New way to make cement may be key to large-scale carbon capture

New carbon capture method turns up the heat

It is estimated that 4 billion tons of cement are manufactured each year. To speed up CO2 uptake, "instead of mixing calcium oxide with sand, they mixed calcium oxide with another mineral composed of magnesium and silicate ions. The heat catalysed an exchange of ions, forming magnesium oxide and calcium silicate: alkaline minerals that react quickly with acidic CO2 in the atmosphere." Far quicker than most concrete, anyway...

4 comments

The method essentially speeds up the natural process of silicate weathering. In this process, CO2 in the atmosphere dissolves in rainwater to form a weak acid. This reacts with common minerals in rocks called silicates, breaking them down into other compounds such as bicarbonate ions (HCO3–), which flow into the ocean and stably store carbon for thousands of years.
Although the carbonation process took weeks to months to occur, it was still thousands of times quicker than natural processes.
If I understand this correctly, it sounds like a terrible idea because this method speeds up a natural process and sees the ocean as a sort of a stable dumpster. If I got this wrong, please let me know.
Btw:
Guide to Investigating Fossil Fuels: Greenwashing | Global Investigative Journalism Network, Feb 2025
The fossil fuel industry promotes solutions such as carbon capture and storage, liquefied natural gas, hydrogen, and renewable natural gas, which critics argue are far more focused on preserving industry profits than significantly reducing greenhouse gas emissions. The tactics they use include funding university research that skews public discourse and policymaking in the direction of their preferred solutions. They have hired management consultancies to conduct skewed analysis supporting those solutions and funded lobbyists, and advertising and public relations firms to promote them.
- Those bicarbonate ions are great for combating ocean acidification, they act as a pH buffer. Ocean acidification is rising due to increased atmospheric CO2 levels and that decrease in pH makes it harder for macro life forms to utilize carbonates to form shells and drives extinction. By increasing the concentration of bicarbonate, the carrying capacity of the ocean to absorb atmospheric CO2 without changing the pH is increased.
  
  Those bicarbonate ions are great for combating ocean acidification
  In this context tho, what you say reminds me of geoengineering and I consider it to be an extremely dangerous approach.