# 63g of HD platten foil I have collected over a few years



## tracar (Feb 17, 2022)

years ago when I was in the computer scene, I did keep every HD I came across and processes every platten each had, first was a sodium hydroxide bath to remove the aluminum then various acid baths. what I was left with was a bag of foil chunks , I have done gold before with great results.
this week I decided to see about purifying this foil in nitric/hydrochloric . and dropping out with amonium chloride. well as usual this batch dissolved really nice with quite a bit of nitrogen dioxide was produced, and the resulting liquid was green, so when I saw the acid could not absorb any more metal I slowly dropper in more until all the flakes are dissolved, as to not have an excess of nitric. I mixed and simmered until I had half the volume left, amonium chloride salt was added a beaker and a saturated solution made, this was added to the main beaker, no change........ hmmmmm. so I left it to simmer down and noticed that the lower it got more yellow started to appear, I let it simmer to almost dry and I ended up with a good quarter inch in the bottom of yellow sludge, I added some distilled water and I could see an immediate separation of the yellow precipitate and the green soluble liquid. now has anyone had similar happen, these are not the average hdd's plattens from as of late but are the older aluminum thick types most the footprint of a dinner plate.

with a wealth of knowledge in here, would the green liquid carry anything worthy? and im assuming the yellow is platinum group ?


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## nickvc (Feb 18, 2022)

I’m far from an expert on refining PGMs but try using stannous to gain an answer.


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## tracar (Feb 19, 2022)

well when I start with platinum and various metals I guess thats what you end up with, so until I find out why nothing settled out the stannous test is irrelevant at this point in time.. what I was more interested in was if anyone here has had the chance to process the older drives and thru their experiences what they recall were the main fractions, or what if there is a average of what metals I should be on the lookout for.

as I said before , when the pot is boiled down I have a lot of yellow granular forming in a green very clear solution.


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## Yggdrasil (Feb 19, 2022)

tracar said:


> well when I start with platinum and various metals I guess thats what you end up with, so until I find out why nothing settled out the stannous test is irrelevant at this point in time.. what I was more interested in was if anyone here has had the chance to process the older drives and thru their experiences what they recall were the main fractions, or what if there is a average of what metals I should be on the lookout for.
> 
> as I said before , when the pot is boiled down I have a lot of yellow granular forming in a green very clear solution.


The stannous will tell you if there are PMs in solution.
If not, the work can be ended and the solution transferred to your waste treatment.
But since you already have precipitated some salts, you need to redissolve that for an accurate result.


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## tracar (Feb 19, 2022)

As i have never done hdd platens before, i obviously have some salts form which i will filter off, but was more interested if there is a way to tell if there are any other optional valuable metals in the green solution.

And will boiling down to dry make the process harder to process the salts ?


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## Yggdrasil (Feb 19, 2022)

Stannous will reveal if you have values in there.
The yellow may be a ammonia salt of platinum, or another ammonia salt.
Try to redissolve a tiny fraction in AR and test it with stannous.
But as more have said.
Test with stannous so you know if you have values or not.


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## tracar (Mar 14, 2022)

had to make some stannous solution. yes I had a positive in the green solution, I did boil it down and added small amounts of chloride until the solution showed next to nothing. took a few days.
I filtered off , and cooked off the chloride, now im left with 21g of goodness.
thanks for the help


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## orvi (Mar 14, 2022)

Concerning PGM salts, you did not want to evaporate to dryness, if you have them in acidic form. It is advised to add 2 times stoichiometric ammount of NaCl before evaporating the liquid. PGMs form chlorocomplexes, which are soluble in water, but if you cook them hot enough, some HCL liberates and remaining stuff will refuse to dissolve afterwards. With NaCl, soluble sodium hexachloroplatinate, sodium tetrachloropalladate etc. form, and you will have no trouble in your next steps.


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