Title: Effect of mineral phases on the leaching efficiency of titanium slag

Abstract

Titanium slag obtained from electric furnace smelting using ilmenite from Panzhihua contains predominately two phases: anosovite and augite. The mineral phase compositions in titanium slag can have severe effects on the leaching process and leaching efficiency. However, the precise role of the effect of mineral phases on the leaching efficiency is unclear. In this work, the leaching behaviour of titanium from slag originated from Panzhihua region was investigated by using kinetic analysis and the characterizations of mineral phases and morphologies of particles involved in the fluid solid leaching reactions. It was found that the leaching rates of titanium slag particles became more rapid with the increase of the concentration of sulphuric acid, temperature and surface area of titanium slag particles. Kinetic analysis using the data from the leaching kinetic study showed that the leaching process of titanium slag conformed to the shrinking core model controlled by surface chemical reaction and internal diffusion, and the apparent activation energy of leaching reaction was determined to be 69.87 kJ/mol. From the characterizations of mineral phases and morphologies of particles involved in the fluid-solid leaching reactions, it was shown that the formation of boundaries between mineral phases in titanium slag acted as resistance to slow down the leaching rate of titanium from titanium slag in sulphuric acid. Because the dissolution rate of augite phase was much slower than anosovite phase, the surface area available for the titanium leaching from titania-rich anosovite phase was reduced due to the coexistence of augite and anosovite phases in titanium slag particles. Our results demonstrate that the formation of boundary structures of anosovite and augite phases is an important factor affecting the leaching efficiency of titanium slag.

Biography

Xiaoping Wu has been working in Ansteel Research Institute of Vanadium & Titanium (Iron & Steele), Pangang Group, as a research director and a senior research fellow in the area of titanium fine chemicals, titanium extraction, and titanium oxide materials. Previously, he had worked as the senior research scientist and senior research engineer in chemical industries and universities in UK. He obtained a BSc and MSc in China, and a PhD in chemistry from University of London.