Precious Metal Ores and their chemical formulas.

Before I go through the process of posting this subject content, I would like some input. Does anyone want this information? Would it be appreciated? I am willing to spend the time to post a rather lengthy list of pm bearing mineral names, complete with chemical formulas, & a link to a forum similar to this one on minerals where they can be looked at, as well as read about them, among other things.
Give me some feed back folks...

Sincerely; Rick.


Well, here it is, study, read, learn, and enjoy! ............

Acanthite Ag2S, Calaverite AuTe2, Sylvanite AuAgTe4, Pyrargyrite Ag3SbS3, Proustite Ag3AsS3,
Chlorargyrite (cerargyrite) AgCl, Polybasite (Ag,Cu)16Sb2S11, Boleite Pb9Ag3Cu8Cl21(OH)16*H2O, Moschellandsbergite Ag2Hg3, Allargentum Ag1-xSbx, Dyserasite Ag3Sb, Hessite Ag2Te, Aguilarite Ag4SeS, Argyrodite Ag8GeS6, Stromeyerite AgCuS, Jalpaite Ag3CuS2, Freibergite (Ag,Cu,Fe)12(Sb,As)4S13,
Sternbergite Ag2FeS3, Argentopyrite Ag2FeS3, Miargyrite AgSbS2, Nagyagite Pb5Au(Te,Sb)4S5-8,
Krennerite AuTe2, Aurostibite AuSb2, Xanthoconite Ag3AsS3, Pyrostilpnite Ag3SbS3,
Samsonite Ag4MnSb2S6, Pearceite Ag16As2S11, Andorite PbAgSb3S6, Stephanite Ag5SbS4,
Freieslebenite AgPbSbS3, Diaphorite Pb2Ag3Sb3S3, Iodargyrite AgI, Sperrylite PtAs2,
Geversite Pt(Sb,Bi)2, Insizwaite Pt(Bi,Sb)2, Laurite RuS2, Erlichmanite OsS2, Gaotaiite Ir3Te8,
Mayingite IrBiTe..................

These minerals should be able to be viewed by going to http://www.mineralgalleries.com
Type in the name of the mineral, then click search, or going to http://www.mineral-forum.com

I hope that the mineral names and formulas are easier to read now that I have respaced them.

Happy prospecting!
Sincerely; Rick.

I prefer to not speak for the masses, but that may be a lot of work for you with very little benefit to the board. Very few of these guys prospect in the sense of looking for ores (primarily e scrap oriented), and fewer yet have the knowledge required to do the extractions, although I'm not convinced they understand that they don't.

Having processed one gold ore, I understand to some degree how difficult it can be---and the necessity of having access to uncommon equipment.

If you don't mind spending the time, it certainly would be a nice addition to the knowledge that is available on this forum! :wink:

Harold

I don't mind putting in the time. The offer is there. I have come to the realization that most of the knowledge on this forum is geared toward the refining of electronic scrap, not ores. I came here with hopes that I might have gained some knowledge in that field, only to find out that the available knowledge base in that field is sparse at best. If it exists, it isn't being posted to the forum. Am I the only one here who has did some study on that process? I hope not! I started this quest 15-17yrs ago with the intention of finding "the big one". As of yet I haven't, but I have gained allot of rock / mineral / vein system / ore processing knowledge. All that I am doing is making an offer to give and provide some knowledge to others, that I would like to have had given to me back at the beginning of my quest.

Richard36 said:

I don't mind putting in the time. The offer is there.

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Go for it! While I don't know, and can't identify the vast majority of ore types, I would find it interesting, assuming I can make sense of your post. Not to imply that you aren't able to post well, just a comment on my lack of knowledge in that arena.

Fact is, I'd appreciate knowing more about the small amount of gold ore I processed years ago. It assayed over 300 ounces/ton----and came from one of the silver mines in Colorado. You may be familiar with the ore.

Harold

Damn!!!! I want some! I'll process it for 1/3 of what I can extract. ( Laugh! ) Wow! that is the grade of ore I dream of being able to find. you found that? Now I am envious. Rock on Harold! Go find some more so that I can process it. I am not thoroughly familiar with the function of the text box for posting a reply, so it will be presented in the same format as this message is being typed. The names, chemical formulas, and a web site to go to in order to check them out,......It's on its way.

Unfortunately, the ore was not mine. It was delivered by a customer to be processed.

The story he related was interesting. He purchased the ore in Grand Junction, Colorado, from an individual that had a garage full. He had it classified, in bins, running up as high as 600 oz/ton.

This all occurred many years ago, in the late 70's. From four five gallon buckets of ore I recovered over 40 troy ounces of gold, and some silver. Silver extraction was not good, but gold extraction bordered on 100%.

Processing the ore (I still have several small samples) required a terrific learning curve that included building a ball mill and an agitation tank, both of my own design. Extraction, by cyanide, included the use of bromine, which was key to success.

Harold

Wow! I think that I would have tried leaching with a muratic acid/sodium nitrate solution, and followed the extraction process for recovering PM,s from this solution, or smelted the ore to lead, scorified it, then cupel the lead, recover the bullion and separate the metals chemically, or granulate the lead and dissolve in AR, then follow the procedure to extract the PM's from the AR. :idea:

If you've ever tried running large volumes of materials by those processes, it doesn't take long to understand why I chose not to. In this, and similar cases, you have to look past the processes that work well in assaying. Not because they don't work, but because they are not practical on that scale.

The method I used was my second choice. I tried a small column with cyanide to see if that would work. I extracted only about 1% of the gold, if that. Truth is, the head assay was lower than the tail assay which I would attribute to the heavy concentration of the samples. A definite sign that I was not removing the values. More studying revealed that using bromine with cyanide could solve the puzzle, which it did. While there was gold visible in the ore, a great deal was microscopic, in quartz. I examined the ore under a 400x scope. That made me understand that I had to reduce the ore to dust in order to liberate the tiny gold particles.

Given the same circumstances today, assuming I was still involved in refining (I am not----I am retired), I would make the same decisions all over again. The agitation tank and ball mill proved to be very useful for other processes as well. They were a necessity, plus were the source of a huge amount of learning. Had I not chosen to go the route I did, I would likely have never experienced cyanide for processing. Anyone that has been around this stuff much will attest, it's a wonderful way to recover gold, assuming the material is suited.

As a result of the agitation tank and ball mill, I also built a 10 ton gasketed filter press. Assuming you have large volumes of material to filter, there's nothing quite like having one. I could run 15 gallons of solution through in short order. I designed the press so I could not only filter the material, but to rinse and then blow down with air, to recover the majority of fluids from the solids.

Harold

Wow! That is impressive. The synthetic AR process is my own idea, the smelt to lead idea is that of C.W.Ammen. Smelting to lead and following the process That I posted comes from his book on "Recover and Refining of Precious Metals". There are other ways, and eventually I would like to learn them all, If possible. The process that you described is one such example, one that I have much to learn about. From what little I have read, a 3% cyanide solution is used to leach the ore, then recovery from solution is made possible by passing the leach solution through activated charcoal to strip values from solution, drying the charcoal, ashing it, then smelting the ashes, or smelting the charcoal with a mix of borax, sodium carbonate, and sodium nitrate. I have also heard of a secondary process of leaching the charcole with AR to recover the values from it, then follow the recovery of values procedure for Aqua Regia. Another recovery process for pregnant cyanide uses powdered zinc to recover the values from solution as a precipitate. How far from accurate am I with what I wrote so far?

Richard36 said:

Wow! That is impressive. The synthetic AR process is my own idea, the smelt to lead idea is that of C.W.Ammen. Smelting to lead and following the process That I posted comes from his book on "Recover and Refining of Precious Metals".

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GD Resources, a now defunct refinery in Sparks, Nevada, used that process on a large scale. They used an arc furnace to melt the values, using litharge along with proper fluxing agents, then cupelled the resulting buttons on huge cupels, something greater in size than 14" square. I sold some of my processed residues to them after the cyanide process. Some of my waste material contained platinum group metals, which are not recovered by cyanide.

The fact that they are no longer in business may well be because of EPA requirements. The idea of cupelling large amounts of lead simply wouldn't stand up today, not with the restrictions placed on industry. It would NOT be a good idea for the home refiner to attempt the process, aside from miniscule batches that are processed in fire assaying.

I trust you understand that my comments about the closure of GD Resources is my opinion-----I don't have a clue why they closed their doors. I knew them only from having done business with them.

I have read, a 3% cyanide solution is used to leach the ore,

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Not by wise operators. High concentrations are not selective. If you restrict the percentage to around .01% (it might be .1%, I don't recall which is correct), cyanide won't dissolve base metals, which can prove costly on a large scale operation. That's especially important when leaching heaps, where cyanicides can raise the cost of operation to the prohibitive point. They use low levels so all they recover is high values. It not only reduces cost of operation by not consuming cyanide, it simplifies refining of the recovered metals, so it's a win/win proposition. In my case, because excess cyanide destroyed the bromine, I kept a very low concentration. I was constantly titrating my solution to keep the delicate balance.

then recovery from solution is made possible by passing the leach solution through activated charcoal to strip values from solution, drying the charcoal, ashing it, then smelting the ashes, or smelting the charcoal with a mix of borax, sodium carbonate, and sodium nitrate.

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While that process works, it's a lot of work and costly. The activated carbon used isn't eager to burn, and there are more favorable ways to extract the values from the carbon without its destruction. I visited an operation in Eureka, Nevada (heap leaching) that was using a series of six carbon piles to recover the values from pregnant solutions. One was always inactive, with the pregnant solution flowing from one to another until it had been through all five receivers. When the solution came out of the last one showing traces of values, the first one was removed from service to be cleaned out, and the previous one that had been out of service was introduced as the last one to receive solution. So then, they were removed from service to be cleaned on a first in, first out basis. The operation was just getting started when I paid my visit, and I never went back. I have no idea how it shook out.

I have also heard of a secondary process of leaching the charcole with AR to recover the values from it, then follow the recovery of values procedure for Aqua Regia.

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That would be a totally unnecessary step. The Bureau of Mines published several booklets pertaining to recovery by activated carbon. One of them detailed a pressure stripping system that allowed the values to be stripped without harming the carbon. Given a situation where I chose to use carbon, that would have been my first priority.

Another recovery process for pregnant cyanide uses powdered zinc to recover the values from solution as a precipitate. How far from accurate am I with what I wrote so far?

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Your last choice was my first choice.

Reason?

It's simple--requires no investment of any kind aside from a couple containers large enough to hold your solutions, which would be required, anyway. It is cheap, relatively speaking, and it's fast and easy. Those that process huge volumes eliminate free oxygen, which makes the operation more efficient, consuming less zinc. I didn't bother. It should be noted that at that point in time, it was easy to buy a 50 pound pail of zinc flour. You could recover a troy ounce of gold for pennies that way. Why screw around with sophisticated processes when that one worked so well?

I refined for many years. One of the things I did was simplify the process, but not at the price of sacrificing quality. I learned what worked, and I stayed with the processes, perfecting them. My ultimate objective was to refine high quality gold-----I was not interested in re-inventing the wheel. My reward was being able to retire at the young age of 54----having been self employed since I was 28 years old.

Harold

Thanks Harold! Anything further that you could add about refining ores would be greatly appreciated. I am looking forward to seeing those photos of that ore!

Thanks for keeping this going guys. I looked at the cyanide/activated carbon years ago and let it slip. Sounded too involved. Do you have time to tell us about your leaching system Harold? Could a 50 or 100 lb. sample of fines be tested? I've got ground slightly downstream of an XRF assay with Au, Ag, Pt, Cu, Pd. with other minors. I had a Au fire assay that showed Au in my tailings. The area is historically known for fine and flat hard to recover Au. Thanks for allowing me to ride along and learn. Have a great day. allan

Rock on Allan! yeah, I intended just to get some feed back as to whether or not it would be worth my while to post all the mineral names and chemical formulas of the PM ores that I am aware of. Seems that this post is turning into a whole lot more than what I had intended it to be, and that is totally sweet, as far as I am concerned. By all means folks, lets keep this post growing! As I stated earlier, the names and chem. comp. of each are on the way. The web site link where they can be investigated has already been posted. Scrap is not the only source, it all starts with ores. :!: Sincerely; Rick.

allanwcoty said:

Thanks for keeping this going guys. I looked at the cyanide/activated carbon years ago and let it slip. Sounded too involved. Do you have time to tell us about your leaching system Harold? Could a 50 or 100 lb. sample of fines be tested?

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There's no reason a person couldn't build a small column for lab work. I started that way, but realized it would have been a failure due to the nature of the ore I processed.

I used a piece of 4" PVC pipe to build the column, with a bell reducer on the end fitted with a disc that had a huge number of small diameter holes drilled to allow the cyanide solution to be discharged. I used a small chemical pump to re-circulate the solution. The process worked, but extraction was hampered because of the nature of the ore. As I mentioned previously, I got very little extraction, but not because the column didn't work.

I still have the tiny button that came from that experiment------my first ever recovery of gold with cyanide.

The problem you're going to have is obtaining cyanide. It's easy enough to use, although you must have a standard silver solution and burrettes for titration in order to monitor the free cyanide. It's all very doable----I learned everything by reading some old books on ore processing. Rose's The Metallurgy of Gold is quite useful if you are interested.

I've got ground slightly downstream of an XRF assay with Au, Ag, Pt, Cu, Pd. with other minors. I had a Au fire assay that showed Au in my tailings. The area is historically known for fine and flat hard to recover Au. Thanks for allowing me to ride along and learn. Have a great day. allan

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Cyanide can be a poor choice, depending on the nature of the material. If you have too many cyanicides, the cyanide is consumed at an alarming rate. Ore that is well suited to cyanide processing often requires no more than an ounce of cyanide per ton. Do your homework well before you leap.

Harold

Mineral names, chemical formulas, and two websites where they can be researched have now been posted by me at the beginning of this thread. Happy prospecting! Sincerely; Rick.

A good website if you want to find minerals containing a certain element is Athena, it has a search function based on chemistry.
http://un2sg4.unige.ch/athena/mineral/search.html

Thank you for the post. I have as of yet to figure out how to access the information from that site that I desire for myself, and others. A good lead though. We need sites to investigate the ores that I posted. Any one else have any to contribute? Hopefully I will have a few more to post soon. Currently, I have a thread going on the Fabre mineral forum in search of web sites that will help with this objective. I will post the links to this thread soon. Sincerely; Rick. :idea: :!:

I can't get that mineralgalleries.com site to show anything but advertisements.

I tried using Firefox and IE. No mineral pictures. :x

Is it me?

Harold

I'm curious about your ball mill. In years past, when I looked at ball mills, the ones I seen had tiny holes in the cylinder, to let the small particles exit.
(For grinding clinker into portland cement.)

The home built mills I've seen on this site, did not have that feature.

Do the mill typically used in mining have holes? (Allowing continuous throughput.) Or are they a solid cylinder, that must be periodically dumped?

Thanks. And thanks to Richard36 for the effort.

semi-lucid said:

Harold

I'm curious about your ball mill. In years past, when I looked at ball mills, the ones I seen had tiny holes in the cylinder, to let the small particles exit.
(For grinding clinker into portland cement.)

The home built mills I've seen on this site, did not have that feature.

Do the mill typically used in mining have holes? (Allowing continuous throughput.) Or are they a solid cylinder, that must be periodically dumped?

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My ball mill was continuous feed, continuous discharge. The trunnions served in that capacity. It also ran wet, so I could shift the pH of the material from acidic to basic, in preparation for running the feed material in cyanide.

I can't speak for the mills built by others----a great deal depends on the amount of equipment available to the builder. I had a full machine shop at my disposal, so making a complex mill wasn't difficult, or beyond my capabilities. Not everyone will have the machines at their disposal.

Harold

So your mill had the material feeding into one end, and flowing out the other end? Or the material fed out though tiny holes in the cylinder?