What is this coming out of my gold bar?

[nvradar]

I've been refining some gold and this stuff comes out of the melted gold bar as it cools down. I melt the same bar a few times and this stuff comes out less and less til no more comes out, so I know it's a good thing to get rid of. nvradar

 

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[Mud Hut]

Chocolate?

 

[nvradar]

LOL!! I'm rich!!!

 

[timemachine]

Slag?

 

[Dochrohan]

Indeed, that's simply just slag the by product of separating the metal.

 

[pepperj]

Slag?

Indeed, that's simply just slag the by product of separating the metal.

Why would there be slag from a gold bar, isn't a gold bar high content to be almost pure?

Why are you melting gold bars?

 

[tamrock]

chia pet

 

[bzbadger]

Bar must have been impure. I hope you remember the weight before you melted it down so you can compare to it's current weight. Was the crucible clean before you melted?

 

[mick56]

Is that black gold?

 

[Ant]

IMO you need to make sure to burn off the sulfides before you start, and you need to find correct flux, and the right flux to gold ratio. Without the correct formula the gold wont get hot enough and you risk vaporizing the run.

 

[Ant]

Mick that dark thing is either an ash or graphite crucible, that yellow stuff is comng out of a square or rectange opening in the top.

Is that black gold?

 

[nvradar]

Sorry fellas I guess I should have explained a bit more. My gold is in black sands,I used chapman flux when melting the gold. I'm relieved to know it's slag. LOL! chia pet! I'm sure I didn't have a spot on formula,I seen a video on you tube about the flux. It's suppose to be made specifically for black sand. The guy said add a little....lol

 

[galenrog]

What is the chia pet looking stuff sitting on?

Tell us about your refining process. What is your feedstock? Are you refining or are you smelting? What is your process? Do not leave out any steps.

That at is all for now.

Edit: looks like a few new posts while I was writing this.

 

[nvradar]

OK , I mix the sand and flux dump it into a graphite crucible and melt it then pour. So when I pour it and it starts to cool this stuff comes up. My end result. Yes the black rectangle is a graphite mold.

 

[Ant]

Aha, are you buring off the sulfides? By the way that's a nice gold to black sand ratio. Did you run those concentrates through a gold wheel or some other small gold recovery system?

 

[nvradar]

I hate to show my uhh not so savvy self here but I'm not sure what sulfides are. Yes I ran the sand through a gold wheel to knock it down alot. It was way richer than I thought. My bar is a bit over 4oz troy.

 

[Ant]

Your doing great if your getting that out of those concentrates, . That stuff on top should turn into glass. Keep at it you'll find the correct formula before long, that will save you time and expense.

 

[galenrog]

You will get a better separation of slag if you pour from the smelting crucible to a conical mold. I prefer cast iron for this. Mold must be properly coated with carbon prior to pouring from crucible.

 

[nvradar]

I check everything before tossing it out and it sure does get everything! Even the super fine dust which really adds weight, this stuff coming out is different from the flux mix,that does turn to glass,this crumbles easily and has just a faint waxy feeling to it.

 

[Ant]

Prospectors Paradise - Recreational Gold Prospecting - Melting and Smelting

Prospectors Paradise - Recreational Gold Prospecting - Black Sand & Tellurides

Sulfides:
A sulfide is a reduced salt of sulfur. Like copper sulfide, CuS2. An oxidized salt of copper and sulfur would be Copper sulfate. CuSO4. Remember about redox? Addition of an oxygen oxidizes the compound. Anytime you see the ending "ide" it means that the compound is in it’s "reduced" form. If you see the ending "ate" it means that it is in it’s oxidized form. You see, us scientific types have our own language so that we can talk without having to explain at every step what we mean. Hang with me and I’ll tell you a little about this language. Hell, it ain’t no harder than learning Spanish.

Sulfides can ruin your whole day. They coat almost everything with surface of sulfide that will prevent you from amalgamating, reacting with cyanide, or dissolving in solutions of halides. If you have a little piece of silver, a little hydrogen sulfide from the local volcano, you will have a piece of silver with a coat of silver sulfide on it. This coat will prevent you from dissolving it in cyanide or any other.

Fortunately for us sulfides are relatively unstable. Want to destroy a sulfide? It’s not too difficult but one that I am afraid most folks ignore. HEAT IT! Almost all sulfides will dissociate with heat. That is, if you heat a sulfide in the presence of oxygen you will boil off the sulfur as either sulfur dioxide or as hydrogen sulfide. If you heat some ore that you suspect of having sulfides present you will smell a rather unique odor.

Have any of you ever been to a "beer and egg party"? A keg of beer and a great quantity of hard-boiled eggs? The next day you are a bit bloated, gaseous, or in scientific terms, "flatulent". When you, as the English say, "pass wind", this is the odor of sulfides being dispelled from the heated ore. When the odor of sulfur is no longer apparent, you can continue to your extraction method.

The time-honored way to deal with sulfides is to boil them off with heat.

Just get some roofing metal, get it up off the ground with a few rocks etc. and build a good fire under it. Spread your material on the metal and let it cook. When you don’t smell anymore sulfur, process it.