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I'm researching ways in how to salvage gold from old electronics. I think I got the process down but I have one question. When you have salvaged the gold from the electronics you are left with gold flakes.
This you want to melt down into a single piece of gold. I have been told that the addition of borax powder reduces the melting temperature of gold, but I'm unsure of how much. My blowtorch can go to 1000 °C and I want to know if this would be adequate to melt the gold/borax mix.
The melting point of gold is 1064ºC, so your blowtorch is inadequate. You have to melt the gold in something, and the borax acts to cover it, allowing the dense gold to settle, dissolving various metal oxides that might contaminate your flakes, and floating above the gold.
You would really need to get a hotter flame, with a fairly large zone of high temperature, because you need to heat all this stuff (container, gold, impurities and flux to somewhat above 1064ºC (1948ºF). There are gold melting electrical furnaces that would be more convenient.
The one shown is among the least expensive - you can pay a lot more, but it is advertised as a gold melter, with about 150ºF extra, so it might work for you. A lot more convenient than aiming a blasting flame for 15 or 20 minutes, trying not to burn the house down.
