· Fig. 1. Scheme for a low-emission, electrochemically based cement plant. An electrochemical decarbonation reactor powered by renewable electricity converts CaCO 3 to Ca(OH) 2 for use in cement synthesis. The decarbonation cell uses the pH gradient produced by neutral-water electrolysis to dissolve CaCO 3 at the acidic anode and precipitate Ca(OH) 2 where pH ≥ 12.5.