Usage patterns
炭を焼くto make charcoal (by burning wood)
My grandfather made his living by making charcoal in the mountains.
炭に火をつけるto light charcoal
We lit the charcoal before the barbecue.
炭で〈物〉を焼くto grill something over charcoal
Fish grilled over charcoal has a wonderful aroma.
〈物〉が炭になるfor something to be burned to charred remains
The pillars of the house were burned to charred remains in the fire.