# sand to stop thermal shock on cat process



## pgm (Dec 19, 2010)

Hi...

i started to drop PGM from Cat's but would have a problem with thermal shock...i had broken 3 pyrex beakers and was getting sick on buying new ones....i asked BUZZ and he had suggested using a buffer....sand and foil plates to heat the beaker so i did....i have done 3 leaches and nothing is getting brokern....i would even say the temp control is better....i have found keeping to set temp is better using this process....here are some pic's


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## rusty (Dec 19, 2010)

I do not see a fume hood in that picture, I hope that your using one. Working with platinum group metals and salts can be hazardous to your health and those in close proximity to your works. Humans and pets.

The sand bath is a good idea, Hoke mentions the use of sand in her book and has been mentioned numerous times on the forum in more than one thread.


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## pgm (Dec 19, 2010)

rusty said:


> I do not see a fume hood in that picture, I hope that your using one. Working with platinum group metals and salts can be hazardous to your health and those in close proximity to your works. Humans and pets.
> 
> The sand bath is a good idea, Hoke mentions the use of sand in her book and has been mentioned numerous times on the forum in more than one thread.



thanks for the update....i have a fume hood but in the picture the liquide is cooling down after the heat treatment...i had taken it out of the fume hood


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## Lou (Dec 19, 2010)

I'm not a huge fan of cat substrate and Pyrex--it's horribly abrasive. If you're breaking glass on a hot plate, check your glass because it's probably Bomex (which is trash). Get true Pyrex (or Kimax by Kimble). 

Sand is a good solution.


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## goldsilverpro (Dec 19, 2010)

I never could figure out how to keep the hot sand from climbing up the outside of the beaker. When hot, it seemed to jump on the beaker - like with static electricity. It was hard to keep it out of small beakers. I only used it when I had to get something real hot, like wet ashing with sulfuric. With 4l beakers, or less, I usually put them in a white, flat, 5qt Corning Ware dish. If they broke, they broke (rare). To me, the main secret was not to get them real hot real fast.

I have also noticed that, although the thick, heavy-duty Pyrex beakers are more durable if you tend to bang them around, the thin, standard ones take the heat better.

What do you think of Kimax - the Kimball stuff? In my experience, Pyrex and Kimax are interchangeable. I have to read the label to know which one I am using. I do agree that Bomex is cheap crap.

Off the subject, but I once had a lot of thin, uniform, beautiful, German lab porcelainware that ran rings around Coors (have you noticed the Coors stuff getting thicker and clunkier over the years?). I also had some Chinese porcelainware. Thick, clunky, imperfect, wavy, and ugly, but functional and cheap. Maybe they've gotten better at making it.

The best open-top dissolving containers I've ever used were 3 gallon, fairly thin, uniform Pyrex jars made locally (in LA) by a lab apparatus glassblower. They were actually fairly cheap. I never saw one break.

I've found that some types of plates or saucers (I prefer all white ones - makes yellow solution really stand out) make better watch glasses than watch glasses. And they're usually much more durable.


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## Lou (Dec 19, 2010)

I think Kimax is now defunct.


To be perfectly honest, in my experience, borosilicate is borosilicate unless it's from China. Schott, Corning Pyrex, Kimax, Kontes...all of them are basically the same formula. I prefer heavy wall stuff but it has to be uniform--that's the killer for any heated glass! Any inconsistency in the thickness will cause a stress point.

My favorite off the shell supplier for things is Chemglass. Their rep for the NE is a hoot, and their prices are great compared to Ace. I still have an account with Ace, but it's been probably 5-8 years since I last ordered from them. My glassblower orders small components from them and he tells me that they're so cheap because they're not a union shop like Ace or Kontes or LabGlass. I'm damn fortunate to have a glass blower who is one of the best. Looking at his product versus that of normal glass supply houses--no comparison! He bullnecks all the joints and thickens up the glass and then anneals and looks for stress under the polarised glass. He used to make glass for a big pharmaceutical company, and his mantra is to build it like a brick craphouse so he won't have to see it again. Can't recommend the guy highly enough--he also does quartz.

Oh, stay away from Quark. Heard bad things about them from an environmental lab.

Chris, I've never been a big fan of open top dissolution vessels just because I tend to be very attention deficit and will go do other things while solutions are on the heat. I don't want things ever to boil, but rather gentle simmer. I once recovered about $400 (back then) in gold, platinum, and palladium off a large Corning hotplate--all from spatter! I much prefer rotovapping with an R-220 if I need to concentrate. They're an expensive investment, but they're really nice for the time saved.


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## pgm (Dec 20, 2010)

Lou said:


> I'm not a huge fan of cat substrate and Pyrex--it's horribly abrasive. If you're breaking glass on a hot plate, check your glass because it's probably Bomex (which is trash). Get true Pyrex (or Kimax by Kimble).
> 
> Sand is a good solution.



thanks will look at kimax


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