Mining consumes a significant portion of global energy, and fracturing rock (comminution) is a large part of that energy budget. Traditional ways to fracture rock focus on compressive forces, such as crushing the rock from the outside. However, the tensile force is much less than the compressive force, so it would be beneficial to break the rock from within.

Transcritical CO2 (tCO2) processing does just that - CO2 and rock are put in a closed container. The temperature and pressure are raised to supercritical conditions, and CO2 goes into the rocks' pores. After a soak period, the chamber is rapidly decompressed. The expanding CO2 breaks the rock within the pore space, exploiting the lower tensile strength.

tCO2 graphical

This work is a collaboration between Rockburst Technologies, the University of British Columbia, and Montana State University, among others. The first demonstration is found in our work here: Experimental demonstration of comminution with transcritical carbon dioxide cycles

Enjoy this video about the process from Rockburst!