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[T]he production of cement alone accounts for 5 percent of human-generated carbon dioxide emissions, surpassed only by some very obvious culprits, including the burning of fossil fuels for electricity generation, transportation, and the manufacture of iron and steel
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https://home.howstuffworks.com/home-...ive-cement.htm
I always heard how bad concrete was, but never thought about how sand and gravel were probably not the culprits. So, the key ingredient in [the inappropriately-named] aircrete and compressed earth blocks?
Aside from hopefully transporting less material, they do not sound much better.
"In total, the traditional approach to making Portland cement emits almost 1,800 pounds (816 kilograms) of carbon dioxide for each ton of cement made."
"Adding carbon dioxide to the cement that would otherwise be emitted into the atmosphere makes it carbon negative. Indeed, Novacem believes that each ton of cement produced could actually absorb one-tenth of a ton of carbon dioxide."
So, we need carbon-capture on cement plants, as well as coal power. Is that easier than replacing both?
If 17% of cement production becomes Novacem, it would break even.
They also mention a company called Calera in California that, by 2011, had received backing from the federal Department of Energy and prominent venture capitalist. They "take the carbon dioxide emissions being spewed out of a power plant and mix them with water and other ingredients in order to make carbonates that go into cement. Calera already has a pilot operation in California and, in 2011, announced an arrangement to build a cement factory next to a coal plant in China."
https://home.howstuffworks.com/home-...ve-cement1.htm
Where has this gone in eight years?
"Between 2011 and 2013, China used more cement than the United States used in all of the 20th century."
https://grist.org/sponsored/the-brea...limate-change/
I wanted good news!
Blue Planet, also in the fantasy land of California, also captures carbon and makes calcium carbonate, but they do not superheat it to make cement, that would release the carbon (which they are fully capable of capturing), they turn it into aggregate.
"Every ton of Blue Planet’s synthetic limestone contains 440 kilograms of CO2."
Who the heck mixes systems?!
Every 907.18kg contains 440 kg of CO˛
Every ton contains 970.03lb of CO˛
That is 48.5%, better than I have earned in some classes!
Is making Portland cement and capturing the carbon cheaper than capturing carbon, making BP cement, and capturing the carbon again?
They could make the aggregate from carbon captured from the cement!
"The annual use of aggregate is over 50 billion tons and growing fast."
"Constantz expects to open its first commercial production facility in the Bay Area within the year, producing a little over 300,000 tons of rock annually with C02 captured from an adjacent power plant’s exhaust stack."
You need to start somewhere!
"The Foundation for Climate Restoration estimates that getting 30,000 Blue Planet plants running by 2030 would create enough CO2 removal capacity to remove all the excess CO2 from the atmosphere."
CarbonCure, from the land of maple and Horton's, injects CO˛ into fresh concrete, trapping it forever, and reducing the need for concrete because it increases the compressive strength.
https://money.cnn.com/2018/06/12/tec...ure/index.html
"Atlanta-based Thomas Concrete, a concrete producer, has been using CarbonCure's system since 2016. Thomas Concrete says it has since prevented 10 million pounds of CO2 emissions."
"Thomas Concrete pays to use CarbonCure and buys captured CO2 from a fertilizer plant where it's emitted, but the company says those costs even out with what they save by using less cement."
Hey!
Also, farming is bad for the environment! Good thing Big Cement is here to save the day!
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A new mixed-use development in one of Atlanta's trendiest neighborhoods, called 725 Ponce, is a real-life example of the impact of building with greener concrete. When it opens in 2019, it will become the largest structure ever made with CarbonCure concrete. Ultimately, the 360,000 sq. ft. office building, which will have a Kroger supermarket on the first floor, will save 1.5 million pounds in CO2 from being released into the air -- the same amount 800 acres of forest would sequester in a year, according to Gamble.
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That is one and a quarter square miles.
Except... a forest would do that year after year, but they construct buildings year after year, too...
90 concrete plants in the US and Canada are using their technology. There are an estimated 5,500 plants in the US alone.
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Other experts have pointed out that concrete naturally absorbs carbon dioxide. It's a slow process, but over the course of decades, it may be able to soak up a substantial amount of the emissions it put into the atmosphere in the first place via the limestone heating process.
A 2016 paper in Nature Geoscience suggested that the world's concrete has been absorbing about 43 percent of those original emissions.
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https://www.scientificamerican.com/a...co2-emissions/
Well, once again freebeard casually mentioned something, and I spent at least an hour researching it.
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