
Revolutionary Aluminum Process Eliminates Emissions, Produces Oxygen - jonbaer
https://www.engineering.com/AdvancedManufacturing/ArticleID/16941/Revolutionary-Aluminum-Process-Eliminates-Emissions-Produces-Oxygen.aspx
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anfilt
The last line makes me sad "proprietary process". I was curious about the
actual chemistry.

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FrozenVoid
Here is the paper about it(not the process specifically, but it describes what
it will does in principle):
[https://www.researchgate.net/publication/262148554_The_Alumi...](https://www.researchgate.net/publication/262148554_The_Aluminum_Smelting_Process_and_Innovative_Alternative_Technologies)

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slededit
That paper shows the chemical formula emits CO2. Are you sure this is the same
process?

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FrozenVoid
Relevant text from the paper: We see immediately that this reaction is
different from Equa- tion 1. Here, oxygen is formed at the anode, which
environmentally is a highly favorable gas, compared with CO2. The dream would
of course be to have anodes that lasted as long as the cell life, which now
may be up to 5 years or longer. Anode changes would then not be necessary
after the cell has been started. Nevertheless, it is a chemical fact that all
materials have a ﬁnite solubility in the very corrosive cryolitic melts at
about 960◦C, so a totally inert anode will probably never be found for use in
these electrolytes. Thus, what we really are looking for is a slowly
consumable anode. But how slow a consumption rate can we tolerate? The
potential inert anode material must have low solubility and low reactivity in
the electrolyte and also show good chemical re- sistance against the
anodically produced hot oxygen gas. In addition, the anode material should be
physically stable at the operating tem- perature, mechanically robust and
resistant to thermal shock. There will be extreme requirements for keeping the
wear rates of these anodes low. A wear rate of the order of 10 mm/y may
perhaps be sufﬁcient, but lower values would certainly be beneﬁcial. There are
two main challenges in the development of inert anode materials. In addition
to the requirement that the anode ma- terial should survive sufﬁciently long
in the electrolyte, the metal produced must be of adequate purity. The
impurity metal content in the aluminum can indeed be very signiﬁcant for the
customers, and the need for making pure aluminum will become more stringent in
coming years. The corrosion products, caused by the dissolution of the anode
material into the electrolyte, predominantly will end up in the metal phase
and thereby contaminate the aluminum produced. Hence, the anode corrosion
should be low enough to give impu- rity contents corresponding to the present
speciﬁcations for smelter grade aluminum. There are three principal potential
advantages in favor of de- veloping a new cell technology with inert anodes:
1\. Cost reduction. All costs directly associated with the consumable carbon
anode will then be eliminated, including the capital saving and raw materials
costs by eliminating the need for the carbon anode fabrication, baking, and
also the anode rodding plant. These cost savings may be signiﬁcant. It has
been indicated that there might be 25% to 30% lower capital costs for a new
potline with inert anode cell technology.3 2\. Environmental friendliness.
Inert anodes would eliminate all greenhouse gas generation and emissions from
the electrolysis cells. Smelters would no longer generate CO2, carbon
monoxide, or perﬂuorocarbon gases (CF4and C2F6), because carbon would no
longer be used as anode material. Carbon residues (butts) will of course
disappear. In addition, the ﬂuoride and dust emissions during anode change
will also be eliminated. 3\. Improved occupational health issues. Inert anodes
would reduce the work practices associated with the present prebaked carbon
anode change. The frequency of anode changes will certainly be drastically
reduced with inert anodes. Working conditions in the potrooms would also be
improved by avoiding all anode effects. The outlook of the primary aluminum
industry may be sum- marized as follows: This is now a mature industry, which
presently (2013) suffers severely from low aluminum prices and a very chal-
lenging market situation. Technologically, the present aluminum production
process can be a close-to-zero greenhouse gas producer. The ﬁrst step, which
is actually ongoing, is to focus on lower speciﬁc energy consumption, and also
to eliminate the occurrence of anode effects. Furthermore, it is possible to
reduce the inherent production of CO2by reducing the net carbon anode
consumption, although this reduction can only be perhaps 10% or even less with
the existing carbon anode tech- nology. Here, an inert anode, if such a
material can be found and developed for use in industrial aluminum production,
would repre- sent a remarkable technological breakthrough, because then oxygen
is formed at the anodes instead of CO2

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olliej
Of course it produces oxygen - aluminum processing is in large part reducing
aluminium oxides.

Given the scant data provided it is unclear if their technique results in
fewer additional airborne pollutants mixed with the oxygen which might be nice

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theandrewbailey
Does this require less energy input?

