Effects of Mechanical Activation on the HCl Leaching Behavior of Titanaugite,Ilmenite, and Their Mixtures

Structural changes of mechanically activated titanaugite were investigated systematically using X-ray diffraction, particle size analysis, and scanning electron microscopy. The hydrochloric acid leaching behavior of mechanically activated titanaugite and ilmenite single minerals and their mixtures also was studied. The results show that with increasing milling time, the crystallite size, lattice strain, and particle size changed continuously. Mechanical activation evidently improved the leaching reactivity of titanaugite and ilmenite with 20 wt pct HCl at 378 K (105 °C). The leaching behavior of ilmenite was promoted at the initial stage and then was inhibited when mixed with a mass ratio of titanaugite to ilmenite of 1:1. When the mass ratio of titanaugite to ilmenite decreased to 1:9, the leaching of titanaugite was promoted, whereas the leaching of ilmenite was inhibited throughout the whole process. The leaching inhibition of ilmenite is related to the formation of hydrous silicon dioxide from the dissolution of titanaugite.