yadavd
31 posts
TimePosted 22/08/2011 12:05:56
yadavd says

Role of methanol in free lime test

Sir What is role of CH3OH used for washing of filterate in free lime test Regards Dilip yadav

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Ted Krapkat
536 posts
TimePosted 23/08/2011 00:29:40

Re: Role of methanol in free lime test

Hello Dilip,

Normally absolute (water-free) ethanol is used to wash the residue of clinker free of filtrate in the glycol/ethanol free lime test. The reason is that the wash solvent must be free of water so that Ca(OH)2 is not formed by hydration of the clinker minerals during the washing process.

Methanol, or denatured alcohol (methylated spirits) can be used as long as it contains <5% water, however absolute ethanol is the preferred solvent.

 

Regards,

Ted.

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norew
99 posts
TimePosted 24/08/2011 08:56:16
norew says

Re: Role of methanol in free lime test

Ted,

We are using the glycol method and we do not directly boil the solution. We are just subjecting it to steam for 30 minutes. Please have your comment.

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Ted Krapkat
536 posts
TimePosted 26/08/2011 04:30:08

Re: Role of methanol in free lime test

Hello Norew,

I assume you are using a steam bath to boil the gylcol/alcohol solution. This is okay because the boiling point of the glycerol/ethanol solvent is ~85 deg C while glycerol/methanol is even lower at ~70 deg C. Both will boil quite happily on a steam bath.

However, the advantage of this method is that it is safer. A hot plate or heating mantle would have the inherent risk of a fire if the vessel broke and spilled flammable solvent over the electrics.

Regards,

Ted.

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