Patent ID: 7919333

Claim:
A process for producing spherical magnetic silica gel particles comprising: a) converting alkoxysilanes into a hydrosol by acid catalysis with an acid as spherical magnetic silica gel particle precursors and then b) obtaining a hydrosol mixture by i) admixing a SiO2 colloid with the hydrosol; ii) adding magnetic particles to the hydrosol; and iii) adding one or more compounds in the form of oxides selected from the group consisting of metal compounds, metalloid compounds, and combinations thereof to the hydrosol; then c) dispersing the hydrosol mixture in a dispersant which is immiscible with a phase of the hydrosol mixture and consolidating the hydrosol mixture by addition of a base during the dispersion process to obtain solid spherical magnetic silica gel particles; and d) converting the solid spherical magnetic silica gel particles by a thermal treatment to form thermally treated solid spherical magnetic silica gel particles (xerogels); wherein the admixing the SiO2 colloid with the hydrosol increases the surface area of the solid spherical magnetic silica gel particles (xerogels) and the magnetic particles cause the solid spherical magnetic silica gel particles to acquire magnetic properties.