strange Au drop

[artart47]

Hi everyone!
I've been doing small batches of verious e-scrap components. honing my skills with AP and dropping small amounts of gold powder SMB) then stockpiling the powder.
All the drops have been the same, but today, this batch acted alittle diferent
My gold powder is always a light tan color and when the smb is introduced to the AuCl solution it becomes clear right away then it goes brown as the gold starts settling.
This batch, when smb was added, went clear, but, it had a blueish color to it. very pail blue like a tint rather than color. now, the powder is a darker brown than the other drops. (more chocolate than tan.
I'm going to wash it with HCl, H2O.and an NH3OH, H2O and then it will get refined again, but I'm curious as to what the contaminent is or what's going on.
If anyone has any ideas I'd like to hear any imput!
Thanks
artart47

 

[Geo]

take the colored solution and add a few drops of sulphuric acid to it and see what happens.

 

[artart47]

Hey Geo!
I added a little H2SO4 and nothing happened. stannis test negative.
The blue tint was only for the few seconds after adding smb when the solution usually turns clear. it was as though the jar was tinted glass, then everything went brown like usual, only a little darker brown.
I redisolved it HCl/Cl after washing with HCl,w/ the H2SO4, then an H2O wash. It was really wierd! Gonna see it rerefining it helps. It is more a curiosity, just wondered if anyone ever saw this happen and if they found out what caused it.
Thanks
artart47

 

[Geo]

ahh, i thought it turned blue and stayed blue. that is odd.

 

[samuel-a]

Light blue is indicative for slight copper contamination in solution...
You can tell it is very low level contamination by the fact that it is blue, more concentrated (very dirty solution) CuCl2 is green (but color also effected byconcentration of free Cl^- ion).
Gold dropped from "dirty" solutions tends to "drag" with it some other metals (Cu and Pd to name a few), giving it darker look.


The fact that you get clear and colorless solution after each drop is an indication that you clean you gold really well before dissolving it.
Keep up the good work !

Edit: clarification

 

[artart47]

Thanks Sam!
Yea! that makes sence. The solution came from the wash from all my plastic buckets and jars that I was cleaning the micro gold particals that accumulate in the seams and cracks. When I do the drop of the rerefined gold, I'll process anything that comes out of it and the wash/ rinses from it, see what is there. It would be nice to find palladium in your oatmeal instead of copper!
Bye-the-way, I've been stockpiling a bucket of any wastes that I think may have palladium in it. I think the time is going to come where it will be extreamly profitable to refine our palladium wastes!
Thanks guys!
artart47

 

[samuel-a]

I'm knowingly pouring Ag & Pd bearing waste solution (very low concentrations) to the copper cementation tank.
It's all get recovered later from the slimes bag.

 

[Harold_V]

Hey Geo!
I added a little H2SO4 and nothing happened. stannis test negative.
The blue tint was only for the few seconds after adding smb when the solution usually turns clear. it was as though the jar was tinted glass, then everything went brown like usual, only a little darker brown.
I redisolved it HCl/Cl after washing with HCl,w/ the H2SO4, then an H2O wash. It was really wierd! Gonna see it rerefining it helps. It is more a curiosity, just wondered if anyone ever saw this happen and if they found out what caused it.
Thanks
artart47

You can easily test the solution to determine what it contains. I expect, like Sam does, that it's copper---but it may not be. It could be nickel.

From the solution, take a drop, which is placed in a spot plate cavity. Add to that drop a drop of ammonium hydroxide. The solution should turn dark blue instantly. That confirms either copper or nickel. To determine if it's nickel, add a drop of DMG. If it's nickel, the dark blue drop will turn vivid pink. Simple, and a valuable test to add to your testing arsenal.

Harold

 

[artart47]

Thanks Herold!
I been meaning to get some of that when I get a chance.
With the price you get for nickel as scrap it would be great to be able to separate it even out of the regular metal scrap that I take to the iron yard, plus the benefit of using it as you sugested in my refining.
artart47