'Furnace' in the Bible

Then the Lord said to Moses and Aaron, “Take handfuls of furnace soot, and Moses is to throw it toward heaven in the sight of Pharaoh.

So they took furnace soot and stood before Pharaoh. Moses threw it toward heaven, and it became festering boils on man and beast.

Mount Sinai was completely enveloped in smoke because the Lord came down on it in fire. Its smoke went up like the smoke of a furnace, and the whole mountain shook violently.