The process study of SiO2 coating on alpha-FeOOH particles by surface hydrolysis reaction in fluidized BED reactor

The process of SiO2 coating on alpha-FeOOH particles by dehydration and hyd rolysis of tetraethylorthosilicate (TEOS) in fluidized bed reactor has been investigated, The results show that the dehydration of alpha-FeOOH promote the hydrolysis reaction on the particle surface, which is used to form uni form layer. The effects of the reaction temperature, reaction time, TEOS co ncentration and the ammonia concentration, respectively, on the contents of silica were also investigated. Using this technique, the processes of dehy dration, coating silica and reduction of alpha-FeOOH were carried out by on e step, and the SiO2 coated by Fe3O4 particles with good magnetic propertie s were obtained.