Sciencemadness Discussion Board
Not logged in [Login ]
Go To Bottom

Printable Version  
Author: Subject: CaO from Ca(OH)2
FrankMartin
Hazard to Self
**




Posts: 50
Registered: 30-5-2010
Member Is Offline

Mood: No Mood

[*] posted on 14-4-2014 at 22:07
CaO from Ca(OH)2


Hello. Has anyone used microwaves for the reaction:
Ca(OH)2 -----> CaO + H2O ?
My intention is to produce quicklime for solvent drying, from the readily-available Ca(OH)2.
The Ca(OH)2 theoretically decomposes at about 500degC

I want to avoid muffle furnaces and molecular sieves.

Frank
View user's profile View All Posts By User
12AX7
Post Harlot
*****




Posts: 4803
Registered: 8-3-2005
Location: oscillating
Member Is Offline

Mood: informative

[*] posted on 15-4-2014 at 00:14


Without liquid water, it may not heat very well. You'd have to try and see if it works. Note: run the microwave with a glass of water in the corner as a load. Microwaves with no load are known to overheat and blow up... And yeah, boiling water isn't exactly the thing you want when dehydrating, so... all the more reason not to.

You might just as well use a (sacrificial) stainless bowl over the stove; a gas stove will reach that temperature with ease, though you may want some insulation to ensure it goes to completion.

Tim




Seven Transistor Labs LLC http://seventransistorlabs.com/
Electronic Design, from Concept to Layout.
Need engineering assistance? Drop me a message!
View user's profile Visit user's homepage View All Posts By User This user has MSN Messenger
hissingnoise
International Hazard
*****




Posts: 3940
Registered: 26-12-2002
Member Is Offline

Mood: Pulverulescent!

[*] posted on 15-4-2014 at 01:04


Quote:
The Ca(OH)2 theoretically decomposes at about 500degC

Hmmm! Wiki gives the temp. at 825°C!

View user's profile View All Posts By User
FrankMartin
Hazard to Self
**




Posts: 50
Registered: 30-5-2010
Member Is Offline

Mood: No Mood

[*] posted on 15-4-2014 at 16:09


The 825degC refers to limestone (Ca(CO3)2), Slaked lime decomposes at a much lower temp.

I tried to decompose some Ca(OH)2 but the microwave itself heats up, so I stopped. Before/after weighing showed no result at all.

This shows a small home-made furnace that might be suitable.
http://www.youtube.com/watch?v=en4yhzLuD9A

View user's profile View All Posts By User
Bert
Super Administrator
*********




Posts: 2821
Registered: 12-3-2004
Member Is Offline

Mood: " I think we are all going to die. I think that love is an illusion. We are flawed, my darling".

[*] posted on 15-4-2014 at 17:35



Or you could use a MICROWAVE KILN

This guy made one, and did a " how to " video


[Edited on 16-4-2014 by Bert]




Rapopart’s Rules for critical commentary:

1. Attempt to re-express your target’s position so clearly, vividly and fairly that your target says: “Thanks, I wish I’d thought of putting it that way.”
2. List any points of agreement (especially if they are not matters of general or widespread agreement).
3. Mention anything you have learned from your target.
4. Only then are you permitted to say so much as a word of rebuttal or criticism.

Anatol Rapoport was a Russian-born American mathematical psychologist (1911-2007).

View user's profile View All Posts By User
hissingnoise
International Hazard
*****




Posts: 3940
Registered: 26-12-2002
Member Is Offline

Mood: Pulverulescent!

[*] posted on 16-4-2014 at 01:02


Quote:
]The 825degC refers to limestone (Ca(CO3)2).

Ooops! Yes, I don't know my carbonate from my hydroxide . . . ?

View user's profile View All Posts By User
macckone
Dispenser of practical lab wisdom
*****




Posts: 2168
Registered: 1-3-2013
Location: Over a mile high
Member Is Offline

Mood: Electrical

[*] posted on 16-4-2014 at 05:09


This should be easily doable. It basically requires insulation
(flame proof) and a special crucible (carbon/ferrite). The
one pictured in the first link is a commercial variety where
the two materials are one unit.

The crucible absorbs the microwaves and produces the heat.
The microwaves themselves don't have much to do with the
reaction since the crucible absorbs them.
View user's profile View All Posts By User
WGTR
National Hazard
****




Posts: 971
Registered: 29-9-2013
Location: Online
Member Is Offline

Mood: Outline

[*] posted on 16-4-2014 at 06:16


Although you don't want to use an electric furnace, it is probably the easiest and cleanest way of doing this. Here's a thread
detailing different electric kiln designs. In the same thread at least a couple of people made their own quicklime.

https://www.sciencemadness.org/whisper/viewthread.php?tid=26...

Have fun.
View user's profile View All Posts By User

  Go To Top