No reaction to SMB?

[ellrabin]

Hi, I'm having a problem with my HCL-CL process. I've obtained clean foils from the AP process, dissolved them in HCL-CL at 3:1 mix, made what appears to be 1/2 gallon of AuCl3, filtered it to a beautiful golden clear solution, then I added 10g of SMB to it and nothing happened. If it had fizzled and dissolved I would expect that excess Cl is to blame, but the SMB just sank to the bottom. I read through the posts here relating to ineffective SMB precipitation and I haven't heard of SMB that didn't at least dissolve. Now there is a catch: My SMB was left outside for quite a while and the jar must've leaked and let moisture in. The SMB instead of the clean white powder that it used to be is now a crunchy off-white almost yellow substance. Could the action of moisture and sunlight have reduced my SMB to a more benign and ineffective compound like Sodium Sulfide? I should've known better than to contaminate my pretty AuCl3 with old junk, but live and learn I guess.

Edit: should I have posted this in the "help" section?

 

[eeTHr]

ellrabin;

I've read that it is the gas which is given off when the SMB is wet that causes the precipitation.

If yours got wet, it might be out of gas.

 

[qst42know]

I would try mixing a small amount in a bit of water and see if you can catch the scent of sulfur dioxide. Careful just a bit of the odor not a nose full. If you can't smell any sulfur dioxide buy some fresh stock.

 

[markqf1]

Ellrabin,
Your smb is probably shot.
It doesn't sound like your using lazersteve's methods.
This is his area of expertise.
Try his website.

Mark

 

[ellrabin]

It gives off the gas when it gets wet? Well that would explain it. I thought it only outgassed SO2 when exposed to HCl. I'll filter it again to get rid of the undissolved Sodium powder now lying in the bottom of my vessel and try again with fresh SMB. I should also have mentioned my stannous chloride test turns brown/black, so I know there's something there to precip. The last time (first time) I did this, everything worked great, so I figured it must be the old crunchy SMB. I wanted to make sure, though, before I further contaminate a clean solution.

Correction from first post: the ratio I used was 4:1 HCL to chlorox.

I'd refer to Lazersteve's site, but after running through the silverlight software and then Hughesnet, it takes 2 hours to load one of the videos. I gave up halfway through to conserve at least some of my "fair use" allotment of bandwidth. Off topic: do not get Hughesnet. Unfortunately it's blocked at work. At least I can see the pdf's

There's no smell when I wet some of the old SMB, must be spent.

Thanks, everybody, I'll update you on whether fresh SMB works as soon as I get some (probably tomorrow)

 

[Palladium]

ellrabin;

I've read that it is the gas which is given off when the SMB is wet that causes the precipitation.

If yours got wet, it might be out of gas.

Stability and Reactivity
Stability:
Strength diminishes somewhat with age. Gradually decomposes in air to sulfate, generating sulfurous acid gas. Contact with moisture (water, wet ice, etc.), will release toxic sulfur dioxide gas.

MSDS :arrow: http://bulkpharm.mallinckrodt.com/_attachments/msds/S4378.htm

 

[ellrabin]

Thanks.

Sorry for that, I hate asking questions when the answer is readily available to me. I should've thought to check the MSDS first. I got some fresh SMB last night and will try again after work today.

 

[ellrabin]

That was it exactly, thanks guys. I filtered out the old SMD that didn't work and tried again with fresh stuff and it worked just like it's supposed to. I know now to never use old SMB. SMB that has changed from white to yellow has gone bad.