Once a platinum ring is made there is platinum dust , scraping
and residue. How do i prepare this for re use. ? because when I re
heat and use , it cracks and its unusable.
Ahmed, refining/purifying platinum is the most difficult of the
refining tasks. i’d recommend that you use a fine seive to sort all
the small scraps from the actual dust. then use a magnet to remove
iron from the larger scraps that did not go through the seive (be
careful here, since if you use cobalt/platinum alloys, they are
magnetic too, and the dust from those will be also stuck to the
magnet. All the dust is perhaps best sent to a full time refiner.
there is almost always significant amounts of iron (from file teeth,
sawblade teeth, traces from other tools), assorted abrasive dusts,
dirt, and all sorts of other junk in there. This can be difficult to
remove economically, unless you are doing larger amounts. The larger
scraps can generally be inspected to be sure they do not contain
solder, and are indeed platinum, and then usually can be directly
melted. If you are certain that the platinum dust does not
contain gold, you can dissolve it in aqua regia, just as one might do
for gold, and then precipitate it back out in similar manner. I’m a
bit rusty on the details, though. Consult a copy of Hoke’s “refining
precious metal wastes” for the full details. It CAN be done. But
it’s complex enough, with several steps, and somewhat costly
reagents, that most people feel it’s more economical to sell the
scrap to a refiner, who’s doing large enough amounts to be able to
economize.
Among other things, just refining the platinum does not return it to
either the fully pure, or the alloyed state you need, such as iridium
platinum, or ruthenium, etc. The refining process tends to not so
easily seperate the platinum group metals, so they all stay in the
final result, at least to some degree, though not always uniformly
so. This means that if you refine it yourself, your finished product
may be of indeterminate alloy, unless you are very careful with the
techniques, and follow all steps precisely. As I said, this isn’t
beginner level refining.
Hope that helps.
Peter Rowe