SCI和EI收录∣中国化工学会会刊

Chinese Journal of Chemical Engineering ›› 2019, Vol. 27 ›› Issue (3): 575-586.DOI: 10.1016/j.cjche.2018.06.020

• Process Systems Engineering and Process Safety • 上一篇    下一篇

Effects of mechanical activation on the digestion of ilmenite in dilute H2SO4

Xiaomei Wang, Chun Li, Hairong Yue, Shaojun Yuan, Changjun Liu, Siyang Tang, Bin Liang   

  1. Low-Carbon Technology and Chemical Reaction Engineering Laboratory, Chengdu 610065, China
  • 收稿日期:2018-04-02 修回日期:2018-06-14 出版日期:2019-03-28 发布日期:2019-04-25
  • 通讯作者: Bin Liang,E-mail address:liangbin@scu.edu.cn
  • 基金资助:

    Supported by the National Natural Science Foundation of China (21236004).

Effects of mechanical activation on the digestion of ilmenite in dilute H2SO4

Xiaomei Wang, Chun Li, Hairong Yue, Shaojun Yuan, Changjun Liu, Siyang Tang, Bin Liang   

  1. Low-Carbon Technology and Chemical Reaction Engineering Laboratory, Chengdu 610065, China
  • Received:2018-04-02 Revised:2018-06-14 Online:2019-03-28 Published:2019-04-25
  • Contact: Bin Liang,E-mail address:liangbin@scu.edu.cn
  • Supported by:

    Supported by the National Natural Science Foundation of China (21236004).

摘要: The commercial sulfate process for pigment production uses concentrated sulfuric acid (>85 wt% H2SO4) as feeding material and discharges 8-10 tons of spend dilute acid (20 wt% H2SO4) per ton of product. Re-using spend acid to leach ilmenite can cut the waste emission and save fresh feeding acid. However, the leaching reaction with dilute acid is very slow and the digestion efficiency is fairly low. This paper describes a wet-milling process to enhance the dilute-acid leaching of ilmenite that makes it possible to produce TiO2 pigment in a more environmentally benign routine. The leaching kinetic study of unmilled ilmenite, dry milled 60 min ilmenite and wet milled 60 min ilmenite was conducted by revision of the shrinking core model (SCM), incorporation of particle size distribution (PSD) into SCM. The results revealed that mechano-chemical activation method significantly increased the leaching efficiency of titanium from 36% to 76% by reducing the particle size and increasing the reaction contact area. On the other hand, the milling process increased the lattice deformation and amorphization of crystalline, which lowered the activation energies in the leaching process. Compared with dry milling operation, wet milling is more effective, the particle size distribution of wet-milled ilmenite was much narrower, smaller, and more uniform. Wet milling of ilmenite makes the leaching reaction with dilute acid (60 wt% H2SO4) practicable and the re-use of spend acid becomes possible and economical.

关键词: Ilmenite, Mechanical activation, Sulfuric-acid leaching, Wet milling, Kinetics

Abstract: The commercial sulfate process for pigment production uses concentrated sulfuric acid (>85 wt% H2SO4) as feeding material and discharges 8-10 tons of spend dilute acid (20 wt% H2SO4) per ton of product. Re-using spend acid to leach ilmenite can cut the waste emission and save fresh feeding acid. However, the leaching reaction with dilute acid is very slow and the digestion efficiency is fairly low. This paper describes a wet-milling process to enhance the dilute-acid leaching of ilmenite that makes it possible to produce TiO2 pigment in a more environmentally benign routine. The leaching kinetic study of unmilled ilmenite, dry milled 60 min ilmenite and wet milled 60 min ilmenite was conducted by revision of the shrinking core model (SCM), incorporation of particle size distribution (PSD) into SCM. The results revealed that mechano-chemical activation method significantly increased the leaching efficiency of titanium from 36% to 76% by reducing the particle size and increasing the reaction contact area. On the other hand, the milling process increased the lattice deformation and amorphization of crystalline, which lowered the activation energies in the leaching process. Compared with dry milling operation, wet milling is more effective, the particle size distribution of wet-milled ilmenite was much narrower, smaller, and more uniform. Wet milling of ilmenite makes the leaching reaction with dilute acid (60 wt% H2SO4) practicable and the re-use of spend acid becomes possible and economical.

Key words: Ilmenite, Mechanical activation, Sulfuric-acid leaching, Wet milling, Kinetics