Abstract: Using silicon powder as silica source, monodisperse and high-purity nano-silica sol was synthesized under catalysis of aqueous ammonia and ammonia gas. The urea-formaldehyde polymer/SiO₂ composite microspheres were prepared after polymerization-induced colloid aggregation(PICA) method in acidic media, and the spherical silica packing material was produced after calcining at high temperature. The purity of monodisperse nano-silica sol was tested by inductively coupled plasma mass spectrometry(ICP-MS), and the size and shape of the composite microspheres were characterized by scanning electron microscope(SEM). The performance of silica packing material was evaluated by non-chromatographic method(BET) and chromatographic method. The results show that the silica packing material has high purity, uniformity and high mechanical strength.

Key words: Silicon powder, Polymerization-induced colloid aggregation(PICA), Silica packing material