Silica spherical particles were prepared in reverse microemulsion from sodium silicate solution precursor. Particle shape and size changes were investigated in function of reactants addition order, sodium silicate solution concentration and water to surfactant ratio (W) and product separation and purification. This paper reports on the uniform spherical silica particles preparation in function of the mentioned different experimental conditions. Scanning electron micrographs show uniform spherical silica particle obtained from the mixture of two reverse microemulsion: microemulsion A with soluble sodium silicate was added to a microemulsion B with nitric acid solution. Concentrated sodium silicate solution was diluted to 1:10 (silicate:water) ratio. Separation and purification was carried out in two steps with hot ethanol and water. The average particle size increases as W increases.
reverse microemulsion; silica; particle shape
