Abstract: The preparing process of TiO₂ superfine particles from homegeneous solutions was investigated by a new instrument designed
(China patent). The effect of pH, concenteration of reactant, anions present on the characteristics of final products was discussed, and
rutile TiO₂ particles about 100nm were obtained. With this instrument, the hydrolysis process can directly be recorded. The beginning time (t₁)
and temperature (T₁) of hydrolysis, the parameters of I/I₀ (generated nucleus concentration), Δ T (nucleus-forming temperature range),
Δ t (nucleus-forming time range) can also be recorded. The relationship between generated nucleus concentration and temperature, time in
different conditions was obtained. It is shown that the changes of reactant concentration and pH values, anion cause the variety of t₁, T₁, Δ t,
Δ T. The characteristics (size, crystalline) of the product depend on these parameters. The higher the beginning temperature of the hydrolysis,
and the narrower the temperature range, the faster the hydrolysis reaction, the smaller the particles size and the more difficult the crystalline transforming.

Key words: nanoscale particle TiO₂, preparing processes, new instrument and method