I'm not certain the differences, but there's been a similar effort as a joint venture between Alcoa, Rio Tinto, and Apple to clean up the aluminum smelting process. [1]
The aluminum industry is notorious for having incredibly high energy requirements, and being price sensitive to changes in energy contracts. The economics behind smelters are challenging and at an unimaginable scale. Having an electricity interruption of more than a handful of hours can cause the aluminum in-process to solidify, causing tens of millions of dollars in damage to the smelter and requiring months to fix. This paper [2] describes a framework for making decisions to enter/exit a market based on variability of inputs, investment required to exit/enter, etc. While the example in the paper is focused around renewable energy, it can be applied to other types of facilities. We covered this paper for about 2 weeks during undergrad, which at the time was painful, but it was one of the most interesting papers and concepts I've read.
A great video outlining the refining process is available in [3]. Having worked there, I promise the safety at Alcoa is now far superior to what's shown in the video. Paul O'Neill hadn't become CEO yet [4].
Alcoa and other big aluminum producers have been interested in eliminating the carbon anodes from aluminum smelting for decades, well before global warming concerns rose to the forefront. It is a very difficult problem to make inert anodes efficient and stable enough for long term industrial use. I hope that these recent advancements are enough to start replacing carbon anodes in commercial plants. Some of the non-CO2 reasons to eliminate carbon anodes:
- Carbon anodes oxidize while they are in use. Their shape and size changes over time as they erode, and the pot has to be shut down to replace ones that are too worn.
- The oxidation of carbon anodes contributes part of the energy needed to transform aluminum oxide into metallic aluminum, but their embedded energy content is much more expensive than the electricity smelters use. The combined materials + electricity cost to produce a ton of aluminum would be lower if efficient, stable inert anodes could be developed.
- The oxidation of carbon anodes, ideally, produces pure carbon dioxide. But in actual operating conditions the anode oxidation also produces toxic gases like carbonyl fluoride and carbon monoxide as minor byproducts. Safety systems and processes to prevent toxic gas exposure of workers make it more expensive to build and operate smelters than if the byproduct gas were oxygen.
> Having an electricity interruption of more than a handful of hours can cause the aluminum in-process to solidify, causing tens of millions of dollars in damage to the smelter and requiring months to fix.
-When touring an aluminum melting plant in Norway (which exists only because of cheap, reliable hydropower - the bauxite is shipped in from Australia, mostly), I was told the last-ditch measure to avoid such a situation was a metric shitload of gravity-fed kerosene burners with redundant fuel supplies located at the critical (that is, hard and expensive to replace) parts of the line.
They really, really didn't want to look at a solidified production line.
I haven't been through a smelter, but would love the opportunity to tour one sometime. Were you on a public tour, or was it through a business dealing?
Business dealing of sorts. My grandfather was an engineer with the utility company and brought me along once, figuring I'd find it interesting. He was right.
I think its interesting in the Northwest, Huge Dams were built on the Columbia River to power Hanford (and the Manhattan Project) and the large glut of power after it was scaled back made it cheap to move Aluminum Smelters there. (and to Send 3GW of Super High Voltage DC power to LA from near Portland) Then, in the 90's, when power got more expensive (and more environmental rules) they moved them all overseas. That left a huge glut of Power in the area. So now, Facebook, Microsoft, AWS, Google All built their datacenters there.
Was Hanford there for power or for cooling water (and general remoteness so people didn't die in an accident)? Can't remember but I worked at PNNL for a few years.
Still lots of aluminum smelting with hydropower in Canada.
I just caught a video the other day about manufacturing on the moon. He referred to this kind of research being a potential game changer for lunar colonization.
There are many metal oxides on the moon, and if you were trying to construct a habitat then a reduction reaction gives you industrial feedstocks and Oxygen to breathe. But electrolytic refinement of aluminum produces CO2 via the sacrificial anode, so you need a different chemistry to avoid that, or a steady graphite supply and a lot of photosynthesis.
He also mentioned that you can use electrolysis to refine iron, but that we have cheaper (but much heavier) terrestrial options.
I helped write a report [1] about the state of the Space Resources industry for 2019. This report should get you up to speed on the science, engineering, and law/policy going on in the field.
Our website specifically covers ISRU, including a monthly newsletter and sporadic articles (including one published this morning about minimizing lunar dust kick-up when landing vehicles on the Moon).
NASA Swamp Works does a lot of research on setting up a moon base, mining on the moon, etc.
They also sponsor the NASA Lunabotics Competition (formerly NASA Robotic Mining Competition), in which collegiate teams build robots to collect material in an environment very similar to the moon.
Philip Metzger is a great follow in Twitter. He was previously at Swamp Works before moving to an academic role. https://twitter.com/DrPhiltill?s=20
I feel this is one of those articles where lots of important information is missing.
Do they have any expectations on how expensive this process will be? Is there a chance that it's cheaper than existing processes or will it cost more? Is this plant they plan to build subsidized? Do they have plans to enforce this technology?
Ultimately for every green technology there's a simple truth: It's only going to be successful if a) it's cheaper than existing technology or b) it's going to be required or incentivized by law.
I've been seeing too many articles about fancy new green technologies that promise so much. The problem is: Most of them never happen at scale. Because they're usually more expensive and there's no political will to enforce them.
Unfortunately this is the only article I can find in English. I recommend looking at the youtube video I already posted. They claim it will run at a lower temperature and use less space.
When I read the headline I thought to myself: Great, the tackled the overvoltage problem successfully. In electrolysis there are two parameters relevant: the current and the voltage applied. (An electrochemist once told me: voltage means costs, current means money). The current is directly proportional to the amount aluminum (in this case) produced, whereas the applied voltage is directly proportional to the energy involved in the process. So a minimization of the applied voltage means a huge increase in efficiency. But I was mistaken. I hope that these new electrodes are not consumed in the process, otherwise this would mean the overall efficiency would be greatly reduced and if that really means a reduction of carbon emission remains to be seen
sadly not just any renewables - if the power goes off the Al in the pot lines hardens and ruins the hardware ... so solar and wind alone are out - geothermal and hydro (or those mixed with solar/wind) are OK
You will notice that this article is from an icelandic newspaper.
The electricity in Iceland is almost exclusively 'sustainable' energy (hydro and geothermal) and the Icelandic power system is one of the least carbon intensive in the world. At present it is #2 (https://www.electricitymap.org) in the world behind Norway at 28 gCO2e/kWh. Smelting aluminium in Iceland instead of say, the USA (~ 400 gCO2e/kWh), is already a great way to reduce the carbon intensity of aluminium products.
This article is discussing the CO2 emissions related to some integral processes within the smelter, and it is a big deal. No, it wont save the world, but also no, it is not bullshit. These are the sort of small incermental improvements that we require in ALL industries in order to dent global carbon emissions.
> This article is discussing the CO2 emissions related to some integral processes within the smelter
In slightly more (but still high school level!) detail, the raw material for aluminum refining is Al2O3. That is dissolved in a bath of molten salt, where the ions dissociate. The 2 Al3+ is electroplated out by adding electrons at the cathode. The 3 O2- comes out by withdrawing electrons at the anode; usually, the anode is carbon [1], and the reaction is:
2 O2- + C -> CO2 + 4 e-
The innovation here is to use an inert anode, so the reaction is:
2 O2- -> O2 + 4 e-
The fundamental chemistry of this is pretty obvious, so presumably there are good practical reasons why everyone was using carbon anode before.
EDIT It seems [2] that the process is using the carbon to do some of the energetic work of reducing the oxygen (carbon loves to reduce oxygen even when it doesn't have two extra electrons, a fact exploited in an earlier industrial process [3]), therefore requiring less electrical energy. This is sort of a way to stealthily burn some carbon to produce energy.
Re-reading this, I realise I've got the bit about carbon reducing oxide ions wrong. The oxide ions are being oxidised here, not reduced. But ending up at CO2 rather than O2 means they don't need to be oxidised as hard - oxygen in CO2 is a bit more reduced than in O2. I think. I probably wouldn't pass A level chemistry if I sat the exams today.
When neutral carbon and oxygen react, the carbon reduces the oxygen because it gives it a fractional share of its electrons when they form a bond. But when oxygen is charged, it already has lots of electrons. In this reaction the carbon is helping oxidise the oxide ions.
Do you know how they might be dealing with the oxygen? I assume it comes out very hot and ready to oxidize stuff. I suppose there are stainless alloys that can cope with it?
Also worth noting that the ore is shipped from Australia and other places to the nordics to get the cheaper smelting. But these large ships are not subject to regulation of emmistions or fuel in international waters. And so they burn bitumen like oil fractions that are very cheap.
There are other forms of carbon-neutral electricity—hydroelectric, solar, wind, tidal, nuclear; you can even capture carbon emissions from natural gas plants if there was a hard requirement to. Since we have to solve that problem anyway it’s a separate problem.
Also, aluminum and bauxite can be shipped to/from where it makes the most sense to process it.
That's a bad response when any comment could easily link to a relevant white paper. GP, MIT+INL had a nice report in 2006[1] covering a lot about that and the resource potential. The GeoVision[2] report and data from DOE is also a good and more recent project.
This is all true, Iceland is the worlds aluminum smelting hub. And the CO2 here is for the process.
However... what people fail to realize over and over is that the route for most of the worlds aluminum is from China to Iceland to China again. In tankers burning fuel like there is no tomorrow.
The biggest gain would be in how to refine the aluminum without shipping across the world twice.
Tankers are extremely energy efficient. A round trip journey from Reykjavik to Shanghai would consume about 90 kg of fuel per ton transported. Since 2 tons of alumina is converted to about 1 ton of aluminum, the round trip cost for aluminum is 135 kg of fuel, which generates about 420 kg of CO2. If the aluminum were produced using electricity from coal it would generate about 14,000 kg of CO2.
Of course, China wouldn't have to use coal if they chose not to, and cargo ship bunker fuel produces some very nasty pollution besides CO2, but in the world we live in it is far better for carbon emissions and probably for the environment in general, to use Iceland as the aluminum smelting hub.
> The biggest gain would be in how to refine the aluminum without shipping across the world twice.
I keep seeing this about "shipping" being a major contributor to greenhouse emissions but some brief googling shows it's only 2.2%. This seems very little considering how much is shipping across the oceans and compared to electricity generation and ground-based transport.
>The biggest gain would be in how to refine the aluminum without shipping across the world twice.
Yes, that'd be nice. People are working on solutions, but the only economically viable way to refine the material is to use a highly intensive electrolysis process. My quick google search is showing 17,000 kWh/ton of aluminum [1].
It's currently economically viable to refine in Iceland, but China is the #1 producer of raw aluminum [1] [2]. Iceland only has 3 smelters, and the combined capacity is less than the 9 largest smelters in the world, 2 of which are in China.
Citation [1] also has mentions of how much better the process of smelting has become.
>So, within 60 years, by improving the technology, fluoride emissions have been reduced more than 15 times (Table 2) and annual amounts of fluorinated residues have decreased from 1500 ton after WWII to 60 ton today.
From a purely energy standpoint, raw aluminum production has become vastly more efficient [4], with kWh/kg dropping from ~27 in 1940 to ~17 in 2000. The theoretical minimum is 5.99 kWh/kg [5]
> It's currently economically viable to refine in Iceland, but China is the #1 producer of raw aluminum [1] [2]. Iceland only has 3 smelters, and the combined capacity is less than the 9 largest smelters in the world, 2 of which are in China.
Great post, saved it for future reference!
Do you know how China powers their much larger smelters?
And do you know if these possible difference in aluminum smelting is considered when the carbon footprint for something like a mostly-aluminum Tesla is made?
>Do you know how China powers their much larger smelters?
Looks like largely coal. [1] This surprises me, as China has some truly massive hydroelectric generation stations which would be ideal for smelting.
>And do you know if these possible difference in aluminum smelting is considered when the carbon footprint for something like a mostly-aluminum Tesla is made?
I'm sure it's considered, but really don't know more than that. There is a big push in the manufacturing field to get ISO 14001 (environmental) certification. Many large manufacturers are requiring that of their suppliers. I'm unfamiliar how well the certification would allow tracing back emissions. Even if there were a higher carbon footprint on production, some of that can be cancelled out by better energy efficiency of the vehicles. The cost per pound and cost of repairs can be higher on aluminum.
Tesla, in its push to be economical, appears to be going with steel on the Model 3 (compared to aluminum on Model S).
>Chowdhry highlighted the key advantages of steel over aluminum as being the lower production equipment costs, the lower worker training/skill needed to work/operate steel, the lower compensation and cost savings of steel workers versus aluminum workers, and the lower repair costs. [2]
We've seen significant increases in aluminum per vehicle [3], though much slower than estimates from 40 years ago would have said. The CAFE standards implemented in the Obama era seemed to kick things into gear, notably with the Ford F-150 switching much if not all of its body to aluminum.
Right. Really what this article is about is a "technology" for "exporting" renewable electricity generation, which is a resource Iceland has in spades but has traditionally been hard to transport.
And it sounds like a great idea to me. It's just not particularly interesting from the perspective of aluminum smelting.
Don Sadoway has a really interesting MIT open course wear course on solid state chemistry.
I think it is in there where he mentions an interesting trade off between the environmental cost of making aluminium vs the long term savings of making, for example, car parts out of aluminium rather than say cast iron which they would have been made from in the past.
Which is to say, it's not immediately clear that increasing the cost of aluminium to encompass the externalities of shipping it is actually a net benefit to the planet as a whole.
I definitely agree that all externalities should be paid for but the co2 emissions from shipping are very low compared to producing aluminium from coal. This comment puts it at 3%
Beginning January 2020 ships worldwide are required to burn fuel with less than 0.5% sulphur or install scrubbers, so the problem has been greatly reduced. It's still way worse than regular diesel, but it's much better (about where diesel was at 30 years ago).
Hey! :) I wanted to edit my post, saying something like "one could argue over the (CO2-)economics of shipping large volumes back and forth", but then i mentally shrugged, seeing that this is how the world (currently) works. So i canceled the edit.
Yes that's true.
But as others have mentioned, there is a tendency to situate aluminum smelting in places with hydroelectric power (Brazil, Canada, etc.) if they have it, either for the environmental factor, just the fact you have a large source of power to use and it can't move. I think if an entity is trying to tackle sustainability, to some extent any innovation is innovation. If you try to swing for the fences every time no one may ever get on base.
depends - the alumina->Al part of Al production is often done in places with cheap, reliable electricity sources. Here in New Zealand it's all hydro power, no carbon emissions, but essentially burning carbon electrodes on the Al pot lines into CO2 is 5% of our national carbon emissions
The aluminum industry is notorious for having incredibly high energy requirements, and being price sensitive to changes in energy contracts. The economics behind smelters are challenging and at an unimaginable scale. Having an electricity interruption of more than a handful of hours can cause the aluminum in-process to solidify, causing tens of millions of dollars in damage to the smelter and requiring months to fix. This paper [2] describes a framework for making decisions to enter/exit a market based on variability of inputs, investment required to exit/enter, etc. While the example in the paper is focused around renewable energy, it can be applied to other types of facilities. We covered this paper for about 2 weeks during undergrad, which at the time was painful, but it was one of the most interesting papers and concepts I've read.
A great video outlining the refining process is available in [3]. Having worked there, I promise the safety at Alcoa is now far superior to what's shown in the video. Paul O'Neill hadn't become CEO yet [4].
[1] https://www.apple.com/newsroom/2018/05/apple-paves-the-way-f...
[2] https://www.imse.iastate.edu/wp-content/blogs.dir/16/files/2...
[3] https://www.youtube.com/watch?v=J5wPJp-hasU
[4] https://www.forbes.com/sites/roddwagner/2019/01/22/have-we-l...