The world's first process for making zero emissions cement

[@MikeTrieu]

Using old cement to purify steel to purify cement. There's something beautiful about that circular process.

[@sjsomething4936]

💯!

[@opticalreticle]

purified steal

[@SG-ni8tk]

There’s beauty and then there’s cost effectiveness. There’s no way this could be comparable… unless in missing something

[@KickCaesar]

It does make me wonder if it can be done again after it's been used for the steel and as cement

[@cally01]

Gotta love the circular economy!!

[@justinlipkin]

They've actually explained it really well rather than keeping the key facts either super complex or hidden out of the way

[@omniphore4913]

What all companies that actually care about change should do. Selflessness

[@damham5689]

I hope you succeed with this. Back in the 1980s my brother was a chemist developing asphalt for a US subsidiarity of Elf Aquitaine. He would occasionally go on job sites to check product and application. Then a new process and machine was developed that could rip up the old asphalt, shred it, reheat it, apply a few additives, and repave a road with it. It was not only good because it recycling existing asphalt, but it was cheaper. What happened. Asphalt companies bribed state legislators to require new asphalt be used on all state jobs, making it impossible to recycle, and sued to run the company out of business.

[@SJR_Media_Group]

WOW... great thinking outside the box... if it scales up to millions of tons per year that is a new beginning for cement... this solves 2 problems... recycling old concrete and recreating new cement to be used in concrete again... I see a Nobel Prize coming to your team...

[@SG-ni8tk]

Let’s do some quick math. How many tons of steel does the world use each year vs cement??

[@Humanity101-zp4sq]

What a joker!

[@carlosdumbratzen6332]

When I read this paper I was amazed. This was stuff I actually dreamed about as a kid. I really hope this can be scaled

[@crawkn]

We need to know about the economics, as well as safety. The entirety of the process involves transport of waste concrete, transport of cement dust, and processing of slag to remove or stabilize toxic impurities. I assume someone has done the calculations to determine if it is theoretically economically efficient.

[@pscheie]

That doesn't sound any more complex than the current processes for making steel and cement which involve lots of mining of raw minerals, transporting those minerals, and then subjecting them to enormous amounts of heat multiple times, splitting off higher and lower grade outputs, etc.

[@KajSeVai]

Agreed. I think it's viable in and of itself because many investors are willing to pay a premium for having an emission-free product, but with enough automation of logistics this will be incredibly profitable it's just a series of questions of: how do we get there?

[@SG-ni8tk]

Exactly, this report is interesting but not the cure

[@HomeFromFarAway]

Given that most new cement is not mined or refined near the cities it's used in, this is probably a huge saving in resource and cost already: essentially as old buildings are taken down to make way for new structures, they become the raw material that's already much of the way to flux-ready state. my main concern would be the proportion of steel to flux being a sensible ratio for the usage rates

[@IntertemporalTraveler]

I think in this case it might be better to not let perfect be the enemy of the good. I get wanting to have everything neutral throughout the chain, but that’s really just not entirely possible in our current world.

[@sjsomething4936]

So glad to hear that smart minds are focused on solving all of these kinds of problems, mankind has been behaving as if profligate energy use and everything being disposable won’t have consequences, we’re now clearly seeing that isn’t the case and hopefully we still have time to fix our processes and behaviours.

[@nathanwforrest]

If finely ground reclaimed cement paste carbonates (reabsorbs CO2) by virtue of its large surface area, what becomes of that CO2 when the material becomes heated beyond calcination temperatures in an EAF?

[@franimal86]

I was thinking, if the CO2 gets released, could some of it be captured and used to power the furnace? I read that about half of the CO2 that gets released during calcination gets reabsorbed when the concrete hardens, so your question is still relevant.

[@napalmholocaust9093]

You can just put sand and slaked lime in a bucket and pour some sodium fluorate or some such (I have it in an old book) on it. It was done to save marble statutes that were more or less chalk after thousands of years in wet ground. Method for hardening stone 1910-ish.

[@laurisafine7932]

I'm here because I wish to make a non-toxic, mini-pizza and/or emergency oven 😊 and possibly some flower pots and sculptures in the future 🙄🤗.

[@RaglansElectricBaboon]

Seems obvious in hindsight. Which means its probably a very good idea :) Well done, I hope it scales well & _fast_

[@brianredbeard]

TIL: Concrete can be used as flux in steel making. 🤔

[@BenjaminGoldberg1]

You mean cement. The gravel and sand have to be separated out.

[@crashmancer]

Portland cement is limestone, and flux is limestone. Pretty elegant really.

[@scottycatman]

Fantastic discovery, and a brilliant presentation. It's great to see the honesty of "We think it's going to be the next big thing, but we're not going to say so with absolute certainty".

[@AndyNicholson]

As part of the rapid cooling process could you harness something akin to a large industrial peltier to draw the heat out of the new material and simultaneously heat water to power a steam turbine for electricity generation to partially claim back some of that energy used in that process too? I guess it wouldn't be a large amount reclaimed, but given the large amount of energy in total only reclaiming a fraction in this process could potentially still be useful.

[@alexlowe2054]

The big problem with peltiers, is that they consume an ungodly amount of electricity. I doubt the cost of running that specific type of heat transfer would work out economically or environmentally. But I'm sure that there's some way to reclaim some of the heat.

[@316jun]

How do you separate the sand from the debris?

[@alexwilsonpottery3733]

Calcium carbonate is lighter than silica

[@jessyjoseph511]

Very good 🎉🎉

[@jjbug1951]

Could this cement be infinetely recycled with minimal degredation?

[@SeedFactoryProject]

This is currently unknown. You would need to make a concrete test structure using this recycled cement, then demolish it and recycle a second time. So you have fresh new cement made the old way, a structure made with cement recycled once, and another with cement recycled twice. Each time you test how strong the structure is, and see if there is any loss in properties. Concrete structures can last a long time, and not every project needs the highest strength. So in theory you could keep using the stuff for hundreds of years with it getting recycled and used in lower strength projects each time. You get much lower lifetime emissions that way. The reason new cement emits so much CO2 is you have to heat it to very high temperatures, and mostly today we burn something in a furnace to get the heat. In principle we could have a renewable energy source for the furnace to reduce the original emissions. That would make it a fully clean process.

[@BenjaminGoldberg1]

Yes, but no. In order to make alite instead of blite, some amount of lime needs to go into the foundry with the recycled cement. Lime is made by from limestone, with co2 as a byproduct.

[@MrAgreeandDisagree]

Original creation of cement also releases CO2 from the material itself, as well as the CO2 from the energy used to do so.

[@jjbug1951]

Thanks!

[@davestagner]

@@SeedFactoryProjectThe required heat is only half the Portland cement CO2 problem. The other is the raw material - calcium carbonate (aka limestone). The process of making Portland cement frees CO2 from the limestone, which is the source of about half the CO2 associated with cement making.

[@rjung_ch]

If this scales, this would be a huge win for the planet!

[@cospittner3526]

What a brilliant idea. I hope it can be accomplished!

[@Vort_tm]

All the senseless destruction across the world has me incredibly worried about the emissions costs of reconstruction. It is some small reassurance that people are making progress in ways to do it in a responsible manner.

[@Humanity101-zp4sq]

This is obfuscatory nonsense...

[@woutmoerman711]

Very hopeful development!

[@OneofMyTurns]

Pretty cool just like the guys found away to reuse old tires for potholes!!

[@scottprather5645]

Love this 👍 using technology and innovation to solve important issues that's a win-win

[@Andrew-rc3vh]

You can improve on that process further by using a medium to store heat energy at very high temperatures so it is available for your furnace when you need it, thereby flattening out the demand curve for electricity and enabling electricity to be purchased at a lower price.

[@joeybream5247]

Incredible. Good job

[@heidilady]

This looks very energy intensive

[@henkmagnetic3103]

Amazing. It's the process and effort of scientific endeavour/discovery, and the great minds that tackle these challenges in front of us all that captivates me.

[@benboys_]

This sounds like a great innovation!

[@Dude29]

I hope this works well and has a future

[@stuz32]

Fantastic work!

[@dec335]

Amazing 👏

[@fredlarson-s1t]

Well done.

[@fliprim]

Potentially huge.

[@davidblackwell614]

Thank you 🙏

[@kabuto3907]

Does this need any extra energy for recycling a given amount of steel compared to using traditional flux? I‘m wondering because recycling cement involves separating out the chemically bound CO2 through heat which is an endothermic process (IIRC) and thus I wouldn’t be surprised if this actually costs a bit of extra energy to compensate for the energy lost by that chemical reaction.

[@Sugar3Glider]

Crushing concrete into a fine powder seems energy intensive, but still a neat discovery.

[@HomeFromFarAway]

valid, but probably less intensive than pit mines, refining and transportation processes we already use for making fresh cement

[@kristianl7117]

The entire process is, but as he said the key is renewable energy.

[@MurrayBishop-g4g]

Thanks for sharing this news. Go you good things!

[@user-pt1ow8hx5l]

Thank you. Wonderful effort. Congratulations seems in order. Two other routes are viable. Too. But none preclude the other. What's needed then, is strong regulation. The price of cement is a minor item in the total costs of buildings. And bridges. And sewage systems...... sincerly from Copenhagen; the town where Portland cement was invented, i am told.

[@Living_Water274]

So what’s the problem with greenhouse gases?

[@toi_techno]

Well done CU

[@funnycrash88]

I work in the white cement industry. This is interesting :)

[@davestagner]

This is exciting, but is it the first process for zero emissions cement? I’m thinking of others working in the same space - Brimstone makes something chemically identical to Portland cement without limestone. Sublime (developed at MIT) makes cement that is functionally (not chemically) identical to Portland cement, using electrolysis rather than heat for the chemical process. Neither uses limestone, which is the source of half the carbon footprint of Portland cement.

[@rubidot]

That's amazing

[@SrikarKura]

Super!

[@roe2012]

This help people to not lose hope on "there's still future of humankind" instead climate apocalypse, meanwhile theres genocide in earth. So depressing.

[@sanwerlalprajapati4773]

Verry good

[@thomaskelly2881]

so it quicklime for portland cement

[@marundale]

Looks promising and hopefully implementable but as others have commented a lot rests on the energy cost and distribution economics? Have you also looked at making synthetic limestone using CO2 emissions from industry which would actually be carbon negative?

[@BrandnyNikes]

This almost sounds too good to be true. Fingers crossed it work out.

[@spoonikle]

The only issue is… you cant make that much cement like this. This process is kind of limited by how much steel you’re recycling.

[@davidmende3409]

I would like to see a more technical / chemical explanation of how and why this works 🤔 because from the footage and the end result being shown it seems like glass & i want to know how this becomes cement once more

[@Eveseptir]

Now we need to find a way to turn desert sand into something more resembling river sand, cause we are running out of the stuff and tearing up the environment to get it.

[@tonyprice1526]

In principle, it's a good idea. But from a mass balance point of view, i dont think it adds up. Likely recycled cement will be a few percent of demand in practice. Contrast that with steel and electro furnaces. Green energy firing established technology, and we have a faster win. Extend that to smelting ore by modified electrolysis using cell technology similar to aluminium refining but for iron ore feedstock and the whole of steel production could be transformed.

[@vivekpraseed918]

This can help recycle old cement into new..but not really create new cement right? Did i miss anything?

[@c.mccracken]

hold up, hasn't blast furnace slag cement been a thing for years?

[@JxH]

*PROBLEM* -- There's not enough steel production to supply enough ex-flux recycled clinker for the world's demand of cement. Evidence for this is as follows: Every town has a cement plant. Every nation has a handful of steel plants. There's a gap of at least two orders of magnitude, maybe three.

[@offmeds2nite]

Its nice but i don't think the scale works with the ratio of cement used as fluux to the steel produced annually

[@gabrielfinneran3611]

Ok but there's not as many old buildings as new ones, maybe like he mentioned blending helps a little but we build everything with concrete now and those buildings last decades.

[@MelindaGreen]

It may be helpful but it doesn't seem like a solution. You still need a source of concrete to recycle, and there needs to be enough steel production to produce enough to matter.

[@danielc6106]

Great if it works. Good luck to them. Good for the planet, too.

[@muktadirbhuyan7281]

Isn't japan already using carbon negative cement, it's seems you guys are one step behind.

[@AndyNicholson]

Have you got any links to papers or products about this please?

[@SuperJay217]

Cambridge uni vs some random in the comment section

[@OffGridInvestor]

THE SOVIETS were doing this without even trying. Using aluminium slag as aggregate

[@christopherleblanc9599]

when one removes the box what is left is endless possibility ,until government makes a box for it to fit back into

[@djtomoy]

I love cement, it tastes sooo good, oh wait I was thinking of chocolate ice cream 😬

[@AreHan1991]

Wow! 😄

[@bartroberts1514]

The Geopolymer Institute may have helpful things to say in regard to this process, while creating a future free from OPC, with stronger, less expensive, longer-lasting, faster curing net negative concrete that better accepts biochar aggregate.

[@dodgygoose3054]

Its interesting how you are merging industries to create a recycle loop ... I hope you get government backing with laws & subsidies to make industries change.

[@lupus7297]

The highest demand for cement is in countries that have little concrete buildings to demolish and extract cement paste to then use for recycling. While this certainly is an innovative new process it will do little to fundamentally solve the binder problem. Rather than optimizing cement further and sinking more financial resources into it we should focus on proven disruptive sustainable technologies. Cambridge has one of the best examples, the Queens Building Emmanuel College by Buro Happold and Hopkins Architects…

[@40KTTR]

Make sure then, that the energy for recycling the old concrete is also net zero. Also grinding old concrete to a fine powder is immensly inefficient energy wise. The presented "new cement" is nothing more then a ordinary CEM III with extra steps.

[@Optimizemore]

Great with recycling. Only way to true sustainability. For new zero emission cement the Swedish company SaltX have a new technique that make the klinker zero emission.

[@petewright4640]

The process requires used cement. It's clear that this is limited and won't provide for all the demand for new cement. Not saying this development isn't usful but it won't decarbonize global cement production.

[@Hector-bj3ls]

Using excess renewable energy to heat sand or carbon and then use that heat in industry. That's my big idea right now.

[@artysanmobile]

There really is.

[@samjl4]

This only works if we have a thriving steel industry, and it’s almost gone.

[@monkeyfist.348]

I wouldn't call it zero emissions, as it requires the emissions to melt the steel. Still, it is an elegant solution to a most serious issue. We need to work on the emissions from steel now. This process could go further if CO2 could be inhected into the cement later. Or if the cement could sequester CO2 from the air or water, like the Romans did.

[@jamesalanstephensmith7930]

Go green!

[@MyKharli]

Only a hundred years to late ! Still might help a weeny bit .

[@3d1e00]

Unfortunately due to primarily the plastic industries corruption of recycling, I don't really believe it until the details come out. What's the quality of the recycled concrete? How can you verify that concrete can go though this process? I wish you all the luck in the world and hope this is all coming from the right perspective of climate security not profit security.

[@arcanondrum6543]

There's a comment on here; worried about _"the economics"_ but I don't recall him complaining about _"the economics"_ of the _"transport"_ of millions of tons of coal, slag and limestone for the current process. Perhaps that person is advocating for 'business as usual' because his interests lie with Mining Corporations??

[@Conus426]

Finally.

[@yatesy117]

Cool 👍👍

[@Pyramidtank]

I think if they look into nanotechnology more this issue could have more options

[@rammedeartheu]

Say it quickly and it sounds like it's emissions free. But the feed stock is cement, a high emission material whose co2 is still in the atmosphere. Then there is the intermediate energy to process the cement out of the demolition materials. Then there is the heat for the steel processing which "in the future" could be carbon free. If remains the biggest word in the English language, we are a long way from carbon free electricity. This just plays into the hands of highly polluting corporations and their willing lackies

[@i.kanishka7703]

I wait for your reply from Cambridge University....

[@morlanius]

Innovations like this is what we need, not things that make people poorer and/or more miserable.

[@neriksen]

I applaud the enthusiasm but doubt the the claim.

[@chrissonnenschein6634]

You still need “non-zero emission machines” to grind & process the concrete and the machines used are made from materials not even close to “zero emission”...

[@BenjaminGoldberg1]

You are missing the point. The steel is already being recycled in arc furnaces, and when recycled cement is used as flux, the SAME AMOUNT of electricity is used compared to steel making with normal flux. No more electricity is being used than normal.

[@camazotzz]

so we can continue to pave the earth without adding as much CO2 to the atmosphere, great

[@adam-g7crq]

It's sounds a great idea, but there's a lot of alternatives to steel now with other composite materials being used instead of steel, so how much production of steel would you need to match the demand for concrete.

[@EcomCarl]

Innovative approach to zero emissions cement! 🌍 Recycling old cement paste as a flux in steel-making could truly revolutionize the industry and significantly reduce environmental impact.

[@franimal86]

I’d rather reuse concrete structures instead of demolishing them to make more new concrete structures. Seems more sustainable without all the extra steps This is fine, though, if you’re going to demolish something, anyway - might as well recycle the concrete.

[@Anthony251]

This is kind of misleading because the massive temperatures of the furnace needed to melt steel isnt so far being done carbon free, efficiently on a large scale UNTIL then its just talk.

[@_Inevitability_]

Came for the human ingenuity. Found instead one of the cornerstones of capitalism... "We have the patent"

[@KristianSrensen-tw9lo]

cement das conk creet baybee

[@srpacific]

Zero emissions? How stupid do you think we are. Steel production is the most energy intensive activity on the planet and it’s not slowing down or getting cleaner; in fact, it’s getting worse

[@tyalikanky]

Only if electricity is from nuclear energy.

[@tristanboyle4450]

thats a nice fix.. but what about using dirt instead of cement?

[@sauravayyagari7606]

what about hempcrete or rammer earth as alternatives?

[@scotthare9670]

John Oliver’s older brother

[@napalmholocaust9093]

You don't blow oxegen through that dirty steel? What about the lead, cadmium and arsenic impurities? You're not doing this with "shred". There is a lot more shred than clean red iron beams getting recycled.