Dear Friends: I have made some very fine gold powder but finding it
very hard to have the powder settle to the bottom when I clean it
with water. It is taking me more than 48 hours for it to completely
settle down. Most of the gold flakes are less than 20 microns. Some
may be even as small as 5 micron. Do anyone of you have a more
effective way of solving this problem? Any answer will be highly
appreciated. Just in case my email is Yuvak@sbcglobal.net.
Yuvak
Yuvak Ratna Tuladhar
G’day; try and find somebody with access to a centrifuge - there
will be one in most University Chemistry departments. A few
minutes in a good centrifuge will drop all the gold out of the
water to the bottom of the tubes… Even a simple hand operated
centrifuge will probably do the job.
Cheers for now,
John Burgess; @John_Burgess2 of Mapua, Nelson NZ
try some of the new dirt settling floor cleaners, it would stand to
reason if dirt will fall then gold should fall even faster
Ringman
Yuvak,
Is the problem that the metal floats on the surface, or that even
when suspended in the water it won’t settle? If it’s floating on
the surface, read on. If not, I’m afraid this post won’t be much
help. When refining if I don’t get the balance right between the
alloy and the gold, I’ll end up with grains of gold so small that
the grains float on the surface, if you have to rinse 10 or 15 times
it can take all day to finish. The problem is one of too much
surface tension. So, often if I have gold floating at the top of
the water I will take a spray bottle and gently mist the grains. If
this doesn’t help, I dip my fingers in distilled water and fling the
water at the surface. More likely that not that does the trick.
Once they are immersed, it is not long before they sink to the
bottom. If your project doesn’t require too much purity, you might
be able to add a tiny amount of detergent to the spray bottle to
break up the surface tension. I would do some research on that
before using it with refining. Wouldn’t want to contaminate the
melt.
Larry
The problem is probably the surface tension of the water, as well as
the fact that the settling rate of tiny particles is very slow
anyway. Try using an alcohol rinse or two at the end of your
process (provided it’s compatible with whatever else you may be
using). The alcohol is less dense than water and allows faster
settling; it also mixes with water and displaces it, and promotes
better final drying of the powder. If this won’t work, you might
check with a local university lab (geology, chemistry, or biology)
and see if a high-speed centrifuge (test-tube spinner) will force
the particles to settle. In this case, though, you might have
problems with having them cake together due to the force generated
during settling.
Dear all, The solution to this, is a can of static release spray that
my wife uses when she is ironing. Spray a little on the surface and
you will see your gold drop to the bottom.
Best Regards.
Neil George
954-572-5829
try and find somebody with access to a centrifuge
Or, I might mention, if you have a centrifugal caster, you could
probably adapt it to do this.
Margaret
Try spraying the surface of the water with “Static Guard”. It
relieves the surface tension that is making the particles float.
Spike Cornelius
RC ArtMetal
Portland Or
Hi Yuvak,
You might try using a centrifuge. Put the liquid containing the gold
in small bottles/test tubes/vials & then centrifuge it.
Dave
Dear all, The solution to this, is a can of static release spray
that my wife uses when she is ironing. Spray a little on the surface
and you will see your gold drop to the bottom.
Best Regards.
Neil George
954-572-5829