When I drop SMB I get crystals at times?

[cmalec1957]

Some times when I am to the point of percipitate gold I use SMB and get crystals that form, now I have also got a gray/silver layer on very bottom of container and then Brown layer on top of that??? Any help please...

More to add picture of material below.. I use AR with a nitric sub from a 120ml muratic 2tbs sub material ... use UREA to neutralize then drop SMB ... temp of material is room temp except begining when reaction starts.... but now I have very black liquid with gray/silver material settle on bottom with thin layer of brown mud (like what it normal looks like.

 

[UncleBenBen]

First guess is too much SMB. But without knowing everything you did to get to that point it can only be a guess.

The more information you put into your question, like starting material, processes used, etc., the more it will help to figure out what is happening.

 

[Anonymous]

Quantity of starting material and quantity of reagents would be the most relevant things to post please.

 

[UncleBenBen]

Please don't edit to add to the post. Makes things confusing. Make a new post.

And also spell out your chemicals. I have know idea what your "sub" might be. Other people using translation software will definitely not know.

This will probably be an easy fix if you take the time to explain exactly what you have done to this point.

Looks like some nice pins by the way. What did they come from?

 

[cmalec1957]

Thanks for info.. I am sorry new to forum. I did get it resolved. However I am not sure what the pins came out of I got them in a lot on ebay. They are supposed to be 22k material weight is 6grams doesn't include plastic. They are unlike any I have seen? So I would like to know as well !!

 

[Barren Realms 007]

Thanks for info.. I am sorry new to forum. I did get it resolved. However I am not sure what the pins came out of I got them in a lot on ebay. They are supposed to be 22k material weight is 6grams doesn't include plastic. They are unlike any I have seen? So I would like to know as well !!

The pins on that chip will be gold plated.

 

[Topher_osAUrus]

Thanks for info.. I am sorry new to forum. I did get it resolved. However I am not sure what the pins came out of I got them in a lot on ebay. They are supposed to be 22k material weight is 6grams doesn't include plastic. They are unlike any I have seen? So I would like to know as well !!

The pins are most definitely plated, with the plating being very thin, and I believe all plating on electronics components is closer to 24k (*i think* 99.6percent gold if i recall correctly).. The pertinent question/s then becomes
-how thick is the plating
-what base metals are under the plating
-why believe anyone on ebay?

When you are posting, it helps everyone here greatly if a very scientific approach is taken.
Weight of material, method of base metal removal, amount of chemicals, heat used or not, method of gold purification (i.e. aqua regia, hcl-bleach, etc), if you denoxxed, how you did, etc.. Every step is very very important, and allows everyone to help better, and it also helps new people that come here with the same problem figure out their issues quickly as well.

When you said white crystals underneath the brown powder, i initially thought silver chloride, or too much precipitant, but, its hard to tell with out the small annoying details (annoying to type out, but not annoying for those of us who have a peaked curiousity)

-topher, the curious

 

[Refining Rick]

Silver. My guess would be silver chloride. My personal bane to refining. Can't stand the stuff. Let it set overnight with ice then decant solution, leaving the silver, before adding SMB.

 

[g_axelsson]

- SMB can precipitate copper I chloride from a dirty solution. It dissolves in HCl, try washing the precipitate with HCl. A very black solution also sounds like a lot of copper I chloride.

- Urea and nitrates could produce urea nitrate, an explosive compound.

- Tin chloride can turn into metastannic acid or other insoluble tin compounds.

6 grams of gold plated pins. Even if it is good plating it will not be a lot of gold in that batch.
I don't see any reason for using any silver in that PGA holder so I wouldn't expect any silver chloride.

Göran

 

[cmalec1957]

Thanks for all the help and education.