Science: Sponge Iron

A strange wartime substitute was in the making last week—a substitute for scrap iron & steel. It is called sponge iron, and the U.S. Bureau of Mines has decided to risk $500,000 in hurry-up development of the hitherto unpractical process by which it is made.

To make sponge iron, ore is not smelted. It is mixed with pulverized coal (natural gas can also be used) and coke, then fed to a large rotary kiln. When the kiln is heated to 1,800°F., the powdered coal first robs the ore (iron oxide) of its oxygen, then turns into gas, leaving fairly pure iron granules...

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