problem with dimetil glioxime

[arthur kierski]

to a pd nitrate solution , i added a dmg alcoholic solution-------both solutions reacted with each other very strongly(perhaps because of the alcohol with the nitrate) and gave a green mass(precipitate)-----is this green precipitate pddmg?if it is,would not the precipitate be yellow and flufy?
please,help-------it is not the first time that this happens to me?
Arthur

 

[seawolf]

Arthur, look in GSP posts for this post, it gives the method for using Butyl Diglyme.

Gold Recovery Butyl Diglyme. Pdf

Sorry for not being able to give a working link but that is how the company computers are set up.
I have not tried it yet but one day I will.
I hope this helps, Mark

 

[Platdigger]

Arthur is asking here about dimethylglyoxime not BD.

 

[seawolf]

OOPS my bad.
Mark

 

[Platdigger]

Easy mistake. Wish I knew the answer to his problem.
Arthur, was there any nickel involved here?

 

[arthur kierski]

Platdigger,no ni involved------the dmg concentration is 1%---that is 10grams per liter
regards
Arthur

 

[skippy]

Is your alcohol pure? Could you try it with a pure source of alcohol or with DMG in water? Just an idea.
You could also see if cementing, hcl washing and redisolving would change anything.

 

[samuel-a]

I have no idea what is the green ppt, but i would lose the alcohol and use a lye solution to dissolve the DMG.
This way you could make very concentrated solutions of DMG so not to have great volumes to filter, Pd[DMG]2 is a pain in the a** to filter anyway.

Freechemist gave a while back the stoichiometrics, look in this posts.

 

[dtectr]

I have absolutely no experience, here, amigo - but I know that sulfuric & organics is a no-no. A 105 year old chemistry reference promoted using alcohol to remove sulfuric from a sulfuric precipitation, but I believe that is not recommended, currently. I tried it, early on, and the result was almost like a thin gel.

Is it possible that the same applies to nitric? just a random, unsubstantiated idea.

 

[freechemist]

Hi Arthur,

Traces of finely divided metals (Pt-/Pd-black) can lead to a greyish-green discoloration of precipitated Pd(HDMG)2. From my own experience I know, that Pd(HDMG)2, precipitated from HCl-solutions containing some gold, looks discoloured too. Alcohol is not only a solvent for dimethylglyoxime (H2DMG), but as an organic compound, also probably a reductant for dissolved Pd.
To see, what you have actually in your mixture, it would be best, to filter the precipitate in question, to wash it 1.) with a lot of water and 2.) with some alcohol. Let dry on the filter-paper and then calcine the whole in a porcelain crucible, first uncovered, with access to air, and then covered with a lid at 800oC for 1-2 hours. The calcined residue should be mainly metallic palladium, which can be examined and treated by known methods.
As an alternative to alcohol you can use aqueous NaOH - 2 moles NaOH per mole of H2DMG - to dissolve H2DMG. NaOH, contrary to alcohol, will not reduce precious metals.

Regards, freechemist

 

[arthur kierski]

thanks Freechemist for your reply and experience-i am dissolving the ppt with naoh and when i reach some conclusion,i will write a thread with the result obtained.
regards
Arthur

 

[Dr. Poe]

Palladium telluride is grayish green. As with any precious metal, the color of the ppt is a result of it's particle size. Concentration, temperature at precipitation and agitation determines the color of the mud that you get. If any gold is colloidially present, a co-precipitation will occur and will change the color of your mud.

 

[freechemist]

Hi Arthur,

Just to clarify: In my answer to your dimethylglyoxime-problem I meant, that for further precipitation-reactions you should dissolve dimethylglyoxime (H2DMG) in aqueous NaOH in place of alcohol.
The green precipitate you have already in your hands, you should filter, wash, dry and calcine as described in my previous post.

Regards, freechemist