montanacreations
Member
Hello all,
I have a couple questions I am needing help with. The cons I am wanting to pretreat is the courser part of my concentrates, +60 mesh, the smaller fraction will be going to another company for leaching. Separating the +60 mesh free gold from the sulfides has proven very difficult, the sulfides are really heavy and difficult to make a complete separation on a table. I would prefer to not crush these cons further do to sliming. I have experimented with roasting and acid pretreatment, but would prefer to avoid roasting if possible. Dilute sulfuric 30% or so seems to break down the sulfides well but need to treat fumes (hydrogen sulfide). I am not talking about large volumes, only a couple pounds at a time. The question I have is will cold 30% sulfuric convert silver sulfide to a sulfate and the same with the lead sulfide. If the sulfuric does convert sulfides to sulfates what would be a good temp to roast at to convert back to oxides, or is there a better way. Also would bubbling the off gasses through sodium hydroxide take care of the hydrogen sulfide.
The make up of the cons from ICP-MS in ppm for just the larger %, I can list all if needed, Ag 1060, Al 2970, As 987, Bi 1580, Fe 117000, Pb 449000, S 108000, Te 397, Ti 40700, Zn 21100. I haven't had the larger mesh cons assayed, the -150 and smaller runs about 24oz gold. This ICP-MS result was from the smaller mesh cons,-150 mesh. I can have another run on the larger fraction if I need to.
I would like to get these cons cleaned up enough to smelt is my goal, as you can see from the ICP-MS I have a lot of base metals that interfere with the smelt. I have experimented with direct smelting but not happy with the results, roasting before hand also and using different collector metals, silver, lead, Pbo etc. and several different flux recipes. I would prefer to not smelt with Pbo, cuppeling I would like to stay away from but can if I have to.
Thank you,
Cliff
I have a couple questions I am needing help with. The cons I am wanting to pretreat is the courser part of my concentrates, +60 mesh, the smaller fraction will be going to another company for leaching. Separating the +60 mesh free gold from the sulfides has proven very difficult, the sulfides are really heavy and difficult to make a complete separation on a table. I would prefer to not crush these cons further do to sliming. I have experimented with roasting and acid pretreatment, but would prefer to avoid roasting if possible. Dilute sulfuric 30% or so seems to break down the sulfides well but need to treat fumes (hydrogen sulfide). I am not talking about large volumes, only a couple pounds at a time. The question I have is will cold 30% sulfuric convert silver sulfide to a sulfate and the same with the lead sulfide. If the sulfuric does convert sulfides to sulfates what would be a good temp to roast at to convert back to oxides, or is there a better way. Also would bubbling the off gasses through sodium hydroxide take care of the hydrogen sulfide.
The make up of the cons from ICP-MS in ppm for just the larger %, I can list all if needed, Ag 1060, Al 2970, As 987, Bi 1580, Fe 117000, Pb 449000, S 108000, Te 397, Ti 40700, Zn 21100. I haven't had the larger mesh cons assayed, the -150 and smaller runs about 24oz gold. This ICP-MS result was from the smaller mesh cons,-150 mesh. I can have another run on the larger fraction if I need to.
I would like to get these cons cleaned up enough to smelt is my goal, as you can see from the ICP-MS I have a lot of base metals that interfere with the smelt. I have experimented with direct smelting but not happy with the results, roasting before hand also and using different collector metals, silver, lead, Pbo etc. and several different flux recipes. I would prefer to not smelt with Pbo, cuppeling I would like to stay away from but can if I have to.
Thank you,
Cliff