cloomis
Well-known member
What is the best way to seperate (PB,AG)silver in lineated tourmalinite with chalcopyrite and pyrite wich has trace amount of gold ?
pb,ag/s seperation
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Richard36
Well-known member
Crush your ore, then recover your sulfides by floatation, or by washing the ground ore through an over sized sluice to concentrate the sulfides, and other heavies. This material should then be leached, then follow the recovery procedure for the leach used in order to recover the values from solution. I hope that this has been of some help. Sincerely; Rick.
What about roasting?
Seems like there are very few leaches that will work on a sulfide ore without roasting off the sulfur first.
Richard, did you have a particular leach in mind?
Randy
Seems like there are very few leaches that will work on a sulfide ore without roasting off the sulfur first.
Richard, did you have a particular leach in mind?
Randy
Richard36
Well-known member
Harold_V spoke of using Cyanide with Iodine added to leach sulfides. I think that info can be found within my post entitled "Precious metal ores and their chemical formulas". It might be expensive, but Nitric Acid could be used to dissolve the sulfides. Recover and dry the residue, then smelt the residue with three times its weight of standard assay flux. Pour to a mold, let cool, recover the lead button, cupel it, and recover the precious metals as a dore bead. Another method would be Aqua regia. Muriatic acid with Sodium Nitrate dissolved within it is supposed to be a poor mans version of Aqua Regia. The directions that I have for making it call for 1 oz. of Sodium Nitrate for every 4 oz. of Muriatic Acid. This solution should aggressively digest sulfides, and the metals that they contain. The solution can then be neutralized with Urea, (from what I have read), and then recover the Gold from solution by boiling it down to concentrate the solution somewhat, if necessary, then bubble Sulfur Dioxide gas through the leach solution to drop the Gold as Gold sulfide, Which can be recovered and smelted with a mix of borax and Sodium Nitrate to burn up the sulfur, and melt the Gold together for casting as a button. Ferrous Sulfate can also be used to recover the Gold from the leach solution. Another method would be to smelt the ore to lead, scorify it down to one third its starting weight, then cupel the remaining lead button to recover the precious metals as a dore bead, which can be sold as is, or split into its seperate metals by dissolving it into AR, and recovering them individually. The cupelation procedure could be skipped, the lead granulated, and dissolved in AR, then recover the precious metals individually from the AR. (check out the forum handbook volume #1 for the AR recovery methods.) I hope that this has been of some help. Sincerely; Rick.
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I used bromine, not iodine. I have no experience with iodine.Richard36 said:
While the material certainly contained sulfides, I have no clue about the real nature of the ore.
I'm of the opinion that you'd have to look past the basics of assaying if you had intentions of recovering values from ores----plus the economics of processing volumes with acids generally excludes ores from that possibility. I shudder to think of the amount of nitric that would have been required to process the buckets of ore I ran in cyanide. Even when paying only about $4/gallon for nitric.
I roasted a sulfide concentrate (not to be confused with the buckets of ore I processed with cyanide), then processed with HCl to eliminate iron. That process worked, but it required roasting more than one time, each time eliminating more sulfur. The process was so difficult I wouldn't recommend it unless the concentration of values was high. Anyone attempting to recover values from ores that are under an ounce/ton is spitting in the wind unless it can be processed in huge volumes.
Harold
semi-lucid
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We have a slightly different expression down here in Texas. :wink:
John
Richard36
Well-known member
Sorry about the mistake in quoting you Harold. I thought that You said Iodine, not Bromine. As far as extraction methods, You have told me the above quote before. I have never had the pleasure of processing any volume beyond a 5 gallon bucket of concentrate, and that is why my methods reflect the methods used in assaying. Larger volumes would require me to change my methods for sure, but until then, my methods seem to work well enough for me, and on a small scale, should work for others as well. Cyanide scares me, I have no hands on experience with it, and am reluctant to give it a try. The only knowledge I have with it is what I have read, and am not sure that my knowledge is sufficient enough for me to take that step forward in processing ores for their values with it, So I continue to use some variation of the methods that I have posted, or combination thereof. I don't mind being disagreed with, It creates better conversation with more info for us all to read. Sincerely; Rick.
cloomis
Well-known member
T hanks for the imput from the best web site in the word perhaps,,, I already started 2 seperate batches one two each idea seeing i have plenty of ore , ill post on outcome when done
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Non-issue, Richard. Just wanted to insure that readers didn't think I knew anything about the use of iodine. I don't have a clue.Richard36 said:
Yep, they often work, and very well. That's not the problem. It is widely accepted that processing ores with acids is generally not economical. That would be particularly true in today's environment where guys are paying better than $3/gallon for HCl, and anywhere from $20 up to $50/gallon for nitric.
That is very understandable, and I don't have a problem with your position. Imagine how I felt the first time I ran cyanide and found I had to add some sulfuric acid to the solution! I had to maintain a very narrow window of balance with the bromine-----otherwise it was rendered useless. I don't recall the particulars now, but there were several times that I had to add a few ounces of sulfuric.
I was in the same position, but realized I had no options. I had committed to process the ore, and time had moved well past the time interval I had expected. In the end, it was a wonderful learning experience, and resulted in my using cyanide for a few other processes, including stripping gold filled from watch bands.
You likely would have more than just a little trouble buying the stuff today. When I purchased the 100 pound drum, it was readily available and used commonly by the plating industry. I made my purchase through my licensed machine shop, so there were no questions. Today that would not be true, and you'd likely have to jump through a lot of hoops.
Cyanide has one unique quality that acids do not. Assuming the ore has no cyanicides, a ton of ore can be processed with as little as a pound of cyanide, maybe even less. Cyanicides destroy the cyanide, so if there are none present, the only cyanide that is consumed is that which dissolves the values. It is used in a very dilute state (less than .05%) to insure it does not dissolve base metals such as copper. It is an exceptionally good process, but dangerous, as you alluded. So then, it's clear, in certain circumstances, an ore may be processed as cheaply as a couple bucks per ton, as opposed to several hundred (or thousand) dollars per ton. It is for that reason that I made my comments.
I agree fully, Rick. My comments are in no way to be construed as me arguing with you. Readers should understand the pitfalls of any process, so they can make informed decisions. Excessive acid consumption, or understanding the dangers of cyanide, are not things that should be omitted from our conversations.
Harold
Richard36
Well-known member
I agree. If I was as good at processing ores as I am at Assaying, I would be a happy man. Refining is an area in which I still have plenty to learn. Hopefully I learn enough to process large batches soon. I am open to all ideas and processes. Any and all comments, as well as suggestions shall be greatly appreciated, by myself, as well as others. Sincerely; Rick.
