# separating gold "dust" from firing flux



## jmelson (Feb 27, 2007)

I have crunched up the blobs of flux after firing some precipitated gold in the crucible, and picked out the larger beads of gold with tweezers. Is there any way to "sluice out" the gold from the flux, or should I pan it as best as I can and then put it back in the crucible and fire it again? I have used strong acid to dissolve as much of the flux as will burn up that way, but what is left is basically glass and crumbs from the crucible. I can see a fair bit of gold in there, but it is very sub-mm specks.

Thanks for any ideas!


----------



## Noxx (Feb 27, 2007)

Wich kind of flux it is ?


----------



## Noxx (Feb 27, 2007)

Hello Jon,
Try separating your powder in small groups... Wich kind of crucible are you using ? I think you have this problem because your torch isn't able to get the powder reach the melting point of gold (+1000°Celcius). Try melting it in smaller amounts. Also, just try using borax as flux for begginning if you think your gold is pure anough (if you got a bright brown powder when precipitation occured). 
Wood Charcoal is a good for a one use crucible... it holds and reflects temperature very easily. Especially if you are using an hotter gas than propane.


----------



## lazersteve (Feb 28, 2007)

Jon,
Noxx is right, lots of heat is required. Practice using the torch in a circular motion when melting, starting from the top lip of the cupel (small 1-2" shallow bowl) and working your way inward to the middle. The gold BB's will appear green thru the torch goggles as you chase them together with the torch. If you are not using small cupels you should obtain some to help focus the heat into a smaller area. A larger crucible (the size of a small styrofoam cup) absorbs a lot of heat and hinders the golds melting. I find that by working the BB's into the center of the cupel they sink to the bottom and merge into a button. At this point I can pour off some of the excess flux using a set of metal tongs while the cupel is still hot. Then I grab the button out with a set of dental tweezers before the flux turns to glass. I put the hot button into a fresh cupel and remelt to purge the last bit of flux into the cupel and to pour the gold into a rod mold.

Steve


----------



## jmelson (Feb 28, 2007)

Noxx said:


> Hello Jon,
> Try separating your powder in small groups... Wich kind of crucible are you using ? I think you have this problem because your torch isn't able to get the powder reach the melting point of gold (+1000°Celcius). Try melting it in smaller amounts. Also, just try using borax as flux for begginning if you think your gold is pure anough (if you got a bright brown powder when precipitation occured).
> Wood Charcoal is a good for a one use crucible... it holds and reflects temperature very easily. Especially if you are using an hotter gas than propane.


Oh, it melts, all right! it gets white hot, and I have to use dark goggles or the light is blinding. I bought 10 little clay crucibles. I am using Oxy-Propylene, it gets as hot as acetylene, and transfers even more heat.

The problem with straight borax (or this "Anti-Borax" stuff I have) is that it is
so thick even when orange hot that I can't pour it out of the crucible. So, using a fire assay flux recipe I found on another site, I use a mixture of borax and washing soda, which pours much more easily. Sometimes I get one beautiful button, and no stray gold. Other times I get lots of tiny round beads that were not there before, so the gold IS melting, it just isn't coalescing into one button.

Jon


----------



## jmelson (Feb 28, 2007)

lazersteve said:


> Jon,
> Noxx is right, lots of heat is required. Practice using the torch in a circular motion when melting, starting from the top lip of the cupel (small 1-2" shallow bowl) and working your way inward to the middle. The gold BB's will appear green thru the torch goggles as you chase them together with the torch. If you are not using small cupels you should obtain some to help focus the heat into a smaller area. A larger crucible (the size of a small styrofoam cup) absorbs a lot of heat and hinders the golds melting. I find that by working the BB's into the center of the cupel they sink to the bottom and merge into a button. At this point I can pour off some of the excess flux using a set of metal tongs while the cupel is still hot. Then I grab the button out with a set of dental tweezers before the flux turns to glass. I put the hot button into a fresh cupel and remelt to purge the last bit of flux into the cupel and to pour the gold into a rod mold.
> 
> Steve


I'm using these TINY clay crucibles. They are actually smaller than a cupel, but deeper. If you know what a 10 ml beaker looks like, the inside dimensions of these crucibles are about that size. I use a pair of pliers to
tilt and turn the crucible, and eventually pour it out. When I get the flux thin enough to move, I can usually pour the flux and gold out onto an aluminum plate. The gold and flux won't stick to it. I then crush the flux with the pliers to see if there are any glod beads inside. Sometimes there's a big one, other times I can't even see the gold dust. But, when I put the crunched flux in a vial and add a little acid and let it sit a while, the gold dust sinks to the bottom, and most of the flux dissolves.

I have some cupels here, I might have to try your two-step technique.

Jon


----------



## Harold_V (Feb 28, 2007)

You guys are chasing your tails. This subject is a no-brainer. 

Assuming you can get a reasonably clean melt, the entire mess, flux and all, should be poured into a small cone mold. Assayers used them routinely. If the flux has done its job, the gold will be one nice button in the bottom with the flux cover on top. You tip it over and the button drops out easily, and is then quickly cleaned of flux. Stubborn flux can be removed by boiling in sulfuric acid and water. If, by chance, the gold hasn't agglomerated totally, it's because your flux is too contaminated, or you didn't get the entire lot hot enough. Dark flux is an indicator of very dirty metal being melted. Pure gold won't discolor the flux aside from colloidal gold turning it purple. 

There are some things you need to understand about fluxes before you get involved with some of these mixes. First off, soda ash is a reducer, so almost any oxidized element that is included with your gold will be reduced and included in the final product. Borax works the opposite, and absorbs oxides. When borax comes out thick and dark, it's because you are working with very dirty material---lots of crud for it to absorb. The addition of fluorspar will thin the flux, but it is very aggressive and destroys dishes, crucibles and furnace lining quickly. Don't breath the fumes if you use it. 

I rose bud is very desirable for dish melting. If you're serious about refining, consider buying one. Jewelry supply houses sell a very nice one.

Rather than make additional posts, there's one more thing you all need to come to terms with. That's the purity of your metals. 

The systems you are talking about are recovery systems, they are NOT purification systems. The cast bars, for example, have a terrible color. There is no doubt they are far from pure------and should have been refined before melting the extracted values. It's far easier and faster to dissolve the gold while it's finely separated-----and until you do so, your gold won't be marketable as pure. While it can be accomplished in an electrolytic cell, the aqua regia method works very well, and should be assimilated into your operations. You'll come to terms with it, just as I did when starting out. I had hoped to short circuit the entire operation, but soon came to realize that I wasn't getting pure gold. 

Harold


----------



## lazersteve (Feb 28, 2007)

> Rather than make additional posts, there's one more thing you all need to come to terms with. That's the purity of your metals.
> 
> The systems you are talking about are recovery systems, they are NOT purification systems. The cast bars, for example, have a terrible color. There is no doubt they are far from pure------and should have been refined before melting the extracted values. It's far easier and faster to dissolve the gold while it's finely separated-----and until you do so, your gold won't be marketable as pure.



The 50 grams of gold in the rods was recovered from fingers about nine months ago and sold to a precious metals refinery for 98% of spot price at the time. The precious metals dealer contacted me with the results of a fire assay and stated the gold in the rods was greater than 99% pure. The color in the photo is not the way they looked in real life, they are actually very yellow. The photo makes them appear reddish. I've sold several ounces of gold to various buyers and all have been very pleased. I realize they are not 100% gold, but I'm very pleased with the fruits of my labor considering I'm only doing this for fun as a hobby. The main reason I recover gold is so that I'll have a retirement fund when I'm ready to quit working. 

I've read about assayers using conical molds with gold using lead or litharge as the flux in the same fashion described by Harold. 

On the subject of Aqua Regia, I started out using it and really don't want anything to do with all the hazards. The chemicals and methods I use now can be handled safely indoors and produce results that please me. Harold you are right, I may end up coming around full circle and start using AR as a final purification step to attain the fully refined gold you speak of.

Thanks for all the good advice,

Steve


----------



## Noxx (Feb 28, 2007)

Wich method are you using steve ?
Renverse electroplating ?


----------



## lazersteve (Feb 28, 2007)

For fingers I use an acid peroxide mix. For larger connectors and pins I use reverse electroplating.


----------



## Noxx (Feb 28, 2007)

I never heard acid peroxide mix... It is made of what ?


----------



## lazersteve (Feb 28, 2007)

It's a method I developed myself to get past the hazards of AR while still getting maximum yields with mimimal effort. I worked up the ratios by trial and error. After working out the details, I fine tuned the process buy researching college web sites. I've put together a pdf file of etchants from several of these sites. Email me and I'll send it to you. The acid is standard muratic acid (HCL) and the peroxide is just the household variety (3%).


----------



## Noxx (Feb 28, 2007)

PM sent.


----------



## NaNO3 (Feb 28, 2007)

jmelson

Sounds like you need to add a little silica sand or smashed glass and some more Borax


----------



## Noxx (Feb 28, 2007)

What does silica sand adds ? Never eared about it.


----------



## NaNO3 (Feb 28, 2007)

.....


----------



## Noxx (Feb 28, 2007)

Where can I get Silicia ? And can I substitute Sodium Nitrate with Potassium Nitrate ? I have 25 lbs of kno3 lol. :lol:


----------



## jmelson (Feb 28, 2007)

Harold_V said:


> If, by chance, the gold hasn't agglomerated totally, it's because your flux is too contaminated, or you didn't get the entire lot hot enough. Dark flux is an indicator of very dirty metal being melted. Pure gold won't discolor the flux aside from colloidal gold turning it purple.
> 
> There are some things you need to understand about fluxes before you get involved with some of these mixes. First off, soda ash is a reducer, so almost any oxidized element that is included with your gold will be reduced and included in the final product. Borax works the opposite, and absorbs oxides. When borax comes out thick and dark, it's because you are working with very dirty material---lots of crud for it to absorb.


Thanks again, Harold! This sure is true, because I haven't done things right.
But, the gold IS coming out pretty clean in the end. So, when it doesn't all melt into one button, it was because there was too much base metal in the mix?


> I rose bud is very desirable for dish melting. If you're serious about refining, consider buying one. Jewelry supply houses sell a very nice one.


I have one, but have not tried using it on the gold.


> Rather than make additional posts, there's one more thing you all need to come to terms with. That's the purity of your metals.


OK, I know you are right about this. I haven't figured out how to get HNO3
without having a visit by homeland security, but I will have to find out how.

I'm still trying to get the precipitation step to work properly. I'm going to run another batch this weekend, I hope.

Thanks,


----------



## NaNO3 (Feb 28, 2007)

...


----------



## Noxx (Mar 1, 2007)

Where do I buy it ?


----------



## Harold_V (Mar 1, 2007)

jmelson said:


> But, the gold IS coming out pretty clean in the end. So, when it doesn't all melt into one button, it was because there was too much base metal in the mix?



Not necessarily. If the flux can absorb the majority of crud, the metal, regardless of degree of purity, often will come out bright and shiny. As long as you isolate it from oxygen, it has little reason to discolor. 

My experience indicates that flux is usually too viscous, which discourages gravity from helping form a uniform button. Just adding fluorspar to the heat will often be more than enough to allow the beads to agglomerate, as will the addition of soda ash. Soda ash, like fluorspar, is rather aggressive and dissolves your dish in the process, so use it sparingly. It's an excellent way to clean a dirty dish, by the way. Get the dish red hot, then introduce soda ash. As it melts, the dark residual flux will start to dissolve, leaving behind droplets of metal, and a clean dish. When you've added enough soda ash to clean the dish, add some borax, then pour the entire heat off into a cone mold. 

Remember that you get metal back. Don't toss old melting dishes, which always contain values, even though you can't see them. 



> (about a rosebud)
> I have one, but have not tried using it on the gold.



I used mine with natural gas----not acetylene. You have to be careful that you have a functional flame before introducing it to the dish. If it pops, you can blow the contents away. It doesn't take very long to get used to the proper setting. I melted lots up to 10 troy ounces that way----rarely used my melting furnace when inquarting. Too slow and cumbersome when I could get the material inquarted and poured into shot in less time than it took to fire the furnace. 

Harold


----------



## Harold_V (Mar 1, 2007)

Noxx said:


> Where do I buy it ?



If all else fails, masonry supply stores usually have it in 100# bags. Ask for silica sand. 

Harold


----------



## Harold_V (Mar 1, 2007)

lazersteve said:


> The precious metals dealer contacted me with the results of a fire assay and stated the gold in the rods was greater than 99% pure. The color in the photo is not the way they looked in real life, they are actually very yellow. The photo makes them appear reddish.



I should have considered that possibility, Steve, and I apologize if I said anything to disturb you. It was not meant that way. To be very honest, it was the color that triggered my comments. Pure gold comes out yellow, and requires no cleaning of any kind to brighten it. If pickling brightens gold, it's because oxides are being removed from the surface. That's a sure sign of contamination. 



> I'm only doing this for fun as a hobby. The main reason I recover gold is so that I'll have a retirement fund when I'm ready to quit working.



I, too, started out with that idea in mind. It was illegal to refine when I got started, but the law was changed shortly thereafter. Several people got a laugh when I told them what I was doing----but you might imagine who got the last laugh. I retired when I was 54. Refining made it possible.



> I've read about assayers using conical molds with gold using lead or litharge as the flux in the same fashion described by Harold.



They work so well that I made a pattern and had a larger version cast in ductile iron. I also had an even larger one cast from a borrowed cone mold, this one about 12" in diameter. It's the only way to separate values from flux effectively. 



> On the subject of Aqua Regia, I started out using it and really don't want anything to do with all the hazards. The chemicals and methods I use now can be handled safely indoors and produce results that please me. Harold you are right, I may end up coming around full circle and start using AR as a final purification step to attain the fully refined gold you speak of.
> 
> Thanks for all the good advice,
> 
> Steve



Indications are you've come up with a system that is rather impressive, and yields gold of acceptable quality. You may not have need as long as you're selling to a refiner. A bench man might not enjoy gold that has traces of the wrong material involved. Lead, for example. It's death on the ductile qualities of gold. To insure that I didn't dispense gold of questionable quality, it was always double refined. I always exceeded the industry standard of 9995. In order to make the second refining worthwhile, I'd hold first run gold until I had a large quantity, then refine it in several 75 ounce lots all at one time. That was a good amount to precipitate in a 4,000 ml cylinder, assuming I started out with the vessel filled with ice. 

Harold


----------



## shadybear (Mar 1, 2007)

So what are the specs and info on this secret acid-peroxide method?


----------



## Noxx (Mar 1, 2007)

I will tell you in few days when I will find how lol.


----------



## lazersteve (Mar 1, 2007)

Hey Guys,

Follow the chart below to see the proper chemical formulas and ratios.

Remember this material is copyrighted ( not by me ).

I've done some work using these formulas and they are definitely accurate. I have more specific information for those who are interested in the 'SUPER SECRET' Chlorine Water Method!!!







Pay close attention to the Dissolution Rate Column, it shows that the peroxide method is nearly triple the effieciency of the Cyanide ( eeek!! ) Method, while the Chlorine Water method is a full 45 times faster than peroxide, of course the "Buzz Saw" of gold is good old Royal Water aka. AR (Aqua Regia)!

Enjoy,

Steve


----------



## Noxx (Mar 1, 2007)

Steve ! I want to know the SUPER SECRET of chlorine water ! Please.
Thanks a lot.


----------



## lazersteve (Mar 1, 2007)

This post has slowly drifted off the original topic. I'll start a new one under the Refining/ Recovery Techniques.

Noxx, 
Here's a sample of what you can do to a 486 cpu using Acid Peroxide:






Steve


----------



## Noxx (Mar 1, 2007)

Lol so crazy. I love it.
We'll talk in your other post, thanks.


----------



## PRECIOUS METALS (Mar 3, 2007)

lazer steve hold the secret ,ok what would it take to get step by step instructions ,lets trade secrets


----------



## TXWolfie (Sep 22, 2011)

lazersteve said:


> It's a method I developed myself to get past the hazards of AR while still getting maximum yields with mimimal effort. I worked up the ratios by trial and error. After working out the details, I fine tuned the process buy researching college web sites. I've put together a pdf file of etchants from several of these sites. Email me and I'll send it to you. The acid is standard muratic acid (HCL) and the peroxide is just the household variety (3%).



Steve just out of curiosity does the percentage of peroxide matter. I have seen products with percentages up to 40% instead of the store 3% type


----------



## Geo (Sep 23, 2011)

TXWolfie said:


> lazersteve said:
> 
> 
> > It's a method I developed myself to get past the hazards of AR while still getting maximum yields with mimimal effort. I worked up the ratios by trial and error. After working out the details, I fine tuned the process buy researching college web sites. I've put together a pdf file of etchants from several of these sites. Email me and I'll send it to you. The acid is standard muratic acid (HCL) and the peroxide is just the household variety (3%).
> ...



sorry, im not steve , but i can answer that one. 3% is just fine for the purpose of acid/peroxide. the only difference of adding more O2 than 3% is more of your gold will go into solution before the reaction starts. remember the objective is to separate the gold from base metal instead of dissolving gold during this process.. the addition of peroxide to the solution is to jump start the creation of copper chloride. hcl acid alone will not dissolve copper and etching will only occur in the presence of copper chloride. ok, as i understand it hcl+H2O2 makes copper produce copper oxide and hcl will convert copper oxide into copper chloride which in turn will dissolve copper in the presence of oxygen so unless you want to spend alot of time agitating the solution and adding H2O2 periodically, you will need to add an air supply.


----------



## TXWolfie (Sep 23, 2011)

Geo said:


> TXWolfie said:
> 
> 
> > lazersteve said:
> ...


That answered my question, thank you Geo.


----------



## asimbilly (May 10, 2012)

hi can any help me plz


----------



## Geo (May 10, 2012)

asimbilly said:


> hi can any help me plz



with what?


----------



## Harold_V (May 11, 2012)

asimbilly said:


> hi can any help me plz


A couple things you need to know if you hope to survive on this board.

Do NOT use text message lingo. I'll ban you in a heartbeat if you persist. When you post on this forum, speak in clear, concise English, to the best of your ability, so readers don't get the wrong message. 

It is very important for you to learn the basics of refining before you can hope to benefit by asking questions. You can do that by downloading a copy of Hoke's book, and by reading the forum, so you become familiar with terminology that is used routinely in refining and the discussion of processes. If you receive advice on processing without that basic knowledge, that will lead to you asking more and more questions, and you won't be able to process what you have. There is no shortcut---you must apply yourself and learn the ways of refining. We help those who help themselves---and often chase off those who refuse. 

Harold


----------



## Dravin (May 11, 2012)

Noxx said:


> Where can I get Silicia ? And can I substitute Sodium Nitrate with Potassium Nitrate ? I have 25 lbs of kno3 lol. :lol:



hi Noxx, from my research it would work out just fine. Same ratio aplies to k as it does to na.


----------

