Novel approach for high-efficiency recovery of titanium dioxide, hydrochloric acid, and organic solvents from titanium white waste acid

In this study, the recovery efficiency of titanium dioxide (TiO 2 ), hydrochloric acid (HCl), and organic solvents in titanium white waste acid (TWWA) is investigated via distillation combined with the calcination method. After distillation under vacuum condition at −0.071 MPa for 60 min, the recovery of diisobutyl phthalate (DIBP), hexane (C 6 H 14 ), ethanol (C 2 H 5 OH), and HCl reached up to 70%, 76%, 68%, and 21%, respectively. Moreover, the metatitanic acid (TiO(OH) 2 ) concentration in TWWA thick slurry obtained at the end of vacuum distillation increased from 72.60 to 416.11 g/L. Anatase and rutile were harvested after 60-min continuous calcination of TWWA thick slurry at 600 °C and 900 °C, respectively, and the TiO 2 content in rutile was as high as 93%. Based on these results, we believe that TiO 2 , HCl, and organic solvents can be efficiently recovered from TWWA via vacuum distillation and high-temperature calcination. This method realizes the reduction and resource utilization of TWWA and has the advantages of simple technological process and low treatment cost. • Integrated vacuum distillation and calcination is proposed to treat TWWA. • 70% DIBP, 76% C 6 H 14 , 68% C 2 H 5 OH, and 21% HCl were recovered via vacuum distillation. • The amount of TWWA thick slurry was reduced by 46% after vacuum distillation. • Rutile with high-purity TiO 2 was obtained from TWWA thick slurry after calcination.