# Precipitation with Oxalic acid Orange Mess



## ttutone1 (Sep 19, 2013)

So far everything I have done with gold refining I have succeeded. But this process I messed up.  
I was following these steps:
•	Oxalic acid (dehydrate) used at 1:1 weight ratio for the expected gold from solution.
(I use a slight excess Oxalic)
•	Dissolve in D. water, water level should not exceed one 1/3 height of the beaker.
•	Raise pH with ammonia solution/NaOH to about 6.
•	Heat both gold solution and Oxalic solution to near boil.
•	SLOWLY add gold solution to oxalic solution, by slow i mean a few drop at a time with a glass pipette. The more concentrated your gold solution is the more vigorous the reaction is. (cover the oxalic beaker almost completely with a watch glass while adding the gold to contain splattering)
•	When done adding the gold, give it a good stir with glass rod and keep the reaction beaker 10 more minutes on the hotplate at near boil.
•	Remove beaker from heat and allow it to settle over night.
•	the following day, Solution should be clear and colorless (assuming it is a second refining), test with SnCl. If negative, filter the solution and discard, if slightly positive, decant the solution to another beaker, add some SMB and let is sit for few more hours or over night.

Where I messed up is I forgot to raise the ph to 6. It didn't look bad but most of the gold would not drop.

So I mixed some more oxalic acid and added about three table spoons of clear ammonia (about 100ml total solution). I didn't think I would have to use all the solution.
Then reheated my auric chloride and oxalic acid. And started adding the oxalic acid solution to the auric chloride. Not much happened. (No fizzing) So I kept adding till the oxalic acid solution that I mixed was gone.
It started to turn clear and some gold was dropping. I thought it looked good.
When the beaker started to cool, the mixed solution started to turn orange. I thought ok this might be normal and let it sit overnight to settle.
The next day the solution is still cloudy orange.
Did I possibly add to much ammonia and raise my ph to high? (My ph test strips are on order so I can't test) :|
Any help would be greatly appreciated. Thank You.


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## Lou (Sep 19, 2013)

You had excess nitric acid. Your gold re-dissolved. 

Either that, or you had Pt/Pd in there and that's what's left.


Important to point out that oxalic acid is the not a reducing agent that should be used on dirty solutions. It is used to purify gold dropped from other methods.


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## mls26cwru (Sep 19, 2013)

just thought i would throw my observations in... to me it seemed that oxalic acid method needs to get above a specific ph threshold to work... I added my oxalic to my auric chloride initially and then heated up the solution. when it got hot enough, i SLOWLY added sodium hydroxide to raise the ph... when you hit the right range, the reaction happens really quick. It almost sounds like you got really close with the color change but didn't quite get high enough to tip the scale so to speak.


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## ttutone1 (Sep 19, 2013)

Thank You for the reply Lou
But I'm still confused. This gold is a combination of different little processes that I have done in the past. I have done small amounts just to learn.
There is some that I removed foils with AP, some is from pins that I dissolved with warm HCL, some came from pins in my cell using Sulfuric acid.
I then used HCL/CL on the gold flakes/powder. Filtered, then the gold was dropped with SMB. This was done twice. I then tried to wash gold powder: 3x water, 3x HCL, 3x D. water. Then tried to dry the powder but it was still dirty so I was unsuccessful. So I did another HCL/CL. This time I decanted the Auric Chloride to remove the salts that I think were water soluble and got through the filter on previous drops. Then I tried to drop it with Oxalic acid (Savogran Wood Bleach). And that is where I am now.
So I believe that there shouldn't be any nitric in the solution. Those are all the chemicals I used. Did the mixed chemicals somehow make some?
Any ideas?


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## ttutone1 (Sep 19, 2013)

Thanks mls26cwru
I was busy typing my reply to Lou when you replied.
That's what I am thinking.
Should I try this after reading my reply to Lou?


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## ttutone1 (Sep 19, 2013)

Oh my :shock: 
I just measured the pH and it is between 1-2.
I am going to try mls26cwru suggestion and add some sodium hydroxide to raise the pH to 6
Thanks!
I will report back.


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## ttutone1 (Sep 20, 2013)

Thanks mls26cwru!
Adding some sodium hydroxide to raise the pH to 6 worked very well.

Also, to anyone that might try this. Be vary careful with the sodium hydroxide. Use all the proper safety gear. Sodium hydroxide is lye and will blind you in a millisecond. Wear your face shield, long sleeved shirt and gloves.

When adding the sodium hydroxide to the auric chloride do so very very slowly. It bubbles up a lot.

Sorry to preach but better safe that sorry.


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## mls26cwru (Sep 20, 2013)

no problem  i figured mentioning something about the pH might be helpful... when i was searching for info on using oxalic, it was not easy to find a whole lot of info and i never ran across anything about the pH threshold, i kinda figured that out after while of searching. my first attempt was almost identical to yours... i raised the pH of the oxalic, but the pH of the auric chloride was enough to bring it back under the needed threshold. When the gold finally started to drop, I was so amazed i just stood there and watched it like a kid watching candy being made 

And what Lou said about using oxalic as a second refining is right... I tried it first once just for the learning experience, and the quality was very poor... my gold dropped a very dark, almost black, brown. 

Make sure to post a picture of the powder and/or button!


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## samuel-a (Sep 20, 2013)

[youtube]http://www.youtube.com/watch?v=0yOBdkxk1IE[/youtube]


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## maynman1751 (Sep 20, 2013)

Sam, you are indeed a man of few words!!!!  :lol:


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## ttutone1 (Sep 20, 2013)

Hi Sam,
Thanks for the reply.
I watched the vid several times. Oh, by the way... Thanks for all the cool info on your website. I have yours and Lazersteve's websites bookmarked. I'm sure you can see my IP address logged in quite a few times. 8) 
I was just afraid to do anything to the solution.
Then I remembered that I had an electronic pH checker. Once I checked the pH and with mls26cwru comment it put me back on the right track. :mrgreen:


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## Lou (Sep 20, 2013)

Good work guys, that's how it's done. To get a (fast) complete reduction I have always had to bring the pH almost to 6. This is not a reductant for gold solutions with high iron content because much rust coprecipitates and contaminates the gold.


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## maynman1751 (Sep 20, 2013)

How come all I get from Sam is a blank post????


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## jimdoc (Sep 20, 2013)

maynman1751 said:


> How come all I get from Sam is a blank post????



It is a video;
http://www.youtube.com/watch?feature=player_embedded&v=0yOBdkxk1IE


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## niteliteone (Sep 21, 2013)

maynman1751 said:


> How come all I get from Sam is a blank post????


Sounds like you are having a system setting problem or maybe a flash player setting that is not correct as the video show and plays perfect on my 2 computer systems.
I remember 2 days ago, "Adobe Flash player" just did an update that I declined, so if you allowed the update, it might have changed a setting on your system thus blocking the video.


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## ttutone1 (Sep 23, 2013)

OK Here is a picture of the cleaned and dried gold. It's not much but about .7 of a gram 8)


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## niteliteone (Sep 23, 2013)

8) 8) 8) Nice job 8) 8) 8)


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## maynman1751 (Sep 24, 2013)

jimdoc said:


> maynman1751 said:
> 
> 
> > How come all I get from Sam is a blank post????
> ...



It wasn't there on the 20th, but it's there now!!!!????? Thanks guys.


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## nh6886 (Sep 25, 2013)

That is great looking powder! Keep up the good work and please share a picture when you melt.

All the best,
John


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