Sciencemadness Discussion Board

Solid volatilisation

Murexide - 12-2-2020 at 20:03

I think this is an interesting topic on safety that many have not discussed before.

Solids are often hazardous (carcinogenic,..) by the inhalation route only e.g nickel sulfate or dichromate. There are two ways this could happen

1) The solid (in fine particles) is suspended in the air in low concentration (like a dust cloud).

2) The solid has a non-negligible vapour pressure (the likes of camphor), which presents an exposure hazard similar to liquids.

How do you prevent this route of exposure? Do closed containers present this sort of inhalation -via- sublimation risk or wholly prevent dispersion of the solid in air?

Also, on this topic how has your experience been with household chemical clean out days? Do they accept hobby chemicals?

Abromination - 12-2-2020 at 20:54

Quote: Originally posted by Murexide  
I think this is an interesting topic on safety that many have not discussed before.

Solids are often hazardous (carcinogenic,..) by the inhalation route only e.g nickel sulfate or dichromate. There are two ways this could happen

1) The solid (in fine particles) is suspended in the air in low concentration (like a dust cloud).

2) The solid has a non-negligible vapour pressure (the likes of camphor), which presents an exposure hazard similar to liquids.

How do you prevent this route of exposure? Do closed containers present this sort of inhalation -via- sublimation risk or wholly prevent dispersion of the solid in air?

Also, on this topic how has your experience been with household chemical clean out days? Do they accept hobby chemicals?

A few things here:
Dichromate is carcinogenic in ANY FORM, not just as a solid.
You are right about nickel salts, but mists from agitated solutions still provide a risk. It is fairly easy to prevent exposure, simply wear proper PPE and work with good ventilation.
I would not rely on household chemical clean outs. I would wait until you absolutely need to dispose of waste until you need it gone and then take it to a hazardous waste disposal station at your local dump. I myself am waiting until I move out for college. Its better to do it once then many times, it is less suspicious if you are afraid of it being monitored. (I’m personally not, but see no reason not to wait.)

BromicAcid - 12-2-2020 at 21:12

I have never gotten rid of hobby chemicals at the disposal days. However I do oil painting with classical pigments (lead, cadmium, chromium, etc) so I bring them boxes of contaminated rags and paint thinner. They never care what it is, just ask if it's flammable.

[Edited on 2/13/2020 by BromicAcid]

Copenhagen1968 - 12-2-2020 at 23:43

I just pack / blend it sensibly (VOCs, heavy metals, acid / base or other fractions) in used plastic containers and hand it off at the local municipality waste disposal station. No questions asked :-)

Murexide - 13-2-2020 at 01:08

Wow, I am surprised at the waste disposal station recommendation. I imagine that they would be more selective/careful in what they accept and high chance of police involvement which is inconvenient?

The local chemical cleanout actually says “hobby chemicals” are allowed. However, their perception of this term is probably different to ours.

B(a)P - 13-2-2020 at 03:25

Back to the safety side of the initial question, for anyone interested. If you want to look at your exposure to the chemicals you are working with, think reagents, intermediates and products, the chemicals TWA (time weighted average) is a good conservative start for the home chemist. The TWA is a concentration that a grown adult can be exposed to 8 h per day 5 days per week for 40 years 'safely'. TWA values for a huge range of chemicals are freely available online.
Nickel dichromate is a good example. The TWA for this compound is 0.015 mg/m3. At this concentration it can not be detected by any visual or olfactory senses, so you need to relay on PPE or engineering controls.
Other compounds will steer you down a path where you can not even use PPE eg vinyl chloride (granted most people won't be coming in contact with this). vinyl chloride saturates respirator cartridges very quickly then passes right though and is also incredibly toxic.
At the end of the day the specifics i have provided are likely of little value, but the underlying principles hopefully of value.

be safe and have fun!

Herr Haber - 13-2-2020 at 04:46

To get rid of chemicals I would first look for the local fablab / hackerspace.
If they have a Chemistry lab you might make people happy.