Study on leaching Ti from Ti bearing blast furnace slag by sulphuric acid

The treatment for leaching Ti using sulphuric acid was investigated in order to utilise Ti bearing blast furnace slag including water quenched slag (WQS) and naturally cooled slag (NCS). Ti bearing blast furnace slag was subjected to direct agitation leaching with dilute sulphuric acid. Variables such as acid concentration, temperature, leaching time, liquid/solid ratio, particle size and stirring speed were studied. It was shown that, when WQS material (size range, 0–0·5 mm) was reacted with sulphuric acid of 50% concentration at a stirring speed of 400 rev min–1 with a liquid to solid weight ratio of 10 at 100°C for 1 h, Ti recovery from leaching was up to 72·3%. However, for NCS, Ti recovery was only ∼45% under comparative leaching conditions. A possible leaching mechanism and the difference of leaching effect between WQS and NCS are discussed. Unlike NCS, WQS is a type of activated slag, making it more favourable for extraction of Ti.