even if this sounds crazy, I’d love a healthy explanation of what’s going to happen. I’m using copper two chloride from a previous run of only ram stick gold fingers.

 

[Martijn]

The copper from the AP will be precipitated out if there are any basemetal ic legs. In time all base metals will dissolve again.
The tin from the solder will form stannous chloride and react with any Pd if present in th AP, but other than that a little solder won't hurt much i think.
But interesting what others have to say.

 

[BShan]

On the topic of "why trim":
rarely will there be gold plating on pads other than the fingers. Therefore, the solder would not have gold in it. (edit: kurtak mentions below how this is generally not true. I should have worded "I've rarely seen evidence of gold plated pads in modern, low-grade consumer dimms") On the chips dimms which ARE plated, you can bet that they did not plate the same thickness over all exposed copper. Otherwise, you are throwing away acid and time, just to dissolve metals you don't care about, which you then have to take back out of acid later when you go to cleanup. The copper could very well be one of the last things to fully go into solution, but it's the main thing that you want to dissolve.

On BGA memory chips:
Twist a DIMM until you hear them making cracking noises, but not so much that they actually break. Then twist the DIMM the other way until cracking noises. Now, you can just pull the chips off with your fingers!

 

[nickvc]

With memory you have more gold in the chips than the exposed gold fingers and separating items makes recoveries easier , why risk messing all your values up when fingers are the easiest to refine

 

[kurtak]

On the topic of "why trim":
rarely will there be gold plating on pads other than the fingers.

Sorry but that just flat out is not true !!!

although it is true that not all "pads" on RAM (&/or other circuit boards) are gold plated - more often then not they are

We are talking about any & all "pads" on a circuit board (including RAM circuit boards) where a SMD (Surface Mount Device) such as IC chips, capacitors, resistors, diodes, etc. etc. get soldered to the board

The very reason for the gold plating on these pads is to keep the copper from oxidizing from being exposed to air over time

Therefore - more often then not (but not always) board manufactures gold plate any & all exposed (copper) pads on the board in the event that some of those "pads" do not get an SMD soldered to them - that gold plating prevents that copper from oxidizing which could lead to the board failing

Therefore, the solder would not have gold in it.

Again - just flat out not true !!!

In modern electronics the solder use to solder the SMDs to the circuit boards is a 95% tin 5% antinomy alloy

In older electronics the solder was a tin/lead alloy

Both tin & lead - when molten - are "solvents" for gold

Therefore - when SMDs are soldered to the "pads" on the circuit board - if those "pads" were gold plated (which is more often then not the case) that gold plating dissolves (during soldering) & becomes alloyed with the solder

Therefore - the solder will in fact have gold (alloyed) in the solder

Therefore - if you take a kilo of solder from modern day CBs (which is 95% tin 5% antimony) & dissolve it in HCl it will dissolve the tin but not the antimony as well as not the gold that became alloyed with the solder during the soldering process --- the antimony & gold will settle out as a black powder

if you then wash the living hell out of that black powder to insure you have washed all the HCl/tin out it you can then treat that black powder with AR to dissolve the gold

Therefore - one kilo of solder - from modern day circuit boards - will yield about 1.5 to 2.5 grams gold (or average 2 grams gold)

Concerning RAM - about (plus/minus) 70% RAM sticks will have the pads gold plated - about (plus/minus) 30% Ram sticks do not have the pads plated (so are copper)

Kurt

 

[kurtak]

On the chips which ARE plated,

Just what chips are you talking about that have gold plating ???

I ask because the ONLY chips I have seen with gold plating on them are ceramic chips --- or a VERY SMALL amount of plating on the fiber part (not the black epoxy part) of BGA chips

I have never seen gold plating on run of the mill black epoxy chips & used to process 500 - 600 pounds of black epoxy chips a year & have never seen them with gold plating --- they are processed for the gold bonding wires inside of them

I would like to see pictures of the chips you are talking about - that have gold plating on them

Kurt

 

[Alondro]

Just what chips are you talking about that have gold plating ???

I ask because the ONLY chips I have seen with gold plating on them are ceramic chips --- or a VERY SMALL amount of plating on the fiber part (not the black epoxy part) of BGA chips

I have never seen gold plating on run of the mill black epoxy chips & used to process 500 - 600 pounds of black epoxy chips a year & have never seen them with gold plating --- they are processed for the gold bonding wires inside of them

I would like to see pictures of the chips you are talking about - that have gold plating on them

Kurt

I've had some of them. I got a huge bag of RAM that I spent about 2 weeks dismantling and de-fingering. About 10% of the chips had little gold-plated contacts on the bottom sides. I burned off the plastic of a few and they also had a large amount of gold bond wiring, far more than usual. They're mostly 'hynix' chips from the later, smaller RAM cards, little square chips that are attached by tiny solder buttons under the chip.

 

[AndrewSuperD]

Martijn,

Thank you very much for your reply, It's what I was looking for.

Kurtak,

Thank you for clearing up all the questions I had about one of the replies. As I'm a newbie, I didn't want to question, but I can provide pictures of the gold I have on the RAM sticks and other senior members have discussed the solvency of these gold pads into the solder. I'm sure that gold is something like enig (spelling?) and not hard plating, but still, if it can be recovered, gold is gold. Some of it is VERY shiny so I imagine "thickness" is manufacturer dependent. I appreciate the HCl/Sn discussion as well. That reply, along with Martijn's reply, is exactly what I was looking for. More of the metal interactions (discussed at a high level) that was going to take place, rather than debates on whether the procedure is best or not. I just naturally assume for the backyard refiner, "the cleaner the input, the cleaner the output". Having said that, I'm going to try a small batch of sticks by just putting it all in Cu(II)Cl solution (again, recycled from AP runs of just fingers) and give it a go.


Alondro,

I have a many cards in the lot that appear to be the 'hynix' chips, I'll have to review them as well before I apply the acids to them. Thank you for that.

 

[Martijn]

A tip: try to get a feeling for the different thicknesses of gold plating by rubbing it off with a pen eraser.

And AP can be reused forever. It just increses until you have too much. It's never really waste.
I get the feeling you make new AP for each batch. You don't have to.

 

[FrugalRefiner]

And AP can be reused forever. It just increses until you have too much. It's never really waste.
I get the feeling you make new AP for each batch. You don't have to.

Well, yes and no.

If all you ever dissolve is copper, AP can be reused indefinitely. The problem comes when other metals are introduced to the mix. For example, if it is used to dissolve pins, the base metal will be brass or some other mix like kovar. Using brass as the example, the zinc component will eventually replace the copper, and you'll no longer have copper chloride solution. Kovar's iron will replace just about everything. So, unfortunately, in most cases, the AP will eventually need to be treated as waste. That doesn't mean you should start a new batch every time, but it doesn't usually last forever.

Dave

 

[AndrewSuperD]

Thanks for all the information. I do reuse my AP (which is what I'm calling Cu(II)Cl, I do understand that it contains a lot more metals) until it becomes a dark brownish color. I have been storing it, but I intend to eventually reclaim the HCl with a process of distillation that I got from "Nurdrage". Looks really simple. Once I reclaim all my HCl (I totally keep it separate from my goldwash and anything with Nitric), I am thinking I'll just smelt the metals and store that way until I'm ready to recover precious metals from that smelt. I am way over my head in that thinking and when I'm ready I'm sure I'll learn more and look back at this post only to SMH. I already have the smelting equipment and would like to use it again one day for this purpose.

 

[ZiegenSauger]

This is the most common scenario for me. I usually sort batches of semiconductors (diodes, transistors, LEDs, and all sorts of ICs). Periodically I process them: if the batches are large enough, I process each separately, or I put them all together.
For most of my scenarios (eWaste or not), I always cook on HCl for hours. And not only once, usually, but I also cook, replace until the liquid is clear.
For the specific case, the memory cards I sort in 4 batches: circuit boards (whatever type of finger and trimmed pieces are often found in the cards as well), MLCCs, surface mounted Tantalum capacitors, and the RAM chips.

The boards, all kinds, I just dip in recycled A/P with some bubbling and low heat, filter, triple check the board leftovers, store A/P back, and keep filtered and washed gold flakes to pile up for processing.

Like MLCC cases, been recovering good Platinum and Palladium. Major surprise but I managed to master the process.

For all types of chips, I cook them in HCl. Then I decide between dry or wet etching. Most of the time I go for wet etching with H2SO4. I have learned to use minimal volume and a method to wash solids off. Dry etching is challenging labor-wise and easy to lose control of tiny flakes, etc.

Sometimes I try to find gold-filled or gold-plated items on garage sales or online. It is cool, once a person sold me a batch like it was gold filled but was gold plated, all pieces except one ring which was solid 18K. Good intent or not, I paid a fraction of what I recovered.

But I like urban prospecting, going for eWaste through and through. Even more, now that I can manage to recover under 1g quantities, I have material almost every week.

 

[stella polaris]

Therefore - the solder will in fact have gold (alloyed) in the solder

Therefore - if you take a kilo of solder from modern day CBs (which is 95% tin 5% antimony) & dissolve it in HCl it will dissolve the tin but not the antimony as well as not the gold that became alloyed with the solder during the soldering process --- the antimony & gold will settle out as a black powder



Kurt

How do you take out the tin, as clean as possible, from the HCL?

 

[Yggdrasil]

My best bet would be an electrolytic cell. Plate it out on stainless or such.

 

[kurtak]

How do you take out the tin, as clean as possible, from the HCL?

one option is to electro win it - the problem with that is controlling a VERY long tin whiskers that grow causing the cell to short out so have to keep a VERY close eye on the cell to keep the whiskers knocked down

also need to have a anode & cathode that doesn't react with HCL

another option is to cement it out with zinc (which is what I do)

Because of how reactive tin is there are a few thing you need to be aware of - don't have time to post details right now but will try to get back to it

Kurt

 

[AndrewSuperD]

So I’m bringing this thread around again because I soaked the entire sticks in AP and recovered the gold with Aqua Regua deNOX with Sulfamic. Dropped with SMB and In process of washing now. But after a day, the filtered “remains” from my cotton filter are exposed to air and turning purple! Did I leave gold behind??

 

[Yggdrasil]

I'm a bit puzzled here. "Cotton filter", do you use cotton as filter?
It will lock up quite a bit of values.

Even a proper filter leaves values behind, locked in the filter, that is why we put them aside and process them later.

If you don't have proper filters, better use coffee filter or even better, a charmin plug. It is slow but filters superbly.

 

[AndrewSuperD]

Thank you for the quick reply. My thought is hmmmmm head scratcher... I "thought" everything I've read and seen is that you should use a cotton filter to filter the AR after adding sulfamic (while still hot, then let cool to draw down any lead). So after that cotton filter process, I rinse the cotton filter through with water. I thought in order to drop gold from AR with SMB you want to double the volume of liquid by adding 100% more water. So my process is to rinse my cotton through with water to about 25% increased water volume, then add 25 - 50% more water+dissolved SMB to the filtered AR solution. This gets me a fairly consistent gold drop.

But something is apparently going on since I have this purple color forming. Either I didn't rinse well enough, or it's something else. I always keep all my filters. I intend to process all filters and "gunk" that the filters catch one day because I know, no matter what, I always wind up leaving some values in the filters. Right now, I only have one and a half large Vlassic pickle jars worth.

So cotton filtering AR is not the way to go? I should use coffee filters? Is that providing enough filtration to filter out any cloudy particulates, I wouldn't think so.

 

[FrugalRefiner]

I'm not sure what you mean by cotton filters. You should use a good quality filter paper to filter AR. The filtrate should be perfectly clear. If it's not, pour it back through the same filter again till it is.

You want to do your dilutions before you filter. Goldsilverpro found that by tripling the original AR volume, any small amount of silver chloride that was in solution would precipitate out. Also add a small amount of sulfuric acid to precipitate any lead. Then filter.

The purple you're seeing might be silver chloride. It starts out white, but will turn purple as it's exposed to light. That's just a guess.

Dave

 

[Yggdrasil]

I can not remember any recommendations on cotton filtering.
Charmin plug for hard to filter solutions, yes, but for that fibreglass is recommended.