# Gold Powder + ingot



## Noxx

Here are two pictures of gold powder who has been refined two times and HCl washed.


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## Harold_V

What are you using for precipitation? 

The color is quite unusual as compared to that which I generally achieved. Not implying that yours isn't clean----just different in appearance. 

I used SO2 from a bottle. Twice refined gold consistently came down a very light tan color. It also came from a very heavily concentrated solution, commonly 17 or 18 ounces in 4 liters. That alone may have spelled the difference. 

Anyway, well done, Noxx. How much does it weigh?

Harold


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## Arcani

will refiners take it like that?(i know u have other plans for it)just wondering :lol:


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## Noxx

Harold, 
I used SMB. Maybe the concentration difference can alter the powder color. It was 10,380 grams initially and I ended up with 10,041 grams.

I succeeded to pour a relatively nice ingot today of 1/4 oz. Unfortunately, I haven't took any pictures yet.


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## Noxx

I also made my AR using Potassium Nitrate. Do you think the resulting salt (KCl) can affect gold quality ?


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## peter i

Smaller particles, darker look.

Very fine metal powders are generally black.


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## Noxx

Yes, the precipitation was very fast (in a matter of minutes). If I remember correctly, fast precipitation means smaller particles.


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## skyline27

I have always shot for lighter, tan powder. Is it possible to achieve high purity with other colors?
(I'm talking cleaned powder, not freshly dropped dirty powder)


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## AKDan

Using SMB mine comes down about the same color. Did you use urea to neutralize your AR, or boil down? The stuff I get that looks the same sure melts down nice.


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## Lou

In general, gold has a marked tendency to agglomerate into larger pieces when it is very pure. 


Concentration and temperature of solution, reducing agent, and the timespan of precipitation all can affect how it agglomerates and what exactly it looks like.

Any of the pure gold I've ever made has been a very light brown. That's not to say that darker powders are no good, it's just that every bit of 99,99 fine I've ever done has been a light brown.


Lou


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## Harold_V

Lou said:


> Any of the pure gold I've ever made has been a very light brown. That's not to say that darker powders are no good, it's just that every bit of 99,99 fine I've ever done has been a light brown.
> 
> 
> Lou


I recall that my finest quality was always a very light color, but I firmly believe that the precipitant plays a big role in how the gold comes down, as does concentration and temperature. 

A good example is when I'd precipitate large volumes. Starting with one liter of gold solution, I'd add ice to increase volume to nearly four liters. That was necessary, otherwise the gold wouldn't precipitate. It appears it's an exothermic reaction, so unless the heat has a place to go, it doesn't happen. On occasion, I'd have a little more gold than I normally would, so the solution, which started out being heavily iced, was heated to the point where the SO2 I used failed to precipitate the last bit of gold. I'd add a little more ice, then start the gas flowing once again. The resulting precipitation was always a darker color, very different from the earlier material. 

Harold


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## Noxx

Then how could I achieve higher purity gold ? This powder has been refined twice and also HCl washed. Maybe I'm missing something ?

I used fertilizer grade urea to neutralize the acid. The urea was quite dirty but I filtered the solution before precipitation.

Maybe next time I should try to evaporate the nitric instead of using urea. The thing is, it's hard to evaporate when you use an erlenmeyer and it's cold outside. The vapours tend to condense on the cold pyrex and fall back in solution.

Thanks


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## Noxx

Here are two pictures of the ingot I made. (I used 7,5 grams of 10 grams)


[img:640:480]http://goldrefiningforum.com/images/lingot%20005.jpg[/img]

[img:640:480]http://goldrefiningforum.com/images/lingot%20006.jpg[/img]


Sorry, I can't take better quality pictures...


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## Arcani

2 nd pic is nice and sharp, looks good. where u get a ingot that small?, u make it?


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## Harold_V

Noxx,

I'm of the opinion that your gold is actually quite good. Did it form any signs of oxide? If not, and you melted it in a clean dish, which remained clear of color, I think you've nailed it-----at least industry standard.

My comments were directed more towards the difference in precipitation with different reagents and processes. I fully expect that each one will yield gold of various configurations and color, and your batch seems to bolster my thoughts. 

Even the same process, over and over, varies. I recall, on at least two occasions, precipitating re-refined gold with SO2 that came down with noticeably large crystals. They glistened, which is very unlike the brown powder most of us see routinely. 

While I don't explain how it happened, nor could I control when it happened, about one precipitation in twenty, I'd introduce the SO2 to my cylinder of solution and ice, and watch it start to lose color, although no gold would form. Suddenly, the entire cylinder resembled gold paint, with the solution flashing back to a gold chloride color, filled with minute particles of gold. It was something to behold!

I don't know that urea is creating any problems for you, Noxx. I never used it, but that was just because I learned refining by a different method. Assuming you have clean material, I don't imagine it's lending any impurities to your gold. Frankly, I think you did real well. Your quality appears to have improved markedly since I joined the group. 

Keep up the good work,

Harold


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## Harold_V

Noxx said:


> Maybe next time I should try to evaporate the nitric instead of using urea. The thing is, it's hard to evaporate when you use an erlenmeyer and it's cold outside. The vapours tend to condense on the cold pyrex and fall back in solution.
> 
> Thanks


Assuming you do explore evaporation, don't use an Erlenmeyer. I started out using evaporating dishes, but soon came to realize that if I used Griffin beakers, I could stay with them start to finish, changing only when I filtered the chloride solution. Even then I used a Griffin, but one that was unscratched. That's was to prevent precipitated gold from sticking. It seems to have an affinity for scratches, and fastens to them quite well. Remember, I precipitated with SO2 from a cylinder, from concentrated solutions. The sticking problem may not manifest itself by other methods. 

By using a Griffin beaker, you can keep it covered well with a watch glass while dissolving, preventing the loss of values, then remove the watch glass when you evaporate. It goes quite well--although maybe not quite as fast as it might in a proper evaporating dish, which would present a larger surface area. Once I was accustomed to using beakers, I used evaporating dishes only for force drying my silver.

Harold


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## Noxx

Arcani, I bought the mold on eBay for around 20 bucks. You can still find it. 

Harold, 

My «melting dish» didn't show any coloration, borax stayed clear.

In fact, I used a disposable melting dish, that's how I call them. They are just a piece of kaowool (insulating blanket) covered with a layer of refractory cement. They are pretty efficient, I can melt gold under a minute using a MAPP torch. The wool stays warm even after a melt.
Take a look at my setup.

[img:1704:2272]http://goldrefiningforum.com/images/lingot%20003.jpg[/img]

[img:2272:1704]http://goldrefiningforum.com/images/lingot%20004.jpg[/img]

It's far from being perfect but it works ok.

I'll try next time to bubble some SO2 instead of using SMB.

Also, imagine if I redissolve everything then use some Butyl Diglyme !
I'm pretty sure I could achieve 99,99+% purity.

Thanks Harold, you helped me a lot to improve my gold quality, especially with your HCl wash technique.


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## Absolutsecurity

Cleaner chems, cleaner glass = cleaner gold!

Mine percipitates light brown the first time! 

DIRT IN DIRT OUT!

Clean up what your refining and it will come out cleaner - try inquarting with silver first and take the silver into solution with 50/50 nitric water (tech grade nitric) & (distilled water), The nitric will also carry the contaminants that the HCL doesnt want to disolve - thats if you are refining Karat gold. 
Try some of the other processes other than the poormans AR unless you can get tech grade acids - you might have a cleaner outcome

I allways use distilled except for washes - that is because there are a lot of minerals in the water here as well as chems


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## Harold_V

That all looks real good to me, Noxx. The flux is as you said, and that's usually a good indicator that the gold is pure. Those two beads sitting near look absolutely beautiful, by the way! Just keep on keepin' on. You're doing very well!

If you're comfortable with SMB, I wouldn't even think of changing to SO2 from a cylinder. No need, really. It was more convenient for me, but I don't think it was any better, just different. 

Harold


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## peter i

If you have ever tried to add SMB to pure acid, you will have experienced the evolution of SO2.
:shock: 

The reaction is:

NaHSO3(aq) + H+ ---> *SO2*(aq/g) + H2O(l) Na+(aq)

So in fact, it's just a question of having your SO2 in a cylinder or as a powder.
In both cases, add until everything has precipitated, then stop. Adding more will do no good.


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## Harold_V

While I didn't understand the reaction, I knew that it yielded SO2----which is why I suggested that staying the course was more than acceptable. 

When I started refining, I used copperas (ferrous sulfate). I realized I was adding iron to the mix, and figured it might not be in my best interest, so I investigated buying a cylinder of SO2. Turns out, at first, it was no big deal------but some time later, my supplier quit carrying the product. I found a second source and continued using the prepared gas. It got to be habit, and was easy, so I stayed with it until I sold the refining business. As a result, aside from using ferrous sulfate, I'm not familiar with other methods of precipitation. 

Harold


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## peter i

If I was doing it large scale, I'd certainly consider SO2 on cylinders very seriously.
It is the pure reactant, clean, no “dissolving the SMB”-step, easy dosage and efficient.

In Denmark renting or buying cylinders is however awfully expensive, and unless it was refining on a rather serious scale, the price would outweigh the benefits, making SMB the better alternative.


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## Arcani

thanks Noxx, i found it
I like the melting dish idea, is it hard to get it nice and smooth or does it not matter if surface is a little lumpy?

Will CO2 precipitate enything? i have alot of it around for paintball.


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## Palladium

So2 = Sulfur dioxide

Co2 = Carbon Dioxide

So2 is what you want.


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## Arcani

> Posted: Fri Mar 21, 2008 9:36 pm Post subject:
> 
> --------------------------------------------------------------------------------
> 
> So2 = Sulfur dioxide
> 
> Co2 = Carbon Dioxide
> 
> So2 is what you want.



What will CO2 drop, if anything?


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## draftinu

My Powder too took on the same tone, almost coco like. Have not melted yet. Trying to get enough for ingot. I will post when I melt for the first time! Nice job Noxx.


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## Noxx

Thanks

But don't forget the ammonia water rinse too !


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## peter i

Arcani said:


> What will CO2 drop, if anything?



It will drop calcium- and barium ions as their carbonates, which is good to know but of little use in this case.
:wink:


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## Lou

It won't drop a thing if it's in acidic media. The question of what CO2 does is of no value to anything we are interested in doing.


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## SilverNitrate

In deed its pure gold powder, At first I used to think it was Au2O3 a gold oxide, but it has a more Mars-red color kind of like ground cayenne pepper. it'll have subdued gold streak. 
Any ways to be sure, make sure its dry then heat the powder to well above 600F if it is the oxide it will lose appx 11% of its weight then exhibit static sintering (the powder tend to clump like moist clay) showing it all metal by then.


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## Harold_V

SilverNitrate said:


> In deed its pure gold powder, At first I used to think it was Au2O3 a gold oxide


Interesting concept, one about which I'd like to hear more.

I looked in my Merck Index and found only Gold Monoxide (aurous oxide AuO2), with no mention of Au2O3. Fact is, it suggests that the existence of gold monoxide is in doubt. 

(Merck Index, 9th Edition, page 4354, item # 4361)

Harold


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## SilverNitrate

Gold oxides may be in a number of states such as Au hydroxide, Au2O, Au2O3, AuO2 and can be a combination of them all. because of instability of the oxides most of the gold is metallic. And a sample of random gold powder can contain the oxides, but all are removed upon heating.


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## Lou

Actually, Au2O3 does indeed exist, but AuO2 does not. A case when Merck is wrong.

Crude gold oxide is produced by basic precipitation of Au (III), while the pure, single crystal ruby-red oxide is made via hydrothermal crystallization at 235-275 deg. C from HClO4/KClO4. Au2O3 dissolves in base to give you Au(OH)4-


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## Harold_V

Thanks, gents. I'm at the mercy of my Merck, not knowing chemistry well. 

Harold


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## Noxx

Here are a few more.
Click to enlarge.

[IMG:150:128]http://img76.imageshack.us/img76/7107/lingot002gw3.th.jpg[/img]

[IMG:150:128]http://img208.imageshack.us/img208/8979/lingot016wd4.th.jpg[/img]


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## Rag and Bone

Noxx,

The photos make my mouth water. Literally. I thought only food could do that.

Why is the first nugget formed the way it is?


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## Noxx

The first nugget is two unsuccessful pours into my mold. It solidified instantly into that unusual shape.

Thanks for your comment 8)


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## lazersteve

Noxx,

Excellent luster on the bars. The ripples are very common with graphite molds. Graphite is the only molds I pour into now days. I save my gold up until I can pour ingots weighing 25-30 grams.

You'll have better luck if you melt your gold with the dish sitting on top of the mold. This preheats the mold to the point where your gold will flow into the graphite before it solidifies.

Also work the gold close to the edge of the melting dish slowly as you tilt the dish. Make sure the dish stays red hot around the molten gold the entire time.

Immediately after pouring play the torch on the solidifying gold to prevent a pipe from forming in your bar.

Super quality on the gold!

Steve


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## Noxx

Thanks for the comment Steve.

But I don't own a MAPP + Oxy torch.

What I'll do (still haven't tried yet) is to melt my gold in a graphite crucible in my electric furnace at 1200°C then pour it in a preheated mold. This way I think it could work. What do you think ?


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## ZiegenSauger

Fellas,

If you please allow me to revisit this thread, I have been searching the forum during last week for references in red gold precipitate. This one is perfect to ask for help since I dropped gold with SMB 3 times from the same batch and all drops came this color.
In summary, the black solution with yellowish reflexes is a very concentrated leftover from "several" Pl and Pd drops. I recovered so far about 2x 30mL and one 10mL vials of Pt, and about 7x 30 mL of Pd. I used different methods (Cu, Zn, DMG, and so forth, depending on the phase and correcting mistakes). Solution was cleaned, evaporated, dennoxed, etc. several times. few cases Pt/Pd were refined twice, most cases once.
The batch originally had decent amount of gold (plating or filling PGMs), about 4 Oz of source material was used and later combined with other failed solutions. So measurement is totally off.
Anyway, the important piece is that I "lost" the gold. Very first drop with SMB came red so I assumed it was wrong and added the power back to process.
Please note Stannous was positive all the way for PGMs and Gold. For this last Gold drop there were small traces of PGM but very positive for gold.
Now Stannous is negative for Gold and still traces of PGM.

The great question is the color of the supposedly gold precipitate being red like this.
Being myself a newb practitioner, do you guys advice or recommend anything? 

But thank you


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## Johnny5

I wouldn't worry about it too much. I've had powder drop out different colors many times. Many years ago my thumbnail picture, was of powder that looked almost gold in color. Only had that happen once.


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## Lou

ZiegenSauger said:


> Fellas,
> 
> If you please allow me to revisit this thread, I have been searching the forum during last week for references in red gold precipitate. This one is perfect to ask for help since I dropped gold with SMB 3 times from the same batch and all drops came this color.
> In summary, the black solution with yellowish reflexes is a very concentrated leftover from "several" Pl and Pd drops. I recovered so far about 2x 30mL and one 10mL vials of Pt, and about 7x 30 mL of Pd. I used different methods (Cu, Zn, DMG, and so forth, depending on the phase and correcting mistakes). Solution was cleaned, evaporated, dennoxed, etc. several times. few cases Pt/Pd were refined twice, most cases once.
> The batch originally had decent amount of gold (plating or filling PGMs), about 4 Oz of source material was used and later combined with other failed solutions. So measurement is totally off.
> Anyway, the important piece is that I "lost" the gold. Very first drop with SMB came red so I assumed it was wrong and added the power back to process.
> Please note Stannous was positive all the way for PGMs and Gold. For this last Gold drop there were small traces of PGM but very positive for gold.
> Now Stannous is negative for Gold and still traces of PGM.
> 
> The great question is the color of the supposedly gold precipitate being red like this.
> Being myself a newb practitioner, do you guys advice or recommend anything?
> 
> But thank you



Red color?
It’s selenium. The precipitate will have the characteristic smell (intolerable to me, who was once poisoned by it). Best described as an odd, musty garlicky odor that is very objectionable.


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## ZiegenSauger

Thank you guys. After drying, the color settles a bit and the brick blood red color fades. Resulting liquid is really dark red, re-syrupping again to see if I can fill get some trace PGM.

Also, @Lou, not smell of scent different than any other drop. Almost no odor actually since I usually wash my precipitates several times.

Really helped me guys. I got almost a full 10mL vial of gold 

Happy because I lost most of the gold I had refining due to mistakes, lack of patience, or supiditty .

Cheers!!!


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## ZiegenSauger

By the way, even though I am open to having Selenium or other element, I sort of don't believe that much. The initial refining and separation from base metals, dirt, or other contaminant was very thorough, and repeated 2 times or more in cases.

So the only concerns an have is Au/PGM cross condamination, the almost certain presence of some other PGM, and Cu in the case of Pd. These are my worse case scenarios.


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