What is left in crucible

[Sslither]

We made our first refined button today, but unsure what is left in the crucible, there seems to be a couple of things left.
After we melted the button, what is left in the crucible is some pink substsnce that has combined with the borax whice we are unsure what this is and some purple stuff but i am pretty sure this is coloidial gold. The raw product was 722 grams of very close cut memory finger's. we ended up with 1.97 grams of pure gold button. Please advise what this pink stuff could be. Thanks' in advance.

 

[ilikesilver]

can you post a picture of your melting dish so we can see what it looks like? also what type of heat to melt it did you use? th

 

[Sslither]

Here is a pic of the crucible. We used oxy acetylene torch to melt and the dropped into water to cool

 

[Geo]

is it just colored borax or something solid? pink to purple-ish colored borax is a good sign. it denotes the purity of the gold powder. any other color of the borax after the melt (blue,green) means the gold powder has impurities. the color is good but the black colored slag looks like it contains some carbon (maybe).

 

[Sslither]

Thank you for the quick replies and your wonderful help the stuff that looks black is actually a dark purple that I think is colloidal gold. I may be wrong though.the pink stuff seems to be something that has combined with the borax

 

[butcher]

Sslither, very nice work, yes the pink color is colloidal gold, it also looks like you used way more borax than was needed, the gold looks great.

 

[Sslither]

Yea way to much borax someone had a shaky hand when putting it in the crucible from the spoon. Hard to get it back out.

 

[Geo]

a hard boil in hcl, dilute sulfuric acid or even water (given enough time) will dissolve the borax. be sure the dish is bone dry before heating again.

 

[ilikesilver]

a hard boil in hcl, dilute sulfuric acid or even water (given enough time) will dissolve the borax. be sure the dish is bone dry before heating again.

Ive got the same issue when i was trying to melt sterling. i used to much and the borax left a nasty blackish sticky residue, then it drys really hard like glass. If i boil it off, can i heat it up in a oven or on a hot plate to take care of it? tim

 

[Geo]

after you remove the excess borax, let it dry in a warm dry place, perhaps out in the sun. if you use an acid, theres no need to wash or rinse as the next melt will remove any traces of the acid. but if you want to rinse, be sure to do it right after you pull it and not later because you will just have to dry it again. be sure to re-coat the dish with borax before using. keep any sludge that comes from the dish for later refining.