Hello
I'm wanting some time to melt some small pieces of gold I have
accumulated into some form of nugget to wear... at the moment I have it
in panned form in small flakes from Idaho. I have my own kiln and can
produce a reduction atmosphere if needed but just wanted to get some
advise from a few folk so that I don't make a mess of it! Anyone fancy a
chat about this sort of thing?
regards
Heather in England
Heather, Get a piece of wood charcoal ( Compressed Bricquets are my
last choice ) and drill or carve an indention deep enough to keep the
small flakes from blowing about. Use an Oxygen + Natural Gas , Oxygen
+ Propane , or even an Oxygen + Acetylene torch adjusted to a nuteral
flame . If you do not have a Oxy - Gas torch, take it to someone and
let them heat it. Heat with a flame large enough to melt but not so
agressive as to blow out the small flakes . When molten dump the gold
into water .
This should form a freeform nugget . Continue remelting untill you
like the form of the nugget . Pickle it in any acid water pickle or
alum water pickle ( 10 % solution ) Solder a 22 K or 24 K jump ring
for a chain and wear with pride.
Use a easy or medium 18 K or 22 K solder .
This Nugget is still native gold unless you add or remove anything .If
You intend to sell it, check with the UK hallmarking authorities
first.
Check Rec.Crafts.Jewelry on the Google groups or contact me off group
.
I can send resources easier via email, than I can over this group.
ROBB.
Seems like good info - but I have a question (open to anyone for an
answer). I know gold is in different "qualities" i.e. 10K 14K 18K
24K, etc., and it's other metals introduced into the gold to change
the "K" of the item, correct? Questions are:
1. When melted, do all the impurities (other metals) float to the
top, sink, or what and how are they removed from the pure gold?
2. What is and how would you do "pickeling"?
Thanks
Ken.
no
no
they (usually copper, silver and other metlas like zinc, and/or nickel or
palladium for "white gold" )form an alloy with the gold.
Definition of alloy: a mixture containing two or more metallic elements or
metallic and nonmetallic elements usually fused together or dissolving into each
other when molten; "brass is an alloy of zinc and copper", "steel is an alloy
of iron and carbon"
This is done in a process called "refining". It is a fairly complicated and
exhaustive process, as well as very poisonous, because of the different
chemicals used. But in a nutshell this is what takes place:
DISSOLUTION: Acids react with gold, silver, copper and other alloy constituents
to form gold chloride solution, silver chloride precipitate and copper nitrate
solution.
FILTERATION: Silver chloride precipitate and insoluble matter is seperated from
solution containing dissolved gold and copper.
REDUCTION: Gold reagent, added to solution, reduces gold chloride to pure gold
oxide precipitate.
WASHING: Gold oxide is removed from the remaining solution containing dissolved
copper, is chemically washed and dried. You can now melt the gold powder and
re-use as required.
In the jewelry workshop, pickling is the process that removes oxides from the
gold alloy after it has been heated with an open flame for annealing or
soldering. Typically a 10% warm sulphurioc acid solution is used for it. Or a
more friendly compound (like SPAREX), which can be bought in granular form and
added to warm water. That is what I use for safety reasons, and because it
doesn't eat holes in my clothes.
WARNING!
If you contemplate making a sulphuric acid pickling solution, remember this:
AAA, ALWAYS ADD ACID!!! I cannot write this bold enough or add enough
exclamation marks. Never add water to acid, you'll regret it. If you're lucky
you'll only lose your eyes!
It's better and a lot safer to use a solution like Sparex, you don't have to
worry about acid explosions.
In goldsmithing school in Germany we were taught a rhyme to remember this:
Erst das Wasser, dann die Sauere.
Sonst passiert das Ungeheure
First water, then acid
Otherwise the "tremendously terrible" will happen
Abrasha
http://www.abrasha.com
That mnemonic reminds me of a cautionary poem told by my science teacher
when introducing us kids to sulfuric acid:
Poor little Billy isn't with us any more
because what he thought was H-2-O
was H-2-S-O-4
Abrasha wrote:
You don't need any sayings or mnemonics for this.
The problem is simple, the dilution is exothermic. So
you put the stuff with the largest thermal capacity
there first, in the largest volume.
Thus any heat developed by the small droplets of
acid as they enter the container of water is
tempered by the large thermal mass of the water.
Doing it the other way causes local boiling and
spattering. :(
Jim
================================================= please reply to:
JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com
=================================================
This just proves that you DO need those sayings AND mnemonics, because your
average goldsmith or person doesn't know about "exothermic" and/or "thermal
capacity". They are not scientists or chemists.
The "people" that I was being trained with in goldsmithing school were high
school aged teenagers.
Abrasha
http://www.abrasha.com
Well. Nobody here anyway. The trouble
with all the cute-sy poems is sometimes
they get twisted around and you do the wrong
thing.
Jim
================================================= please reply to:
JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com
=================================================
I dunno.... I kinda like the AAA always add acid.... Simple to
remember and pretty tough to screwup I mean it's not always add WATER
because that'd be AAW, which is what you would be saying if you did it
wrong.
Ken.
Lot more complicated than I would have thought..... I was thinking you
would just melt an old ring or two in the ladle, the skim off the
copper, zinc, etc., and then you would be left with pure gold to play
with... Figures - nothing can be simple.
Thanks for all the info - that was great.
Ken.
Hi Ken... I liked your little explanation here, and want to chat more
with you in private if I may... write to me,
snipped-for-privacy@dawnmist.demon.co.uk
speak soon I hope
Heather
Interestingly, very few metals will stratify when once alloyed. Silver
will separate from iron, but not if gold is present. Gold and iron
readily form an alloy, although it has poor qualities.
The precise method for separating gold from other elements is not difficult,
but it does require the use of three acids, nitric, hydrochloric, and
sulfuric. I'd willingly provide a very satisfactory chemical process to
anyone so interested. I refined gold for over 20 years before selling my
refining business when I retired back in '94. I was fortunate to have a
loved hobby turn into a business, getting me off my machines after 26
marathon years of machining.
Harold
I'd very much appreciate you posting for us the chemical process for
removing gold from alloys.
Thank you for your time.
On Wed, 17 Dec 2003 02:06:07 -0800, "Harold & Susan Vordos"
Hi Joe,
I'm not sure that posting this information would be the best way to go.
The process is extensive if you desire enough information to actually do the
refining, so the post would be a lot more like posting a book. There are a
lot of steps along the way that should be described in order for the process
to be successful. If, however, you are more curious about what is done,
and not necessarily why, then I could probably cut it down to a couple of
pages, maybe even less.
Because all the metals encountered in alloyed gold don't behave the same
way, you have to jump through a few hoops to get to the gold. The main
culprit in yellow gold, silver, makes the separation impossible if you do
not follow the right procedure. Also, because the platinum group is often
encountered when refining, the process is far more involved than may be
apparent. Depending on the nature of the material being refined, there
are various processes that, while they resemble one another, are different
from one another. Processing filings from a jeweler's bench is different
from processing old rings, for example. Different yet again for polishing
wastes.
If you'll give me an idea what interests you, I would be willing to provide
more information, but hesitate to spend days typing, only to find that you
were more interested in a Reader's Digest version to satisfy curiosity. It
would be likely that I would send the information directly to you instead of
posting.
Harold
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