The Simple Method of Synthesizing Calcite and Aragonite from Indonesian Limestone

Precipitated CaCO۳ (PCC) with calcite and aragonite phases have been successfully synthesized using natural limestone. Synthesis of PCC was carried out by the simple method of carbonation using slurry Ca(OH)۲ with a variation of CO۲ gas flow rate at room temperature and variation of temperatures at a constant  CO۲ gas flow rate. The raw material used is a very high purity Madura Island limestone. The PCC product was characterized by X-Ray Diffraction (XRD), Fourier Transform Infra-Red (FT-IR), and Scanning Electron Microscope (SEM). PCC on CO۲ gas flow variation produced the same phase, calcite with the characteristic of ۲θ = ۲۹.۲۳° (۱۰۴), rhombohedral cubic morphology, and a wavenumber of ۷۱۲ cm-۱ as displayed from the FTIR spectra. The mixture of aragonite and calcite phase was observed in PCC products with temperature variations of ۶۰ - ۹۰°C. The characteristic aragonite was observed at ۲θ = ۲۶.۲° with needle-like morphology. The highest fraction of aragonite was at the temperature of ۶۰°C at ۷۱.۳۵%.

کلیدواژه ها:

Electron microscopy ، Aragonite ، Needle-like ، Crystal morphology ، Calcite