This is focused, from what I’ve read, on shutting down the blast furnaces.

Not really an area of my expertise, so I asked a friendly language model for a summary of the difference between arc and blast furnaces.
Take it away, Kagi:

The main differences between a blast furnace and an electric arc furnace are:

• Raw materials: A blast furnace can melt both raw iron ore and recycled metal, while an electric arc furnace can only melt recycled or scrap metal.

• Energy source:
  A blast furnace uses coke as fuel and hot air or oxygen as an oxidizing agent blown into the top of the furnace to sustain the chemical reactions and heat required.
  An electric arc furnace uses electric arcs to melt scrap steel.

• Emissions: An electric arc furnace produces a mere fraction of the carbon emissions and requires less energy intensity than a blast furnace.

• Flexibility: Blast furnaces operate continuously for years, while electric arc furnaces can rapidly vary production and shut down more easily.

In summary, while blast furnaces can process raw materials, electric arc furnaces are more energy efficient and produce lower carbon emissions when recycling scrap metal. Most steel production today uses electric arc furnaces due to their operational flexibility and environmental advantages.