I've built a few & settled on an open kiln made out of corrugated iron.
I've found just getting charcoal in the ground to be super beneficial. My priorities are getting the most charcoal with as minimal time/effort as possible. I've no shortage of branches & debris to burn here.
Basically cut 5 or 6 lengths of corrugated iron about 1.2m long. Bolt then together top and bottom with some overlap, making sure 1 side is even (it will be sitting on this end). You need it to be about 4.5m long because you'll fold it up into a 1m² square. Wire some old star pickets to the top to provide structural support & you're done.
You're best bet is to build a kiln using corrugated iron to both reflect the heat back in & restrict the oxygen. You still need to quench at the end but it produces a lot more biochar.
Simply cut lengths of corrugated iron to 1.2m (4ft) & bolt/screw them together to form a cube that's open at both ends. Star pickets wired to the top hold the general shape & support it when you throw long branches in.
Feed the fire when the wood burning starts to turn to charcoal. Only the top layer of wood will be combusting because of the restricted oxygen.
View quoted note →
