[Cob] has anyone made their own quicklime?

[Amanda Peck]

Roasted = quicklime, I'd guess.

Even small operations used to use kilns.  Why we have a Lime Kiln Road in 
the county here.

If you don't transform the rock pretty completely you'll have nasty lime 
putty, with pieces of stone in it.  Might be able to overcook it as well.

from the pottery people--here are two links, one talking about earthenware, 
the other giving final termperatures for the cones.

http://www.claytimes.com/claybscs.htm

"Earthenware clay contains a percentage of iron and mineral impurities high 
enough for it to mature at firing temperatures from "bonfire" heat at around 
1300 degrees F, up to about 2120 degrees F (cone 018-cone 3*). In its raw 
state, the presence of iron oxide makes this clay appear brown, red, gray, 
or greenish. When fired, it's anything from red or tan to brown or black."

http://www.pbapottery.com/pdf/ConeTemperatureChart.pdf

I think I'd try to fire a piece of earthenware in the fireplace, maybe even 
with a cone.   Earthenware will fire at "'bonfire' heat" so a piece of well 
worked clay (no air bubbles, they can explode) should tell you a lot.  When 
I picked up pieces of pre-Colombian pottery--earthenware, the lowest 
temperature firing--in Mexico about half the time they looked very much like 
they had not fired completely, distinct color change in the center of a 
shard.

When I was a kid I'd try this, never got anything that I thought looked like 
it was fired worth a flip.  Just well dried.  Of course this was in the 
ashes at the bottom.

But remember that limestone will give off CO2 when it's heated.  Won't help 
the burning process any.

===============
Jon asked Robert:

Usually I'm not so pedantic, but since this is a fairly dangerous  process, 
I'm going to request a little bit of proofreading/ clarification here:

>I make my lime putty from roasted limestone.  I buy it pre-roasted.
--Okay, where does one buy pre-roasted limestone?
>
><snip>
>
>What your friend says seems correct.  Roasting at 140 degrees
---did you mean 1400 degrees?
>should
>dehydrate it. How long did he suggest roasting it?
>Best wishes
>Robert
\