Hello,
I've been working with a sulfide concentrate that is approximately 3% gold, before roasting
I haven't had a full analysis done on it to see what else is present yet.
I've messed with a few flux recipes, and have gotten the highest recovery with a modified fire assay type flux, using litharge.
44% litharge
12% soda ash
20% borax
24% slica
I've been fine grinding my concentrates from my shaker table before doing a roast. My roast consists of a slow raise in temperature to about 1100f, stirring until it stops smoking in my electric furnace, with the door slightly open.
I've been smelting a 6:1 ratio of flux to concentrates, with 10 grams of flour added
100g of concentrates
600g flux
10g flour
I've been getting about an 85 gram button reduced from this
I had thought it was going well because the slag would break off so clean, leaving a shiny clean lead button.
But I was tapping one with a hammer to knock off some slag, and realized that the button was very brittle, and had a matte layer, that was only distinguishable from the lead after breaking it up with a hammer
I thought that matte was only formed in the presence of sulfur?
Am I not roasting it well enough?
flux change recommendations?
I've been working with a sulfide concentrate that is approximately 3% gold, before roasting
I haven't had a full analysis done on it to see what else is present yet.
I've messed with a few flux recipes, and have gotten the highest recovery with a modified fire assay type flux, using litharge.
44% litharge
12% soda ash
20% borax
24% slica
I've been fine grinding my concentrates from my shaker table before doing a roast. My roast consists of a slow raise in temperature to about 1100f, stirring until it stops smoking in my electric furnace, with the door slightly open.
I've been smelting a 6:1 ratio of flux to concentrates, with 10 grams of flour added
100g of concentrates
600g flux
10g flour
I've been getting about an 85 gram button reduced from this
I had thought it was going well because the slag would break off so clean, leaving a shiny clean lead button.
But I was tapping one with a hammer to knock off some slag, and realized that the button was very brittle, and had a matte layer, that was only distinguishable from the lead after breaking it up with a hammer
I thought that matte was only formed in the presence of sulfur?
Am I not roasting it well enough?
flux change recommendations?
