Ironmaking sequence: Pig iron is produced from iron ores by a process chain that includes ore preparation and thermal/chemical steps prior to tapping metal from the blast furnace. Which option best captures this overall sequence?

Difficulty: Easy

Correct Answer: All of the above (ore dressing, calcination/roasting as needed, followed by smelting)

Explanation:


Introduction / Context:
Pig iron production from ore involves more than simply melting. The upstream steps condition the ore to the appropriate chemistry and physical form, enabling efficient reduction and separation in the blast furnace.


Given Data / Assumptions:

  • Typical route: ore dressing (beneficiation), thermal pretreatment (calcination/roasting depending on ore type), and final smelting/reduction in a blast furnace.
  • Fluxes and coke provide slag formation and reducing atmosphere.


Concept / Approach:
Ore dressing improves grade and size distribution. Calcination removes moisture and CO2 from carbonates; roasting oxidises sulfides and other deleterious components. Smelting in the blast furnace reduces iron oxides to molten iron, while gangue forms slag with limestone/dolomite. Thus, the complete chain encompasses all listed steps rather than any single one in isolation.


Step-by-Step Solution:

Acknowledge ore preparation: crushing/screening/washing (dressing).Apply thermal treatment as required: calcination/roasting.Carry out smelting reduction in blast furnace to obtain pig iron.Therefore, the correct overarching answer is “All of the above.”


Verification / Alternative check:
Standard ironmaking flowsheets show beneficiation → agglomeration/thermal treatment → blast furnace smelting, confirming the combined nature of the process chain.


Why Other Options Are Wrong:

  • Any single-step answer is incomplete and omits critical stages.


Common Pitfalls:

  • Confusing calcination with smelting or assuming dressing is optional for all ores (quality and process economics depend on it).


Final Answer:
All of the above (ore dressing, calcination/roasting as needed, followed by smelting)

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