Process Optimization and Kinetics of Titanium Leaching from Mechanically Activated Titanium-Bearing Blast Furnace Slag

摘要

Abstract The single variable method?was employed to investigate?the?general?behavior and describe the kinetics of titanium leaching from mechanically activated titanium-bearing blast furnace slag. The optimal leaching characteristics were determined by varying the leaching temperature, leaching time, stirring intensity, hydrochloric acid solution mass fraction, and liquid-to-solid ratio (volume:mass). The optimal mechanical activation characteristics were determined using the optimal leaching process by varying the mechanical activation time, activation rotation rate, and milling ball-to-material mass ratio. The results indicated that the optimal leaching process characteristics comprise leaching temperature of 100?°C, leaching time of 120?min, stirring intensity of 600 r/min, hydrochloric acid mass fraction of 50%, and liquid-to-solid ratio of 100:1. According to the variation of titanium leaching rate from mechanically activated titanium-bearing blast furnace slag with different mechanically activation conditions, the optimal mechanical activation time, activation rotation rate, and milling ball-to-material mass ratio were determined to be 170?min, 400 r/min, and 20:1, respectively. The kinetics of titanium leaching from mechanically activated titanium-bearing blast furnace slag were effectively described by the linear relationship 1-1-α13=ktdocumentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} begin{document}$$1 - left( {1 - alpha } right)^{frac{1}{3}} = kt$$end{document} and the apparent activation energy of the reaction calculated from the slope of the line is 55.52?kJ/mol, which is consistent with the characteristics of the contraction model interface chemical control step. Therefore, the shrinking core model was identified as the leaching reaction kinetics model. The XRD patterns of leaching residues of unactivated and mechanically activated slag provided evidence that mechanical activation indeed promoted the reactivity of titanium-bearing blast furnace slag and significantly improved the titanium leaching rate.Graphical Abstract