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How does the hearth of a blast furnace collect molten iron?

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How iron is turned into steel — iron processing Iron ore is one of the most abundant elements on Earth, and one of its primary uses is in the production of steel. When combined with carbon, iron changes character completely and becomes the alloy steel.

In a blast furnace, the hearth is a parallel-sided, crucible-shaped structure located at the bottom of the furnace. As the furnace charge descends through the stack, it is reduced into liquid iron and slag, which then collect in the hearth.12

Because slag is less dense than iron, it floats on top of the molten iron within the hearth. The hearth is equipped with specific openings to manage these materials:32
* Taphole: Molten iron is periodically drawn off from the bottom of the furnace through a taphole.32
* Slag hole: Located higher up on the hearth, this opening is used to remove the accumulated slag.2

The hearth is constructed with thick walls lined with carbon-type refractory blocks, which provide superior resistance to the corrosive effects of the molten metal and slag compared to other materials. To prevent these refractory materials from burning out due to the intense heat, cooling systems such as water-circulating plates, staves, or sprays are integrated into the structure.12