The cost of Aluminum depends on the cost of electricity, so it is usually made where the cost is very low and typically using Hydroelectricity.
Reducing CO2 emissions during production by 50% is not a big deal. To get rid of the rest requires a different anode. Your iPhone already uses it.

Read this:
https://www.aluminum.org/anode-technology-game-changer-aluminum
https://www.elysis.com/en/what-is-elysis

Hi Gryf.

Interesting stuff!
I wonder what the efficiency of the process you refer to is?

Two additional references. Inert Anodes do use more electricity, however do not need to be replaced or create CO2.
“The Role of Inert Anodes in Aluminum Decarbonization“,
https://www.nrdc.org/bio/ian-wells/role-inert-anodes-aluminum-decarbonization
“U.S. Aluminum Production Energy Requirements: Historical Perspective, Theoretical Limits, and New Opportunities“,
https://www.aceee.org/files/proceedings/2003/data/papers/SS03_Panel1_Paper02.pdf

Now I have had my breakfast I am as fit as I will ever be to tackle the not inconsiderable task of reading and maybe understanding a little Gryf's links! ;-)

“U.S. Aluminum Production Energy Requirements: Historical Perspective, Theoretical Limits, and New Opportunities“,
https://www.aceee.org/files/proceedings/2003/data/papers/SS03_Panel1_Paper02.pdf'

On page 8 it states:

' The theoretical minimum energy requirement of 9.03 kWh/kg Al for an idealized
Hall-HÈroult cell using an inert anode can be calculated from the thermodynamics of the reaction 2Al2 O3 → 4 Al + 3 O2 (Note: if the O2 gas emission at 960∫C is included then the total theoretical minimum energy requirement is 9.30 kWh/kg Al). The theoretical energy requirement for an inert anode reaction is 45% higher than the carbon anode requirement.
This makes the inert anode reaction voltage about 1 V(dc) higher. However, three factors are likely to provide the inert anode with an overall improved, operational energy performance than carbon anodes:

a) Elimination of Carbon Anode Manufacturing - Carbon anodes require 5.90 tf kWh/kg Al for manufacture while inert anodes will require approximately 0.75 kWh/kg Al.
b) Reduction of Anode Polarization Overvoltage ñ Inert anodes can shaped to allow for better release of the O2 generated and experimental evidence has shown that the
oxygen evolved in the bath has a different froth/foam dynamic than carbon dioxide
and these physical properties, in practice, also contribute to a lower anode
overvoltage (DOE, 1999).
c) Reduction in ACD - a stable anode surface combined with a wetted cathode will allow for a greater reduction in ACD.
Overall inert anodes when combined with a wetted cathode, compared to traditional
Hall-HÈroult cells, are expected to provide: 10% operating cost reductions (elimination of carbon anode plant and labor costs associated with replacing anodes), 5% cell productivity increases and a 43% reduction of carbon dioxide equivalent greenhouse gas emissions (DOE and The Aluminum Association, 1998)
These scenarios provide the inert-anode cell with an overall lower-energy
requirement than the state-of-the-art Hall-HÈroult cell. However, the engineering designs for an inert-anode system must incorporate effective approaches for minimizing thermal losses from the cells, new current-carrying bus systems, and the connectors external to the cell.'

That a technology exists that can potentially produce carbon free aluminum at reasonable costs relative to the Hall–Héroult process is a good thing. However, if you are hoping to drive down carbon emissions over the next couple of decades serious barriers still exist. For one thing the inert anode process is not ready for prime time and once it is ready sunk costs in existing plant will slow down the transition to the new technology. In the mean time in a business as usual economic scenario global aluminum consumption is projected to rise at 2.6% annual rate (https://www.statista.com/statistics/863681/global-aluminum-consumption/). Furthermore an adequate carbon free energy supply with a good time profile and direct costs comparable to fossil sources is not a slam dunk within the next couple of decades.

A significant reduction of total emissions from aluminum in the next couple of decades within a business as usual economic growth scenario is not guaranteed. And we do need a reduction and not just a slower growth rate. I suspect that we will have consider lower per capita consumption of aluminum in addition to technological innovation if want to do something serious about climate change.

Hi Dave,

I have read previously about the possibility of using basalt fiber to reinforce concrete in place of steel rebar. The problem with rebar is that it rusts so that the life time of such composites is limited compared say to the dome of the Pantheon which is close to 2000 years old and still going strong. Your reference is the first time I have heard about the possibility of general usage of basalt fiber in composite materials.

Roger:

I am putting the other couple of links here in a separate post to avoid spam filters:

https://www.greencarcongress.com/2024/02/20240209-ornl.html

https://www.greencarcongress.com/2024/02/20240209-ornl.html

Note from my post:

' BFRP Rebar does not rust, it has the same thermal expansion coefficient as concrete, it is resistant to water, alkaline, and ultraviolet radiation, therefore it can have a life expectancy of more than 100 years!

Steel, on the other hand, is prone to rust and corrosion, especially where moisture is present; it is also prone to cracking due to its different coefficient of thermal expansion compared to concrete, causing buildings to require frequent maintenance, so according to general standards, steel has an average lifespan of 35 years.'

Just replacing steel rebar with basalt would be a major win in terms of energy use, CO2 emissions and structural longevitey, but the uses of basalt fiber by no means stop there.