AuMINIMayhem
Well-known member
:idea:
I haven't seen anyone approach this idea from this particular angle, so I'm going to propose this idea... now I figure there's probably a reason it hasn't been addressed, so if anyone knows why or it just hasn't really been explored, let me know.. I'm kinda curious if I'm on to something here..
here's my idea...
Assuming you had a vacuum chamber with some sort of "scrubbing" capabilities to keep the corrosive fumes from destroying the insides of your vacuum pump.. could you degass pregnant AR solution by way of vacuum rather than doing the typical boil off without losing pgm's/precious metals?..
What got me thinking of this is I use a vacuum chamber quite often at work to de-gas epoxies, etc. for a space firm and it's really quite effective at getting gasses out of a solution quickly.
Some of the drawbacks would obviously be:
1) the corrosive gases slowly eating away at the insides of a rather expensive vacuum pump or chamber (if it's metal and not a glass bell jar) by way of going into solution within the pump oil or condensing on the insides of the pump itself as well as any metal connectors, tubing, etc..
2) rapid expansion/boil-over.. you would have to run VERY small batches at a time and monitor the chamber for a while as liquids violently "boil" at first as gases saturated within the liquid boil off vigorously in the beginning stages. This can be abated by using a pressure relief valve that you turn to allow a little pressure back in the chamber occasionally (every few seconds) at first until things settle down. This is how we vacuum out our epoxies/adhesives, etc.. it first starts bubbling up, but we slowly allow some air in so that it's still boiling but not going over the edges of the container until it slows down. The time it takes is usually based on the viscosity of the product (thicker solutions boil over less rapidly, but expand like crazy and make a hell of a mess if you don't pay attention, while thinner solutions boil like crazy but also cause an issue with spattering and "atomization" if allowed to go unchecked at first)
To remove ("scrub") the fumes exiting the vacuum chamber and entering the pump, we use a glass trap submerged in a Dewar filled with LN2, which is actually VERY effective at getting anything not gaseous to sublimate... sometimes a "cartridge" of "activated charcoal" has also been placed in line after the Dewar to scrub other particulate/gases...
Anwyays, just a thought... I'd like to try it eventually, but thought I'd throw it out there in case it's been tried and found ineffective..
The advantage is that it can greatly (in theory) decrease time spent getting the nitrogen out of your AR, especially if you have a large batch of it (even though you would have to do it in rather small batches depending on the size of your chamber, containers, etc..)
Cheers! :mrgreen:
note: we usually range from 25 to 29.9 inches of mercury to fully degass our epoxies.. seems to be industry standard.
I haven't seen anyone approach this idea from this particular angle, so I'm going to propose this idea... now I figure there's probably a reason it hasn't been addressed, so if anyone knows why or it just hasn't really been explored, let me know.. I'm kinda curious if I'm on to something here..
here's my idea...
Assuming you had a vacuum chamber with some sort of "scrubbing" capabilities to keep the corrosive fumes from destroying the insides of your vacuum pump.. could you degass pregnant AR solution by way of vacuum rather than doing the typical boil off without losing pgm's/precious metals?..
What got me thinking of this is I use a vacuum chamber quite often at work to de-gas epoxies, etc. for a space firm and it's really quite effective at getting gasses out of a solution quickly.
Some of the drawbacks would obviously be:
1) the corrosive gases slowly eating away at the insides of a rather expensive vacuum pump or chamber (if it's metal and not a glass bell jar) by way of going into solution within the pump oil or condensing on the insides of the pump itself as well as any metal connectors, tubing, etc..
2) rapid expansion/boil-over.. you would have to run VERY small batches at a time and monitor the chamber for a while as liquids violently "boil" at first as gases saturated within the liquid boil off vigorously in the beginning stages. This can be abated by using a pressure relief valve that you turn to allow a little pressure back in the chamber occasionally (every few seconds) at first until things settle down. This is how we vacuum out our epoxies/adhesives, etc.. it first starts bubbling up, but we slowly allow some air in so that it's still boiling but not going over the edges of the container until it slows down. The time it takes is usually based on the viscosity of the product (thicker solutions boil over less rapidly, but expand like crazy and make a hell of a mess if you don't pay attention, while thinner solutions boil like crazy but also cause an issue with spattering and "atomization" if allowed to go unchecked at first)
To remove ("scrub") the fumes exiting the vacuum chamber and entering the pump, we use a glass trap submerged in a Dewar filled with LN2, which is actually VERY effective at getting anything not gaseous to sublimate... sometimes a "cartridge" of "activated charcoal" has also been placed in line after the Dewar to scrub other particulate/gases...
Anwyays, just a thought... I'd like to try it eventually, but thought I'd throw it out there in case it's been tried and found ineffective..
The advantage is that it can greatly (in theory) decrease time spent getting the nitrogen out of your AR, especially if you have a large batch of it (even though you would have to do it in rather small batches depending on the size of your chamber, containers, etc..)
Cheers! :mrgreen:
note: we usually range from 25 to 29.9 inches of mercury to fully degass our epoxies.. seems to be industry standard.
