# This bar gave me fits - 5.445 Troy Ounces



## kadriver (May 4, 2011)

I started last evening at 5pm and finally finished at 10 am today.

I have never attempted to refine this much gold at once.

I had to dissolve the base metals in two seperate containers. The amount I was working with exceeded the capicity of all my glassware.

I had a problem when I tried to drop the gold - it took over 1/2 pound of Sodium Metabisulfite and over an hour before I could get the gold to drop completely - is this normal?

Even then, as I was filtering I seen some yellow color, so stopped and I re-tested with stannous chloride and some of the gold had re-dissolved!

I may have to get bigger containers when I do the next batch this size.

I did not enjoy this one as much - I was a nervous wreck while toting that much dissolved gold around in a glass container over a concrete floor.

I was was glad to get the gold into a bar.

Sadly, this bar is already on the way to the refiner - my last act bofore I could get some sleep..

Thanks for looking - any input or advice would be greatly appreciated

kadriver


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## Barren Realms 007 (May 4, 2011)

After a couple more of those lot's it will get easier for you. Just have some patience. 8)


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## Harold_V (May 5, 2011)

kadriver said:


> Even then, as I was filtering I seen some yellow color, so stopped and I re-tested with stannous chloride and some of the gold had re-dissolved!


Most likely that's not at all what happened. 

When you precipitate a large amount of gold, what happens is that some gold chloride is dragged down along with the precipitated gold. It gets covered up by the succeeding gold, and does not get precipitated. To avoid that problem, you should stir the gold vigorously, so it is exposed to the SO2 gas that results from the SMB you introduce. I faced this with every beaker of gold I precipitated when I'd re-refine my gold. The only difference was I started with exceedingly concentrated solutions, and used SO2 from a bottle. 

If, by chance, some of your gold did, indeed, re-dissolve, you should have noticed traces of colored gas escaping from the vessel. 

Harold


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## stihl88 (May 5, 2011)

Beautiful bar!

A Shame you have to sell it already.


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## Oz (May 5, 2011)

Given the amount of SMB you used I would guess that you were fighting oxidizers still in your solution such as Cl2 gas or nitric. Pay particular attention to your wastes acids cementing them on copper.


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## goldenchild (May 5, 2011)

To reduce your stress level get a 2-5 gallon bucket to dissolve your scrap. Get a bucket band heater to speed up the process.


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## kadriver (May 5, 2011)

Harold_V said:


> I faced this with every beaker of gold I precipitated when I'd re-refine my gold. The only difference was I started with exceedingly concentrated solutions, and used SO2 from a bottle.



Harold, what do you mean when you speak of "exceedingly concentrated solutions"? Do you mean large quantities of material?

So the amount of SMB and the time it took was normal given the amount of material I was trying to precipitate?

I get my SMB from Home Depot. It is called "stump-out". It is about $6 for a 1lb bottle. I consider this very inexpensive.

Would I gain a benefit by using SO2 Gas instead of SMB? Would the purity of my final product by improved by using SO2 gas intead of SMB?

I will be processing about 5 to 8 ounces of gold per month - depending on how much scrap gold jewelry we are able to find.



goldenchild said:


> To reduce your stress level get a 2-5 gallon bucket to dissolve your scrap. Get a bucket band heater to speed up the process.



I am not sure I understand what goldenchild is advising. A bucket made of plastic? Can I use a Homer bucket from Home Depot? I know what a band heater is, but would this type of heat melt a plastic bucket?

Processing this amount is not normal for me. My wife just happened on to a deal that produced this much all at once. Next time I get this much I will probably just do two batched of no more than 3 troy ounces of pure gold yield each.

I started with two batches. Then after I did the first dilute nitric acid treatment I combined all the gold into one container and proceeded with the rest of the process.

I should have left both batches seperate and processed each individually, combing the gold powder at the end in the drying pan over low heat.

I am still new to refining and I learn something new with each batch.

I used to fly a Kingair for a guy a few years back. I remeber that every landing was different from the last. It would seem that refining is similar in that every refining experience, while procedurally the same, is different.

Thank you for your input - kadriver


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## goldenchild (May 5, 2011)

Yes plastic buckets are exactly what I mean. For the amount of material you had you could get it all done in a 2 gallon bucket. If you start getting greater quantities you can use 5 gallon buckets. For a more automated process you could put your gold in the bucket with a lid paritally open and let it sit over night. I can see you are more tentative though so I would recommend a band bucket heater. 

Take a look at this video.

[youtube]http://www.youtube.com/watch?v=bhRJAnwALAA[/youtube]


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## Harold_V (May 5, 2011)

kadriver said:


> what do you mean when you speak of "exceedingly concentrated solutions"? Do you mean large quantities of material?


When I'd re-refine, my solution contained roughly 17 to 18 ounces of gold, all that in one liter. Prior to precipitation, I'd add enough ice to result in about four liters of solution when the ice had melted. The gold that was first precipitated came from the very heavily concentrated solution. That was dragged down and covered by the gold that came down later. Stirring vigorously exposed the trapped gold chloride to the depleted solution, which by now was saturated with SO2. 

I've commented on this very thing before. Gold precipitation is an exothermic reaction, so the added ice melted rapidly. I often ended up with a hot solution, in spite of adding three liters of ice. 



> So the amount of SMB and the time it took was normal given the amount of material I was trying to precipitate?


I hesitate to comment due to my not knowing is you had eliminated all of the nitric, or not. Because I always used an added button of gold when I evaporated (to concentrate my solutions, as well as to eliminate free nitric), I didn't have to worry about nitric. 



> Would I gain a benefit by using SO2 Gas instead of SMB? Would the purity of my final product by improved by using SO2 gas intead of SMB?


In my opinion, yes, you would benefit. I'm not firmly convinced that you can add ANYTHING (including tap water) to your gold solution and not expect it to contribute to contamination. However, some of the contaminants that are added don't report in the final product (once melted), so I think you'd have to know what you were adding before you made a decision on how important it would be to eliminate any particular substance. 

Reality forced my hand. I had to limit the size of vessels I used, if for no other reason, I didn't have enough capacity to heat large vessels. I concluded, early on, that if I stopped using ferrous sulfate and started using SO2 gas, I could accomplish that mission. The convenience of simply attaching a hose to a glass tube and turning on a valve won me over instantly. YMMV!



> I will be processing about 5 to 8 ounces of gold per month - depending on how much scrap gold jewelry we are able to find.


There were days when I'd process over 20, so our circumstances are different---although I still feel you'd benefit from the use of a bottle of SO2, assuming you can procure one. It's not easy to obtain. I had my share of problems through the years, including one supplier dropping the line entirely. I ended up with the bottle when they no longer exchanged them. Luckily, I was able to convert that to a filled bottle by another firm. 

Harold


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## kadriver (May 5, 2011)

Harold: did you use distilled water to make your ice? 

My container got very hot - near boiling point of water. I had to stop and let it cool a bit several times. Adding ice sounds like a very good idea.

kadriver


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## qst42know (May 5, 2011)

If you don't get an SO2 bottle at least consider food grade SMB. You should be able to find it for $3 a pound or so shipping included. As a food grade additive it's likely handled and stored better than something intended to apply to stumps. :mrgreen:


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## samuel-a (May 5, 2011)

If it's not to much hassle, one can always generate SO2 on demand and bubble it through gold solutions.
It's not as effective or convenient as a pressurized gas bottle, but will do the job eventually...

(P.S. - If you do create a gas generator, for any kind of gas, make sure you have back flow protection)

just my 2 cents...


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## lazersteve (May 5, 2011)

If you decide to generate your own SO2 gas be sure you also have a way to stop the production of SO2 once it's started. If you add too much of the required reagent(s) to the gas generator you may find your self with too much SO2 to handle.

Steve


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## samuel-a (May 5, 2011)

lazersteve said:


> If you decide to generate your own SO2 gas be sure you also have a way to stop the production of SO2 once it's started. If you add too much of the required reagent(s) to the gas generator you may find your self with too much SO2 to handle.
> 
> Steve



Good point.


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## Harold_V (May 6, 2011)

kadriver said:


> Harold: did you use distilled water to make your ice?


No, but my ice comes (and came) from an ice machine that makes clear ice. Contaminants are rejected. Still, ice from a refrigerator, aside from containing chlorine, is likely to be just fine. So long as the contaminants don't report in the melted gold, it doesn't matter if you add a little by using "dirty" ice. That may not be true if your goal is ultra-pure gold. 



> My container got very hot - near boiling point of water. I had to stop and let it cool a bit several times. Adding ice sounds like a very good idea.


It's more than a good idea--it's mandatory. You may have noticed that it got more and more difficult to precipitate your gold as the temperature rose. That's why I iced my solutions. 

Now that I understand you had issues with heat, I fully expect my assessment was correct, and it likely explains why you used so much SMB. You most likely did an acceptable job on evaporation---but as temperature rises, precipitation becomes very difficult. When re-refining, I often had to add additional ice to get mine down fully. Solution was too hot to handle, and that's after starting with a huge amount of ice. 

Those that precipitate a few grams from several hundred ml of solution don't have a clue about the problems of heavy concentration. 

Harold


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## kadriver (May 6, 2011)

Oz:

I have saved all my wastes from every ounce of gold I have ever refined. The wastes are in a large bucket.

I know there is some very fine gold dust that has settled on the bottom. I can see it swirle up when I add more liquid.

This waste is full of SMB and Urea - It will gag a maggot so i have to wear a respirator when I open the lid on the bucket. It even makes my eyes water.

I will draw some of this out and try to cement with some copper.

What should I expect to see - if anything?

Is there any other processes that can be used on this waste?

Thank you for your input - kadriver


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## Harold_V (May 7, 2011)

kadriver said:


> I will draw some of this out and try to cement with some copper.


That's a waste of time. If there's anything of value in the solution, it will show with stannous chloride. Only then would I recommend you do any cementing.



> What should I expect to see - if anything?


Platinum and/or palladium comes to mind. You may also be somewhat surprised to find a trace of gold in solution, although I hope you don't. Not finding any would be a good sign that you have done your work well when evaporating and precipitating. 



> Is there any other processes that can be used on this waste?


Once tested and found barren, yes, you can put scrap steel in it, which will remove copper and nickel, rendering your solution rather barren of heavy metals. It can then be neutralized and discarded appropriately. There may even be a ready market for the recovered copper now, although when I was refining, at my level, there was not. 

I highly recommend you NOT store spent solutions. Test them after precipitation and treat according to your findings. If you start saving solutions, it won't be long until you're up to your hips in them, and if you continue combining them as you've done, all you do is complicate matters when it comes to recovering traces of values. 

Harold


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