Transformation of a Silicate Material for Carbon Negative Magnesia‐Based Cement via Electrochemistry

Abstract Magnesium silicate hydrate cement (M‐S‐H) can be formed from magnesium oxide (MgO) and silica phases which offer unique properties compared to traditional calcium‐based Portland cement (PC). The present study explores the transformation of a magnesium trisilicate material (Mg ₂ Si ₃ O ₈ ) into the precursor phases of M‐S‐H cement via the electrolysis of water. The investigation examines the change in pH as a consequence of water electrolysis, resulting in the dissolution of the Mg ₂ Si ₃ O ₈ and formation of Mg(OH) ₂ and SiO ₂ . The material phases collected after dissolution are characterized via SEM, EDX, XRD, IR, ²⁹ Si NMR and BET analysis. The results indicate brucite accumulates in large platelet‐like structures and analysis of the residual silicate phase present after electrolysis‐induced dissolution reveal protons have replaced the Mg ²⁺ ions. Amorphous SiO ₂ can be recovered from the system through pH adjustment, producing SiO ₂ with a high surface area ideal for cement production. As this process is conducted electrochemically, this approach to silicate material transformation represents an avenue toward cement manufacturing devoid of CO ₂ emissions. Through carbon‐curing, the M‐S‐H cement can constitute a carbon‐negative system. Mg ₂ Si ₃ O ₈ , a synthetic material, serves as a model for extrapolating this processes to earth‐abundant silicate minerals enabling their potential use in large‐scale sustainable cement manufacturing.