The foundation and visible symbol of progress is the construction of new facilities, and the cornerstone of any modern construction is access to quality cement. Making cement requires so much energy that its production accounts for up to 5% of the world's total CO2 emissions. This direction needs to be optimized, and the Massachusetts Institute of Technology proposed an idea - to use volcanic ash.
Ashes from volcanoes are found as raw materials in almost all regions of the planet; they fill the slopes and calderas of long-extinct volcanoes and are thrown out from the vents of the active ones. At the same time, the components in the composition of the volcanic substance have already undergone a kind of processing by high temperatures and pressure in the bowels of the earth - by analogy with how the components of cement are prepared in industry. There is an opportunity to take ready-made raw materials and save on costs.
Ashes need to be crushed before being added to the cement mixture, and here the widest scope for experimentation opens up. American scientists have conducted hundreds of experiments with granule sizes from 17 to 6 microns and ash concentration in cement from 10 to 50%. The best result was a 30% reduction in total energy consumption when organizing the entire spectrum of construction work, but in practice everything will depend on the specific conditions at the facility.
The authors of the idea emphasize that ash does not improve the quality of cement, but serves as a cheap natural component that can replace man-made ones that require high energy consumption during production. By eliminating this process from the overall production chain, you can minimize resource consumption and reduce emissions into the atmosphere. And the rest is a matter of technology.