 |
| New Zealand Steel - rotary kilns |
Construction Physics got me started:
Mesabi Metallics is planning a $15 billion steel mill in Iowa, the “largest single investment ever made in a US steel facility.” It looks like instead of a blast furnace, the mill will use direct reduction of iron ore, which will then be fed into electric arc furnaces. [ENR]
The new plant will be built in Lee County, which is in the very southeast corner of Iowa. Fort Madison is also in Lee County.
The MIDREX Process is the world’s leading gas-based direct reduction ironmaking technology, converting iron ore into solid metallic iron without melting it.How It Works
- Shaft Furnace: Iron ore pellets or lump ore are fed into the top of a vertical shaft furnace and descend downward by gravity.
- Countercurrent Gas Flow: A hot reducing gas—primarily a mix of hydrogen (H₂) and carbon monoxide (CO)—flows upward from the bottom, stripping oxygen from the iron ore.
- Gas Reforming: The reducing gas is typically produced by reforming natural gas, though modern setups can operate with up to 100% hydrogen via MIDREX H2 or flexible gas mixes via MIDREX FLEX.
- Recycling: Top exhaust gas from the shaft furnace is cleaned, scrubbed, and recycled back through the system to maximize energy efficiency.
 |
| Blast furnace in early 20th century Pittsburgh |
More Construction Physics:
The modern world uses shocking amounts of steel. In the US, we make roughly 575 pounds of steel per person per year. At the peak of US steelmaking in the late 1960s, it was closer to 1500 pounds per person, which is roughly how much China makes now.
 |
| Lebeddinskv GOK-1 unit at Gubkin (Russia): HYL process started up in 1999, capacity 0.9 Mt/year. |
 |
| The Mesabi Metallics construction site in Nashwauk, Minnesota (dead link) |
.jpg)
.jpg)
.jpg)
.jpg)
.jpg)
