Sciencemadness Discussion Board

Pure White Sand UN Class. NR Cas No. 7631-86-9 EC No. 231-545-4

CHRIS25 - 22-3-2013 at 03:02

UN Class. NR
Cas No. 7631-86-9
EC No. 231-545-4
Pure white sand at 30 euro for 5Kg. Just wanted to make sure that this is a high quality silicon dioxide, I did read that it was 95% SiO2. If a CAS/EC number is given for a product that is sold anywhere in the world does this mean that it conforms to a universal standard?

watson.fawkes - 22-3-2013 at 06:27

Quote: Originally posted by CHRIS25  
If a CAS/EC number is given for a product that is sold anywhere in the world does this mean that it conforms to a universal standard?
No. CAS numbers are just identifiers (i.e. names) for chemicals in trade. They make no statement about purity, contaminants, etc.

bahamuth - 22-3-2013 at 07:47

I might be able to get semiconductor grade quartz if anyone is interested... This material will be in the 50 micron range.

Morgan - 22-3-2013 at 15:38

Some beach sands are fairly pure quartz. I've often wondered if I could find some interesting new use for it. These pictures were taken near the pass, the one where the sailboat is leads out to the Gulf of Mexico. A lighthouse was used for the reference shot. There wasn't anyone on the shoreline when I went for a walk there.
Tidbit
http://practical-microscopy.blogspot.com/2011/06/where-is-be...

Quartz Sand.JPG - 93kBThe Pass.JPG - 98kBEmpty Beach.JPG - 104kB

Morgan - 23-3-2013 at 18:03

I was looking at this ~$15.00 container of SiO2 fumed silica the other day thinking it might be rewarding to try some thixotropic experiments with it. But why is it so often everything fun or unusual has some risk to it?
A fellow Down Under who made a video of his young son playing with a bucket of thixotropic clay wrote me back with this caution.
"However if-You're Working-With Such 'Fine' Particulate Silica-Flour ... Take-Precautions &-Learn From ASBESTOS Capital-Central:AUSTRALIA ... Mesothelioma Is-'Not' R-Pleasant-Way to-Die."

About Fumed Silica
Physical Properties
* Average Primary Particle Size: 12 nm
* Specific Surface Area (BET): 200 m2/g
"Natural Pigments offers a hydrophilic fumed (pyrogenic) silica with a specific surface of 200 square meters per gram. Fumed silica has a chain-like particle structure that bonds together to trap liquid, thereby increasing the viscosity. Add to thicken and increase the transparency of paint. Stirring or brushing paint containing fumed silica will cause it to flow, but when stopped, the paint will 'thicken up' again. This property is called 'thixotropy.'"
"WARNING: The product contains crystalline silica - quartz, which can cause silicosis (an occupational lung disease) and lung cancer."
http://www.artistsupplysource.com/product.php?productid=5503...

fumed silica
http://www.youtube.com/watch?v=ndWHsGCt6qk

[Edited on 24-3-2013 by Morgan]