Written by Andrea de Santis, PhD student from University of Leeds, whose attendance at the Biannual Meeting was supported by the UKCCSRC ECR Meeting fund
The presentation was given by Professor Fredrik Glasser as part of the Solid Adsorption Technical Session at the UKCCSRC BIannual in Cambridge 2-3 April 2014. Fredrik Glasser is Professor of Chemistry at the University of Aberdeen. He has worked on the application of physical chemistry to basic science in geochemistry and materials science and has made fundamental and applied advances in diverse fields including glass, ceramics, extractive metallurgy, and inorganic cement materials.
The work illustrated in this presentation is based on the concept of converting carbon dioxide into a useful material, such as building materials containing more than 30% of CO2 in weight.
The production of magnesium hydroxide from sea water simply by raising the water’s pH is a well-known process; the uptake of carbon dioxide happens during precipitation.
The present work is focused on the production of magnesium hydroxyl carbonate hydrates (MHCH) as precipitation phases; MHCH are best made in two stages process:
- Carbon dioxide is removed by scrubbing with slightly alkaline solution at atmospheric pressure and temperature between 10-50 °C.
- The CO2-containing solution is mixed with a magnesium solution and MHCH are collected as precipitate.
A test rig consisting of two reactors has been developed for studying the process. In the first reactor the carbon dioxide coming from a fixed source is diluted and the solution is interfaced with an Mg-containing solution (magnesium is coming from desalination water process) in the second reactor; the MHCH is precipitated into a vessel; temperature, pressure and partial pressures are controlled during the process.
The experimental results have also been used to validate specimen calculations based on the Gibbs energy minimisation system; the agreement with the experimental data is fully satisfactory.
Materials made from MHCH phases like hydromagnesite and nesquehonite can be useful employed as building materials for thermal insulation, due to their physical properties like density and thermal conductivity. It is possible to produce building materials containing 32 wt % of carbon dioxide.