[HN Gopher] New technology for aluminum production promises zero...
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New technology for aluminum production promises zero CO2 emission
Author : dagurp
Score : 92 points
Date : 2020-06-24 16:19 UTC (6 hours ago)
(HTM) web link (icelandmonitor.mbl.is)
(TXT) w3m dump (icelandmonitor.mbl.is)
| awinter-py wrote:
| > Iceland's three aluminum smelters ... emit more than 1.6
| million tons of CO2 a year ... 30 percent of Iceland's total CO2
| emissions
|
| this presumably doesn't include the volcanoes, which globally
| emit hundreds of millions of tons per year per this
|
| https://www.forbes.com/sites/startswithabang/2017/06/06/how-...
| Lavery wrote:
| Unfortunately, the volcanoes have thus far resisted public
| pressure to reform.
| catalogia wrote:
| Yes well plugging volcanoes up is a bad idea.
| Taniwha wrote:
| This would drop 5% of New Zealand's carbon emissions too
| DavidPeiffer wrote:
| 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].
|
| [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...
| briffle wrote:
| 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.
| ogre_codes wrote:
| > So now, Facebook, Microsoft, AWS, Google All built their
| datacenters there.
|
| Along with piles of bitcoin miners at least for a while.
| philipkglass wrote:
| 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.
| lb1lf wrote:
| > 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.
| DavidPeiffer wrote:
| 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?
| mrfusion wrote:
| How much energy is one soda can's worth of aluminum?
| philipkglass wrote:
| It's about 14.9 grams of aluminum:
|
| https://recycleusainc.com/how-many-aluminum-cans-equal-1-pou...
|
| Modern aluminum smelters consume 12,500 to 15,000 kilowatt
| hours per metric ton of metal produced:
|
| https://agmetalminer.com/2015/11/24/power-costs-the-producti...
|
| If we take the higher value of 15,000 kWh, that's
|
| (14.9 / 1000000) * 15000 = 0.22 kWh for one can's worth of
| aluminum.
| bufferoverflow wrote:
| Sounds like bullshit. Doesn't most of CO2 (in aluminum
| production) come from all the production of electricity that you
| need to smelt?
| probablypower wrote:
| 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.
| chrisco255 wrote:
| Correct me if I'm wrong, but geothermal is only useful in
| volcanically active regions, right?
| philwelch wrote:
| 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.
| [deleted]
| TheRealPomax wrote:
| wrong, but it's worth finding out why that's an incorrect
| assumption on your own. Don't trust comments on the
| internet.
| cwal37 wrote:
| 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.
|
| [1] https://energy.mit.edu/wp-
| content/uploads/2006/11/MITEI-The-...
|
| [2] https://www.energy.gov/eere/geothermal/geovision
| SV_BubbleTime wrote:
| 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.
| sacred_numbers wrote:
| 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.
| ClumsyPilot wrote:
| There are only two options i can think of, bith of them are
| daynting: massive transmission line across the oceans, or
| nuclear powered cargo ships.
| VBprogrammer wrote:
| Probably not a very popular option but Chinese nuclear
| power stations would also do the job.
| DavidPeiffer wrote:
| >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]
|
| [1]
| https://www.sciencedirect.com/topics/engineering/aluminum-
| pr...
|
| [2] https://en.wikipedia.org/wiki/List_of_countries_by_prim
| ary_a...
|
| [3]
| https://en.wikipedia.org/wiki/List_of_aluminium_smelters
|
| [4] https://www1.eere.energy.gov/manufacturing/resources/al
| uminu... (page 40 of the PDF, numbered 25 on the page)
|
| [5] https://www.aceee.org/files/proceedings/2003/data/paper
| s/SS0...
| kanox wrote:
| > 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.
|
| https://ourworldindata.org/grapher/ghg-emissions-by-sector
| diroussel wrote:
| 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.
| twic wrote:
| > 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.
|
| [1] https://en.wikipedia.org/wiki/Prebaked_Consumable_Carbon_
| Ano...
|
| [2] https://chemistry.stackexchange.com/questions/6774/why-
| do-th...
|
| [3] https://en.wikipedia.org/wiki/Fire
| twic wrote:
| 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.
| catalogia wrote:
| 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?
| Taniwha wrote:
| 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
| LargoLasskhyfv wrote:
| Not for their location, they have 99,9% electricity by
| geothermal and hydroelectric, as in _renewable_.
|
| _That_ is what makes it economical to _ship_ bauxite from all
| over the world there, and have it manufactured to aluminum, and
| exported.
|
| So this is a nice topping on the cake, to have even some of the
| last bits of CO2 from the process eliminated.
|
| I don't see why this wouldn't apply to other sites elsewhere.
| How _they_ generate their elictricity is another matter.
| pengaru wrote:
| Now if only we could get the externalities of burning all
| that bunker fuel shipping the bauxite paid for up front...
| mhandley wrote:
| One possible solution there would be Green Ammonia, which
| Iceland is also well placed to produce:
|
| https://royalsociety.org/topics-policy/projects/low-
| carbon-e...
| thinkcontext wrote:
| 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%
|
| https://news.ycombinator.com/item?id=23632148
| pengaru wrote:
| Which would be great if co2 were all they emitted,
| burning bunker fuel is very dirty. Of all forms of
| emissions co2 is relatively harmless.
| VBprogrammer wrote:
| 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.
| LargoLasskhyfv wrote:
| 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.
| ajross wrote:
| 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.
| gimmeThaBeet wrote:
| 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.
| hannob wrote:
| 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.
| philwelch wrote:
| A surfeit of technical solutions and a lack of social and
| political solutions define our age.
| wolfi1 wrote:
| 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
| jeffdavis wrote:
| "using multiple, vertical inert metal-alloy anodes and ceramic
| cathodes"
|
| What is the process? Why was it hard before, and why does it work
| now?
|
| I'm not expecting a thorough analysis, but the article was _very_
| light on what they are actually doing, even for a casual reader.
| thepangolino wrote:
| Could be a matter of finding the right alloys to act as
| catalyst.
| hinkley wrote:
| 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.
| travisporter wrote:
| Would love to watch it! Is there a good youtube channel or book
| for this sort of ISRU stuff? The ones I have found are too
| hand-wavy
| hinkley wrote:
| Pretty sure this is the one:
|
| https://www.youtube.com/watch?v=-dL28N5yPmQ (October 2018)
| BorisTheBrave wrote:
| > potential game changer for lunar colonization
|
| It's featured in the presmise of Artemis by Andy Weir.
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