Facile synthesis of ultrafine and high purity spherical strontium carbonate via gas-liquid reaction

Abstract In this work, a simple gas-liquid precipitation reaction was developed to fabricate spherical strontium carbonate (SrCO₃) particles using strontium hydroxide (Sr(OH)₂), carbon dioxide (CO₂) and ethylene diaminetetraacetic acid strontium salt (EDTA-Sr) as raw materials. The effects of the concentration of EDTA-Sr and Sr(OH)₂, airflow rate of CO₂ and reaction temperature on the morphology of SrCO₃ were investigated. The results showed that spherical SrCO₃ particles can be formed when the concentration of EDTA-Sr reached 0.02 M as well as that of Sr(OH)₂ was less than 0.1 M. The airflow rate of CO₂ gas had little effect on the spherical morphology, and SrCO₃ microsphere with good dispersion could be obtained when the reaction temperature reached 50 °C. Under the optimal conditions ([EDTA-Sr] = 0.02 M, [Sr(OH)₂] = 0.1 M, 50 °C, [CO₂] = 1 l min⁻¹), high purity spherical SrCO₃ particles with diameter of 200–800 nm can be easily obtained. Finally, the growth mechanism of spherical SrCO₃ has been preliminarily presented, which indicated that EDTA-Sr is an excellent structure-directing agent for forming pherical SrCO₃ particles. Our work offers an effective method for large-scale production of high purity spherical SrCO₃.