Anyone use a melting furance?

[FrugalRefiner]

the term "gold filled" means that the "gold filled" layer only has to be at least 1/20th gold. that's 1k ... or less. CAVEAT EMPTOR.

That's not quite accurate. Gold filled means the object has a layer of gold on the outside, and is filled on the inside with a base metal. It is designated by two numbers, like 1/20 12K. The first number, 1/20, means that the gold layer on the outside makes up 1/20 of the total weight of the object. The 12K indicates that the outer layer of gold is 12 karat. In this case, the gold layer is 50% gold, but the overall gold content of the object would be 1/20 of 50%, or about 1/40 of the total weight (about 2.5%). There are better variations like 1/10 14K, and there are lesser variations like 1/30 10K.

The caution I always give is that since the gold layer is on the outside of the piece, it is the first material to be worn away, so the overall gold content decreases with wear and use.

Dave

 

[Martijn]

Will it still be 12 to 14k. Ir is it easy to separate the gold.

Do you want to just melt karat gold or refine gold?

 

[Martijn]

Cause it is gold filled. It is mixed with other metals. So it comes up as 12 -14k on the xfr.

I have a good grasp for it. Just have to start somewhere. You can't master anything with research. Experience is boss. I don't see how cupealing is diving into the deep end. The boiling acid is the deep end for me.

There are different pyrometallurgic processes to purify precious metals.

Smelting is done to collect all metals in a bead from an 'ore' and to reduce metal sulfides and oxidize base metals in the slag. It's chemistry in a molten bath. Here fluxes are used.

Melting is just that. Melting a metal to pour it in some kind of mold. No flux needed, and often even undesirable.

Cupelling is driving off base metals as oxides into a bone ash cupel with lead or bismuth oxide to leave an alloy of pm's

For each purpose there is a different setup of furnace, crucilble and additives like flux.
Graphite crucibles do not like borax. Only for melting pure metals.

Gold filled is not to be melted. You need to treat it to concentrate the goldvand get rid of the base metals. That is called recovery. Then you can separate and refine it.