Gold Melting furnaces

[Anonymous]

Hi I'm new here and I have a lot of questions about refining gold concentrates in your own furnace. Any recommendations? I found one at Lost And Foundry that is only a few hundred dollars. I have a flux recipie using 5 parts Borax, 20 parts Sodium Nitrate, 10 parts sodium carbonate and 40 parts sand. I would rather not use harsh chemicals or mercury at all and this seems the best solution. I have a couple of sample pounds of what I assume to be gold concentrates from very fine sandy sediments laid down durning heavy spring runoff but I certainly could be wrong. I'm certain it isn't Iron pyrite since I gave it the acid test, it doesn't "glitter" and doesn't crumble when pressure is applied., but it COULD be mica in there instead! Sure LOOKS like the gold dust I saw as a kid. Should I soak them in vinegar first? Do I need to roast them at all since I will presumably be burning off the sulphides in the furnace? I intend to use an acetylene torch on a small crucible sample first just to make sure there is gold before purchasing the furnace. Does this sound like a plan and what am I overlooking. Any tips would be appreciated

 

[butcher]

roasting sulfide first is advisable, also lead oxide for a collector, unless you have a large amount of gold in melt, I would think this would be an expensive way to process if you were doing it much, you would want to concentrate your values as much as possible, roasting them then grind them fine, then concentrate the heavy materials, then, I would smelt a small portion of this with lead oxide and flux, remove lead bead and cupel this will give you an indication of values, if no gold button, why heat up the big furnace?

 

[butcher]

somehow I double posted so I will edit this post,I don't know how to erase it, the material may not be sulfides, as rock can be made up of many different acids, although sulfuric acid in volcanoes can form rock-mineral sulfides there are other possibilitys, like carbonates, oxides arsenic and so on roasting will remove these from ore, note the arsenic and other gases can be deadly, if sulfide was the only problem Iron nails in melt will make Iron sulfate in the slag, keeping the melt hot enough for enough time for values to collect is also important, otherwise if gold it can just be in very small beads mixed in the slag.

gold in a miners pan is very easy to tell if it is gold and not mica or pyrites, can you smah it or will it flatten, or break? how long have you been panning?

try this get yer pan through in some sand and gravel add some very small piece's of lead, bb size and smaller, now pan this off into a tub.
when you can keep the lead in the pan, even after panning out the black heavy sand your gold will still be in the pan, mica and pyrite will be panned out along time ago.
if you see very much gold dust I would be suspect its not gold or else you hit the motherload, but new miners always hit the motherload, its gold fever.

furnaces are easy to build also burners are too, no reason to spend much money on one if your handy with tools.

 

[Anonymous]

Thanks for the info. I have some mica samples and the stuff doesn't look or feel the same. I roasted a small bit of the panned concentrate and the specks that were a sort of tarnished bronze turned a bright gold color as if the sulphur tarnish had been cooked off. It did not dissolve in hydrochloric acid. I found the concentrates right where and when you are supposed to according to what I have read.I picked a creek known to have gold in it. backpacked up about 6 miles during a wicked spring snowmelt runoff and then looked in the back eddies on the inside bend flood channels - few that there were - for sand that has been washed up by the flooding. Took home about 2 pounds of panned sample concentrates. All the "gold" is quite fine. I don't plan on purchasing much of anything until I get some melted down with a friend's welding torch to see if it is actually gold. I'm just waiting for a crucible I ordered to come in the mail. Not many chemistry stores around here. Hopefully that flux recipe I found will work with the torch. it is supposed to. I haven't panned for over 30 years, just lots of backpacking in areas that don't have much gold like the Grand Canyon. But I had a pan and thought with prices what they are why NOT take it along to areas known to have gold. Doesn't weigh that much!

 

[butcher]

.The flux will work with a torch, but with a torch keeping the mix melted for a long enough periods for the metals to join together is a challenge, and can waste a lot of fuel as the open environment will wash away the heat generated, if values save the slag for when you build your furnace. Maybe Steve’s mini furnace might work? A small furnace and burner are easily built by some one handy with hand tools.


If platinum was suspected in the mix (here in southern Oregon we have some) adding ten times the silver with the lead when you smelt, remove button and cupel remove button.
Boil in concentrated sulfuric acid till SO2 gas quits fuming to dissolve the silver,
let settle overnight, decant rinse the precipitant with boiling water, dissolve in aqua regia, denoxx by evaporation, add water to precipitate any silver, concentrate to almost salts add a little HCl, add ammonium chloride crystal to hot solution mix well a yellow or orange salt will be a good indication of the platinum in the ore.


Gold will melt mica will not, iron pyrites will just oxidize, gold can be hammered flat mica or pyrite will powder, have you tried panning it with lead, if so will it stay in the pan last ?

if you crush and incenerate it (can be done on hotplate a small propane torch helps to get it red hot) then you can dissolve a small sample in aqua regia evaporate noxx and test with stannous chloride.

there should be no mistaking gold in a miners pan, this seems like alot of trouble to find out whats in yer pan, but once you know you'll not mistake it again.