Studying On The Preparation Of The Light Calcium Carbonate Via Phase Transfer And Carbonation Route And Its Surface Modification

In this dissertation, the preparation and modification of light calcium carbonate werestudied using the lime rock as raw material via the phase-transfer carbonization routeand wet chemical surface modification method respectively. The main work and resultsincludes:1. Taking the activation grade of the lime as the main index, the calcination time andtemperature were investigated by single-factor experiments. The reaction conditionswere optimized as follows: the time of calcination20min and the temperature ofcalcination900℃. The activation grade of the sample under optimized conditions was8.63mL.2. Taking the phase transfer ratio of Ca2+as the main index, the phase transferreaction conditions were investigated via single-factor and orthogonal experiments. Thereaction conditions were optimized as follows: the molar ratio of Ca2+to phase transferagent1:1.5, the concentration of Ca2+0.5mol/L, the mixing temperature30℃, and themixing time30min. Repeated experiments under optimized conditions showed that theaverage phase transfer ratio of Ca2+was99.02%.3. Taking the yield of the light calcium carbonate as the main index, the carbonationreaction conditions were investigated via single-factor and orthogonal experiments. Thereaction conditions were optimized as follows: the concentration of Ca2+0.5mol/L, thereaction temperature60℃, and the carbonizationtime2.5h. Repeated experimentsunder optimized conditions showed that the average yield of the light calcium carbonatewas96.34%.4. Taking the sedimentation volume as the main index, sodium hexametaphosphate（SHMP）was chosen as the dispersant of the CaCO3sample. Taking the oil absorptionvalue as the main index, sodium dodecyl benzene sulfonate (SDBS) was chosen assurface modification agent and then the modification conditions were investigated bysingle-factor and orthogonal experiments as well. The modification conditions wereoptimized as follows: the dosage of modifier6.5%, pH value9, the modificationtemperature20℃and the modification time2h.Repeated experiments under optimizedconditions showed that the sedimentation volume reduced from91.25mL to61.03mL.