Preparation of nano-structured strontium carbonate from Dashte kavir celestite ore via mechanochemical method

In the present investigation, nano-structured strontium carbonate was synthesized by mechano-chemical reaction of raw mineral celestite ore (SrSO4) collected from Dasht-e kavir, Iran, without initial acid leaching and chemical beneficiation, and sodium carbonate during high energy mechanical milling. X-Ray diffraction (XRD), X-ray fluorescence spectrometer (XRF), atomic absorption spectroscopy (AAS) and scanning electron microscope (SEM) were used to characterize the obtained samples. XRD results showed that at a Na2CO3:SrSO4 molar ratio of 1.05:1, mechano-chemical reaction started after 1 hour of milling. Although the longer milling times gives a more conversion of SrSO4 to SrCO3 but it has not been completed even after 16 hours of milling. However, by increasing the molar ratio of Na2CO3:SrSO4 to 1.25:1, the SrCO3 formation was completed after 2 hours. The results also showed that the mean crystallites sizes of produced nano-powder were approximately 32 nm. XRF result indicated that the final product was obtained with a purity of 95 wt.%. AAS results specified that the recovery rate for production of SrCO3 from celestite concentrate was about 97%. SEM studies confirmed the formation of SrCO3 nano-powder with a mean particle size of 80 nm.