Selective precipitation and in situ separation of rutile crystals from titanium bearing slag melt in a super-gravity field

Abstract

This manuscript proposes a novel method of selectively precipitating and separating rutile (TiO₂) crystals from titanium bearing slag melt using super-gravity, and also develops a new approach for investigating a specified crystal from various melts through selective precipitation, in situ separation and ex situ characterization in a super-gravity field. The precipitation behaviors of titanium bearing slag melt with decreasing temperature indicate that the titanium precipitated selectively into rutile crystals under the conditions of a slag basicity of 0.5 and a TiO₂ content of 22–25 wt%, with 1573–1473 K as the optimum precipitation temperature range. Consequently, in situ separation of rutile crystals from the slag melt was conducted in a super-gravity field at the precipitation temperature, where rutile crystal was the only solid phase and other minerals formed molten slag. The slag melt went through a filter as driven by super-gravity, whereas the rutile crystals were overall intercepted by the filter and separated from the slag. In addition, the efficiency of the rutile-slag separation and purity of the separated rutile crystals were enhanced significantly with increasing the gravity coefficient. Accordingly, the high-purity rutile crystals with a dendritic structure were attained with G = 600 at T = 1553 K for 5 min, and the mass fraction of TiO₂ in the separated rutile phase was up to 95.56 wt%.