'Kiln' in the Bible

Then the LORD told Moses and Aaron, "Take handfuls of soot from a kiln, and let Moses throw it into the air in front of Pharaoh.

So they took soot from the kiln and stood before Pharaoh. Then Moses threw it into the air,and it became boils producing running sores on people and animals.

Mount Sinai was completely enveloped in smoke because the LORD had come down in fire on it. Smoke went up from it like smoke from a kiln, and the whole mountain shook violently.