[Terrapreta] vascular elements

[Mark Ludlow]

Dr. Haard & List,

I am interested in the morphology of carbonized angiosperm (or gymnosperm!)
wood, including, of course, typical char from TP sites. Is there a reference
or paper that includes SEMs or x-ray characterizations that you are familiar
with? 

Many functional attributes claimed for biochar (at least on the TP list)
seem contradictory; some, such as a purported ability to adsorb at the
molecular scale, seem more characteristic of activated chars which have
cage-like fullerene structures far too small to allow biogrowth. I assume
that not all biochar is homogeneous, even at the microporous level, but what
structural/functional relationships exist between char and its immediate
biological communities? What balance of macro/micro structures are ideal?
For now, it seems as if we are seeking to specify temperatures of production
with the end result of not volatilizing, completely, some compounds which
are recognized as being beneficial to soil flora. But surely the mechanisms
of benefit must not be proportionately static over the millennia(?)

http://www.pnas.org/cgi/reprint/6/4/178.pdf suggests that activation can
occur at room temperature over a time span of some years.

Mark


-----Original Message-----
From: terrapreta-bounces at bioenergylists.org
[mailto:terrapreta-bounces at bioenergylists.org] On Behalf Of Richard Haard
Sent: Monday, June 02, 2008 11:24 PM
To: Robert Klein
Cc: Terrapreta
Subject: Re: [Terrapreta] vascular elements

Not sure what you mean here Robert. Do you have scanning EM of coke  
that compares microstructure to carbonized angiosperm wood?

Are there studies that have shown benefits of powdered coke in soil or  
is this your own opinion?

I would also be concerned about trace elements that come along with  
the coal/lignite/coke. Such as As, Hg and Cd.

Coke could be powdered in a ball mill or mining processing equipment.  
Sequestering coal carbon after gasification would indeed eliminate  
greenhouse gasses. Is this alternative under study anywhere. ??

Rich
On Jun 2, 2008, at 10:59 PM, Robert Klein wrote:

> If the temperature is high enough, we get a porous end product with  
> all other constituents reduced or eliminated.  Biochar is done at a  
> temperature that likely yields only a fraction of the potential  
> inert high temperature form of carbon.  In other words the product  
> is a blend that is likely better accepted by the soil.
>
> At very high temperatures coal becomes coke which is also incredibly  
> porous and as tough as steel.  I think powdered coke would be very  
> good in soils, but I suspect that it is almost unmakable.
>
> That is why biochar must be produced from plant waste since it is  
> naturally prepowdered.  Wood is not.  I suspect that the best  
> results can pass  a very fine screen, wheras very little wood  
> charcoal can do so.
>
> arclein


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