Kumai Eri, Yang Fan, Xiang Lan
Department of Chemical Engineering, Tsinghua University, Beijing 100084, China.
ACS Omega. 2024 Aug 14;9(34):36635-36639. doi: 10.1021/acsomega.4c05004. eCollection 2024 Aug 27.
Titanium-bearing blast furnace slag (TBFS) is formed during the smelting of vanadium-titanium magnetite ore, containing more than 10 wt % Ti. The metal resource in TBFS has not yet been utilized because of the difficulty of extracting the objective phase from the complex eutectic. In this work, thermodynamic and experimental studies of selective leaching of diopside phase in TBFS in 20 wt % HSO were conducted. The Gibbs free energy of reaction with HSO calculated by applying a mechanical mixture model was in the order of Ti-bearing diopside < MgAlO < Ti-rich diopside < CaTO. The extraction rate of Ti ions was controlled by the leaching temperature and leaching time in 20 wt % HSO. The extraction rate of Ti reached as high as 0.50 under optimal conditions. The diopside phases in TBFS were completely decomposed, while the perovskite (CaTiO) was almost unaffected by 20 wt % HSO. The experimental results agreed with the trend of thermodynamic calculations, supporting their validity. The hydrolysis of TiOSO showed the possibility of obtaining high-purity TiO. This work shows the selective leaching of the diopside phase in TBFS and suggests an environmentally friendly method for utilizing Ti-bearing blast furnace slag and waste acid.
含钛高炉矿渣（TBFS）是在钒钛磁铁矿矿石冶炼过程中形成的，其钛含量超过10 wt%。由于难以从复杂的共晶体中提取目标相，TBFS中的金属资源尚未得到利用。在这项工作中，对TBFS中透辉石相在20 wt% H₂SO₄中的选择性浸出进行了热力学和实验研究。应用机械混合模型计算得到的与H₂SO₄反应的吉布斯自由能顺序为：含钛透辉石＜MgAl₂O₄＜富钛透辉石＜CaTiO₃。在20 wt% H₂SO₄中，Ti离子的萃取率受浸出温度和浸出时间的控制。在最佳条件下，Ti的萃取率高达0.50。TBFS中的透辉石相完全分解，而钙钛矿（CaTiO₃）几乎不受20 wt% H₂SO₄的影响。实验结果与热力学计算趋势一致，支持了其有效性。TiOSO₄的水解表明了获得高纯度TiO₂的可能性。这项工作展示了TBFS中透辉石相的选择性浸出，并提出了一种利用含钛高炉矿渣和废酸的环保方法。
