Viscosity of 25% Caustic Soda at -8 degrees Celsius

[TheBen]

thread798-309187

Hi hi,

The previous discussion was about 20% Caustic at -10 to -20 degrees Celsius.

Where could I find concrete proof (graphs) for 25% Caustic at -8 to -10 degrees Celsius?
I have tried to find the Orica Chemicals handbook, but I could not find anything.

 

[EmmanuelTop]

I have spent quite some time digging into various materials and I could not find viscosity values below 5-10 degC. Caustic Handbooks from OXY and DOW (see links below) do not have the <0 degC temperature ranges plotted on the Viscosity vs Temperature charts.

For 25% wt Caustic Solution, the temperature at which solution turns completely solid is -18 degC. According to the GBH Manual for Caustic pumps (see attached file), for 25% wt Caustic solution solidification already starts between -13 and -14 degC (see page 31 of the document), which is very close to -8 degC. I think that extrapolating Viscosity curve for lower temperatures than those shown on the charts will likely introduce potentially large error.

Can you hire a lab to do the actual viscosity measurement for you? That will eliminate any uncertainty.

http://www.oxy.com/OurBusinesses/Chemicals/Products/Documents/CausticSoda/caustic.pdf

http://msdssearch.dow.com/Published...soda/pdfs/noreg/102-00011.pdf&fromPage=GetDoc

Dejan IVANOVIC
Process Engineer, MSChE

 

[georgeverghese]

This was mentioned in a previous reply, and if you are still keen, you could email the author of this paper and ask for details in this reference 24?

http://www.iapws.jp/Proceedings/Symposium02/086Alexandrov.pdf

 

[EmmanuelTop]

As the solution approaches solidification temperatures, the gradient d(Visc)/dT rapidly increases (see attached Excel for 50% NaOH and the reference PDF embedded in the worksheet). On the other hand, charts in DOW and OXY handbooks show only the value ranges where viscosity change with temperature is almost linear. I'm afraid any extrapolation from these curves will yield inaccurate results. Depending on what these results will be used for, this approximation could turn into something very dangerous.

Dejan IVANOVIC
Process Engineer, MSChE

 

[25362]

Try page 11 on:

http://msdssearch.dow.com/Published...soda/pdfs/noreg/102-00011.pdf&fromPage=GetDoc

 

[TheBen]

Thank you for your help.
I think the lab is a good option.
Go well