Particle adhesion induced by calcium carbonate nanoparticles at 900 °C

Particle adhesion is a typical characteristic of particulate materials. The addition of poorly packed nanoparticles to microparticles may control their adhesiveness at high temperatures. Herein, we focused on calcium carbonate nanoparticles (CaCO3 NPs) to control particle adhesion at high temperatures. The CaCO3 NPs were added to stable and less-adhesive silica and kaolin microparticles. At 900 °C, the tensile strength of the kaolin powder bed increased 6.8 times with the addition of CaCO3 NPs, but that of SiO2 did not increase. We found that the addition of CaCO3 NPs to kaolin promoted sintering of particles at high temperatures, which was responsible for the increase in tensile strength. Size and amount of CaCO3 NPs are important factors to determine the particle adhesion. The addition of alumina nanoparticles (Al2O3 NPs) to the kaolin-CaCO3 NPs system successfully suppressed the increase in tensile strength at high temperatures caused by CaCO3 NPs. [Display omitted] •Controlling the particle adhesion at high temperatures is important.•Addition of poorly packed nanoparticles may control tensile strength of powder bed.•Calcium carbonate nanoparticles increased the tensile strength of the kaolin.•Tensile strength of silica did not increase with addition of the calcium carbonate.•Addition of calcium carbonate nanoparticles promoted sintering of particles.