[Terrapreta] Earthen Kilns Conjecture

[Robert Klein]

Hi 

good points - check my comments.

----- Original Message ----
From: Greg and April <gregandapril at earthlink.net>
To: Robert Klein <arclein at yahoo.com>
Sent: Wednesday, April 16, 2008 7:24:17 AM
Subject: Re: [Terrapreta] Earthen Kilns Conjecture

  Interspaced in Blue.
 
 
----- Original Message ----- From: "Robert Klein" <arclein at yahoo.com>
To: "terra preta" <terrapreta at bioenergylists.org>
Sent: Tuesday, April 15, 2008 
22:49
Subject: [Terrapreta] Earthen Kilns 
Conjecture



> Hi Sean
> 
> I do not know where you get your information from, but it would behoove you toread the various postings that I have made on this subject here and on my blogwhere I tackle every sub issue that I can.
> 
> I cannot think of anything more important than understanding how it was possible for the Indios with a stone age tool kit to produce biochar in theform of powdered carbon no less!  They clearly produced millions of tonswhile we so far have produced a few hundred pounds or so using drums and thelike.  Obviously we are idiots.
> 
> And they did not do it by using much wood.  The little they used is stillthere to see and it is not much.  Charcoal does not powder itself withoutmechanical intervention.
> 
 

Would it help to first think 
of why they might be making charcoal in the first place?
 
Just doing some 
speculation here:
 
Burning out logs to 
make dugout canoes ( and since there was allot of people along the river and 
wood canoes would probably rotting away fairly quickly they would need to make 
allot of them ) ?
 
Fire hardening wood 
tools ( where the char is scraped off ) ?
 
Firing 
pottery?
 
In other words making char not for the char it's self 
but as a side product of making something else.
 
Is there any indication that they used charcoal as a fuel rather than wood?    To see where i'm going on this, just look in the bottom of any bag of BBQ charcoal, to see all sorts of fine char.

The charcoal volumes are too low to for this to hold.  The only reason they wold ever make chacoal as a separate product is as a convenient fuel, and even then it would likely be used for firing pottery.




SNIP

> 
> Much more interesting however is the fact that this earthen kiln design willalso tend to capture a lot of the heavier volatiles in the earthen shell sothat we actually have a blend of combustion products mixed into the soil. This is not as specific as producing pure activated charcoal but I think thathaving a wide range of such molecules maximizes the possibility of results.
> 

The problem with the theory of earthen kilns, is that such earthen kilns would also fire them selves into a ceramic - yet no indication of such a structure has been found.    There is a man that builds ceramic structures, by building structures out of adobe bricks, then fires the entire building, making a monolithic ceramic structure.

This is an important question.  Biochar temperatures are running at around 300 to 400 degrees for most of the stack.  high temperatures would only exist within the chimney were the earthen ware cap would also exist.  An important question is to determine the firing temperature of the so called pottery in the soils.







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