Electrochemically Induced Chemo-Morphological Changes in Magnesium Silicate on Dissolution

The coupling of electrochemical silicate mineral dissolution with co–product generation offers a promising approach to enable the weathering of silicates for applications such as metal recovery and CO2 capture and mineralization. Magnesium–rich silicates are among the most abundant resources worldwide, presenting significant potential as sources of magnesium and silica. To accelerate the kinetics of Mg–silicate dissolution, an electrochemical approach is developed in which Mg–silicates are dissolved via in situ generation of protons through water splitting in an electrochemical system. This approach eliminates the need for external agents for dissolving Mg–silicates. Detailed chemo–morphological analyses of the silica–rich product recovered on electrochemical dissolution showed that the surface area increased from 13.84 to 20.87 and 32.56 m2/g on dissolution at 5 and 20 V, respectively. Similarly, the cumulative pore volume increased from 0.030 to 0.048 and 0.126 cm3/g at 5 and 20 V, respectively. Electrochemical dissolution resulted in a decrease in particles smaller than 20 μm and an increase in particles larger than 20 μm. The observed increase is attributed to the reprecipitation of silica contributing to particle agglomeration. Thus, these results unlock fundamental insights into the chemo-morphological evolution of Mg–silicate particles on electrochemical dissolution and inform process-scale tuning that is needed to enhance the energy efficiency of these pathways.