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Difficulty: Very hardManufacturing and Industrial Development in Nigeria

Arrange the following sequential stages in the integrated manufacturing of structural steel at the Ajaokuta Iron and Steel Complex in Nigeria, starting from raw material preparation to the output of finished industrial goods.

  1. 1Beneficiation and washing of raw iron ore at the Itakpe deposit to elevate its feeder grade concentration.
  2. 2Blending of beneficiated ore with limestone flux and carbonized coking coal to prepare sinter and coke furnace charges.
  3. 3High-temperature reduction smelting of the charge inside the blast furnace to yield molten pig iron.
  4. 4Decarburization and refining of molten pig iron inside the basic oxygen furnace converter to form liquid crude steel.
  5. 5Continuous casting of liquid steel into solid billets and subsequent thermo-mechanical rolling into finished structural sections.

Answer

The correct operational sequence begins with the beneficiation of raw iron ore at Itakpe, followed by sinter and coke blend preparation, blast furnace reduction to produce molten pig iron, converter decarburization to refine liquid steel, and finally continuous casting and hot rolling into structural steel products.
The manufacturing process of integrated steel production at Ajaokuta follows a strict chemical and physical progression: Upstream raw material upgrading (iron ore beneficiation at Itakpe) -> Feed agglomeration and fuel preparation (sintering and coke baking) -> Primary chemical reduction (blast furnace smelting of pig iron) -> Secondary metallurgical refining (decarburization in the basic oxygen converter) -> Physical shaping (continuous casting and hot-rolling into finished structural sections).

Step-by-Step Solution

1
Identify the primary raw material extraction and concentration phase.
Raw iron ore from Itakpe requires beneficiation first to achieve the required purity for blast furnace smelting.
Unrefined ore contains silica gangue that reduces furnace thermal efficiency if not removed upstream.
2
Determine the burden preparation process.
Concentrated ore is sintered and paired with metallurgical coke derived from coking coal.
Blast furnaces require porous sinter and strong coke to allow gas permeability and thermal reduction.
3
Sequence the primary smelting operation.
The burden is fed into the blast furnace to yield molten pig iron.
Blast furnace reduction converts iron oxides into high-carbon liquid iron.
4
Identify the steel refining stage.
Molten pig iron is transferred to the basic oxygen furnace for decarburization.
Pig iron is too brittle for structural use due to high carbon content (>4%>4\%), requiring oxygen blowing to reduce carbon levels to steel specifications.
5
Establish the final milling and forming stage.
Refined liquid steel is cast into billets and rolled into merchant bars and wire rods.
Mechanical deformation in rolling mills imparts final structural strength and dimensions to the commercial steel products.

Key Concept

Sequential processing stages of integrated heavy industry in Nigeria (Ajaokuta Steel Complex)
Estimated Time:2m 0s
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Topics

Manufacturing and Industrial Development in Nigeria

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