Aluminum hydrolysis in mixed liquid reactors is a problem with multipl
e kinetic and mixing time scales Since some of these times scales over
lap, and since aluminum hydrolysis has multiple pathways (some of whic
h are slowly reversed), we have modeled aluminum precipitation as a co
upled mixing and chemistry problem. For the base neutralization of dil
ute aluminum chloride in a standard stirred reactor with Rushton impel
ler, mixing submodels are combined with simplified aluminum chemistry
models to predict the effect of mixing on steady-state pH at various f
ormation or neutralization ratios. Our simulations and experiments cle
arly show that mixing speed influences the shape of the pH titration c
urve, which suggests that the conversion of aluminum into amorphous an
d polymeric species is mixing-sensitive. The experimental and simulate
d results show less sensitivity to position of base injection in the r
eactor.