Abstract: In order to improve the sharpness of classification of acid hydrolysis waste residues of titanium dioxide,the process optimization was made by numerical simulation and experimental investigation.Simulated results indicated that when inlet velocity was 1.78 m/s,the efficiency of the coarse particles by spigot was 91.1%,which reduced the recovery rate of TiO₂.On the other hand,when inlet velocity was 2.78 m/s,the efficiency of the fine particles by vortex finder was 62.9%,which reduced the separation rate of impurities significantly.As a result,for achieving high sharpness,inlet velocity should be 2.28 m/s.The further results of experiments validated that when inlet velocity was 2.28 m/s, D4,3 of overflow and underflow products were 9.2 μm and 43.6 μm,respectively.Meanwhile,90.3% of the fine particles of impurities were removed,and the recovery rate of TiO₂ was 59.3%.