Running the numbers on a zero-emission way to make cement

Limestone might not be the only source for Portland cement.

See full article...

 

[clackerd]

concrete solutions are welcome

Dammit I hate that I love this

(great article)

 

[Wheels Of Confusion]

Always great to see Scott writing for Ars again!

But there is another interesting aspect to this idea: The other components of the basalt also have value. Iron, magnesium, and aluminum could also be separated and recovered, and leftover silicate material can serve as the additive for Portland cement instead of something like coal ash. So if these things were done together, the process could become more economically feasible.

So in a way it'd be almost analogous to the petrochemical refining process rather than traditional metal ore: raw material goes in, various magic happens in a step-by-step process, several valuable outputs are extracted at different stages, not just a single metal and accompanying waste stream.
In this case, instead of crude it's basalt, and instead of diesel and naptha and petrolatum you'd have aluminum, sad, and cement.

 

[barrattm]

That's an interesting idea.

I wonder if there's an extension. The other problematic aspect of cement / concrete is the need to mix it with sand. And sand is in short supply; folk are increasingly digging up environments they really shouldn't (either because they're natural wonders, or because they belong to someone else, or both). If in crushing and processing basalt they could have a sand-like product too (maybe the bits of rock that don't doing into the cement?), then that could be completely transformational. Low / no emissions, and no more sand quarrying. I've no idea if its at all feasible, but it'd be cool if it were.

 

[Dassassin]

My understanding is that the beauty (and pain) of CaCO3 is that it just takes heat to free up the Calcium and turn it into Portland cement ("driving off" the CO2).

The paper proposes dissolving silicate minerals in hydrochloric acid then precipitating the calcium hydroxide. That's insane, right? Impossible at scale even remaking the HCl via electrolysis as the last step? Driving off CO2 from CaCO3 is so straightforward (and admittedly harmful) that it's hard to imagine a world where we replace "heat rock up" with HCl -> precipitate with NaOH -> clinker Ca(OH)2 -> electrolyze NaCl -> repeat.

 

[nartreb]

There's a company in Massachusetts that's been trying to commercialize this process for years (starting with the easy part, using electric furnaces instead of carbon-fueled ones). They were starting to build a factory when their federal grant got suddenly cancelled, which led to a board shakeup and major layoffs. They're basically walking dead at this point, with the DOE stalling them about the grant and no new investors stepping up that I can see. Seems they might have done better with a more aggressive legal strategy to get their grant back:
https://www.latitudemedia.com/news/...to-be-the-bellwether-for-canceled-doe-grants/

 

[rbf072858]

"The material we call “Portland cement” was developed in the 1800s"

Uh... See Roman cement; made in the same way. Heating limestone and seashells (both are calcium carbonate). Differing additives made different kinds of cement. It took until about 20 years ago to re-discover that volcanic ash made Roman cement self-healing under seawater.

 

[Kavinsky]

...

In this case, instead of crude it's basalt, and instead of diesel and naptha and petrolatum you'd have aluminum, sad, and cement.

Superb typo, I insist you leave it up.

You do indeed get an output of Sad - from the companies that go out of business if this works at scale (note, it's not that different from what we do with Aluminium, where the main input is energy, so we just . . . process it in NZ and Iceland, where cheap, abundant, renewable energy is.

 

[noahmayer]

Just yesterday I went down a rabbit hole on ways to reduce CO2 emissions in cement and steel. Cement is going to take a while to reduce as different kilns or materials that don't require kilns will take years to set up supply lines. Completely worth it as cement is a major CO2 contributor world wide, so that's something we really need to tackle. Lotta different ways to approach it to reduce CO2, including CO2 capture, injecting CO2 during concrete mixing, replacing some clinker with calcined clay, using green hydrogen as a fuel, recycling material into the mix, etc.

 

[SomewhereAroundBarstow]

"The material we call “Portland cement” was developed in the 1800s"

Uh... See Roman cement; made in the same way. Heating limestone and seashells (both are calcium carbonate). Differing additives made different kinds of cement. It took until about 20 years ago to re-discover that volcanic ash made Roman cement self-healing under seawater.

Yes, but we call that "Roman cement." The process may be the same but process and formulation are different things, as you illustrate in your final sentence.

 

[SomewhereAroundBarstow]

Sitting here on the edge of the Columbia Basalts I find this idea very intriguing.

 

[norton_I]

The paper proposes dissolving silicate minerals in hydrochloric acid then precipitating the calcium hydroxide. That's insane, right? Impossible at scale even remaking the HCl via electrolysis as the last step? Driving off CO2 from CaCO3 is so straightforward (and admittedly harmful) that it's hard to imagine a world where we replace "heat rock up" with HCl -> precipitate with NaOH -> clinker Ca(OH)2 -> electrolyze NaCl -> repeat.

I hear you, but also look at the level of chemical processing we do for oil, which is produced in similar quantity as cement.

 

[RetconRob]

The dream of concrete is dying in Portland.

 

[Alex Enders]

Obligatory (?) Veritasium episode, where Derek does a great job explaining how concrete is made, and why Roman cement is so darned good, even after all these years.

View: https://www.youtube.com/watch?v=rWVAzS5duAs

 

[Ceedave]

From the article

Basalt contains a mix of minerals that include calcium, aluminum, iron, magnesium, sodium, silicon, and oxygen.

A few of those elements occur relatively rarely as minerals (iron in meteorites), but most of these elements don't occur as natural, fixed composition, crystalline forms…that is, not as minerals. Important minerals in basalt include olivine, pyroxenes, and plagioclase feldspar.

Many of these minerals, especially olivine, sequester CO₂ when weathering, so that might add more benefit.

 

[spacespektr]

The authors of the new paper include the CEO and an engineer from a company that says it has made Portland cement from silicate rocks like basalt—at the lab scale.

From the Nature article (open access!) the company is Brimstone out of Reno, Nevada.

 

[SeeUnknown]

There's a company in Massachusetts that's been trying to commercialize this process for years (starting with the easy part, using electric furnaces instead of carbon-fueled ones). They were starting to build a factory when their federal grant got suddenly cancelled, which led to a board shakeup and major layoffs. They're basically walking dead at this point, with the DOE stalling them about the grant and no new investors stepping up that I can see. Seems they might have done better with a more aggressive legal strategy to get their grant back:
https://www.latitudemedia.com/news/...to-be-the-bellwether-for-canceled-doe-grants/

Taco strikes again

 

[GenericAnimeBoy]

And given that cement is one of the tougher nuts to crack in the struggle to reduce global greenhouse gas emissions, concrete solutions are welcome.

 

[agt499]

Superb typo, I insist you leave it up.

You do indeed get an output of Sad - from the companies that go out of business if this works at scale (note, it's not that different from what we do with Aluminium, where the main input is energy, so we just . . . process it in NZ and Iceland, where cheap, abundant, renewable energy is.

Re Aluminium, in NZ the abundant renewable energy is cheap for the Rio Tinto smelter (due to sweetheart contracts backed by government eg. taxpayers ).
It is not cheap for we consumers.

Edit: I made a similar remark re the Lake Tahoe power article yesterday and only just noted this reply from @taxythingy, which is infuriatingly on point

Just for context, five minutes ago they were pulling around 800MW from a total national load of 4826MW, so between 1:6 and 1:7 of the total, depending on time of day and season.

 

[radarskiy]

The dream of concrete is dying in Portland.

It's where old rocks go to retire.

 

[llanitedave]

"The material we call “Portland cement” was developed in the 1800s"

Uh... See Roman cement; made in the same way. Heating limestone and seashells (both are calcium carbonate). Differing additives made different kinds of cement. It took until about 20 years ago to re-discover that volcanic ash made Roman cement self-healing under seawater.

And the way it's self healing is by re-absorbing the carbon dioxide that was originally emitted during its manufacture, to generate calcite crystals that seal the cracks. So the emissions calculations for hydraulic concrete should be (I would guess already are) adjusted for the CO2 that's resorbed over time.

 

[Boskone]

One thing to note re: the memetic benefits of Roman concrete, is that it requires relatively huge amounts.

A common house slab of Roman concrete would be several times the size of one poured from Portland cement.

There are uses and benefits for it, but it's not perfectly fungible with Portland.

 

[jock2nerd]

That's an interesting idea.

I wonder if there's an extension. The other problematic aspect of cement / concrete is the need to mix it with sand. And sand is in short supply; folk are increasingly digging up environments they really shouldn't (either because they're natural wonders, or because they belong to someone else, or both). If in crushing and processing basalt they could have a sand-like product too (maybe the bits of rock that don't doing into the cement?), then that could be completely transformational. Low / no emissions, and no more sand quarrying. I've no idea if its at all feasible, but it'd be cool if it were.

This article, plus your idea, combine to be a "good start" on updating the formula for Portland cement to greatly reduce CO² emissions.

 

[crazy_vag]

Over time, concrete will degrade and fall apart. Doesn't that chemical reaction actually take CO2 out of the air? In effect, all the concrete we have made, is slowly dedgrading and offseting the original emissions needed to make it?

 

[Fatesrider]

Toss that in a kiln with additives of your choice, and with less heating than you need for limestone, you’ve got Portland cement, with only water vapor released.

Um... What a about this?

Given the compounding effects of water vapor on climate change, and the ubiquity of construction with concrete, I'm not sure "only" applies.

I mean, if concrete production and use creates 8% of climate change issues, but water vapor adds 50% to the problem of increasing the heat capacity of the atmosphere, is that still a net plus for water vapor over carbon, given the apparently smaller amount of energy used in the new way to create the concrete in the first place?

My maths don't want to work well today, but seems to me that's a legitimate consideration.

 

[graylshaped]

Found the thing we could spend energy on other than chatbots!

 

[nartreb]

Over time, concrete will degrade and fall apart. Doesn't that chemical reaction actually take CO2 out of the air? In effect, all the concrete we have made, is slowly dedgrading and offseting the original emissions needed to make it?

Sure, let's assume that's completely correct. (Which it isn't, you'd need a 100% efficient fabrication process.) How long does that degradation take? (Hint: the Colosseum was built of concrete.)
Given we need to be cutting atmospheric carbon emissions NOW, not 4000 years from now, it doesn't actually help us.

 

[real mikeb_60]

Superb typo, I insist you leave it up.

You do indeed get an output of Sad - from the companies that go out of business if this works at scale (note, it's not that different from what we do with Aluminium, where the main input is energy, so we just . . . process it in NZ and Iceland, where cheap, abundant, renewable energy is.

The NW US was a focus for aluminum production during WW2 for a number of reasons, but chiefly because hydroelectric power from the Columbia River was cheap and abundant. Same reason, of course, that AI datacenters are moving there now. If there's any power left after the AI people are done, that might be a good area to locate this alternative cement production (if it works at scale). A bonus, of course, is that much of inland WA and OR is covered by a flood-basalt plateau, so the raw material wouldn't have to be hauled very far,

 

[real mikeb_60]

Um... What a about this?

Given the compounding effects of water vapor on climate change, and the ubiquity of construction with concrete, I'm not sure "only" applies.

I mean, if concrete production and use creates 8% of climate change issues, but water vapor adds 50% to the problem of increasing the heat capacity of the atmosphere, is that still a net plus for water vapor over carbon, given the apparently smaller amount of energy used in the new way to create the concrete in the first place?

My maths don't want to work well today, but seems to me that's a legitimate consideration.

My impression is that the water cycle is quick, perhaps even better than the methane cycle, when it comes to removing moderate excess amounts from the atmosphere (once the excess production ends, of course). Both operate on time scales that are potentially observable in human-species-relevant (though probably not for individuals) timelines.

CO2 otoh takes thousands of years to be removed by vegetation and weathering of rocks (and, yes, concrete) in amounts that observably and usefully change the atmosphere, even after actual (not just net) zero human addition is achieved. So the kind of excess already being added is likely to make things difficult if not unsurvivable for humans (and many other species) for a long time. Hence the concern about mass extinction.

All of them can, of course, be pushed to levels that are effectively unrecoverable in less than geological time, even if things don't go as far as tipping into a Venusian state.

 

[theotherjim]

Um... What a about this?

Given the compounding effects of water vapor on climate change, and the ubiquity of construction with concrete, I'm not sure "only" applies.

I mean, if concrete production and use creates 8% of climate change issues, but water vapor adds 50% to the problem of increasing the heat capacity of the atmosphere, is that still a net plus for water vapor over carbon, given the apparently smaller amount of energy used in the new way to create the concrete in the first place?

My maths don't want to work well today, but seems to me that's a legitimate consideration.

Hot water vapor can be trivially condensed into liquid water if desired. And as noted by @real mikeb_60, it's going to equilibrate between vapor, liquid, and solid forms in the atmosphere really quickly anyway. So yes it's a greenhouse gas,, but it's not one we can control very well other than by lowering the temperature of the atmosphere and oceans. Which we're doing a craptastic job of.

 

[SomewhereAroundBarstow]

The NW US was a focus for aluminum production during WW2 for a number of reasons, but chiefly because hydroelectric power from the Columbia River was cheap and abundant. Same reason, of course, that AI datacenters are moving there now. If there's any power left after the AI people are done, that might be a good area to locate this alternative cement production (if it works at scale). A bonus, of course, is that much of inland WA and OR is covered by a flood-basalt plateau, so the raw material wouldn't have to be hauled very far,

Funny thing. I happen to know where there is an enormous disused aluminum smelter with high tension lines running straight to it from the Grand Coulee Dam.