CO2 assisted geo-polymerization: a win-win pragmatic approach for the synthesis of soda ash leading to reversal of the climate clock

Abstract

It is surprising to note that there are very few literature reports available that envisage CO₂ utilization with sodium silicates. Our research extends this concept by integrating CO₂ assisted utilization of fly ash with sodium silicate. The alumino-silicate polymeric material was characterized using FT-IR and NMR techniques confirming the presence of Si–O–Al and Si–O–Si linkages, which are the foundations of the hardened structure, contributing to the strength in the block. Chemical tests and spectroscopic measurements further confirmed the phase and crystallinity of the synthesized soda ash. A feasible reaction mechanism has also been proposed for the alumino-silicate polymerization, which not only leads to the formation of industrially important chemicals like Na₂CO₃ (soda ash) but also results in the making of construction blocks with strengths of 11–14 MPa and water absorption of 11–15%. The presented chemical scheme utilizes a voluminous amount of CO₂, thereby this approach may conserve the global carbon budget, and hence it may play an important role in reversing the climate clock.