EDIT: Zinc Question not Making SMB question

[wop1969]

Will metal zinc power at 325 mesh grain and 99+% purity work for making SMB?
Or does it have to be granules and 100% pure?

EDIT: see 3rd post for the right question

 

[Harold_V]

Are you possibly confusing using SMB as a precipitant with using zinc as a precipitant?

I do not understand how SMB is made, but I expect the process does not include zinc.

Harold

 

[wop1969]

OPS, I have the flu and my head is not in the right place.

I have SMB on the brain

Steve sent me a list of Chems that are needed to go along with making use of his DVD, he mentioned Granulated Metallic Zinc 100%, I can only assume it is for precipitating Pt. With that in mind my question is:

Will metal zinc power at 325 mesh grain and 99+% purity work in place of the mentiond zinc above ? Or does it have to be granules and 100% pure?

I have a feeling that steve will answer this one

 

[lazersteve]

WOP,

The fine mesh zinc is shipped with Cab-O-Sil, an relatively insoluble ultra fine mesh stabilizer in it. This contaminates the mixed PGM powder when the fine mesh zinc is used for precipitation. Lou has determined the stabilizer can be dissolved by boiling the PGM in a caustic solution.

The granulated zinc does not suffer from this condition and is preferred for this reason. I am working on producing a sizable quantity of the granulated zinc to be sold on my website. Mark and I have already tested some sample batches that I have previously made. The granulated zinc works great and actually goes a little further than the same weight of 325 mesh zinc.

Steve

 

[wop1969]

Thanks for the answer, and that is why I did not order it I hade a gut feeling it might not work.

 

[jamthe3]

Do you prefer zinc over SMB? I'm assuming there's probably pros & cons for each under varying circumstances, but in general?

 

[lazersteve]

John,

I use zinc for precipitating mixed PGM powder from my cat extractions.

I use SMB for precipitating gold from solutions.

Steve

 

[jamthe3]

Thanks Steve,

I'm actually getting better I think...just as I was hitting the submit button, I went back to the original post to see if it mentioned when dropping PGMs as I thought that might be the case, and I suspected that from watching your DVD again earlier this evening because it was on my mind all day from a different question I asked you last night.

Hopefully, there's hope for me yet...LOL!!

Cheers,
John

 

[Harold_V]

It should be noted that when zinc is used, there is no selective precipitation. It is a good recovery procedure, but not a good refining procedure.

Harold

 

[Lou]

Harold basically covered it. Think of zinc as a way to concentrate what you're after from a relatively clean solution. It's a recovery method, NOT a refining method (although there is indication that it can be tweaked to offer limited selectivity).

SMB is pretty selective, but it works better when dealing with concentrated solutions. If you want to know more on the selectivity of SMB, see my stickied post in techniques.

Zinc is best used for stripping leach solutions from catalytic converters, where most of the stuff in solution is precious in nature. It also washes out quite nicely with dilute HCl, with no solubilization of the precious metals.

 

[goldsilverpro]

To Re-fine means to make the gold "Fine" again. Most all gold was "Fined" at some point in its life. Fine gold is considered, by the industry, as 999.5 Fine or better. If the process in question doesn't result in 999.5 gold, consider it a "recovery" process and not a refining process. A recovery process "recovers" the gold and gathers it together so that it can be subsequently "refined".

 

[Traveller11]

Steve

Will SMB precipitate gold from an iodine leach?