An interesting HCL CL reaction. What is happening?

[Bjc835]

Something I found interesting, but I don't know what reactions are taking place...

I had a bunch of pins and other motherboard parts (about 100grams)... All extracted...I didn't really know how I should go about processing them because if I put them in HCL peroxide, the foils and pins would all be at the bottom of the vessel all mixed together (this may have been the proper way to go about it, but I didn't, and that is not what this post is about), so I decided to pour them all into a beaker and pour over them, HCL and CL...

The mixture immediately turned yellow, and obvious reactions were taking place...I let it sit while I went to work. When I got home, the solution was blackish and I could see that a lot of my pins still contained gold on them. So I decided to add some more CL and again the solution turned yellow, and a few hours later was clear again. I was finding this reaction interesting, and wondering what is happening...I decided to add a bit more CL again the same reaction at first, so I let it sit over night...when I woke up the top layer of the solution was yellow and under that was clear solution...and at the bottom with the pins looked like a bunch of white powder which I am assuming is salt from the CL...

I am more curious about the reactions taking place than the gold yield...has anyone had this happen before? And do you know what is taking place?

 

[yar]

The gold is going to plate back onto your pins because the base metals were not removed prior to hcl/cl. The white precipitate that is in the bottom is probably tin that is being dissolved by the hcl
Without knowing what other parts you but in with the pins that is the best guess i could give.

You kind of have a mess on your hands now. I would put all of it in a bucket with a tight lid and read up on the AP process as well how to deal with waste solutions. Good luck.

 

[Bjc835]

Thanks...that is interesting...the metals used were CPU pins (all of these are pins only), IDE pins, printer pins, and some other motherboard pins...

I have successfully processed RAM more than ten times...I have just never processed such tiny pieces before, and I had my doubts before starting....if the white powder is tin...that is very interesting...I can use that ...but I guess you are right. I am going to have to figure out how to sort this mess out now...

Also I mistyped the weight in the original post...it was about 20grams

 

[Anonymous]

The gold is going to plate back onto your pins because the base metals were not removed prior to hcl/cl. The white precipitate that is in the bottom is probably tin that is being dissolved by the hcl
Without knowing what other parts you but in with the pins that is the best guess i could give.

You kind of have a mess on your hands now. I would put all of it in a bucket with a tight lid and read up on the AP process as well how to deal with waste solutions. Good luck.

If it's an HCl/Cl mix then the white material is more likely to be something other than Tin. Depending upon whether or not the solution was diluted it could simply be NaCl. To test for this add some water and it would probably disappear if it was salt.

 

[johnny309]

When the pins tend to come together is a strong indication of iron in pins......be patient...... the salts left behind is tin salts ...lead chloride is
dissolvable at normal concentration......
Try to add more water....and some HCL..... and let it sit for one day or two.......the crystal....will remain even after AR....will be filtered out...

 

[bswartzwelder]

Like almost all NOOB's to the forum, you jumped in without reading enough to know what you were doing. Put your solutions aside. Your gold is still right there and won't go anywhere else. It is as safe as it could be.

Put everything aside and start reading. Read Hoke (It's a free download here on the forum), read the safety section, then start using the search engine. Everything you need to know is right here.