The Metallurgy of CO2 absorption with resulting Hydrogen gas production _Wedge a War

The first post on this theme was entitled "Wedge-A-War: Any Old Iron?, Corrosion & Natures Processes, the latter "Nature's Processes" being the title of a book of poems by John Updike. It draws attention to the role of corrosion of iron in a wet (humid-H20) carbon dioxide (CO2) environment resulting in the production of iron carbonate and hydrogen gas as the products of the reaction. This is repeated in the chemical form below together with a little poem written for the occasion. Full references were given in the previous entry "Wedge-a-War. Any Old Iron?"

Fe(s)+ H2O(l) +CO2(g)=> FeCO3(s) +H2(g)
iron +water+carbon dioxide => iron carbonate + H2
(where s=solid, l=liquid, g=gas.)

Let the Heavenly Steel Chorus hear -
Metallurgists, Steelmakers, Geologists, dear
Chemical Engineers and Ecologist's plea.
From humble steelmaking, sometime war-mongering,
To white knight planet saviour - eco-engineering,
For "Now's the time and now's the hour" for CO2 sinking,
For scientific method and controlled tinkering.
The above corrosive reaction begs the question:
Any old iron?

ref: to initial back-ground from "Corrosion Mechanisms & Control in Hydrocatbon Exploration and Production Operations", by Dr. Dan Kirkwood in the now, out of print; "Journal of the Metallurgical Club -Strathclyde University" 1992-93, p43-58.

In fact it is well known that several other metals behave in a similar fashion in these matters. A fairly recent reference to such metals and reactions has been echoed by Kurzweil [Link] reported initially and at more length in CNet news [Link].

Both tech watchers, Kurzweil and CNet report two approaches:

I. Involves Aluminium catalysed,dis-inhibited by Gallium,The method is outlined, costs estimates given, patents filed and a company, "AlGalCo", created to exploit the inventions and innovations.

"Purdue University professor Jerry Woodall has discovered a way to make hydrogen out of a reaction of water and an alloy of aluminium and gallium. Woodall estimates that the technique could produce fuel that would compete with gas at $3 a gallon (assuming current prices for aluminium, which are above $1 a pound). Woodall considers that the higher actual fuel cost could be off-set by the higher efficiencies of hydrogen engines.

The Purdue Research Foundation holds title to the primary patent, which has been filed with the U.S. Patent and Trademark Office and is pending. An Indiana start-up company, AlGalCo, is licensing the patent and will try to commercialize the idea."

II. Involves Magnesium. The company Ecotality associated with the Jet Propulsion Lab (USA) managed by CalTech [Link] to exploit the the so called Hydratus principle[Link]. More on the uses of magnesium may be found at Magnesium.com's[Link]

III. Involves extracting hydrogen from a reaction between sodium, water and silicon. The company exploiting this avenue is New York's Signa Chemistry [Link]

IV. Last but not least is the EU and Israel's Weizmann Institute, Zn powder produced H2, Solzinc process[Link] Unlike the previous examples whereby hydrogen is obtained from corrosion like processes the Solzinc project is a classical reduction of zinc oxide by carbonaceous material at elevated temperatures (>1000°C)readily depicted by the Richardson-Ellingham Diagramme. High temperatures are obtained by using mirror concentrated solar power installation at the Weizmann Institute in Israel.



If this is not sufficient, the biologists too, seem keen to "Wedge some Wars" from their angle, if only to keep the metallurgists on their toes. CNet news reports again
"Stanford University professor James Swartz, who by contrast,has found a micro-organism that takes sunlight and splits water molecules. Swartz's work has generated a start-up called Fundamental Applied Biology."

I would not like to end on a note highlighting our biologist colleagues no matter how highly distinguished.

Let me point out that there is a very interesting list of metals and their carbonates all of which by definition are capable of absorbing CO2, and most likely producing Hydrogen subject to determining the correct thermodynamic, kinetic conditions. Choices will subject to the economic, "social and environmental" climate in which they are required to operate.

The efficiency of the hydrogen energy vector for combustion has been dealt with in depth in a very well reference section of the free Encyclopaedia "Wikipedia" [Link].

Metallurgy, Materials Science,Applied Science