The archaeologists found 28 pounds of slag in a hearth that they believe was used to roast iron ore prior to smelting it in a furnace. Photograph by Robert Clark, National Geographic.

After the slag has formed, the steel is poured into molds to make ingots. Since 1920 steelmaking has had a big swing to the open-hearth process. These furnaces, lined with dolomite ...

IN open-hearth steel-making, chemical reactions take place between the metal bath and a supernatant slag layer, and any material balance on the process demands an accurate knowledge of the masses ...

Blast furnace hearth drainage and liquid level management are critical components in maintaining the operational ... The opening through which molten iron and slag are discharged from the ...

Cement trucks rumbled down Minnesota Highway 135 all winter, delivering the nearly 5,000 yards of concrete needed to support Mesabi Nugget's giant rotary hearth. When completed, the 180-foot ...