Traces of Orange Color On My Newly Poured Gold Bar

[Ag and Au]

Hi All.... I recently poured my second gold bar, and unlike the first bar last year (which was bright, brilliant gold), this one has areas of orange discoloration that I wasn't expecting nor have I ever seen.

-- The material I used was PCBs and gold plated pins; I liberated the gold using the AP process.
-- I performed three (3) AR processes (using SMB for the drops each time) and five (5) HCL/hot distilled water washes at the very end.
-- The gold precipitant color was perfect. See photos 1 and 2.
-- I melted the gold inside a once-used crucible (only for gold), with less than adequate borax glazing, using two MAPP torches (video attached).
-- The first melt resulted in a brilliant color, but I was dissatisfied with the shape of the bar...so
-- I melted it again and had the same result....so
-- I melted it again and had the same result, but then I realized that the mold wasn't hot enough and I needed to pour it faster.

--Now comes my dilemma...on the 4th melt...I observed an orange color on the surface of the molten gold. Nonetheless, I poured it
and got a better shaped bar, but a strange orange color remained. See last three photos.

-- There is a piece of borax on the top of the bar. I have not washed the bar in diluted sulphuric acid yet.

Any thoughts?

 

[4metals]

Often slight discoloration can be treated by sprinkling just a pinch of niter (potassium nitrate) on the molten metal. I am not sure how this works with a torch melt but it is quite effective for crucible furnace melts. It is an age old technique called toughening. The niter oxidizes any surface impurities which will stick to the crucible wall as a bead of niter bounces around the surface sharing it’s oxygen with all base metal impurities it meets on the way.

 

[nickvc]

One way to avoid problems with final melt results is to change the reactants used when re refining fairly pure gold , if you have powder and decide it could be a better color is to change the method of dissolving it, there.are many choices here and come the time to precipitate your gold change the precipitant, for some reason which I’m sure a decent chemist could explain some elements can keep sneaking through the refining process especially with e scrap.
A single pass refine with mixed e scrap is almost guaranteed to produce less than perfect results, if you don’t believe me ask anachronism who only does e scrap and in large volumes.

 

[Ag and Au]

What puzzles me is why on the 4th melt the discoloration appeared?

 

[Yggdrasil]

What puzzles me is why on the 4th melt the discoloration appeared?

It must have picked up something.

 

[Martijn]

Hi All.... I recently poured my second gold bar, and unlike the first bar last year (which was bright, brilliant gold), this one has areas of orange discoloration that I wasn't expecting nor have I ever seen.

-- The material I used was PCBs and gold plated pins; I liberated the gold using the AP process.
-- I performed three (3) AR processes (using SMB for the drops each time) and five (5) HCL/hot distilled water washes at the very end.
-- The gold precipitant color was perfect. See photos 1 and 2.
-- I melted the gold inside a once-used crucible (only for gold), with less than adequate borax glazing, using two MAPP torches (video attached).
-- The first melt resulted in a brilliant color, but I was dissatisfied with the shape of the bar...so
-- I melted it again and had the same result....so
-- I melted it again and had the same result, but then I realized that the mold wasn't hot enough and I needed to pour it faster.

--Now comes my dilemma...on the 4th melt...I observed an orange color on the surface of the molten gold. Nonetheless, I poured it
and got a better shaped bar, but a strange orange color remained. See last three photos.

-- There is a piece of borax on the top of the bar. I have not washed the bar in diluted sulphuric acid yet.

Any thoughts?

Maybe you can wash it off in hot dilute nitric?
Nice bar by the way.

 

[Ag and Au]

I am now convinced that the discoloration was caused by unwelcomed, "chrome particles" entering the crucible, from the tips of my scorched, cheap, metal crucible holder. Hopefully this will help other refiners avoid the same mistake.

As always, thanks for your input.

Photos coming soon.

 

[Ag and Au]

The discoloration was limited to just the surfaces of the bar - I chose to carefully file the bar and save the filings for reprocessing next time.
Here is my 2024 bar. Thanks for all your help.

 

[grainsofgold]

i’ve had this happen as well. Maybe something in your melting crucible. When melting 24k use dedicated dishes and crucible’s only for 24k. even your stir rod if you use one.

Also if you are torch melting , sandpaper your torch tip and run the cleaner brush rods thru the holes , makes a difference.

If you use salt peter it will create white smoke
Good luck

 

[Abdoulapapatte]

Hi buddy, I'll try to help you as best I can, to start with here's a 24k bar, believe me it's 24k but with a disgusting appearance, in fact here in my case several factors:

1) I work with colleagues who don't understand cleanliness, the ingot mould is always for sale, I don't use much oil in the ingot mould and I prefer to heat it to get rid of the moisture. They love to use car oil to lubricate and wick away moisture, so if you go after them you'll never get a decent ingot out of the mould .......

So the cleaner the mould, the cleaner the ingot.


see spectro 60 seconde

précipitation SMB (denox with uréa : disgusting, green , but result is good , 999.9 , (lot of silver , agcl particule) ,result whitout electrolyse, i will explains how i doo (if you want).

View attachment FB_VID_5978966826357848931.mp4
2) I can't quite see the torch you're using, but don't forget that sometimes certain gases can dirty the metal, depending on the angle of the flame. It's not great if the flame hits the ingot directly when casting (Mr Kardriver ‘streetips’ paid the price for a long time if you watch his videos carefully).

I've just downloaded your video. This kind of torch opts for oxy-acetylene, possibly a bit cleaner, but your torch is dirty. Invest in a small $200 induction furnace. Otherwise, you'll melt with bigaz. Propane can be good for eliminating air when you melt, but the flame must not touch the metal directly. Here's an example of the induction oven I'm using at the moment. See the photos.




3) I site above the remarks of some:


“One way to avoid problems with final fusion results is to change the reagents used when refining fairly pure gold” NickVC

----> possible but if precipitated beforehand, with the same reagent, and good results, this hypothesis doesn't really hold, see if product deteriorates over time.

“this has also happened to me. Maybe something in your melting pot “gold grains"
“He must have picked something up.” Yggdrasil

----> quite likely. And for me his torch is not of good quality (big shit).

4) your precipitated gold mustn't be dry, I think it looks like crap, be careful to dry your powder well after washing with HCL and H2O. when you're at the last stage and you wash well with water, you must dry, it's important, and your gold must have more or less this color, very light.

5) Finally, the color reminds me a little of the 2 ingots cast here




as you said and congretulationt, it's the ultimate solution, clean your ingot after melting, of course.

Economical : 1$ any sponge and washing up liquid, you will have a clean aspect and your ingot will have a neutral ph (not acid or alkaline if you put your tongue on it( it's not a joke it happens to me).

to finish, when you're doing between 200 and 400 kg a month, after a while you don't give a damn about the beauty and appearance of things, the most important thing is quality, not appearance, but I understand your perfectionist side, my friend.


see you bro i hope all will be good for you.

ps : Yggdrasil it might be time to finally incorporate an automatic translator into your site, it would really change my life.