Preparing Metatitanic Acid from Perovskite-Type Titanium Slag Using a Sulfuric–Chloric Mixture Acid

To reduce Ti-bearing blast furnace slag wastage, our group previously developed a metallurgical process in which Ti-bearing slag was produced using Na 2 CO 3 instead of CaO. This process increased the TiO 2 content—in the form of Na 2 Ti 16 O 33 (40.93%) and CaTiO 3 (42.77%)—of the slag from 22% to ~43%. In this report, a method based on the use of sulfuric–chloric mixture acid (SCMA) is proposed for slag decomposition, and a decomposition rate of ~80% is achieved. After hydrothermal hydrolysis, at a titanium concentration of 1.1-1.4 mol·L −1 , the titanium conversion is > 90%, and uniform particle sizes of metatitanic acid (2-4 µm) are produced. The mechanism for decomposition process is based on two-stage kinetics and is controlled through diffusion of Ti–Na and Ti–Ca. SCMA method is more economic and environmentally friendly than existing methods because of an energy-efficient decomposition process and acid recycling.