# Precious Metal Ores and their chemical formulas.



## Richard36

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.


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## Harold_V

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


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## Richard36

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.


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## Harold_V

Richard36 said:


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


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


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## Richard36

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.


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## Harold_V

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


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## Richard36

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:


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## Harold_V

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


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## Richard36

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?


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## Harold_V

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".


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,



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.


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.


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?


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


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## Richard36

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!


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## allanwcoty

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


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## Richard36

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.


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## Harold_V

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?


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



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


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## Richard36

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.


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## g_axelsson

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


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## Richard36

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: :!:


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## semi-lucid

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.


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## Harold_V

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?


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


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## semi-lucid

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?


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## semi-lucid

After searching around a bit on google, it seems the ball mills I seen were specifically made for grinding portland cement, and most mills do not have holes in the cylinder. 

Which makes me wonder how you control the size of particle exiting the mill. Do you grade the output, and return the material that is too course back to the mill? :?:


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## Richard36

Probably. That is why I built my own mill. A hammer mill. A simple drum with horizontal and verticle strike bars to reduce ore to a fine powder. The discharge end of the drum has a very fine gap between the recessed lid, and the drum itself, allowing fine powder to escape due to constant vibration during operation.


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## Richard36

Try these sites. They were Given to me as reference material cites by the fabre mineral forum. mindat.org webmineral.com http://www.handbookofmineralogy.org I hope that these help. Sincerely; Rick.


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## Harold_V

semi-lucid said:


> Which makes me wonder how you control the size of particle exiting the mill. Do you grade the output, and return the material that is too course back to the mill? :?:


The discharge rate was controlled by the fluid feed rate. Crushed ore was fed at a constant speed, but I could vary the amount of fluid that was introduced. The less fluid, the longer material remained in the mill. I classified inside the ball mill by having restricted exit ports (parallel bars spaced about 1/8" opening), then the slurry ran down a chute to a classifying screen. Anything that didn't go through the screen was fed back to the mill. Very little got recycled through for a second run. 

Harold


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## semi-lucid

Harold

Interesting. When I try to imagine this, it seems like the hardness of the ore would have a big influence on throughput. (obviously) And having a fluid slurry inside the mill would have a cushioning effect on the impact of the balls.

I suppose the depth of the slurry, and the size of the balls would be important design factors. The shallower the slurry, and the bigger the balls, the harder the impact. :?: Harder ore might require a shallower slurry. :?:

The ore you showed looked like it might be pretty hard and difficult to grind. What size balls did you use? Did you build a large mill?

Rick

How long do the strike bars last if you get into some granite like material? How much power does it take to run? (hp or kw) Whats the noise level like? Do you crush the ore first?

I wonder how the energy efficiency of a ball mill vs a hammer mill would stack up. :?:

Thanks.
John


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## Richard36

I am using 1 in. shaft and strike bars in my mill. It is powered by a 3 1/2 horse briggs and straton, with 4:1 gear reduction. An 8 horse motor would be better. I have ran a couple of yards of quartz through my mill and the strikes are still in good condition so far. They will need to be changed eventually, but not for awhile. My mill is built out of scrap steel, so the strikes are probably all made of mild steel. The drum is an old water pressure tank, and is allot harder than mild steel. It eats 2.5" material pretty fast, and spits it out beach sand fine, and finer. I too have the option of running my mill wet, but have found that I like to run mine dry. The discharge some times plugs when ran wet, and has to be unstopped with a piece of wire or hacksaw blade. I don't have this problem in dry mode. I chose a hammer mill design due to ease of operation, and speed of throughput. A concrete mixer sized ball mill would probably take 20 min. to grind a 5 gallon bucket of 2.5" material beach sand fine. The hammer mill that I built can do it in About 8 min. The noise? LOUD! Very loud. Earplugs are recommended equipment. The sound of rock being struck by the strikes, and bouncing off the inside of the drum is a very noisy event. It will wake the neighbors if they live close by, so night time operation is not an option.


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## semi-lucid

If you followed your hammer with a ball mill, you could get down to fine clay, which I would guess might be necessary for some ore. 

You can get hard surfacing welding rod, to put a hard steel impact surface on your hammers. And you can build them up repeatedly, as long as your bearing point holds up.

There is another type, called a "Vertical Shaft Impactor" in which the material is fed down a rotating pipe, and thrown out arms at the bottom, after which it fly's through the air and impacts a hard surface on the inside of a drum. "At speeds in excess of 400 miles per hour."

http://en.wikipedia.org/wiki/Rock_crusher
http://www.keeneeng.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=RC1&Category_Code=RC

How do you get your rock down to 2.5"? I had the same question about Harold's operation. He said he fed crushed ore to the ball mill. Jaw crusher?

John


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## Richard36

Jaw crusher, or sledge hammer. It depends on the amount of material you have, and the size of your operation. I used a sledge hammer to reduce the material to baseball and smaller sized pieces to run in my mill. The smaller the material, the faster the through put, and the lower the noise level is. It will eat a gallon of 3/4 minus gravel per minute, maybe faster.


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## semi-lucid

Harold

On the first page of this thread, you stated:

*"The problem you're going to have is obtaining cyanide."*

I thought sodium cyanide was available. Wiki says: "Worldwide production was estimated at 500,000 tons in the year 2006"

I have a friend who has been using it for years to heat treat steel. 

Environmentally, it doesn't seem to be that much of a problem. It degrades. (Unlike PCB's (Polychlorinated biphenyls) or heavy metals.)

As a toxin, from what I remember reading years ago, (I was reading because I was concerned about my friends operation.) people can have a limited amount of exposure without consequence. Your body clears it out quickly, and you don't accumulate it like you would with mercury or PCB's. It occurs naturally in some foods, such as almonds. 

If you get enough to make you sick, that can be very bad. If I remember correctly, it can cause organ damage, even if it doesn't kill you. Obviously, if you get a big enough dose, your dead.

When you say it's difficult to obtain, are you referring to government regulations? If they are producing half a million metric tons per year, somebody must be obtaining it.  Have Enviro-nuts and Terrorists deprived us of the use of this valuable compound?

Regards.
John


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## semi-lucid

I found something online that gives an indication of the bulk price of NaCN.

http://www.sriconsulting.com/CEH/Public/Reports/770.9000/

*"World consumption of sodium cyanide in 2005 was about 510 thousand metric tons, with a value of about $600 million, based on mid-2006 world market prices."* 

If I'm punching my calculator correctly, that's $1176.47 per metric ton or about $0.535 per pound. I don't see why it is not usable, unless they won't sell it to you.

*"There is pressure worldwide to prohibit the use of sodium cyanide in the recovery of gold. Montana and Wisconsin have legislated that there can be no new operations involving sodium cyanide, but existing operations are allowed to remain. In 2004, Montana voters rejected a ballot that would have repealed the state’s ban on cyanide use in the processing of gold and silver at newly mined deposits. There have been accidents and spills involving sodium cyanide that have prompted a voluntary industry program titled “International Cyanide Management Code for the Manufacture, Transport and Use of Cyanide in the Production of Gold.” *

And this has got to be relevant reading, although I havn't read it yet.

http://www.cyanidecode.org/

John


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## semi-lucid

Harold

Could you give us a description of the viscosity of the slurry in your agitation tank? Was it thick with clay particles like thin mud? Or did you have enough water to be like tomato soup?  Or enough water to be close to the viscosity of water?

I'm just trying to get a picture of it.

Also, in my ongoing reading, I found this:

*"The pH value of cyanide solutions during dissolution must be maintained above pH 12 to avoid the volatilization of hazardous hydrogen cyanide (HCN) gas."
*
Apparently they use lime to achieve this pH. Did you adjust the pH of your solution in such a way?

I remember a post by goldsilverpro where he described loading e-scrap in a cement mixer, and stripping with cyanide, but I can't find the thread. The search engine on this site seems a little "iffy" to me.
I don't remember him talking about an extreme adjustment to the pH. (Or any adjustment at all.)

Best regards.
John


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## Harold_V

semi-lucid said:


> Harold
> 
> Could you give us a description of the viscosity of the slurry in your agitation tank? Was it thick with clay particles like thin mud? Or did you have enough water to be like tomato soup?  Or enough water to be close to the viscosity of water?


The best I can offer is that I ran about 50/50 solids/solution. It was kept in suspension by a propeller that was housed inside a 4" diameter steel pipe in the center, which projected almost to the bottom of the agitation tank. The tank bottom was conical. The slurry was lifted to the top of the inner tube, where it was discharged inside the tank. You can see that the material flowed upward inside and downward outside the inner pipe. 

I have some pictures of the agitation tank, but not in the computer. If I can locate them, I'll post one so you can see how it was built. A half hour search hasn't yielded the pics. Be patient. 



> Also, in my ongoing reading, I found this:
> *"The pH value of cyanide solutions during dissolution must be maintained above pH 12 to avoid the volatilization of hazardous hydrogen cyanide (HCN) gas."*
> Apparently they use lime to achieve this pH. Did you adjust the pH of your solution in such a way?



Yes. I introduced (hydrated) lime along with the water and crushed ore. In reality, you are safe as long as the pH is above 9½----but I shot for roughly 12. I recycled the water, instead of adding new. I simply tested the discharge from the mill and added lime as required. 



> I remember a post by goldsilverpro where he described loading e-scrap in a cement mixer, and stripping with cyanide, but I can't find the thread. The search engine on this site seems a little "iffy" to me.
> I don't remember him talking about an extreme adjustment to the pH. (Or any adjustment at all.)


Not having any experience similar, I can't comment, but processing an ore that is a sulfide is very different from processing boards that are likely not acidic. In either case, pH is important, but it may not drift with e scrap. Sorry, I don't know. 

Harold


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## goldsilverpro

semi-lucid said:


> I remember a post by goldsilverpro where he described loading e-scrap in a cement mixer, and stripping with cyanide, but I can't find the thread. The search engine on this site seems a little "iffy" to me.
> I don't remember him talking about an extreme adjustment to the pH. (Or any adjustment at all.)



I think it's your search procedure that's a bit iffy. I had no problem searching for it. Go to advanced search or the search listed at the top of the page between FAQ and Memberlist and type in cement mixer in "search for keywords". Click on "search for all terms". Type goldsilverpro in "search for author". Click on "search" at the bottom. The thread you're looking for is now the second one listed.
http://goldrefiningforum.com/phpBB3/viewtopic.php?t=4374&highlight=cement+mixer

If I remember right, a solution of sodium cyanide has a pH of 10.3. I didn't raise this pH while stripping but, if you would feel safer, you could add a small amount of NaOH. Before zincing out the gold, I raised the pH to 12.0. I always stripped outdoors and kept my face out of the mixer.



Harold_V said:


> Not having any experience similar, I can't comment, but processing an ore that is a sulfide is very different from processing boards that are likely not acidic. In either case, pH is important, but it may not drift with e scrap. Sorry, I don't know.



Harold is right. The process I gave was strictly for e-scrap. Working ore with cyanide would be completely different. Don't use my method for ore. It could be dangerous and inefficient.


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## g_axelsson

goldsilverpro said:


> Harold is right. The process I gave was strictly for e-scrap. Working ore with cyanide would be completely different. Don't use my method for ore. It could be dangerous and inefficient.



I agree, a lot of sulphide bearing ores creates sulphuric acid when it weathers. I've seen one mine (a complex sulphide ore with copper, pyrite, lead, zinc, gold, silver...) where the ground water pumped out had a pH of below 2. They had to change the pump every month as the water was so corrosive. :shock:

I've only seen one sulphide ore where the ground water pumped up was above 7 in pH. That was a fantastic ore, 30% copper, 15% zinc, some lead and silver and 1g Au per ton. Although, it contained huge amounts of arsenic. I actually found a 6.8 kg solid chunk of metallic arsenic there. Most part of the arsenic was in the form of arsenopyrite.
They never used the gold in the calculation of the ore value but during five years of production they managed to produce over two tons of gold! A nice bonus for the owners.

I see that my mind is wandering off again... the bottom line, every ore is unique and should have a tailored process to keep it safe and to extract the most value from it.


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## semi-lucid

Harold_V said:


> It was kept in suspension by a propeller that was housed inside a 4" diameter steel pipe in the center, which projected almost to the bottom of the agitation tank. The tank bottom was conical.
> 
> Harold



I was imagining a propeller, but open, with a flat bottom tank. I figured the tank would be plastic rather than steel. Did you oxygenate the slurry? 



goldsilverpro said:


> I think it's your search procedure that's a bit iffy.


I don't know why I didn't see that advanced search link. (Good thing it wasn't a snake.)  I searched "cement mixer" in the regular search box, and it returned a full page of hits.



goldsilverpro said:


> I usually used a cement mixer - OUTSIDE. I put about 1/2 pound (1/2 of a 4" X 6" aluminum scoop) of sodium cyanide in the mixer, followed by about 2 gallons of hot tap water. Then, I added 40 to 50 ml of 30 to 35% H2O2.


Wow, that sounds like *a lot* of NaCN, compared to the concentration that Harold was using, or compared to what I found on another site:

*"Typical cyanide concentrations used in practice range from 300 to 500 mg/l (0.03 to 0.05% as NaCN) depending on the mineralogy of the ore."* 

If you reduced the concentration, and slowed the process down, couldn't you avoid attacking the copper, and conserve reactant? (speaking of e scrap)



g_axelsson said:


> the bottom line, every ore is unique and should have a tailored process to keep it safe and to extract the most value from it.



Understood. We were mostly disscussing Harold's particular situation, but I've been reading anything I can find on the subject.


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## goldsilverpro

> Wow, that sounds like a lot of NaCN, compared to the concentration that Harold was using, or compared to what I found on another site:



I repeat. My process is for e-scrap and has absolutely nothing to do with ore. Harold was talking about ore.



> If you reduced the concentration, and slowed the process down, couldn't you avoid attacking the copper, and conserve reactant? (speaking of e scrap)



You can do whatever you want. Those are the amounts I used. Cyanide was cheap and the quantities I used stripped the gold in a minute or two. To me, speed was essential. Most gold is plated over nickel, so there was no attack on the copper. When the gold was plated directly on copper (rare), it sometimes took a little extra cyanide and H2O2. Even then, only a small amount of copper was dissolved. As long as the gold completely stripped, I didn't mind if some copper dissolved.

After stripping, the nickel should be white and the copper pink. If a black powdery coating is observed, it is gold that has been re-deposited. If enough H2O2 is used, this should not happen. However, if too much H2O2 is used, the solution will overheat, the NaCN will break down (the DuPont method of decomposing CN uses H2O2), and foam could come flowing out of the mixer. The amounts of H2O2 I gave should work fine.


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## Harold_V

semi-lucid said:


> I was imagining a propeller, but open, with a flat bottom tank.


There was method to my madness. At the time I ran this particular ore, I had no filter press. Instead, I'd allow the material to settle in the agitation tank, then siphon of the pregnant solution to recover the values. I had two sets of solution, so once I decanted the agitation tank, I immediately started the second round of solution. 

In order to get the solids back in suspension, without having any blind spots, a flat bottom vessel was out of the question. Also, in order for the propeller to start turning, it had to be above the level of solids. While I have no engineering credentials, I designed the tank to operate at a given level, which established the location of the propeller, as well as determining the length of the inner tube. That tube projected towards the cone bottom, stopping short by about 3/4". That way, the material would all get suspended. In theory, it worked great, but in practice I had to encourage the solids to start moving, which I'd do by probing the outside of the inner tube with a pointed 7/8" diameter aluminum rod. That seemed to get the material started, then it was but a matter of a few minutes and all of the solids were in suspension. 



> I figured the tank would be plastic rather than steel.


Nice deduction, one that is correct. Note I have posted a picture of the agitation tank, below. The tank was lined with PVC, so no steel parts were exposed to the slurry. The one component that didn't hold up well was the propeller, which slowly ended up with exposed steel edges. That didn't appear to create any problems, so I ran it that way. The balance of the PVC coating held up quite well. 



> Did you oxygenate the slurry?


No, I did not. I ran other materials, not just the ore that I mentioned. When I ran the ore, I used bromine in limited quantities, which made all the difference in the world towards extraction. For the other material I ran, I didn't use bromine, not having a need. I achieved success simply by the small amount of oxygen the charge accumulated just being in operation. I have no idea if I would have benefited by adding more. 



g_axelsson said:


> the bottom line, every ore is unique and should have a tailored process to keep it safe and to extract the most value from it.



True. Only a fool would expect a single procedure to work on all types of ores. 

I was VERY fortunate to have figured out a procedure for the ore I processed, especially not having a chemical background. 

Harold


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## semi-lucid

Harold

Thanks for posting the picture. Nice looking machine. Too bad you didn't have 1000 buckets of that ore, instead of only four. :!:


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## Richard36

I would like to have at least a couple of 5 gallon buckets of high grade ore like that. That grade of ore in todays market would be worth a few dollars.


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## EVO-AU

Richard36: I am not as sophisticated in the chemical search for Au and such as I have only been at it for a couple of years. I have been prospecting with hand tools/detectors for more years than some of the forum participants have been on this earth. A lot of fun, hard work and the budget balanced. But I do agree with you, I would like to hear from some others who have been looking for ores and not circuit-boarding, so to speak. Electronic searching really doesn't interest me. There are a couple of searchers on this forum that have given me some valuable info and have bailed me out of sticky scenes. And I thank you guys, you know who you are! So Richard, and Harold who has given me some info over the past years, thank you. But anybody out there doing ores and not electronics? Simple and succinct. Phill


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## Richard36

Thanks Phill. I can't help it, I'm a RockHound. I have been for most of my life, and have been into prospecting since I was quite young. Approx. 15 yrs ago I got serious about finding something good, and started to study all that I could read about prospecting, and all related subjects, with heavy emphasis on Petrology, Economic Mineralogy, and element identification through various qualitative testing procedures. Later on I took a course to become an assayer, seeing that it would be cheaper to pay for the course, and learn how to do an assay for myself than to pay someone else to assay every interesting , and promising mineralized chunck of rock that I had hammered out of some outcrop. (I can't drive through the woods around here without finding at least one highly mineralized outcrop on every trip that I take.) Chemical formulas have their place, but the main objective of my post was for people to look at them, and become familiar with what these ores look like. Why look for native element when you can see an outcrop of mineralized rock yielding several ounces of precious metal(s) per ton? In closing I will make this point, seeing it does not do you any good if you do not know what it is that you are looking at. Read, study, learn, then go find. Sincerely; Rick.


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## EVO-AU

Rick: An adventurer at heart. Right ? I don't get out too much anymore, but I do love to wander the streams and poke and test. You sound well versed and focused. Good for you. Go for it !

Have you by any chance read Rockpeckers book on minerals and testing? His tables are mind boggling. I believe he took up where Dana left off. Have fun, Phill


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## Richard36

Thanks for the compliment Phill. No, I have not Read "Dana's Mineralogy," or "Rockpeckers Notes." I know the books though. Far too many good books on related subjects to buy, and read them all. (Anytime soon anyway.) Yes, I do consider myself an adventurer. I do like to explore old underground mines, and caves. Especially those in regions that have undergone hydrothermal alteration, and are highly mineralized. (Metals are not all that I look for.) Mineral specimens are nice finds, and can be worth quite allot to collectors as well. Sincerely; Rick.


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## markqf1

It always " pays" to know what your looking at.  

Mark


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## EVO-AU

Rick: Back in the 1800's, Tiffany ( of Long Island,NY ) sent whole families into the mountains of western NC for minerals, gold, and whatever. They were highly successful.l Among the finds was a new mineral labeled Hiddenite, after the person that found it. Look it up on the net, most interesting story. There are gem mines all over this part of the country. back in the eighties a young boy was screening a bucket of soil at a gem mine in Western NC. As the story goes, he found a rock about the size of a golf ball and took it home. About two years later an uncle ( a retired geologist ) looked it over and asked if he could take it home and play with it. Well, long story short, the rock yielded a small emerald worth some 400 thousand dollars. Gold and then some is where you find it. Fun and games, huh Rick ? Have a nice weekend. Phill


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## Richard36

Wouldn't it put a smile on your face to find something like that? I am familiar with the mineral Hiddenite. I have looked at several pictures of it in mineral books, and cut varieties on JTV. An interesting, and valuable mineral. I hope that you have a good weekend as well. Sincerely; Rick.


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## Richard36

It has been awhile since I made a post here. I hope that all is well with everyone on this forum. If anyone has found anything of interest, post a photo, and I will see what I can do for you by visual identification. Hopefully, This will revive some interest in this thread. I like to "Talk Rocks".


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## Palladium

Welcome back Richard.


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## Richard36

Thanks for the welcome back. Hopefully someone will post some photos of some mineralized rocks for me to check out. Questions are welcome as well.


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## Richard36

For all those interested in following the conversation, the topics "Washington State Gold Ore" and "The Rock Man" under "Prospecting" picks up where this topic left off by covering the geology of precious metal vein systems, as well as other related Rock & Mineral topics. Lots of good info there that does not quite fit in this thread.

I check those threads daily, as well as this one, so if you have a question, comment, or sugestion, make a post in either of those threads, or here, and I will reply. General chat is welcome as well.

I hope to hear from you soon.

Sincerely; Rick...


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## Richard36

Photo's of the ores listed at the begining of this thread are now available in the "GoldBug University" Thread.

I hope to chat with you there.

Sincerely; Rick. "The Rock Man".


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## CHARLIE GREENLER

YES SIR COULD YOU FIND OUT ANYTHING ON MINERALISED RHODITE AND TIGHT COMPACT CUBIC RHODIUM PYRITE FROM MOLEBDONITE HYDROTHERMAL MUD VEIGNING.Who test minerals that have isotopes for precious metals and that are sulfide /phophosphate pgm complexes that also contain rare earths.


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## Richard36

CHARLIE GREENLER said:


> YES SIR COULD YOU FIND OUT ANYTHING ON MINERALISED RHODITE AND TIGHT COMPACT CUBIC RHODIUM PYRITE FROM MOLEBDONITE HYDROTHERMAL MUD VEIGNING.Who test minerals that have isotopes for precious metals and that are sulfide /phophosphate pgm complexes that also contain rare earths.



I can assay sulfides for their Gold and Silver content. 

Fire assays for PGM's I am uncomfortable doing. 
If a bead contains PGM's, I would recommend having an ICP ran on it. 

As for testing Minerals with chemical tests to determine if Gold, Silver, or any of the Platinum Group Metals are within it, 
that I can do as well. The only drawback to chemical tests is that they are not as sensitive as an assay.

Aside from myself, "Reed Labs' has a pretty good spectrographic test that might meet your needs.
For the Rare Earth metals, you will have to go to Reed Laboratories for those tests.
I can't help you with those metals, and I do not know of anyone aside from Reed Labs that can test for the Rare Earth metals.

Thanks for the question, and the post.
I hope that this has been helpful.

Sincerely; Rick."The Rock Man".


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## goldsilverpro

As I learned the hard way, the people on this forum are extremely cheap. Or, maybe, they just are so ignorant that they don't understand the importance of knowing the value of the material they are dealing with. Anyway, I got almost zero support in my assaying endeavor and shut my business down. I would hope that you would give Richard36 some assaying business. You will always be money ahead by knowing values. Duh.


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## Richard36

goldsilverpro said:


> As I learned the hard way, the people on this forum are extremely cheap. Or, maybe, they just are so ignorant that they don't understand the importance of knowing the value of the material they are dealing with. Anyway, I got almost zero support in my assaying endeavor and shut my business down. I would hope that you would give Richard36 some assaying business. You will always be money ahead by knowing values. Duh.



Thanks for the Support GSP.
I truly do appreciate it.

Sorry that your assay business didn't work out for you.

Sincerely; Rick. "The Rock Man".


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## ashir

Harold_V said:


> 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


I wish i could have some experts like you, to prepare a filter press, According to liqued chracteristics. 
I have only SS made filter press, assurely not withstand to acidic liqued. Any idea to make a filter press that filter 50 liters at a time?


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