Re: Powder Surface Area
I have to say that I pondered over this query as I am not very familiar with this method of particle size measurement.
Fundamentally, this seems an exceptionally odd result, as any that is fresh surface created by breakage is in addition to that previously existing and for the change from a D50 of 25 um to one of 5 um would expect to see a large difference in surface area.
Regretfully, I cannot explain it, and can only suspect some anomaly in the technique.
Lyn ■
Back To The Grind.
Have you examined the particle shapes, e.g. microscopically, before and after?
As Lyn says there might be some anomaly in the technique, it seems so.
Does this silicon dioxide grinding process have a history of producing unusual surfaces? ■
John Gateley johngateley@hotmail.com www.the-credible-bulk.com
Support Of Back To Grind
Hello Martono,
what is your situation now?
--> Did you double check on material and device?
--> Did you do visual check (re microscope) of raw material and grinded powder?
--> Did you follow no-influencing rule when moving / treating raw material / grinded powder?
--> What does literature say about comparable raw / fines combinations, seen all details of your setup?
Explanations might be found as per results above and considering the cristalline OR amorphous character of SiO2 (quartz / melt or glass) and the respective character of it's grinded fines.
Regards
R. ■
Powder Surface Area
Hi Lyn,
I am a process engineering student and I encountered a result that I could not understand.
Is it possible for a material ( specifically Silicon dioxide powder ) to have a smaller particle size, but the same BET surface area?
i.e. BET surface area of particle size of D 50 = 25 um is the same as surface area of particle size D 50 = 5 um?
What we did was grinding the the 25um powders into 5 um powders.
If so, what is the explanation ?
Thanks
Rgds,
Martono ■