A two-step sulfuric acid leaching process of ti-bearing blast furnace slag

The leaching behavior of water-quenched Ti-bearing blast furnace slag in sulfuric acid was investigated. The leaching process proceeded fast in the initial period, as shown by the dissolution results of aluminum and magnesium compounds, and part of amorphous titanium compounds. The leaching reaction was slowed down in the last period due to the formation of insoluble layer over the un-reacted calcium titanate particles. A two-step leaching process was designed, in which the slag was pre-leached with a 20% sulfuric acid solution. The pre-leaching could dissolute most of aluminum, about 64% of magnesium and 46% of titanium. The residue of pre-leaching was further leached with the help of mechanical milling. The two-step leaching operation resulted in a total Ti leaching rate over 94%.