Effect of liquid circulation in the draft-tube reactor on precipitation of calcium carbonate via carbonation

Influence of ethylene glycol on CaCO3 particles formation via carbonation in the gas–slurry system

“…(Curve A). The dissolution of formed calcium carbonate in the presence of bicarbonates in the suspension is the cause of the observed conductivity increase [14]. Lower conductivity increase of the suspension with ethylene glycol (Curves B and C in Fig.…”

“…fulfils the conditions of the constant supersaturation, and the constant conductivity of the reactive mixture is indicated. The drop to the lowest conductivity corresponds to the complete consumption of Ca(OH) 2 and can be assumed as the end point of precipitation [3,14,25,26]. The conductivity of the reactive mixture without additives increases significantly after the precipitation when CO 2 is introduced into the reactor as it is shown in Fig.…”

“…The size distribution and the shape of precipitated calcium carbonate mainly depend on both reagents concentrations but also on operating variables such as temperature, pH, reaction time [2,4,5] and the presence of inorganic and organic additives [2,[6][7][8][9][10]. An important factor influencing the characteristics of calcium carbonate particles are the type of reactor, its geometry and mixing intensity [11][12][13][14].…”

Precipitation of Spherical Vaterite Particles via Carbonation Route in the Bubble Column and the Gas-Lift Reactor

“…The role of pH in vaterite synthesis is not clear, because some researchers found that pH > 9 favors vaterite precipitation, 2,15 others that vaterite is formed in solutions of pH < 8 16 or of pH in the range between 7.5 and 9.5. 12 The influence of mixing intensity on vaterite precipitation has not been reported, but the size of the final particles usually decreases with an increase of mixing rate when calcite [17][18][19][20] or aragonite 21 crystals are formed.…”

“…12,31 To model the precipitation process, agitated vessels with a flat gas-liquid surface were used. 32,33 Also, reactors with special constructions such as a gas-lift reactor, 17,19,34 multistage column crystallizer, 35 spinning disc reactor, 36 Couette-Taylor reactor, 37 rotating disc precipitation reactor, 38 membrane dispersion minireactor 18 and high-gravity rotating packed bed reactor 39,40 have been applied.…”