engleski

Influence of sodium stearate on precipitation of calcium carbonate in a semicontinuous process

The influence of sodium stearate (NaS) on the precipitation of calcium carbonate during the semicontinuous carbonation process of slaked lime was studied in the systems in which process parameters, like temperature, CO2 flow rate and addition rate of slaked lime, have been controlled. It was found that calcite was the only calcium carbonate polymorph that appeared under the investigated experimental conditions, while FT-IR spectroscopy and thermogravimetric analysis of samples confirmed the presence of stearate on the surface of precipitated calcium carbonate (PCC). Specific surface area of PCC increased with increasing stearate content: the highest value, s = 52.8 m2 g-1, was obtained at t = 20 °C, κ 25 = 7.0 mS cm-1 and the stearate content of wNaS = 2 %. It was also found that hydrophobic PCC could be prepared at wNaS > 1 %.

Precipitated calcium carbonate; carbonation; adsorption; stearate; hydrophobicity

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