Extraction of Valuable Components from Ti-Bearing Blast Furnace Slag Using Sulfuric Acid Calcination Process

This article presents a clean and efficient method for extracting Ti, Al, and Mg components from Ti-bearing blast furnace slag with sulfuric acid. TBFS was calcined with concentrated sulfuric acid and then leached with deionized water. Variables such as acid-slag ratio, calcination temperature, and calcination time were studied. It was shown that when TBFS was reacted with concentrated sulfuric acid with an acid to slag weight ratio of 1.4 at 130 degrees C for 40 min, the percentage of Ti, Al, and Mg recovered from deionized water leaching was up to 82.85%, 93.16%, and 96.96%, respectively. A possible calcination mechanism is discussed, in which less SO2 was generated than could be completely absorbed by water, and no CaSO4 center dot 2H(2)O formed during the reaction. The main phases found in the calcined slag were II-anhydrite, aluminum sulfate, titanium sulfate, and magnesium sulfate. This method solved an issue present in traditional H2SO4 leaching processes, in which substantial CaSO4 center dot 2H(2)O colloid would be produced and coat the TBFS particles, thus hindering the extraction of components.