posted on 2024-01-10, 22:11authored byAmmar Abu Fara, Mark R. Rayson, Geoff F. Brent, Timothy K. Oliver, Michael Stockenhuber, Eric M. Kennedy
The
major aim of this research was to understand the effect of
the addition of sodium bicarbonate (NaHCO3) on the reaction
yield and products in the direct aqueous mineral carbonation of heat-activated
lizardite under single-step reaction conditions (130 bar, 150 °C)
developed by the Albany Research Center. This was achieved by tracking
the evolution of the aqueous and solid species produced over the duration
of the reaction. Analysis of solid and liquid samples was performed
using a variety of analytical techniques, including thermal gravimetric
analysis mass spectrometry, inductively coupled plasma optical emission
spectrometry, qualitative and semiquantitative X-ray diffraction analysis,
and laser diffraction particle size analysis. Carbonation experiments
were conducted with and without NaHCO3 using heat-activated
lizardite to study its effect on the reaction rate and overall yield.
It was found that NaHCO3 controlled the magnesium carbonate
phase formed in the carbonation reaction [hydromagnesite or magnesite
(MgCO3)]. It can be concluded that NaHCO3 elevates
the concentration of carbonate ions (CO32–), leading to a heightened level of supersaturation in the carbonate
phase. This, in turn, contributes to an increased extent of MgCO3 precipitation.