Zero CO2 cement/concrete

[-rick-]

Saw this on making portland cement using basalt resulting in zero CO2 emissions during manufacurer (assuming green energy input):

 

https://arstechnica.com/science/2026/05/running-the-numbers-on-a-zero-emission-way-to-make-cement/

 

Obviously it's a long way away from being put into practice and lots of roadblocks but it's an interesting concept. Even at 2x the energy input as the initial concept is seems like a big win, guessing the plant involved would be very expensive though so likely not a cheap produce for a while. I'm pretty sure Basalt is widely available but maybe that's an issue.

Edited 7 hours ago by -rick-

[Gus Potter]

I had a quick skim over, thanks for the post. To quote:

 

"Acid can be used to leach elements like calcium out, then a chemical or energetic process precipitates that calcium as calcium hydroxide. 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."

 

We are going to need a lot of acid? But what kind? 

 

Remind any of the raves for older members of BH? The music was great, some great Scottish bands like TTF came along at the end of that period just at the end of the 1980's (The time frequency). 

 

The acid (catalyst) is the key possibly, plenty Bassalt in Scotland. 

[SteamyTea]

Old news. My comic mentioned it 12 months ago, and it wasn't new then.

 

Environment

 

Carbon-negative cement can be made with a mineral that helps catch CO2

A process to dissolve the mineral olivine in acid could provide a plentiful, energy-efficient material for carbon-negative cement

 

James Dinneen

1 May 2024, updated 22 January 2025

 

A sample of cement made from the mineral olivine, which can also help sequester carbon during production.

A sample of cement made from the mineral olivine, which can help sequester carbon during production.

 

An abundant mineral called olivine can help make carbon-negative cement. This process could help tackle cement’s large carbon footprint – the material contributes about 8 per cent of global CO2 emissions.

 

Olivine is one of the main components of Earth’s mantle and reserves sit on every continent. “It’s one of the few minerals that is available at the gigatonne scale,” says Sam Draper at Seratech, a UK-based company that has patented a process to turn olivine into cement.

 

Dozens of start-ups like Seratech are developing low-carbon methods to produce cement, such as supplementing with steel by-products or recycling the CO2 released in cement production. Most emissions occur when heating limestone to produce clinker, a binder in cement, along with burning fossil fuels to generate the heat.

 

 Net-zero living: How your day will look in a carbon-neutral world

Draper and his colleagues looked to the more abundant olivine to find a replacement for some of the usual clinker. Olivine contains silica, which makes cement stronger and more durable. Magnesium sulphate can also be extracted from it, and this salt reacts with CO2 to form minerals that sequester the gas.

 

The researchers extracted these compounds by dissolving powdered olivine in sulphuric acid. After separating the silica and magnesium sulphate, they bubbled CO2 through the magnesium slurry to form a mineral called nesquehonite. To scale up the process, Draper says a cement plant would use CO2 captured from an emissions source or from the air, rendering the entire process carbon negative. The leftover nesquehonite could be recycled into new construction materials like bricks.

 

Replacing 35 per cent of the regular cement in a concrete mix with silica from this process would produce a carbon-neutral cement, the researchers estimated, while subbing 40 per cent or more would make it carbon negative. Draper says current building standards allow this type of material to replace up to 55 per cent of cement, although he says they haven’t yet made enough of it for robust testing.

 

The process utilises well-known reactions, says Rafael Santos at the University of Guelph in Canada, but offers a novel and “reasonable” way to combine them. However, some of the chemicals involved may prove tricky to recycle, he says.

 

Journal reference

 

 Royal Society Open

Science DOI: 10.1098/rsos.231645

[Gus Potter]

31 minutes ago, SteamyTea said:

An abundant mineral called olivine can help make carbon-negative cement.

It may be that the percentage of Olivine in good Scottish Bassalt is around 5%. Us up in Scotland would welcome the investment. But we might get a bit naffed off if you destroy the environment and wreak our tourist industry.