"This concealed the underlying process until an investigation by Jeff Severinghaus and Wallace Broecker of Columbia University's Lamont Doherty Earth Observatory using isotopic analysis showed that carbon dioxide was reacting with exposed concrete inside Biosphere 2 to form calcium carbonate in a process called carbonatation, thereby sequestering both carbon and oxygen."
That was one of the most unexpectedly crazy Wikipedia articles I've ever read. The level of intrigue seems completely out of proportion with what the project is. Steve Bannon (yes, that Steve Bannon) makes an appearance, a hostile takeover occurs, Federal Marshals and local police are called in on 2 separate occasions, former employees sabotage the site, experiments go awry, accusations of research fraud are constantly thrown around. It sounds like the plot of a TV show about a research project.
There is, this episode was so unfunny we stopped watching the series. I don’t know how you can have that much talent in a potentially funny space and blow it that bad.
Yeah, I couldn't finish it. Lost interest after the monkey episode. Wisecrack did a criticism video on YouTube that I thought had some fair points: https://youtu.be/49v6m7jQPaQ
Biosphere 2 was very inspiring. The name felt a bit corny but it was a good brand and they should have extended it to the missions: the first crew would have performed Mission 2, etc.
The fundamental project conflict between — as I understanded them — we’re here to prove this works vs we’re here to learn and iterate is fascinating food for thought.
The organic soil was too rich, resulting excess carbon that that could not be absorbed by photosynthesis. Concrete absorbed excess CO2 and that removed too much O2 (oxygen) causing problems.
Farmer Bob Cannard of Napa has been saying this for 25 something years now. All that I knew about growing, I know from him and his students. Even though I never had the opportunity to learn from him, I absorbed second and third hand. Farmers have enormous knowledge of earth and plants and trees. I wish they’d be given the recognition they deserve as domain experts. We are just wasting time.
What exactly has he been saying? That rock weathering captures CO2 has been known for at least 30 years (https://www.nature.com/articles/345486b0, from 1990, introduced the idea to crush rock to speed up the process)
This paper estimates how much carbon could be captured globally and at what price point.
It would not surprise me if farmers have been saying the first for decades, but it would surprise me if they already did those calculations decades ago.
This is a red herring. Consuming energy doesn't produce CO2, generating the energy does. The answer to "how much CO2 is produced by the energy required to <do action>" is always "as much as your power generation method".
Still crushing the rock is an activity you'd not do without the goal to bind co2. If the CO2 equivalent of the energy required for this is higher than the amount of CO2 that can be offset by the rock dust, it becomes a CO2 producing activity in total.
If your energy generation process is CO2 friendly you might simply offset other energy use with this energy and generate a better CO2 balance by this, skipping all the rock crushing.
The other question is, what if you do not have the rocks on site?
Transportation of tons of material is not free either. Neither is spreading it on field (labor notwithstanding).
That said, if farmers are already putting tons of imported materials, this could be a matter of switching it up. But if it would be better just to not do this, the whole thing just starts to look silly and worth it only locally at best.
This made me think of early civilizations that always sprouted on river valleys. Indus Valley, Nile valley, Danube, Yangtze ..when nomads became pastoralists and then agriculturalists, they must have relied upon water that came down from glaciers or flowed across other lands. River bed silt always has the best soil minerals for growing.
The river bed is full of minerals that it had carried with it..perhaps flowing over different rocks, it brings some with it? Contrast that today..where we have a 45 billion dollar Ag industry in California ..legit Desert.
Biochar had a lot of attention several years back. It still seems like it would be worth pursuing because it sequesters carbon and helps to build up healthy soil.
Directors Maude Plante-Husaruk and Maxime Lacoste-Lebuis met expert botanist Raïmberdi while travelling in Central Asia. His reflections on the nomadic life, and on practices that are rooted in an ancient rural lifestyle, offer a fascinating personal record of the region's history, and the extreme hardships its population experienced after the collapse of the Soviet Union.
Partnerships and collaborations. Have tech companies sponsor farms by letting them use tech.
Many farmers are land rich, cash poor, labour costs eat up profit margins. Many will die. And with these farms, the knowledge. They will sell the land and retire on the proceeds as rich farmland is paved over.
What they need is accessible, affordable tech. And where their inherited generational and practical knowledge can be tested and validated and adopted by tech. It needs to be with trustworthy partners who don’t see farmers as future consumers but as collaborators and partners.
Current Agtech is geared towards commodity crops and industrial Ag. All farming knowledge that is soil and environment oriented comes from small family farms. Their goal is to keep the soil fertile. The purpose of a farming corporation is to make profits. Not soil health or environment.
By asking big Ag concerns to take care of soil, we are burdening them with a job they don’t want..but that requirement towards soil and environment should be part of the tech they use.
So the domain experts of soil..the ones who actually have dirty hands by working in the soil should be the ones who help create the tech. Right now, wrong allocation of responsibility to skill is what’s not working.
Farming is intuitive. A farmer tries to maintain the soil and make it better. Industrial Ag razes* down soil with each harvest and supplements With inputs and brute mechanical force, they bring soil back to a threshold that is bare minimum for cultivation. That’s why a farmer says that only sun, water and soil is needed to grow food. Industrial Ag needs inputs, machinery and data.
As a small acreage soil focused farmer, I say that we need soil, water, sun...and tech. Tech that would replace manual repetitive labour ..labour costs that is killing our profits can be boosted by small acreage automation/mechanization.
*i like to illustrate this with a personal example. When I wanted to redo my garden, I wanted to move a couple of structures, add a fountain, plant a few trees, remove some vegetation and put down a walking path with pavers.
When I called a landscape architect, he said that we will have to remove everything, create a blank slate and implement the landscape design.
That is the difference between farmers and industrial Ag.
Yeah, last time Big Tech and farmers crossed paths, we got John Deere tractors with DRM.
If family farms are gonna use tech to automate and survive as such, the tech will come from smart rural folks. Think more Temple Grandin and less Elon Musk.
Do you see any other areas in addition to mechanization that tech can be valuable?
In other words, are there problems that software alone can help solve or is it simply down to replacing some of the manual labor with robotics and smarter machines?
I think we need a systems approach in Ag ..in both small or industrial farming..too. So we can achieve systems level results.
Software can be helpful but it’s enhancements contribute very little to the profit margins.
Take for example this cost analysis of orient eggplant for 2005(I picked this eggplant because it’s not a commodity crop grown by industrial Ag and is niche. In other words, it’s not like lettuce or strawberries or corn or soy)
Check the percent of labour costs and capital/equip costs wrt operating costs. Software will help as part of the bigger systems approach, but at the end of the day, the urgent problem we need to tackle is labour costs and labour availability.
Systems example: farmers are paid per pound for tomatoes. They therefore want to water heavily before harvest so the tomatoes get as heavy as possible. Then they ship the heaviest possible tomatoes to a factory to be dehydrated into ketchup, sauce, and other canned goods.
The energy loss comes in 3 different parts - water waste, extra fuel in shipping, and in energy to dehydrate. Everyone pays more.
The system solution would be to price the tomato solids, not the water.
Sampling. It is already the case that grains are tested and priced based on dry weight, it would not be hard to do the same for some of the larger veg crops.
This point is moot. Canning tomatoes are different from market tomatoes grown for weight. Most tomatoes are harvested mechanically while green and unripe. They are gassed to ripeness.
> Many farmers are land rich, cash poor, labour costs eat up profit margins.
This is only a problem for people who own agricultural land, not a problem for operating a farm.
Of course, often farmers both own agricultural land and operate the farm. But the roles are separate in principle, and some people farm on leased land.
Now to substantiate my claim: in the longer run, any change in the amount of profit a typical farm makes, will just drive prices of agricultural land up or down. (For the usual arbitrage reasons.)
The rest of your comment is, of course, still very worthwhile. It just has little to do with being land-rich.
I meant in terms of coming up with cash for operating costs in the beginning of the year. Just because you own 100 acres doesn’t mean that you have quarter million liquid cash to get the farm season going until harvest and sales can cover it. Most farm operations run on credit. And uncertainty.
The uncertainty of labour and it’s lack is one more nail on the coffin.
Fun fact: insurance companies and pension funds routinely invest in farmland. This is a risk and speculative game at this point.
Late season chunk of mowing down summer crop, cover crop seed broadcasting, spring mowing, primary and secondary tillage and bed prep as one service. All of this can be automated with existing implements.
That’s a 5 month chunk of field work I can outsource to a Robotics As A Service type outfit. I like to divide chores by seasonality.(that’s how a farmer like me would see it..an engineer might not see that as optimal). It doesn’t require my knowledge or skill, it just needs horsepower. That’s capital and infrastructure cost and maint/labour expenses I can consolidate and probably will save.
It’s a diff set of automation when growing season starts. Of course, that flips when a farmer has winter/fall croppings.
From a duplication of effort standpoint, how much of this can be combined (-intended) into a single process with the right implement? I know little about farming.... What is the purpose of the mowing? I know that things like alfalfa are often tilled into the soil to improve fertility. <p> Would a mower/tiller/broadcaster (all in one pass) be feasible or is there a reason these things happen separately? It would represent a substantial time & cost savings
Hmm. That’s a really complicated question/answer. It would depend on soil type, crop rotation and the kind of residue we are tilling in...
To be honest, we have great soil in CA and I can’t speak broadly ..but almost every big farm will have their own system. Broadly, there is standard tillage, bed disc system and strip/conservation tillage in CA.
Strip tillage is often conservation tillage and sometimes used near Davis/Sacramento area where our wheat and tomatoes are intercropped..(our most impressive crop) In Salinas valley , our lettuce producing ‘salad bowl’, they have almost always had minimum tillage protocols. A sub soiler/ripper. I know a farmer who rips it in the beginning of the season and discs it FOUR times before listing.
You can’t really make a decision without evaluating soil, moisture and soil microbial activity.
Having said that..I am interested only in small acreage farm automation..that is sub 100 acres ..2-3 times bed flipping vegetable growing farms. I don’t have experience with industrial ag systems. That’s like factory production assembly line. They got all their ducks in the row. My interest is in automation for small farmers and market farms. It’s super sub optimized market.
I would recommend a minimal till-no till approach focused on soil health. Maybe rip the fields every 2-3 years. Single pass implements will reduce compaction due to machinery but when you make a light farm bot, compaction of paths between short semi permanent beds shouldn’t be an issue. The holy grail would be a no toll system. But it’s not without its issues.
So..to your question. A single pass Solution with implements on a gang. Yes. It’s possible. But you have to remember that this would mean higher HP. Upwards of 200-350. At which point, it defeats the purpose of finding automation for small farms. Which small farm can afford those mega tractors? It becomes a scale/$ issue.
If it’s electric, then HP decision is even more complicated because now you have to decide between draft implements or PTO implements. And as that adds up, so does the weight of the tractor/pulling unit. And boom! We are back to ‘size matters’. We can only grow in 1000+ acre farms.
Small acreage automation is a difficult but interesting challenge. That’s why I am interested and also because right now because food crops are mostly Imported and cheap, Agtech doesn’t care. But that will soon change. Sooner than we expect. We should build.
Your farm looks really cool (from the tiny bits I could find online). My dream has been to do something like that but take it up to the next level (bootstrapping a community).
Just liked your FB so I can follow your adventure.
Thanks. I haven’t updated my social media for many months now..just sharing articles and stuff. You will have to go back to see actual farm updates from then..social media is exhausting! I gave up!
i think a good first step would be to remove farming subsidies so that they don't make decisions based on the fact that growing corn and soy is profitable because of the subsidies.
I'm donate to project vesta yearly. Personally, I think the lack of attention is due to its relatively slow pace (compared to the typical news cycle) and the fact that it's simply not going to ever be a revenue generator.
What is the financing and implementation plan? Will it be donor-funded, publicly-funded, or are they looking into some revenue options?
If I donate now, what will the money be used for? Will it put green sand on beaches, or be used for bureaucratic paperwork, or be used for marketing to raise awareness?
Hi, Project Vesta is a non-profit focused on advancing the science and logistics for deployment of coastal enhanced olivine weathering. Right now, your money will be going to fund our Phase I experiments focused on demonstrating the safety of the process, along with weathering rate and dissolution kinetics. The goal of our Phase I experiments is to use the data to create an open-source model that brings all of the relevant parameters together into a single model. We plan to create an algorithm called the Coastal Enhanced Weathering Integrated Assessment Model (CEWIAM) that will be able to take inputs related to a specific beach site, and combine the Weathering Rate and Safety Data with a Life Cycle Assessment so that it can output a "Net $ cost per tonne of CO2 removed per year" from a given site. The model will be open-sourced and peer-reviewed by the scientific community, in additional to having it validated by 3rd parties so that it can be the foundation for an entirely new field of carbon dioxide removal. It is our belief that once this model exists and is validated and demonstrated successfully, massive projects would be financed by the private sector potentially for carbon dioxide removal credits, etc, as well as enabling governments to deploy this on potential gigatonne scales as beach nourishment projects that also help them make up for the shortfall in their Paris Agreement emissions commitments.
Correcgt! We have already generated $250,000 in revenue from our first customer, Stripe. Even though we are a non-profit focused on advancing the science, we can still generate all the revenue required, and we hope our project will be self-sustaining...
Thank you for your kind words! We have been getting a decent amount of attention lately, but we are very much heads down, working on our science and deployment of our experiments. We announced in April, on Earth Day, that we have found a pair of bays in the Caribbean where we will run our first experiment(s). And in May, Stripe announced their selection of CDR purchases and we were selected for 3333.33 tonnes @ $75.
There was a lot going on in the world at the time when it was announced (and for whatever reason Stripe's post or the following article didn't receive traction on HN), but
that announcement made it into Reuters-> Stripe picks $1 million in carbon-removal projects to spur industry
https://www.reuters.com/article/climate-change-stripe/stripe...
This was our first bigger article, that came from our poster in December at the American Geophysical Union with our plan to take our coastal enhanced weathering "from the lab to the beach"-> Could putting pebbles on beaches help solve climate change?
https://www.sfchronicle.com/environment/article/Could-puttin...
And more are on the way! That said, we are working really hard right now to have our pilot projects and foundational research completed, published, peer-reviewed, and CDR process certified in time for the UN IPCC's first global stocktake in 2023. At that time, countries will have to take account for how they will meet their targets and update their plans. We are working to make sure our process is ready to go by then for deployment.
>"The Paris Agreement offers a dynamic but durable framework for increasing climate action over time. One of the sources for this dynamism is the “global stocktake“ – a moment every five years for all countries to pause and account for what has been achieved so far, and what must still be done, to achieve the goals of the Paris Agreement."
https://www.wri.org/blog/2017/05/insider-designing-global-st...
Can you please explain where all the olivine is found? I can't think where I have seen any amount of it, other than on a few beaches in Hawaii. Descriptions of the project seem to suggest it is extremely abundant somewhere. Where?
Just in case somebody jumps to the conclusion that this is some kind of panacea.
> The researchers are clear that cutting the fossil fuel burning that releases CO2 is the most important action needed to tackle the climate emergency. But climate scientists also agree that, in addition, massive amounts of CO2 need to be removed from the air to meet the Paris agreement goals of keeping global temperature rise below 2C.
Basically we need to stop burning fossil fuels and spread rock dust. Short of some miracle, humanity is screwed.
Paris agreement is also built on IPCC models that ignored methane and many other feedback loops. The new model runs for the updated report coming out soon do not and their estimated temps are almost double in many cases (and more in some).
Roughly half of the greenhouse forcing in this century is expected to result from hydrofluorocarbons vented from refrigeration systems and industrial processes. Thus, just cutting CO2 accumulation is not enough; we have to remove enough CO2 to make up for the HFC load. HFC is overwhelmingly harder to remove from the air once vented, and no natural process does.
Anything that can be done to remove and incinerate HFCs before they get vented pays handsomely. A ton of HFC traps as much heat as 2500 tons of CO2.
HFCs, ironically, were once considered world saviors, supplanting CFCs that were destroying the ozone. Now We Know. Ammonia is the best refrigerant I know of, now. I gather it is heavily used in big industrial applications, but people still worry about it in consumer applications. Toxicity is extremely unlikely to be an actual problem, but people panic if they smell a trace amount.
Spreading green vehicles on the Earth's surface would stop vast amounts of CO2 being added to the air. The fuel cost is none (and sustainable for roughly the Sun's lifetime), fuel-transportation costs much lower, the waste costs almost nil. The investment would be large, the likely return on that investment substantially greater. The more quickly we make this choice, the sooner the world benefits.
Removing CO2 may be necessary; stopping CO2 addition has to become a critical priority.
US$80-180 per ton of CO2 * 16.50 metric tons of CO2 emissions per USA capita (2014)
= between 1,320 and 2,970 USD per year for keeping our planet in check. Maybe multiply by 3x to exclude children, retired and unemployed. Not too bad for a median USA income. Same for Indian - 10x less emissions so about 130-300 USD per year.
Crops also sequester CO2. Breeding and/or engineering for traits like deeper roots can increase the rate of uptake and also improve yield. There is a lot of potential computational work in this area (automating phenotype data collection with robotics, growth modeling, data engineering and web development for science gateways) and more research is needed. The funding is there for this in the U.S., e.g. from the DOE.
Can't find the basic science of the idea in the article - which chemical process makes rock (also which rock) capture CO2? Is there a ton of rocks out there that are rich with unbound metal oxides?
There are many minerals which are ionic compounds of silicon oxides on one side and metal compounds on the other. Grind them up real fine and many of the metals will preferably react with carbon dioxide to make, for example, calcium carbonate (CaCO3) and the silicon and oxygen become silicon dioxide which is ordinary sand.
There are indeed a ton of rocks out there bound less tightly to other things.
High heat (say, magma) would break up the carbonate so thats why the rocks arent already in that chemical state.
2CO, + H,O + CaSiO, -> Ca'+ + 2HCO,-+ SiO, -29.6 kcal
Underlined digits are lost after copypaste.
So in the end you have Calcium bicarbonate that becomes unsoluable carbonate in the end. Its just proof of concept, in the terraforming scales(time + volume of chemicals) it can work, but dropping dust on fields seems like joke
Carbon dioxide is emitted as a by-product of clinker production, an intermediate product in cement manufacture, in which calcium carbonate (CaCO3) is calcinated and converted to lime (CaO), the primary component of cement.[1]
Farmland is a good place to put it because rock dust is also high in phosphorous and other minerals and for that reason is often used anyway as a fertiliser, particularly in organic agriculture.
Basalt is one of the types of rock that can react with CO2 to trap carbon.
Grinding rocks to 200 mesh (74 microns) takes about 20 Kwh per ton. Using 100% coal electricity that would lead to 20 kg CO2. Transporting a ton of cargo by truck 200 km creates about 22 kg of CO2. Basalt seems to remove less CO2 per ton than other minerals, but I'm guessing it would still be more than 100 kg CO2 removed per ton of basalt (perhaps much more). Olivine (see Project Vesta) and serpentine are quite efficient; they remove about 1.2 tons of CO2 per ton. Basalt is extremely common, though, so it might win out in some circumstances.
Sometimes you will hear the expression: "We think technology will save us. Technology got us into this mess"
Or, you might hear about the moral hazard of suggesting that technological approaches could reduce the need for reduced consumption [1]
These seem to be compelling arguments for many people -- including those who fund science. Geoengineering is, one might say, a dirty word in the sciences today. Are there any scientists who could weigh in?
[1] Hale, B. (2012). The world that would have been: moral hazard arguments against geoengineering. Engineering the climate: The ethics of solar radiation management, 113.
Geoengineering refers to any attempt to engineer the planet. It isn't just aerosol injection, but would also include solar shades, dumping iron in the ocean, modifications to forest cover, creation or destruction of biomes (e.g., turning the Sahara back into something other than a desert), and in the future, conceivably things like bioengineering species to obtain desired goals (e.g., consider a plant we could farm that somehow sequestered CO2 in a form we could more easily bury). It's the terrestrial equivalent of the term "terraforming".
There are different types of mine waste. Certainly you don't want to spread waste contaminated with heavy metals, but most mine waste is just rocks that have been ground up and filtered by a sluice or shaker table to get the tiny fraction of the ore that is actually valuable.
That doesn't quite generalize to all mining/quarrying. For instance, talc(um) is often contaminated with asbestos because the two minerals often found in close proximity to one another. I don't think anyone is suggesting spreading either of those on fields, but a modicum of care needs to be taken regardless.
The problem is, once there's a commodity market for this product, unscrupulous suppliers are going to be adding the more hazardous mixtures to the market place.
You're allowing second-order effects to dominate your thinking about a first-order problem. I see this a lot, here, and in real life. Example:
A: "lets fit a defibrellator at the pool"
B: "but what if we get sued" ?
outcome: nothing. Were they sued? were they less likely to be sued? what if they are sued for NOT having a defib? This is racionation to endless effect.
yes, there will be bad actors who contaminate their dust. There are bad actors who contaminate food, drugs, water, fertiliser, music, books, Luis Vuitton suitcases, Lobsters...
Typically speaking, if you're mining rocks, that's a quarry. The article also suggests using waste from steel and cement manufacturing, which is crazy.
The article also suggests using waste from steel and cement manufacturing, which is crazy.
<citation required>
If the production process is happening anyway, and if the waste exists anyway, why is it definedly crazy to re-purpose it? It isn't neccessarily the best at scale economic source of the kinds of rock dust we need, but if you have it, and it worked, then (without citing specifics like cross contamination risks or at scale problems) why is this specifically more crazy than the idea itself?
> 1. Why did they choose the two axis powers to draw their comparison?
Post WWII Germany and Japan are not the axis powers, so this question seems quite irrelevant. More likely Germany and Japan are two industrialized nations the sum of whose carbon emissions roughly equals the amount of carbon that could be offset by this process.
> 2. What would be the cost, in additional carbon emissions, to procure, distribute, and deploy all that basalt?
For the procurement, they claim near zero:
"Basalt is the best rock for capturing CO2, and many mines already produce dust as a byproduct, so stockpiles already exist. "
"Basalt is one of the most common rocks on Earth, and waste dust from mining could be used for ERW, as could waste from cement and steel manufacturing. This would remove the need to grind the rocks into fine particles, which requires energy. But how big these waste stockpiles are is unknown."
"“We are calling on nations to make inventories,” said Beerling. He said mines in Northumberland, UK, that produce basalt aggregate for construction produced 20-30% waste dust. But he said some mining specifically to produce basalt rock dust would probably still be needed, using existing mine capacity rather than new mines."
I expressed myself poorly on point #1. I did not intend to ask for a reason behind the axis power thing so much as amusedly draw attention to the coincidence.
Probably because these industrial countries are in the top 4 in terms of GDP and China and USA were excluded because offsetting their emissions is not possible with basalt.
Germany and Japan being two axis powers is so irrelevant to the given topic... GPT-2 is probably smarter than you if this is all the skill you have in correlation.
I expressed myself poorly on point #1. I did not intend to ask for a reason behind the axis power thing so much as amusedly draw attention to the coincidence.
reply
Parent implies there is a correlation, but GP doesn't see it because they're stupid. My assumption is they were referring to post Fukushima nuclear shutdown.
Even if I'm misreading it and parent is instead saying there's no correlation, there's still no need to be mean.
I hate to be the bearer of bad news, as I am happy to see this issue making headlines, but this sounds like something out of Mike Judge's Idiocracy universe.
It's probably a really bad idea to spread rock dust on arable land. The mixture will probably retard the natural soil microbiota, and at worst render land unusable.
Just try adding a bunch of concrete dust to your basil plant in the window sill, see what happens. Most likely this will be the source, as concrete waste is a huge issue in most population centers. Natural microbiota, the life in soils, are our best bet at sequestering our overabundance of atmospheric ghg, because we literally have to do nothing. Just leave it the fuck alone. Most land is not past the point of no return, and most land is not being used to grow essential food crops. Our actual food is grown on a very small part of farms worldwide and has lots of room to intensify while reducing energy and chemical inputs.
Rebuilding and growing bogs, marshes, and wetlands should be our top priority if we want our great-grandchildren to enjoy the world outside of a cave or a bubble.
you know, if you showed us you are a soil agronomist, and cited something we might agree. Or, we might look at the other people commenting some of them who do cite references, who say this isn't retarding natural soil microbiota and isn't going to the at-worst case, making land unusable.
your example of "try this at home" is not actually good. concrete dust before hydration is completely different to the dust made post hydration, or fly ash, or surplus rock dust from mining. The properties of the pre-build and post-build chemical reactivity of concrete (its an exothermic reaction) need to be borne in mind.
That said, aggressive de-carbonisation of industry and agriculture, biochar, wetland remediation, re-forestation are probably vital, and urgent.
Maybe you are confusing (or I am not understanding) concrete dust with cement dust.
Concrete dust should be the result of demolition of concrete (already hydrated when it was cement to form the concrete, i.e. post exothermic reaction).
But, allegedly, the concrete surfaces (not reduced to dust) exposed in the Biosphere2 was sequestering both CO2 and oxigen, and - at least in that case - the "solution" was a supplement of oxygen, so maybe the concrete (not cement) dust uses both CO2 and oxigen while basalt only or mainly uses CO2?
Also, whether it is basalt or concrete dust, wouldn't this treatment alter the pH of the soil? (at least here historically where there is an excessively acid soil it is often corrected with additives like calcium carbonate or similar).
my answer was an attempt to get to this point because the OP said "get some cement and sprinkle it on your garden and see what happens" and the whole point was "thats not what people are doing in the farm sector here, they're not using pre-moistened cement dust, they are using post-pour concrete dust, the chemistry is different"
altering the PH can be desirable or harmful depending. thats where the 'get a soil agronomist into the convo' comes in.
from memory, there can be a significant non-bound component of
concrete, and it can persist for years. so I accept there is a continuing risk of aggregation of the dust, because it doesn't completely process in immediate time-frame of the pour (I am told that the hoover dam continued to bake off for years afterward)
Sure, I was only trying to distinguish cement dust from concrete dust, the OP mentioned concrete dust, not cement, and he mentioned it being "waste":
>Just try adding a bunch of concrete dust to your basil plant in the window sill, see what happens. Most likely this will be the source, as concrete waste is a huge issue in most population
About aggregation, there are usually big differences between the different kinds of cement, modern Portland cements tend to end hydration (and thus hardening) within months, whilst good ol' Pozzolanic went on for years.
But I wouldn't be surprised if such a massive pour as a dam would go on hardening for many years.
"This concealed the underlying process until an investigation by Jeff Severinghaus and Wallace Broecker of Columbia University's Lamont Doherty Earth Observatory using isotopic analysis showed that carbon dioxide was reacting with exposed concrete inside Biosphere 2 to form calcium carbonate in a process called carbonatation, thereby sequestering both carbon and oxygen."