Titanium Recovery from Ti-Bearing Blast Furnace Slag by Alkali Calcination and Acidolysis

摘要

This research mainly focuses on recovery of titanium from Ti-bearing blast furnace slag using the process of alkali calcination, water leaching, and acid hydrolysis. The Ti-bearing blast furnace slag contained approximately 24% SiO2, 12.73% Al2O3, and 20.74% TiO2. The main minerals in the slag were perovskite, diopside, and spinel. In the calcination process, the chemical products were NaAlO2, Na2SiO3, Na2CaSiO4, and Na2TiO3. In the leaching process, NaAlO2 and Na2SiO3 dissolved in water, Na2CaSiO4 remained in the water-leached product, and Na2TiO3 was hydrolyzed to an amorphous state. After alkali calcination and water leaching, 45% of SiO2 and 83% of Al2O3 were removed, while the TiO2 content increased to 36.13%. The extraction rate of titanium was 91.21% after hydrolysis by dilute sulfuric acid at 120 degrees C for 2 h of the water-leached product, and nano-anatase TiO2 was obtained by hydrolysis and calcination of the resulting titanyl sulfate solution.