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Re:A new way to make steel could cut 5% of CO2 emissions at ... by qbrass on Tuesday November 06, 2018 @02:40AM (#18389098)
Steel is an alloy of iron and carbon. They mix coke with the iron to add carbon to it. The article is talking about the CO2 released from that coke, and not the coke used to fuel the furnace.
Re:A new way to make steel could cut 5% of CO2 emissions at ... by hexane360 on Tuesday November 06, 2018 @03:04AM (#18389197)
Actually it's 100% the opposite.

Look at your iron-carbon phase diagram: https://www.tf.uni-kiel.de/matwis/amat/iss/kap_9/illustr/fe_...

Cast iron contains a high concentration of carbon, which makes it brittle. To make steel you need a heavy oxidizer to extract the (reduced) carbon. This is usually done using a "basic oxygen furnace", which is basically injecting a high pressure, very high velocity stream of oxygen into the metal to game thermodynamics into combusting the carbon without combusting the iron.

Re:A new way to make steel could cut 5% of CO2 emissions at ... by foobarian on Tuesday November 06, 2018 @09:20AM (#18391170)
Wow, TIL. This has some details at "5 year old level:" https://www.quora.com/What-is-the-difference-between-iron-an...

The phase diagram is very interesting too. Very little carbon is needed to go from elemental iron to steel, looks like about 0.008%. Thanks for posting that!

Re:A new way to make steel could cut 5% of CO2 emissions at ... by testrun on Tuesday November 06, 2018 @06:58AM (#18390165)
This is correct, and the carbon is a byproduct. The reason is to get rid of the oxide in the iron-oxide compound.

The way I understand it, is that when mined they get iron-oxide, Fe(2)O(3), or Fe(3)O(4), so there is no carbon present.

They use the coke to make carbon monoxide (CO). And this process removes the oxide and adds carbon to iron to create pig iron.

From there it will be further processed to create different steels, alloys and iron products.

Wikipedia (https://en.wikipedia.org/wiki/Iron_ore) under the smelting paragraph describes the oxide removal process.

Re:A new way to make steel could cut 5% of CO2 emissions at ... by SomeAmerican on Tuesday November 06, 2018 @01:13PM (#18393432)
The coke that is mixed with the iron ore is the coke that heats the furnace. As the coke (carbon) reacts with oxygen, some of the carbon monoxide then strips oxygen from the iron oxide in the iron ore.
Re:A new way to make steel could cut 5% of CO2 emissions at ... by cauldron on Tuesday November 06, 2018 @02:47AM (#18389121)
You sound like confused, from my limited knowledge, the making of steel is exactly opposite of what you said, they extract carbon atoms from iron, that makes carbon monoxide into carbon dioxide.
Re:A new way to make steel could cut 5% of CO2 emissions at ... by SomeAmerican on Tuesday November 06, 2018 @01:20PM (#18393506)
Iron ore has no appreciable carbon in it before it enters the blast furnace.