KINETICS OF FORMATION OF PARTICLES OF AMORPHOUS SILICA.

The authors attempted to overcome the various difficulties and to use the Sears procedure to study the formation of particles of amorphous silica in neutralized solutions of alkali silicates. As shown by investigation of the kinetics of formation and growth of particles of amorphous silica in sodium silicate solutions with a modulus of 1. 0 neutralized to pH 3-7, the linear segment of the dependence log left bracket (D//m//a//x-D// tau ) multiplied by (times) 100/D//m//a//x right bracket - tau is retained during all states of their aging, with their slope decreasing with increasing tau and with the fraction of SiO//2 in the composition of particles of the new phase increasing. It was also found that there is a continuous transition between the values of the rate constants of silicomolybdate-complex formation reactions found by O'Connor for alkali silicate solutions of diffferent moduli and SiO//2 concentrations and those obtained by us for different moments of their aging after neutralization. This sugests that the CCF in alkali silicate solutions and the colloidal particles formed during their aging after neutralization differ only in their sizes.