Degradation of Ca(OH)2 powder

[nemo2007]

Randy said in his articles that solution of Ca(OH)2 will degrade if exposed to the air, because it react with the CO2.

But, what about the Ca(OH)2 powder, if exposed to the air, will it
react with CO2, and make it degrade? How fast?
Thanks...

[bertoni]

Yes, to some degree, although likely very slowly. The more humid the air is, the faster the reaction will be, I think. I just store my lime in a covered container.

[nemo2007]

How to know if our lime become degrade or not?

[bertoni]

The more of the lime that turns into calcium carbonate, the more precipitate there will be at the bottom of the container. A TDS meter with the appropriate range could also be used, but I think that's overkill.

[five.five-six]

I keep my bulk in a sealed bucket and perioticly refill a med sized retail container, this cuts down on contamination. also, if I do contaminate, it is not my whole supply. the stuff is cheep but beter safe than sorry

[J. Montgomery]

<a href=showthread.php?s=&postid=10711435#post10711435 target=_blank>Originally posted</a> by nemo2007
But, what about the Ca(OH)2 powder, if exposed to the air, will it
react with CO2, and make it degrade? How fast?
The powder should be just fine, I don't think you need to worry about it degrading. If it does go bad, I'd guess that it would clump (from absorbing moisture out of the air, not b/c of carbon dioxide).

[bertoni]

Lime will convert over time back into calcium carbonate, if not sealed:

http://archive.reefcentral.com/forums/showthread.php?s=&threadid=241240&highlight=lime+air+carbonate