Electrochemistry Stripping HD Platters

[publius]

Having used the H2SO4 cell to remove gold plate and the Balbach-thum cell to refine silver and capture Au and PGMs I have a question or two.

Preface: After a search of this forum there seems to be a school of thought that the platters in hard drives that are plated with Pt should be sold as Al scrap and that the time, effort and material cost is not worth the value of the PM recovered.

Question 1: Is it possible to reverse the plating process? (My thoughts were to use CN as the electrolyte. I have worked with CN before and am "comfortable" that I am taking the proper precautions. But I know that Al reacts with basic solutions so CN may not be viable.)

Question 2: Why is it so cost prohibitive to strip the Pt values using wet chemistry? The glass ones could be sent to a ball/rod mill and the Pt powder panned to separate it. I was thinking that the Al ones could be chucked up in a lathe and 0.001 removed from the surface of each side in no time and treated using conventional wet recovery methods.

Thoughts

 

[cobrawearer]

I believe the problems arise from the manufacturing process of the platters. There is a protective layer between each layer of material on the platter. Crushing would eliminate this problem. Do the math, does crushing all the platters make the Pt recovery profitable?

 

[publius]

Thank you for responding. For a while I though I had fallen on the proverbial "Stupid Question."

Discounting the cost of a ball mill (I saw a really creative one here on the forum!!!) the cost would be minimal for glass platters but aluminum doesn't "crush." Here in the Old Dominion (Virginia) the cost of electricity is about $0.10 to $0.15 kwh. A 1/4 hp motor running 115 volts @ 5 amps (575 watts) would cost $0.06 to about $0.09 if it ran for an hour. Not factoring in my labor (the machine is running unattended except for charging and discharging) worst case $0.10 per charge of say 1,000 glass platters.


But do I really need to do that if flexing them introduces enough Pt to the solvent(s) to effect solution?

 

[Geo]

muriatic acid (hcl acid) reacts very strongly to aluminum and a little goes a long way. place the platters in a plastic bucket large enough to hold them and the acid solution with room for the reaction which will become vigorous with steam and heat and it will foam up,diluting with tap water will slow down the reaction with less heat but it will take longer.dont try to dissolve the whole piece of metal but just to deplate it.ive used this method and it works just fine on aluminum disc.by the way,take a knife and cut a couple of deep scratches across both sides.

 

[publius]

Thank you, Geo!

[Hurries off to Home Depot site to check the cost of HCl]

 

[butcher]

I sometimes use the (cut to small pieces with tin snips) aluminum disks to process my waste solution, this remove's the foils from hardisk.

inceneration is a must of the foils, the disk foil contains a hard carbon film.

cannot say they are worth processing the foils. the foils after inceneration and leaching other metals from them are added to some scrap silver to be melted.

glass disks you would have no aluminum to deal with.