Sciencemadness Discussion Board

quicklime with a bunsen?

pneumatician - 28-8-2016 at 14:44

hi, can I make quicklime with a bunsen? I make a try in a 7 cm ceramic flat bottom capsule with egg shells but after a bit of fumes the matter go to grey color and no more fumes, so I stopped because I don't see this too much efective :)

maybe with a direct over the egg shells propane torch?? how many minutes? hours? I need to calcine?

perhaps with some invent like this ?

http://www.makeyourowngoldbars.com/gold-melting-mini-propane...

or maybe with focused sunlight? I have a 12cm convex lens, a 600 mm mirror photo lens... a lot of work but free...

so when the matter is well "cooked"??? I don't need kilos, only some gr

blogfast25 - 28-8-2016 at 15:45

How long have you got? At red heat this can take as long as 24 hours. Lime kilns operate at much higher temperatures than Bunsens.

NEMO-Chemistry - 28-8-2016 at 23:26

try charcoal and air type furnace? Put your crucible inside on top of the charcoal and blast some air into it. Although if you need it, rather than want the experience of making i think its better to buy it.

I tried this with a BBQ but it didnt seem to get there, i think i used too much and too chunky material. Egg Shells are thinner so maybe they should calcine quicker?

PHILOU Zrealone - 29-8-2016 at 04:10

Sunlight must be smarter than propane torch direct onto shells because:
CaCO3 <==--> CaO + CO2 is an equilibrium reaction.
If you direct burning gas onto CaCO3...you increase the amount of CO2 in disfavor of the reaction.
Alcanes while burning provide CO2 and H2O.
so also CaO + H2O --> Ca(OH)2happens.



[Edited on 29-8-2016 by PHILOU Zrealone]

pneumatician - 29-8-2016 at 15:00

Quote: Originally posted by blogfast25  
How long have you got? At red heat this can take as long as 24 hours. Lime kilns operate at much higher temperatures than Bunsens.


wow, 5' to 10' at most :)



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pneumatician - 29-8-2016 at 15:25

Quote: Originally posted by NEMO-Chemistry  
try charcoal and air type furnace? Put your crucible inside on top of the charcoal and blast some air into it. Although if you need it, rather than want the experience of making i think its better to buy it.

I tried this with a BBQ but it didnt seem to get there, i think i used too much and too chunky material. Egg Shells are thinner so maybe they should calcine quicker?


I read previously to open this new topic yours? thread about this but I see you can't get a happy end :)

so is necessary a mega power caloric fire to calcine shells, stones... and yes I think egg shells is more easy...

for little quantity a solar disc like the video, but this need mirrors to focus the light over the matter... and maybe "5000 suns" is a bit too much and the matter is volatilized??? :)

https://www.youtube.com/watch?v=TtzRAjW6KO0


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NEMO-Chemistry - 31-8-2016 at 04:31

Wasnt my thread, yes i would assume eggs shells were easier as they are alot thinner. But i have no idea how much energy it takes to calcine it.

On the other hand lime kilns were used back when Moses and certain other members here (:D) were kids.

So its got to work, just depends how much heat and for how long you can get it going for.

Apart from the fun from doing it, i wouldnt do it as it would make more sense to buy it. But i often do things that make more sense not too.

Try making a small kiln, build in as much heat retention as you can and use charcoal, personally i would use a fan or other blower to get it as hot as i could. I would aim to make it hot to the point you have to squint to look at the fire.

Let us know how it goes.

Melgar - 31-8-2016 at 05:16

Calcium hydroxide will calcine at much lower temperatures (540C vs. 840C) and can be done in an oven. If you're looking to buy industry-grade stuff, it's called "hydrated lime" and is incredibly cheap:

http://www.homedepot.com/p/Oldcastle-50-lb-Type-S-Hydrated-M...

Smaller amounts can be purchased as "pickling lime" but this is harder to find. If I had more storage space, I'd personally just buy the hydrated lime, then use it for every reaction that needs a base, where it's not that important what the base is.

NEMO-Chemistry - 31-8-2016 at 05:21

I think garden centres sell similar stuff in the UK cheap, its used for soil conditioning or something like that. Builders merchants also sell it.

aga - 31-8-2016 at 05:43

A small qty can be made in a charcoal fired furnace.

http://www.sciencemadness.org/talk/viewthread.php?tid=15171&...

It really is not worth the time & effort though.

vmelkon - 31-8-2016 at 12:25

Quote: Originally posted by PHILOU Zrealone  
Sunlight must be smarter than propane torch direct onto shells because:
CaCO3 <==--> CaO + CO2 is an equilibrium reaction.
If you direct burning gas onto CaCO3...you increase the amount of CO2 in disfavor of the reaction.
Alcanes while burning provide CO2 and H2O.
so also CaO + H2O --> Ca(OH)2happens.



[Edited on 29-8-2016 by PHILOU Zrealone]


No, it works. I have done it with a propane torch but it is a slow process. I put the flame direct on the CaCO3 which causes some to blow off all over the place.
Also, it displays candoluminescence which is neat.

Melgar - 31-8-2016 at 14:37

Quote: Originally posted by PHILOU Zrealone  
Sunlight must be smarter than propane torch direct onto shells because:
CaCO3 <==--> CaO + CO2 is an equilibrium reaction.
If you direct burning gas onto CaCO3...you increase the amount of CO2 in disfavor of the reaction.
Alcanes while burning provide CO2 and H2O.
so also CaO + H2O --> Ca(OH)2happens.



[Edited on 29-8-2016 by PHILOU Zrealone]

You're disregarding the effects of temperature. CaCO3 is unstable and decomposes at high temperatures, even in an environment of pure CO2. Ca(OH)2 is even less stable at those temperatures.