The process of making charcoal is fairly simple. It involves heating wood or other combustible (root, husk etc.) in an oxygen deprived atmosphere beyond its flashpoint. The process that you have mentioned involves putting the wood or root or whatever in the drum, sealing bung but having a small hole in the bottom where the tar can be removed without burning. They used to use a piece of pipe running under the firebox (I'll get to that in a bit) and collecting it in a bucket. Using pine root, you get pine tar. That was used as a preservative and sealant in the old days.
The drum with the pre-carbon material is then surrounded with a fire made of the same or similar material so it is heated just like it's burning but without any air, so there's no real burning. It just gets "charred" and the tars and turpins drain out the bottom. After that stuff stops draining you let the fire go out and when it all cools, open it up and you have charcoal. Just that easy. As far as activating it
According to
www.makezine.com/extras/17.html
Activating
the charcoal is the hard part. To activate charcoal, you need to remove all of the tarry residues
and non-carbon impurities that clog up its pores. There are two basic ways to do this: (1) soak the
charcoal in an acid solution and then cook at high temperatures for a few hours, and (2) immerse the
charcoal in superheated steam (around 1,800 F) for 30 minutes.
V. Forgione describes a process of
activating the charcoal using acid from the car battery:
CAREFULLY open the vent caps on the battery. The locals should have a plastic container to collect
the acid from the battery. CAREFULLY pour the acid into the container. Now, you should have anywhere
from 1.8 liters to over 4 liters of acid, depending on the size of the battery. Let's just say we only
need 1 liter of acid, since any more would cost you too much of your drinking water. Battery acid is
about 36% sulfuric acid and 64% water. We should use 2 liters of bottled water to get the acid down
to 9%. When mixing acid with water, add the acid to the water, NOT WATER TO ACID. HOT ACID WILL
SPATTER! Pour 2 liters of water into another plastic container that the locals have provided, and
SLOWLY add acid to the water, stirring all the while. You have 3 liters of acid and that should
treat enough charcoal for our use. Soak the charcoal in the acid, and then reheat in the charcoal
pile. With luck, this will activate the charcoal.
I do not take any responsibility for any damage or injury caused by attempting this as it is REALLY dangerous. Please make sure you know the risks and take adequate precautions or better still, spend the few bucks to buy it from the professionals.
Hope that helps
Peace...
John