[Stoves] Coal and biochar stoves

[ajheggie at gmail.com]

[Default] On Thu, 24 Sep 2015 15:05:05 -0400,Crispin Pemberton-Pigott
<crispinpigott at outlook.com> wrote:

>Dear Todd
>
>You raise an interesting point and it should not be missed.
>
>Wood and coal both contain mercury, sulphur, lead, uranium and other heavy metals, and the fire emissions contain fly ash?, polycyclic aromatic hydrocarbons, numerous chemical species, and particles of incomplete combustion including condensed volatiles.

You are batting on a sticky wicket there Crispin, whilst PICs may be
similar (but they probably aren't as wood  has less phenol type
compounds) the very fact that it is a living tissue is what limits how
much heavy metal plants can support.

Whereas, if you think back to the thread about producing salt crystals
from seawater, coal is formed in an environment where it is in a
superheated aqueous environment under pressure sufficient for the
water to have dissolved heavy metal salts with otherwise low
solubility but now super saturated, release the pressure, lower the
temperature or flash off the water et voila a carbon rich seam with
precipitated heavy metal compounds.

AJH