Hi again, sorry delays, been really quite busy,
I would firstly suggest you (& us/we/them/everyone) do some smaller scale experiments before you commit to doing this in bulk, as I'd hate for it to be a complete waste of time, money, and effort for you, and we end up with nothing more than some worthless white aluminium goop and a drop of nickel... :shock: Then again, we need a guinee-pig to do some platters in bulk and see if low platinum content is why its not showing up on tests. The process I describe is quite cheap, and I guess the worst part is if you are manually cutting the platters up - blister city!
Anyway, on with the show..
I purchased it from a hardware store in NZ called Mega Mitre10, it is only NZ$5 for 500grams. Brand is Tergo Drain Unblocker - 100% sodium hydroxide. (eats aluminium but copper (plumbing & Pb?) is left unharmed)
I used a 2 liter container almost filled with warmed tap water and roughly about 50 grams of powdered sodium hydroxide.
Mix it as you pour powder in as it will cake up on the bottom, and become more troublesome to mix.
I dropped in about 10 cut up platters. Also do this outside, or with something protecting surrounding area and maybe a loose fitting lid on the container (dont seal it, as gas will build up) as while it initially fizzes away, alot of splatter exits rim of vessel for about 2 ft all around! I did not notice any odours whatsoever from this process, and without further study, I dont know what gas is emitted. (I didnt really want to get too close with my nose on this job!
On the subject of the remaining white powdery goop (aluminium something oxide maybe? I don't know if its worth reclaiming or useful for anything, but there is a fair bit of aluminium in there)
The platter foils remain and I simply tipped off white goop, discard, rinsed & cleaned the foils in water a number of times.
These remaining foils have a shiny side, a dull side, and are quite sharp/brittle. I decided to try and refine further with 68% nitric acid. From memory, after a few days, the nitric turns blue, and the foils are reduced to a shiny powder-like dust floating in solution. Some foil bits don't dissolve down to dust size, and are still elongated.
I am wondering greatly at this stage what I am left with!
I have now also tried a similar process, but dissolving foils in aqua regia, as I would hope that everything would go into solution except the platinum, but, I accidentaly mixed aqua regia with 50% water, and nothing happened. Having no more nitric or hydrochloric, I decided to gently heat this mixture. I have written about this elsewhere on the forum, but to quickly summarise. When it got warm, it began a chain reaction, sustaining its own warm temperature & fizzing mildly away for a half hour. I was left with a lovely lime green liquid, with extremely fine silvery (colorwise) dust particles floating about. These dust particles are magnetically sensitive, with me being able to change their magnetic polarity in solution with a powerful neodymium magnet. This creats a wave of reflection in the liquid when mixed.
(NOTE: Anyone doing this, to be wary of magnets above aqua-regia solution should particles jump out. I dont think these particles are that attracted, but warning just in case)
This is where I'm at until I get some more hydrochloric, and some tin powder to make some stannous chloride testing solution.
Also, next I am going to run a new batch using non-diluted aqua regia! :lol:
Then, if anything is left, collect it all up, and dissolve in hot AR, and precipitate !?!?!? - one day
I am also trying to find out (more re-search/study forum) how to drop out the (probable) nickel, just to see how much there is in solution.
Regards
SK