Ceramics are fired for several hours inside this kiln near al-Khalil (Hebron), Palestine. The fuel used in the yard is wood, although in this case, there is a feeder line that drips oil too. To raise the temperature inside the firebox, an electric fan acts as a bellows and forces air to the flame. By just looking at this picture, it is difficult to imagine the heat. It was hot on my face just taking the picture.
I'm suddenly reminded of the story of Shadrach, Meshach, and Abed-nego.
For the word-mongers among us, the term used throughout Daniel 3 is the Aramaic attun, translated as "furnace." It is likely a loan-word from a Mesopotamian dictionary. The Greek kaminas (used in the LXX) is more fully attested. It is used to describe an oven for baking lime, smelting metal, or --are you ready for this -- a kiln for firing pottery!* Greek readers may have pictured a ceramic kiln as they read Daniel 3 (now go back and peer with imagination into the "manhole" pictured on top of the kiln here or here)!
"So the men were bound . . . and they were thrown in the furnace of blazing fire. Because the king's command was urgent and the furnace was so overheated, the raging flames killed the men who lifted Shadrach, Meshach, and Abednego. But the three men . . . fell down, bound, into the furnace of blazing fire" (Daniel 3:21-23).
*Agathocles is described as a "potter and furnace-man" in Diodorus Siculus (Library of History 20.63, see link here for English translation).