# Hydrazine Sulfate ?



## grainsofgold (May 16, 2008)

Does anyone use Hydrazine sulfate for precipiting gold from AR solution containing gold?

A refiner in Ca uses this to drop their gold- Didnt know how it compared to SMB....

Pros?

Cons?


Thanks

Grains of Gold


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## goldsilverpro (May 16, 2008)

I have used it to drop 1000s of ozs over the years. The purity is not as good as SMB. I always used it as a first drop when I have high nitric in the solution. It's not necessary to eliminate the nitric. There have been several threads discussing this. Search. Lou, I believe, mentioned that nitric and hydrazine sulfate can produce an explosive combination, under the right conditions.


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## Irons (May 16, 2008)

goldsilverpro said:


> I have used it to drop 1000s of ozs over the years. The purity is not as good as SMB. I always used it as a first drop when I have high nitric in the solution. It's not necessary to eliminate the nitric. There have been several threads discussing this. Search. Lou, I believe, mentioned that nitric and hydrazine sulfate can produce an explosive combination, under the right conditions.



Hydrazine readily nitrates. It will make a very dangerous mixture by just mixing it with Nitrate salts. The Sulfate is more stable.

I've already done the experiment several times as a demonstration under controlled conditions at a demolition range. It's impressive.


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## grainsofgold (May 16, 2008)

Thanks for the info

Grains of gold


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## Art Corbit (Jun 7, 2008)

I have used a good bit of Hidrazine both testing for gold and dropping gold out of AR and SSN. What I used was just a liquid form and I cut it to 27.5%. I have heard the 55% like you buy it will explode and sometimes just catch fire. After all it is Rocket fuel you know. I don't care for it because too much copper or iron will kill it and your gold will drop but everything else drops with it. If you have good clean gold chloride it will do a fine job. If it's real clean the gold will drop in dark brown clumps and if you will just let it set a few minutes air bubbles will build up in the clumps and they will float to the top. Then just dip them out with a spoon.
It is just a little more sensitive for testing with AR or SSN than the stannous chloride. It is hard for me to get though so I stopped using it.

Art


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## Irons (Jun 8, 2008)

If your solution is without contaminants, it works well. For a final precipitation it's great, if not a bit expensive. 
For Gold, there are other reducing agents that are a better choice for general use.

Hydrazine will even reduce Selenium, so for a first precipitation from a dirty solution, it's probably the worst choice.


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## Art Corbit (Jun 8, 2008)

That's what I have found out. If your sample or the gold chloride is pretty clean it does a good job and if it isn't it will probably make a mess. Untill now I have never run into anyone other than the ones on another group that has used it. I'm the one that started it on the other group and none of us really knew much about it. I have read what I can find on it but it hasn't helped much. It is far too expensive for me to use and much too hard to get. I am really thankful for the information that has been exchanged on it here in the past couple of days. It's one of those deals where I had gone about as far as I could with it on my own.

Art


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## lazersteve (Jun 8, 2008)

Thanks to Lou I have some hydrazine sulfate that I've used to precipitate my redissolved PGM complexes from solution. It works really well. I plan on doing a short video of the simple process just to show everyone how it works.

As you guys already know it's a real shame that it's not selective, but it makes for a fast way to convert your PGM complexes into metallic form. I really like the way the precipitated metal dries in a heavy clump. It makes for easier melting without as much worry for the PGM being blown away in the draft of the torch.

Steve


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## Art Corbit (Jun 8, 2008)

I like the large clumps too. The next time you run some of this try this. Take one of the clumps wet and lay it on a piece of copy paper. Take the flat side of a kitchen knife blade and lay on the clump and press down pretty hard. Then drag the blade across the clump. I know gold will turn to a pretty yellow metal but I would like to know how the platinum would react.

Also I want to ask you and you alone a direct question. I don't want to start another debate on this thread. What is the reason for the glycerin you use in the cell? There has been some talk about this on another thread and I would trust your opinion on it. Some say it isn't necessary and some say there is a danger of it exploding. I was jumped on for mentioning you used it in the video. Thanks

Art


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## Shecker (Jun 8, 2008)

This is a thought I would like to interject into this conversation. I have never used hydrazine primarily because none of my regular chemical resources carry it. I have found that in a pgm bearing hydrochloric acid solution Everclear pure grain alcohol does an excellent job of precipitating rhodium -- it comes out of solution in the form of a black floc that is very easy to filter and wash. I use metallic replacement for the rest of the pgm's by reacting the solution with the high purity aluminum heat sinks that comes with the computer processors. The aluminum produces a gray metallic powder that is also easy to filter and wash. Just a thought. Everybody have a great day.

Randy in Gunnison


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## goldsilverpro (Jun 8, 2008)

I think there are some patents using hydrazine sulfate on PGMs. I know that the large PGM refiners use it. I seem to remember that it is selective by controlling the pH.


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## lazersteve (Jun 8, 2008)

Art,

I answered the glycerin question in the appropriate thread.

Steve


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## Irons (Jun 8, 2008)

goldsilverpro said:


> I think there are some patents using hydrazine sulfate on PGMs. I know that the large PGM refiners use it. I seem to remember that it is selective by controlling the pH.



The Shor PGM refining method uses Hydrazine Sulfate to sequentially reduce the PGMs. It's covered in their patent.

http://tinyurl.com/5pwuqe


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## Shecker (Jun 8, 2008)

I had a friend once who used hydrazine to reduce platinum. One day he took a coffee filter filled with hydrazine reduced pgm and washed the pgm's into another container. Then he absently mindedly put his fresh hot cup of coffee on the filter paper. He said as he headed for the fire extinguisher that it looked just like the flame of an upside down rocket. Among other things he had to get a new coffee cup. 

Randy in Gunnison


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## Lou (Jun 8, 2008)

And Steve, let me know if you want any more of it (if there is enough demand, I will make a bunch of the stuff). Keep in mind that I deal usually with things like what I sent you: pure metal complexes of known or stated purity. In this, hydrazine and its salts far exceed the others. It is clean, fast, and complete in its reduction.

For a mixed bag of PGMs, as Chris mentioned, it can be made selective depending on pH and temperature. The hotter the hydrazine solution is, the more indiscriminate it is. There are always other factors, namely solution concentration, and what the anions involved are. For Pt, Pd, and Rh, individually, I always make the values solution basic with either NaOH or preferably, ammonia. Then I dissolve up the hydrazine sulfate or dihydrochloride in hot water and add it to the beaker with the values. I do that slowly, because as the metals is reduced, the hydrazine is oxidized, and one of the products is nitrogen gas. 


As for using pure ethanol for rhodium, I do not advocate its use at all. Only for Os and Ru is it of any use in my honest opinion. Starting from pure rhodium compounds and using EtOH as reducer, I always end up with rhodium black, which, unlike what Randy from Gunnison has said, is murder to filter, even on fine glass frit with a powerful vacuum. It's not something I'd recommend anyone to do unless they have patience and the equipment. Patience most here have, but I probably wouldn't be wrong if I said you lot aren't equipped like I am.



Hydrazine is a waste on gold. According to GSP/Chris, it can however be used to avoid the whole ''boil down to HAuCl4 syrup'' deNOx procedure. I've never actually used hydrazine *sulfate* to drop gold from aqua regia (bold because I would NEVER add hydrazine free base to any solution containing nitric acid!). In fact, this is quite tempting to do as it would save time. Again, all fine assuming your gold is pure in its solution. If it isn't that's when the more mild reducing agents like SO2, oxalic acid, ferrous sulfate, etc. come into play.

As for Shor patenting basic chemical knowledge, to hell with that!!! That pisses me off. I've done probably everything in that patent many times without ever even reading it til now. There's nothing novel about that at all! Typical example of a patent that should not be a patent.



Lou


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## goldsilverpro (Jun 8, 2008)

Lou,

I sure agree with you about people patenting common knowledge. It's amazing how often this happens. I often find things patented that I knew way before the patent was issued. And, these are not things that I had come up with. They were, as you said, common knowledge, at least in the industry. I aways have the same reaction as you. It really pisses me off. The examiners must be total idiots.


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## lazylightning (Sep 17, 2010)

Hi!

I used HYDRAZINE HYDRATE(98%) to precipitate copper in a protective solution to get nanoparticles of copper using one patent and I am wondering if it will reduce gold from a pure chloride solution also.

Best Regards,
Paul


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## arthur kierski (Sep 17, 2010)

could formic acid be used as a substitute for hydrazine sulfate?


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## Lou (Sep 17, 2010)

Yes, just make sure you make ammonium formate out of it. Also, the product isn't a heavy gray sand like with hydrazine, it's usually a bit finer.


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