# Gold and Black Sand



## Art Corbit (May 18, 2008)

I know there must be a few placer miners on here that operate their dredges, high bankers and pans and I am looking for their opinion on something.

I'm working on a method to separate black sand and other junk fron fine gold without using magnets or chemicals. It uses molten lead. As most of you probably know gold and the pgm's will sink to the bottom of molten lead. Black sand, dirt, sand a most other junk won't sink. Instead it will float on top of molten lead where it can easily be skimmed off.

I have seen people that had buckets of black sand saved up and no idea how to get the gold out of it. If this will work it would open a door that has been closed much too long. If any of you have tried it or would to just express your opinion then step up and ley me hear from you. Thanks

Art


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## goldsilverpro (May 18, 2008)

Gold alloys with lead. It doesn't sink to the bottom. It may stratify a little bit, but not much.


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## ChucknC (May 19, 2008)

Art,
As I'm sure your aware, you need to super concentrate the blacksands to have an efficient recovery. Check out the popandson scleanup sluice. It's almost a new idea, but I think Steve has just about perfected the idea.

Here's a couple of links that will give you the idea.

http://www.youtube.com/watch?v=KdikUKNLCHY

http://www.youtube.com/watch?v=0jXGbp8KJAo&feature=related

Pay attention to the cleanup sluice he uses. It elliminated the blond sands and really highly concentrates the gold.
More info:
http://bb.bbboy.net/alaskagoldforum-viewthread?forum=2&thread=694&postnum=0&highlight=

Chuck


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## Art Corbit (May 19, 2008)

I have heard gold alloys with lead but I have not found anything to support that. If you have anything please post it.

Chuck, There is one huge problem with concentrating the black sand. By the time you get it concentrated you have already lost most of the fine gold. The gold in that vial in the video is large gold compared to what I can get. I can get it down where you can't even see it with the naked eye.

I would say that small sluice in the video will do about as good as any sluice ever will but it is still loosing fine gold. ANY movin g water will carry a lot of the super fine gold roght out the exit of the sluice. Don't get me wrong that is a fine design on that small sluice aqnd who ever designed and built if is pretty sharp indeed.

The kind of gold I am talking about you can't even pan it. It can take a full minute for it to settle just 1" deep in totally still water. I don't know if Alaska even has much fine gold but if they do the sluices working in AL's hole in the video are loosing most of it.

Art


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## goldsilverpro (May 19, 2008)

Art,

Take your pick
http://www.google.com/search?q=%22gold-lead%22+alloy+phase+diagram&sourceid=navclient-ff&ie=UTF-8&rlz=1B3GGGL_enUS259US259&aq=t

A 15/85, gold/lead eutectic has a melting point of 250 deg. C. The gold/lead alloy is the basis of fire assay.


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## Art Corbit (May 20, 2008)

Some of those explanations don't make sense like the one below.

_*The three intermediate compounds of the Au–Pb system were synthesised by melting the pure components in suitable proportions and annealing at a temperature just below their melting point. Their structural states were verified by X-ray studies.*_

What is the third compound used with the gold and lead?

Art


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## Art Corbit (May 20, 2008)

Looks like you must use a third compound of somekind to produce a gold/ lead alloy.


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## Harold_V (May 20, 2008)

Art Corbit said:


> As most of you probably know gold and the pgm's will sink to the bottom of molten lead.


Actually, Art, that simply isn't the case. Molten lead is a powerful solvent of other metals. I offer you this for consideration; solder from wave soldering machines gets contaminated with gold as it is used. It reaches a point where it must be replaced. 

At no time is the melting temperature of gold achieved, nor is the melting temperature of platinum or palladium achieved in a fire assay, yet the litharge that is included in the crucible reduces to lead, which, in turn, dissolves and absorbs any of the metals that may be present. The oxygen that is liberated from the litharge in the process of being reduced is used to oxidize the charge. 

Lead is a very thorough collector of values, which go *into solution*. They do NOT settle to the bottom. Rarely will metals separate from stratification, although some will. I offer you silver and iron as an example. 

Harold


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## Oz (May 20, 2008)

I thought silver was often found in lead as a naturally occurring ore???


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## Platdigger (May 20, 2008)

Not sure Oz, but I think Harold meant silver and iron separating from stratification with each other. 
Randy


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## Oz (May 20, 2008)

Platdigger,

I’m not sure, that’s why I asked. I thought silver was often found in natural lead ores. But from the lead I’ve messed with in the past I know steel will float on it. If some of the steel dissolves into lead I don’t know. I never tried floating silver on lead. 

Ps; with your name… do you mine or pan platinum nuggets?


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## Platdigger (May 20, 2008)

Something like that......real small ones...

Yes, I agree, silver is often found in lead ore.

I meant to say silver dropping out of stratification with iron......no lead involved.
Randy


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## Oz (May 20, 2008)

"I meant to say silver dropping out of stratification with iron......no lead involved."

Got me on that, I never had a reason to mix silver and iron molten.

You sound positively discouraged with platinum panning. You out to try panning out where I live in Pennsylvania :?


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## Harold_V (May 20, 2008)

Platdigger said:


> Not sure Oz, but I think Harold meant silver and iron separating from stratification with each other.
> Randy


Yes, that's correct. I apologize if I posted confusing information. 

I'm not sure where I read the comment, but if a person had gold and iron alloyed, it's fairly straight forward to separate the gold from the iron. One simply melts the gold/iron alloy in the presence of silver, which has a greater affinity for gold than does iron. Once they have had a chance to make the transition, the metal is allowed to cool. Virtually barren iron would be found on top of a layer of silver/gold alloy. 

Very few metals behave in that fashion once alloyed. Great effort is normally required to separate them. The idea of the heavy elements settling to the bottom simply doesn't hold water, in spite of common logic. The alloying forces are far stronger than gravity. 

Harold


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## Oz (May 20, 2008)

No problem Harold! I wasn’t sure so I asked. I am however intrigued by your last post. If you could remember where you heard this it could be very useful for some black sands. I wonder how many ppm virtually barren is. Back to the silver thing, it was zinc they put in with the lead/silver galena. The silver formed stronger bonds with the zinc than the lead. The newly created zinc/silver alloy would float on top of the lead.


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## Art Corbit (May 20, 2008)

A little corerection Harold. The flux you must use to get molten lead to stick to any metal, including gold, is what eats other metals not the molten lead. You can't get hot lead to stick to any metal that has a higher melting point than the lead, Gold, Silver, Copper, Iron or what ever.

And yes Silver is found in Galena. In fact you can look at Galena and tell if it contains very much Silver. Galena fracyures where it has flat sides and if the sides are bulged out in the center then it contains silver. If they are flat it doesn't.

Art


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## goldsilverpro (May 20, 2008)

Melting points:
Lead - 327 C
Gold - 1064 C
Eutectic alloy of 85 lead/15 gold - 250 C

What would happen if you melted lead @ 327C, sprinkled gold powder on it, and stirred it? I think that the gold would alloy with it, at least to the extent of whatever the Pb/Au composition is on the phase diagram @ 327C. I've never done this, but that is my understanding. Someone correct me if I'm wrong.


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## Art Corbit (May 20, 2008)

250C won't even melt lead. You are going to have to get over 330C to melt the lead. Yet this article says 250C will melt a gold/lead alloy. They are full of bull. It might sound good on paper but you get out here in the field and it doesn't work so good.

Think about what they are saying there. They are saying an alloy will melt at a lower temp than the lowest temp metal in the alloy. This is impossible.

Art


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## Platdigger (May 20, 2008)

62 percent tin/38 percent lead: melting temperature 183C

Lower than the melting point of either pure lead (327C) or Tin (232C)

They call it an "eutectic mixture"

It is from greek meaning "easly melted"


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## Art Corbit (May 20, 2008)

OK I stand corrected. Evidently I don't know what I am talking about so I'll shut up and go on my way.

Art


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## goldsilverpro (May 20, 2008)

Not impossible at all. Pretty standard stuff. I also thought it didn't make sense when I first heard it 30 years ago.

Working backwards on this, let's say you have an alloy of 50/50, Pb/Au, if one exists. You heat it until everything just melts. You then cool it slowly. When you reach almost 250C, you have a molten phase of 85%Pb/15%Au.

Here's the only Pb/Au phase diagram I could find. It's the last drawing in the patent. It's a complicated one and I'm not very good at reading the complicated ones. The way I read it, the eutectic of 85%Pb/15%Au is even lower - 212.5C.
http://www.google.com/patents?id=oo8XAAAAEBAJ&printsec=abstract&zoom=4&dq=5985692#PPA5,M1


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## Harold_V (May 20, 2008)

Art Corbit said:


> Think about what they are saying there. They are saying an alloy will melt at a lower temp than the lowest temp metal in the alloy. This is impossible.
> 
> Art


No, it isn't impossible----it's fact. You should start reading instead of sticking with your own concepts. It's commonly known and accepted that combining metals lowers the energy it takes to melt them in their pure states. 

How do you suppose materials like Cerro-bend exist if it wasn't for a eutectic point?

When you post information that is misleading, your credibility suffers. It won't be long until no one will read anything you have to say without dismissing you as a nutcase. 

Harold


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## Art Corbit (May 20, 2008)

Not to worry if I can find a way to get off this forum I won't be posting any more bad information. No wonder there is over 3,000 members on here. The door you come in at only swings one way.

Art


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## goldsilverpro (May 20, 2008)

Art, you're taking this all wrong. We don't want to lose you. If I offended you I sure didn't mean to. I doubt if anyone else did either. When I first heard about that concept, I had trouble with it also.


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## Art Corbit (May 20, 2008)

I am the first to admit I make mistakes but I figure I have the same right as anyone else. I had never even heard about this lower melting temp thing. That just doesn't fit in with logical thinking. This stuff about gold dissolving in molten lead doesn't fit either. I have seen this process done and I know it works. At least to some extent.

A couple of years ago a fellow came to my place to show me some of the gold he had collected. He was trying to get into fire assaying and he had come lead balls the had melted. He had one that had a bunch of fine gold on the bottom of it. He said he had run a bunch of black sand across it like I have been talking about but he had more lead than he needed and was trying to add more black sand to it.

This tells me if molten lead will dissolve gold then as fine as this gold was it would take a long time for it to do it. Also by using magnification you could tell the lead wasn't stuck to the gold. If he had juswt poured off the molten lead he would have had the gold in the bottom.

The reason I am trying so hard with this is it will be the last stage of a fine gold recovery system I have designed. I can concentrate the gold all sizes but if is left in black sand, silt and a bunch of other junk. I can concentrate a 5 gallon bucket of bank run material down to about a cup full. If I can perfect that final separation I will have a complete system.

Art


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## Harold_V (May 21, 2008)

Art Corbit said:


> Not to worry if I can find a way to get off this forum I won't be posting any more bad information. No wonder there is over 3,000 members on here. The door you come in at only swings one way.
> 
> Art



Perhaps you might consider asking for explanations instead of posting your recent comments. There are people here that are trying to help you better understand something you appear to not understand at all. 

The problem I'm having is your insistence that processes that are supported by scientific evidence, and known to work as described, are dismissed by you----because you choose to not believe what is described. Here's a couple examples:

"250C won't even melt lead. You are going to have to get over 330C to melt the lead. Yet this article says 250C will melt a gold/lead alloy. They are full of bull."

and

"A little corerection Harold. The flux you must use to get molten lead to stick to any metal, including gold, is what eats other metals not the molten lead."

Both cases are known to be true. Lead, as well as other metals, are strong solvents. Molten aluminum will dissolve steel (iron)---and molten gold or lead, given enough exposure to pure platinum, will dissolve it as well, even though you may be 1,000° cooler than the melting point of platinum. 

You would do well to do some research, so you can better understand the powers of molten metals. 

I would also suggest that you not dismiss what others know to be fact, just because you don't understand it, or don't agree with it. 

Harold


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## Harold_V (May 21, 2008)

Oz said:


> No problem Harold! I wasn’t sure so I asked. I am however intrigued by your last post. If you could remember where you heard this it could be very useful for some black sands.



While I read several books, the vast majority of information I gleaned was, believe it or not, from Hoke's book. The other book I trusted was Sir. T.K. Rose's The Metallurgy of Gold. I'm certain it was in one or the other, but am unable to verify because my books are not available to me at this time. 



> wonder how many ppm virtually barren is.



I'm of the opinion that you could achieve a near perfect separation by the method. Certainly far better than the effort required to otherwise process the iron for gold recovery by other means. 

Should you find anything in print, I'd appreciate hearing from you. 

Harold


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## Art Corbit (May 21, 2008)

Harold, 

I'm not trying to be a know-it-all or a hard case but you need to understand what I am trying to do. I know some metaIs will attack others but that doesn't have anything to do with what I am doing. Even if molten lead does dissolve gold, which no dought it would over time, my gold won't be in it long enough to matter.

What I am trying to do has never been done before without the use of chemicals or Carbon. My main goal is to get completely away from Chemicals and develope a cheaper methof of getting the gold. I'm going after the super fine gold that no form of gravity separation with moving water will trap. If the water is moving at all you can collest gold down to a certain size and that's it. I have gold that is small it will take it a full minute to settle just 1" in totally still water. There is a lot of this kind of gold around and people keep loosing it over and over.

I'll get off this subject after this post


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## Harold_V (May 21, 2008)

Art Corbit said:


> Harold,
> 
> I'm not trying to be a know-it-all or a hard case but you need to understand what I am trying to do. I know some metaIs will attack others but that doesn't have anything to do with what I am doing.


Actually, it does, Art. You can use the solvent powers of molten lead to advantage. You just have to change how you look at things. 

Assuming the lead can wet the gold, it may recover it by dissolving. What's wrong with that? The difference is you'd have to use a follow-up process to separate the gold from the lead-----but in either case, you'd capture the gold. Key to success, here, is if the gold wets the lead, or not. Just like using mercury, there are cases where it may not. If the gold has any kind of covering, it may be enough to isolate the flakes from intimate contact. In such a case, it's also possible that the surface tension of the molten lead would continue to float the particles, so they wouldn't be recovered. 




> Even if molten lead does dissolve gold, which no dought it would over time, my gold won't be in it long enough to matter.


Assuming it wets easily, that isn't a factor. If it contacts the gold and wets it, dissolution is immediate----not suggesting that it happens fast, but some gets dissolved. That's the problem with wave soldering machines. They slowly accumulate gold until the solder is too contaminated to be useful. 



> I'll get off this subject after this post


No need to do that, Art. Just don't insult those that have tried to help you by refusing to acknowledge information in which you have no confidence. If you continue a course of tunnel vision, you may well ignore the very process you seek, simply because you choose to disagree with a concept that you don't understand.. 

There are some very bright people on this forum. They may well have the key to your success. If you've followed the posts much, by now you should have come to terms with those that appear to know what they're talking about. 

Harold


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## Oz (May 21, 2008)

Harold,

Thanks for the tip on The Metallurgy of Gold. I have searched the 1898 edition of it as well as Hoke for “iron” and did not see it readily but I will need to set aside a couple of hours to check more carefully. Its kinda funny hearing you say “the vast majority of information I gleaned was, believe it or not, from Hoke's book”, at least to anyone that pays attention to what you say. I will most certainly get back to you if I find something in print. I’ll get a copy or link to you for it.

Thanks as always for your help


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## Oz (May 21, 2008)

I agree there is a lot of very small gold out there but hearing you say “I have gold that is small it will take it a full minute to settle just 1" in totally still water” makes me wonder if it is cost effective to recover. If it is so light that gravity will not separate it if there is any water movement then how many gallons of this do you estimate you need to recover a gram or troy ounce of fine gold? 

Then again I may be missing the point if this is just for fun. I do much that doesn’t pay other than the joy of learning.


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## goldsilverpro (May 21, 2008)

I bought a copy of "The Metallurgy of Gold," awhile back for $45 from Legend. It's the 7th edition, which is much more complete than the earlier edition that you can download free from Google books. Good price, but I paid $15 for shipping.
http://www.lmine.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=assaying

I just noticed that the Bugbee and the Shepherd and Dietrich Fire Assay books are available here for $20 each. I've had both books for about 30 years and think they are the best out there. If you have any interest in assaying, you have to have at least one of these books. They are both classics.


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## Oz (May 21, 2008)

Thanks GSP but that will have to wait until my wallet isn’t so light. 

I don’t even think I have a pennyweight in there :wink:


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## Art Corbit (May 21, 2008)

OZ,

If a person could get in the right place I believe they could make it pay. You wouldn't get rich but you could make a pretty good living. In some of the mining area the super fine gold is really concentrated but untill now the only way you could get it was with chemicals. Even then there is usually so much black sand (Iron) in it chemicals are also just about worthless.

Another thing that would help is it costs very little to do it. Your cost to get to where you work it is about it. I'm going for something cheap to operate and simple to use that will pay a pretty good profit.

Art


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## Harold_V (May 22, 2008)

goldsilverpro said:


> I bought a copy of "The Metallurgy of Gold," awhile back for $45 from Legend. It's the 7th edition, which is much more complete than the earlier edition that you can download free from Google books. Good price, but I paid $15 for shipping.



Damn, Chris! That's one hell of a deal. I have a (poor) copy of the 6th edition---which I cherish, flaws and all. I learned a great deal from that book--including the theory on ball mills----and agitation tanks. I designed mine after combining features of various types known to have been built. Both worked exceedingly well. 

Anyone interested in gold from almost any perspective should own a copy. I've commented on Rose's book on many occasions. 

Harold


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## Art Corbit (May 22, 2008)

Ok everyone seems to be against my molten lead separation ides so what do you say to just a heavy liquid? (LST for example). Other than it's expensive? LST is non toxic, doesn't put off harmful fumes, Itr's a cold liquid so no burns. If a person had a good amount of black sand with an ounce or so of fine gold the $670 + shipping might not be a bad deal. Us see what you can find wrong with this.

Art


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## Art Corbit (May 22, 2008)

Sorry. That is $670 + shipping per litre for the LST. Here's a link.

http://www.heavyliquids.com/ 

Art


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## Shecker (Jun 7, 2008)

The process of separating precious metals from molten lead because of their higher affinity for zinc is called the Parkes Process. It has been used for a very long time. The zinc will stripped all of the precious metals from the lead
leaving the separation of the lead and zinc as the only real problem. Aluminum has a similar property and will also strip precious metals from lead. Because of aluminum's affinity for precious metals it might serve as a better collector than lead with far less toxic side affects.

Randy in Gunnison


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## Irons (Jun 7, 2008)

The EPA has regulations relating to the use of Lead. Anyone using over 50 Lbs per year must register with the EPA and maintain detailed records.


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## P_CARROLL (Jun 7, 2008)

Im going to say the evil M word. Mercury. There I said it. When used properly and I mean properly it will effectively seperate your gold from black sands. Then heat in a retort and recover the mercury for another use. A company on AZ is selling modern made retorts for about 130 bucks


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## Traveller11 (Mar 22, 2009)

Art,

I'm working on a placer deposit concentrated on the beach here by the ocean. There is no question as to how extremely rich this deposit is but, like your placer gold, it defies any attempt at gravity separation due not only to its microscopic size but also due to its flaky nature, almost foil like.

I am currently trying to gather information on an iodine leach as it seems to be the most selective and readily available of leaches and it is also seems to be somewhat safer than some of the acid based leaches.

Your idea about separation by means of a heavy liquid is very intriguing and, I must say, has crossed my mind more than once. The ideal liquid would have a specific gravity of at least 6.0 or 7.0; enough to make all of the sand, magnetite, hematite, pyrite, garnets, etc., etc., etc. float off its surface leaving the gold and PGM's at the bottom of the liquid to be filtered through a 50 micron filter.

Only fantasy to me up to this point, though, Art. 

What on earth is LST ??? (besides being a US Navy ship designed for beach landing Marines LOL)


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## Art Corbit (Mar 22, 2009)

OZ,

I'm not sure that it would pay but if a person did it right in the right place I believe it would. A good example is to have one of the filters running below a couple of dredges in the upper Arkansas River in Colorado. Very little of this super fine gold has ever been recovered. Even then how much you recover will depend on several things. The type of filter you use , how much water you put through it, the design of the water pickup, how far below the dredges you were and several other things. Most important is how much of the fine gold is suspended and traveling with the water.

To really answer your question a person would just have to try it and refine the operation to a point you are pretty certain you are getting all of the gold you can get. There is still a lot to be learned about this but I honestly believe it could turn a profit. I have done enough testing to know the carbon will collect the gold and as near as I can tell it collected at least most of what I put through it. The design of the filter and the speed you put the water through it has a lot to do with this part of it.

Art


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