# smelting fine gold for the first time



## dannymak

Hi, name's danny. I've spent the last few months reading about melting fine gold and seperating from black sands. Any advice is welcome. 
I have just recieved all the ingredients to make my own chapmans flux, (borax, manganese dioxide, soda ash and silica) i also have flourospar and lime 50/50 for a thinner. Is this correct for a start? I have a 1kg graphite crucible only. I gather i mix the cons and flux at a ratio of 1 part cons to 2 or 3 parts depending in the ratio in my cons. I don't need to line the crucible with borax using graphite yeah?

If this is all correct, the last thing I'm curious about is, do i have to do one big pour from the one batch or can i do little pours. I plan on using fire bricks with a few hand drilled moulds in them, hence why I'm asking can i pour into, say, 8 moulds?
Thanks in advance
Danny


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## butcher

I would separate the gold from the black sand mechanically, once separated I would refine the gold before melting, or just sell the gold as is.


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## dannymak

I've used a blue bowl and some of it is 100 mesh real fine cons. I still cant 100% separate the gold from the black sands, hence why i want to use flux to accomplish this. And i don't want to sell my gold. I don't see the point in exchanging something of value, (gold) for something that only has psychological value, (fiat currency).


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## butcher

If I cannot pan the gold from the black sand it is not worth my effort.


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## dannymak

Is your gold as fine as talcum powder but? I have panned larger gold with no problems, but this stuff round here is a headache. So i researched smelting with the black sands and the appropriate flux. Any tips? And what do you mean by seperate mechanically?


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## butcher

If the gold was as fine as talcum power, I would look into other recovery methods, tables, floatation...
Or even as a last resort leaching, as the iron will become a problem.

In any case I would concentrate the values before attempting any smelting process, smelting black sand with little gold, your gold will likely just be lost in the slag, in small beads if your lucky.
Smelting gold with very little black sand involved would work better to form gold button with a slag iron glass on top.

Gold here normally comes in nuggets, they can be very small, and as small as powder, and we can pan it (sometimes traces get by and can be collected in a tub, and collected in a second panning, but with good panning skills you can easily pan even very fine gold.
If your gold is that fine screening your materials for size will help, this way you are panning material of similar size with a wide variable of density...

If the gold is finer than black sand, and as fine as talcum powder, you may be able to run the gold through the screen with most of the black sand held back in the screen???

Adding dish soap can help to keep the fine gold from floating, very fine gold can float because of oils (even oils from your hands, or waters surface tension.

I have seen so many new miners who think the powder pyrite is gold, and wonder why they cannot pan it, or why it does not work when they try smelt it.

I am not saying that is a problem here, But are you sure what you are dealing with is actually gold?


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## dannymak

Definately gold mate. It sounds like it's too big a job to separate the gold from black sands using the smelting process. Does smelting not work this way?


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## butcher

If your trying to smelt black sands your dealing with mostly Iron ore, some magnetic and some nonmagnetic, the iron is in various states, roasting will help to improve the ore somewhat.
driving off acids and putting the ore in a better state for oxidation (or reduction).

The flux would need to be able to get the iron and other base metals to form a slag glass, the gold would need to be able to melt and combine into one mass of molten gold, fluxing has to be chosen to do several jobs at once, oxidize base metals to form slag glass of those metals, reduce or not oxidize the metals you wish to keep elemental and to recover as a molten mass or button, to increase the fluidity of the melt so that the fine gold particles can combine and melt together, and not just become trapped in the glass slag as small beads.

As I see it, smelting is a mechanical and chemical process that is using high temperature and the chemical reactions of the flux and ore to accomplish a task. To oxidize and form a metal-silica glass out of the unwanted metals and to reduce the wanted metals into a molten lump of metal.

Like other chemical reactions the type and state of the ore, the chemicals used (flux) and processes used, will make a big difference in what happens with the chemical reaction.

Will smelting be a good option to recover your gold from black sands, this is a hard thing to say if it will work or not, (basically impossible to judge from here, where I cannot even see what you have), there are many variables here, pretreatment like roasting, how much gold to the amount of black sands, would you need a collector metal involved in with your flux, to collect the gold in the melt. or would the gold to iron ratio be such that you can flux the gold to melt a molten combined lump of metal, and oxidize the iron into the silica glass.

What I can say without seeing what you have is that the better you can concentrate your gold, (separate the gold from the unwanted material or ore), the better you will have success with any type of recovery method you choose.

I would concentrate my time and energy on concentrating the gold, using the gravity methods, to separate the black sand as much as possible from the gold first before using any method of recovery either with chemicals or furnace.

The less trash you have to deal with, the easier the recovery of your gold will be, I would eliminate as much trash as possible mechanically as I could, before trying to use the furnace or chemicals to attempt at removing more trash. Or to recover the gold in proceeding steps, So your gold is not just lost in the melt of the trash, (or leaching process of the trash whatever the case may be).

If you melt gold with iron you can form an alloy, although the iron would fairly easy oxidize.

In the smelt with flux you can reduce or oxidize the iron from the black sand, the flux chosen and the properties of the ore involved, will make a big difference in what happens in the smelting process.

If you melt a lot of iron with very little gold your gold could be lost in the iron and the slag of the melt.

Smelting uses chemicals (flux), to oxidize or reduce metals, the chemicals (ingredients of the flux) have to be chosen for the chemical reaction you need to achieve, a collector metal may be needed to collect the gold from the melt, or you may be able to use flux to oxidize the metal into the slag away from the gold, the flux also has to improve the Flow of the melt, so that the metals can move or flow to combine in the melt and separate from the slag which is lighter.

Smelting like assaying ( or other forms of recovery) is a science and art, like with other chemical reactions you cannot just put a bunch of junk in a crucible with some chemical flux, or pot of acids and get out what you want without having a fairly good idea of how to do it, pretreatments can be very important, the higher the gold to trash ratio the better, the better you understand the reactions involved, and chemistry needed, the better you know how to do tests to see if changing the chemistry of the reactions, which may be needed to recover the gold from the process, the more skill you have in this...

You may get lucky by buying some ready made flux recipe, (from say action mining) and dumping it in a crucible with your black sand, and forming a gold button, but it may or may not work, you may or may not get all of the gold from the sand, or you could lose it in the slag, there are many variables involved.



Concentrate the gold first, separate it from the black sands mechanically. This would be my first goal, with less trash involved, what ever method you choose after that would make later recovery and refining processes of the gold much easier.


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## kurtak

dannymak said:


> I have just recieved all the ingredients to make my own chapmans flux, (borax, manganese dioxide, soda ash and silica) i also have flourospar and lime 50/50 for a thinner. Is this correct for a start? I have a 1kg graphite crucible only.
> Danny



That may or may not be the right flux mix - as Butcher said it depends on a number of things - there are a number of things that need to be done before you smelt (if you go that way) or before you chemical leach the gold (if you go that way) 

The first is to dry the black sand & separate the magnetic from the non-magnetic --- then roast each the magnetic & non-magnetic (as suggested by butcher)

when you get that far we can talk about what to do next

as far as the graphite crucible goes that is a very poor choice of crucible for smelting - the flux will destroy it in no time at all (they are ok for melting but not smelting - & I would not even waste my money on them for melting)

you really want something like this :arrow: http://www.morganmms.com/crucibles-foundry-products/crucibles/ultramelt/

or this :arrow: http://www.morganmms.com/crucibles-foundry-products/crucibles/salamander-super/ (wont last as long as the first choice)

or you could go with the cheaper clay "one shot" crucible - but I would put that inside one of the first two for insurance

It all depends on how aggressive the flux is & time/temp in the furnace

Also - for smelting you "need" a gas fired furnace --- you will destroy the elements in an electric furnace in no time at all

Kurt


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## montanacreations

Hello, First time posting but long time member, spent last couple years just reading and studying. Thanks to all of you involved with this forum, I have learned so much from you! Smelting gold cons is something I have spent a lot of time and money working on, and still trying to perfect. I have a hard rock gold mine here in Montana and dealing with free milling gold with some sulfides. It sounds like maybe you have read Chapmans smelting book, if so he is very specific about what can be smelted with his recipes, and smelting general gold cons from black sands is not something he recommends or has a flux for. Everything Butcher and Kurt are saying is true and apply fully, I would add that to smelt anything of value there needs to be the right percentages of gold and trash, the norm from what I have read and found is 30% gold is a minimum, or a collector needs to be added, I use silver. But if the 70% trash is black sands your still going to find that very difficult to work with, getting that to fuse or melt and be thin enough to separate and pour is going to be a challenge. When I first started out with placer gold it could sure look good in the pan with the black sands, but you will find that it takes a whole bunch of gold to make 30%. I have also found that I can only use silicon carbide crucibles as Kurt mentioned, graphite, clay, or fused silica may not make it through one smelt, I have made lots of messes! Also from my trials and tribulations, smelts need to be poured to a cone mold that will hold the entire smelt, that helps to collect all the metals if the flux is thin enough.
I am using a gold wave table for concentrating currently, that works very well on gold 100 mesh and smaller with close classifying. If you have any other questions I would be happy to share anything I have learned. 
Good luck,
Cliff


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## kurtak

montanacreations said:


> Also from my trials and tribulations, smelts need to be poured to a cone mold that will hold the entire smelt, that helps to collect all the metals if the flux is thin enough.
> 
> Cliff



Cliff

Thanks for adding to what Butcher & I have already said - I was going to mention the "need" for a cone mold when smelt but somehow spaced it out - thanks for catching that

Hope we will hear more from you now that you posted your first post :lol: 

So is your hard rock mine a full time deal or a part time hobby kind of thing ?

Kurt


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## montanacreations

Thanks for the welcome Kurt, I have been a full time miner for a shaft sinking company until I had to get a full neck fusion a couple months ago, so will be laid up for a couple more months. My father and I have ran ours hobby level up till now, hoping to at least start paying for our hobby at some point soon, or at least our wives think we should! We will be pretty limited as far as any surface disturbance, everyone wants the entire state of Montana to be a national park. I also live in the most restricted national forest (Kootenai) do to the grizzly, bull trout, lynx etc. so permitting is very difficult. I have got to run for now but will go into more detail later what we have tried and where we are at today, been a long road and a limited budget so been very interesting.
Cliff


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## kurtak

montanacreations said:


> Thanks for the welcome Kurt, I have been a full time miner for a shaft sinking company until I had to get a full neck fusion a couple months ago, so will be laid up for a couple more months. My father and I have ran ours hobby level up till now, hoping to at least start paying for our hobby at some point soon, or at least our wives think we should! We will be pretty limited as far as any surface disturbance, everyone wants the entire state of Montana to be a national park. I also live in the most restricted national forest (Kootenai) do to the grizzly, bull trout, lynx etc. so permitting is very difficult. I have got to run for now but will go into more detail later what we have tried and where we are at today, been a long road and a limited budget so been very interesting.
> Cliff



Cliff

That is some absolutely awesome country - I lived in Spokane for about 5 years - I am a country boy all the way & that was the one & only time I lived in a city of any (city) size --- hated it - So spent my week ends up around Naples, Bonners Ferry & north to the border & managed to get over to Troy & Libby a few times

I know what you mean by the restriction thing - I lived in the Salmon Trinity Alps of the Klamath N. F. in Northern California for about 20 year & worked mostly as a logger but also did a lot of mining (both placer & hard rock) & was put out of work because of the spotted owl

What gets under my skin about the people that don't want a tree cut, ground moved or hole drilled (for oil) is that they want their car (iron & oil) & house (wood) wired (copper) & computer (gold) but then with a loud mouth demand restriction & even shut down of the industry that provides it all

Don't get me wrong - I believe in the practice of sound environmental management of resources - but they want more then that - they forget that the National Forest belong to ALL the people - which includes the resources that build economies --- Our National Forests don't belong JUST to the people that like to camp, hiker & fish

Its like a vegetarian tell me I can't kill anything because I like steak with my potatoes - but they don't

Ok - enough of my rant - here are some pictures of when I lived in Northern California that you might enjoy :arrow: http://goldrefiningforum.com/phpBB3/viewtopic.php?f=67&t=21401&p=220853#p220853 

Edit to say: - by the way the pic to the left of the pic of me on the horse with the pack mule was an old hard rock mine - it was about a mile off the road & we couldn't punch a spur road down to it so we were using horses & mules to pack the ore out - it was running 3 - 4 ozt/ton 

Kurt


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## montanacreations

I live in Libby, and our mine borders the Cabinet wilderness area. Born into a logging family and community, all has been pretty much shut down, not one mill left in Lincoln county. The only mine working in the area shut down last week do to low metal prices, that is also why I would be called a tramp miner, worked mostly out of state. It is very sad to see where we are headed with this new thinking, no common sense left. There are to many laws on the books today to rape and pillage the country as far as the mining or logging ways of the past. Just wait for a bad fire year and you will see the entire northwest up in flames, there is so much dead and dying timber here do to the pine beetle.
Our mine was the richest in its day in the area, but was never fully developed do to the lack of oxidized ore, flat bed veins and its location. We can get to it with side by sides but that's about it, no trucks. This mine has been mined since the late 1800s so lots of the ore has seen a lot of oxidation since then, has made for some very pretty specimen pieces. The old timers dumped the sulfides, that is looking to be some of the very best ore without finding a pocket on vein. We have all the past smelter returns and some assays as well as our own, icp ms, etc. They had hit some very rich ore in places, we have been mainly doing cleanup and getting vein exposed and re-supporting as we go. I attached a couple pictures, need to get better equipment for close ups.


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## dannymak

Yep guys, I am screening my cons, 50, 70 and 100 mesh. I use a black sand magnet but have now ordered a super earth magnet for the less magnetic ore. I'm still getting used to the blue bowl and am getting better at separating the cons. I'm also thinking of taping the wife's vibrator to the bowl to assist with this.
I am making a cone mould out of metal. I have read that you need to line it with graphite powder to stop it sticking. Is this true?
Also on the smelting topic, I've read some guys soaking their black sands/gold in citric acid. And one comment I read one fella put rubbing alcohol in the mix just before smelting? 
Thanks again for the imput guys, I'm learning heaps and as the rest of you, want the best results. I looked at the above links regarding crucibles but the site wouldn't allow a hotmail address. EBay doesn't have them either. Any other places have these crucibles?

I live in Australia in gold territory, close to a gold mine. There are nuggets here but more so fine alluvial gold. I'll work on getting the most concentrated gold i can, so my last question is can i just use straight borax as a flux to bind the gold, and if i put one of my small nuggets into the mix will that help the rest of the gold form together?
Oh and does stirring help too? (i have a graphite stirring rod coming soon)


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## montanacreations

Morning, I have found with my ore that I also use a 150 and 200 mesh screen, 200 is very slow going though, for small amounts its fine. A very good free web site I have found is www.goldhog.com, they are selling some products but have over a 100 free videos with very good info on final cleanup of gold cons etc, they go in depth into the science behind gravity separation I found very interesting. One of their videos is on hydraulic equivalence, very interesting. I am currently using their sluice matting and very impressed with the results, collecting the larger free gold from my crushing before over grinding in my rod mill. 
I personally found the blue bowls to be very touchy and any placer that is very flat will be lost, close classifying is very important with a blue bowl from my findings.
As far as a mold release I only use acetylene smoke, works very well if you have a torch set, just smoke it up a bit. I buy my Silicon carbide crucibles from Legend, http://www.legend-reno.com/, these are not cheap, a #4 is about $115 US, that's the smallest they sell. 
I have tried several methods of pretreatment of black sands, roasting is a good start if you can do it safely, same with all the acids, it just depends on what is in your black sands that may cause you problems. With patience though and some simple techniques like from gold hog you should be able to get pretty clean gold without dealing with to much black sand. What little gold you cant get out of black sand just save until you can run on a table or something.
As far as fluxes it just depends on whats in with your gold, if your gold is real pure borax may be all you need, I personally would still use a flux combination. If you don't care about silver being left you can use a chapman flux recipe which would use borax, soda ash, and silica, if you want to remove silver chapman has a flux for that also. I don't have my book in front of me if you want an exact flux, I can get it for you tomorrow. The silica would help to keep the flux from eating your crucible.
Take care,
Cliff


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## kurtak

Cliff

Thanks for the Gold Hog link :!: I just skimmed it so far - they have some interesting mats - will have take some real time to look the site over better

I have Legends hard copy catalog & yes they have a lot of good stuff as well 

By the way - that is some real nice looking ore :shock: :mrgreen: 8) 

Kurt


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## butcher

montanacreations,
Welcome to the forum, thanks for sharing, and helping out on the forum.


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## montanacreations

Thanks Butcher, spent a lot of years reading your posts, have really appreciated your knowledge and the others that contribute to this site.


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## butcher

It has been a shame you have not joined in on the conversations before now, I learn from everyone on the forum, you could have helped me with your experience, even your trials and errors, well now that you broke the Ice, and decided to join in on the chatter, I look forward to reading and learning from you also.


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## montanacreations

It has been good for me to spend what time I had available listening and learning, guess I was raised that way. I am trying to do the entire process our selves as we cant produce enough concentrate to sell at this point, and may never be able to get to that level. So learning the chemistry side of this has been really interesting and fun, want to be able to just sell to a refiner at some point with somewhat clean metals, smelters are about a thing of the past for small scale operations. Our sulfides carry a lot of value but pretty complex, so finding myself at a point where I need to get more involved and start asking educated questions hopefully! Thanks again for all the info and help available on this forum.
Cliff


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## Lindowitz

Maybe the aqua regia method could help?


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## Lindowitz

https://sciencenotes.org/aqua-regia-definition-and-preparation/

I've only read of it in passing. But I think it is dangerous yeah but it could help.


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## galenrog

Using aqua regia on ore of any kind is foolish, and possibly dangerous, without first knowing exactly what your ore consists of. Same goes for placer concentrates. Very toxic gasses can easily form from a variety of materials present in ore. Compounds that are difficult to remove can also be produced, making recovery and refining a lengthy and wasteful process. Do some study, with real books, on mining, recovery, and refining of precious metals. This forum has a plethora of information, but Neanderthals like myself prefer hard copies.

Time for more coffee.


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## Yggdrasil

Galenrog, he is commenting a 6 years old thread in his 2 first posts.

Lindowitz, listen to the advice you are given.
It is wise to read and learn first, and this forum will give you the opportunity to learn most within refining of precious metals, but it will take dedication and effort.


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## galenrog

Yggdrasil said:


> Galenrog, he is commenting a 6 years old thread in his 2 first posts.
> 
> Lindowitz, listen to the advice you are given.
> It is wise to read and learn first, and this forum will give you the opportunity to learn most within refining of precious metals, but it will take dedication and effort.



I know he was replying to a six year old post. Since I was feeling charitable, I did not bring it up.

Lindowitz, now that Yggdrasil has brought it up, why were your first two posts in response to a six year old post? 

Time for more coffee.


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