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Playing with palladium


Paladium solder…i make my own here=B4s the recipy :-


this flows at about 900=BAc colin waylett (spain)


Hello Douglas, There may be a new type of “pickle” for the platinum
group metals, especially palladium and platinum. A British patent
describes dissolving PdO with an ionic solvent (AKA ionic liquid).
PdO, in the form of spent automobile catalyst, was dissolved at less
than 60 deg. C in a 2:1 oxalic acid-choline chloride (vitamin B4)
ionic solvent. The length of time required was not given. A clear
green solution was formed which contained the Pd value. The Pd was
recovered by electrodeposition using a Ni cathode and a Ti anode at
5 volts for 30 minutes at a current density of 1 mA/cm2. The
question of a possible effect of the ionic solvent on Pd metal is
moot. The literature indicates that there are ionic solvents
capable of dissolving plastics, rock, metals and all manner of
materials. There are a great many ionic solvents of various
compositions, many of them formulated as a solvent for a specific
reaction or process. It would seem reasonable that an ionic solvent
could be formulated for silver and gold, or any other metal used in
the production of jewelry.

The components used in the British patent to prepare the ionic
solvent are readily available. There are no real safety issues with
choline chloride. Many millions of pounds are produced each year
for use in animal and poultry feed. Oxalic acid is widely used in
metal cleaning. It requires no more care than does boric acid,
sodium bisulfate, or any other of the chemicals used on a daily
basis in the shop The ionic solvent is clear with no appreciable
vapor pressure and probably very little, if any, odor. There is no
water or any other normal solvent present. Sounds amazing doesn’t

Captain Blood
"Marlinespike Seamanship in Precious Metals"

It would seem reasonable that an ionic solvent could be formulated
for silver and gold, or any other metal used in the production of

Captain B:

My chemistry is a bit I HOPE that you are considering

manufacturing and marketing this marvelous pickle for us! I would
also like to order a pickle that can remove ALL the accidental oxides
on white gold, too. I wish this stuff was around earlier, when I was a
Baby Goldsmith, and was still struggling to keep the oxides off in
the first place.

Douglas Zaruba
33 N. Market St.
Frederick, MD 21701
301 695-1107


Douglas: You would not need much chemistry to evaluate the pickle
potential of the ionic solvent used in the British patent to recover
Pd values from spent catalyst. The Edison approach should be
sufficient. Some chemical concepts would be helpful in designing
trials. For example, boosting the chloride anion concentration to
promote metal chloride complex formation (people use this kind of
complex every time they add salt to vinegar when cleaning copper
pots!) and using acids like citric acid or EDTA
(ethylenediaminetetraacetic acid) in place of oxalic acid to promote
clathrate complex formation, etc. These types of reaction rate
increasing complexes are understood and used by non-chemists on a
regular basis.

I don’t believe the oxalic acid-choline chloride system would attack
Pd metal. Dissolving an ionic substance with a strongly polar ionic
solvent is one thing. Oxidizing the metal with the ionic solvent is
a horse of another color. I don’t see what could/would be reduced in
the system. One would have to add an oxidizing agent.

I intend to check the British ionic solvent out as a potential
pickle. If it shows promise then some obvious substitutions would
be in order for evaluation. I am too long in the tooth to consider
diving into the thicket of patent, manufacturing and marketing
considerations if an effective general metal pickle does emerge.

Captain Blood
"Marlinespike Seamanship in Precious Metals"