If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.


Green Chemistry


August 7, 2021 | A version of this story appeared in Volume 99, Issue 29


Letters to the editor

Green steel

C&EN's cover for June 14, 2021, showing a large container pouring molten metal into another container, with sparks flying.
Credit: Shutterstock/C&EN

C&EN and writer Mark Peplow are to be commended for the article “The Race for Green Steel,” focusing, as the title might suggest, on the deleterious consequences for the atmosphere of conventional steelmaking processes and methods for remediation (June 14, 2021, page 22). The graphics on pages 24 and 29 were particularly instructive.

I was particularly interested in Sweden’s use of hydrogen generated electrolytically using wind power as well as hydrogen produced by other means to produce steel in an arc furnace, as these methods had the lowest carbon dioxide footprint (see chart page 29).

The other methods of producing hydrogen were not discussed in detail, but some did seem to involve shale gas (chiefly methane). In this context, the catalytic cracking of methane could be mentioned (see Chem. Eng. Sci. 2001, DOI: 10.1016/S0009-2509(00)00270-0). It should have the benefits of not being restricted to a small number of sites and not being dependent on the wind.

Thomas F. Spande
Bethesda, Maryland

I was intrigued by the discussion of the direct electrolysis of iron ore without using any reducing agents such as hydrogen or carbon.

It got me thinking, What if dry NaCl were added to the iron ore? Its melting point of 801 °C is lower than that of iron, about 1,500 °C, so it would melt and form a separate layer. Could the reaction then be forced to

Fe2O3 + 6NaCl J 2Fe + 3Na2O + 3Cl2
(1 kg of Fe2O3 to 2.2 kg of NaCl)

with gaseous chlorine captured? Then if the Na2O could be separated and reacted with water and CO2:

Na2O + CO2(aq) J Na2CO3

So the result is to produce commercial chlorine and sodium carbonate and to absorb atmospheric carbon dioxide. Three commercial products and one environmental benefit. Also a sink for the oxygen reported to be excessively generated. Not too bad for an industrial reaction. Of course I don’t know the thermodynamics or the kinetics or the phase mixing, so I’m only daydreaming. But what if it could be made to work?

Paul Palmer
Vacaville, California

The cover story in the June 14 edition caught my attention. The author did an admirable job in several respects:

The fundamental chemistry of steelmaking was very useful.

The brief history of steelmaking was quite interesting.

The description of multiple alternative approaches was very well done and required very few pages.

I do question some aspects of the article, however:

All the alternative technologies under consideration rely on “eye-watering” quantities of electric power. The quest to eliminate carbon from life will require huge quantities of electric power in this and countless other applications in daily life. I wonder what source will generate this quantity of power. Wind and solar have well-documented and fundamental limitations.

I would have been interested in a spreadsheet showing the total cost of traditional versus green steelmaking methods. I suggest that the current economic analysis depends heavily on taxes and government force. Human history tells a story. In the long run, in science, entropy always wins; in like manner, in the long run, true economics will always trump government-mandated selections of winners and losers.

Mike Kerner
Lisle, Illinois

The article on page 26 emphasizes the efficiency of electrolytic processes that require a stable supply of copious electric power. This seems like an ideal situation for one of the small, modular nuclear electric-power-generation plants that currently are on the horizon. Coupled with a small nuclear plant, these iron-smelting plants could operate independently with their own power supply.

Martha Dibblee
Portland, Oregon


This article has been sent to the following recipient:

Chemistry matters. Join us to get the news you need.