Preparation of barium sulfate nanoparticles in an interdigital channel configuration micromixer SIMM-V2

BaSO₄ nanoparticles were synthesized by precipitation of Na ₂SO₄ and BaCl₂ at their concentrations close to their saturation concentrations in a commercially available micromixer, SIMM-V2. The particle size of BaSO₄ was dependent on the flow rate at the saturation concentrations, exhibiting a Z-type change with increasing the flow rate. The average particle size of BaSO₄ particles could be adjusted by decreasing the Na₂SO₄ concentration. Decreasing the molar ratio R to less than 1 resulted in agglomerated round BaSO₄ particles, while dispersible rod-like ones were produced when R = 1.2-1.8. The wastewater separated from each synthesis solution could be reused to prepare the BaCl₂ solution, resulting in a slight increase in the mean particle size and broadened particle size distribution after eight cycles. The optimized preparation process could produce 2 kg/h of BaSO ₄ nanoparticles with a mean particle size of 28 nm with a narrow particle size distribution.