Chinese Journal of Chemical Engineering ›› 2020, Vol. 28 ›› Issue (3): 923-932.doi: 10.1016/j.cjche.2019.10.001

• Materials and Product Engineering • Previous Articles     Next Articles

Preparation of nano-sized tungsten carbide via fluidized bed

Feng Pan1, Zhan Du2, Shaofu Li1, Jun Li1, Meiju Zhang1, Maoqiao Xiang1, Qingshan Zhu1,3   

  1. 1 State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences(CAS), Beijing 100190, China;
    2 Information Research Institute of Emergency Management Department, Beijing 100084, China;
    3 University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2019-06-11 Revised:2019-09-14 Online:2020-03-28 Published:2020-06-11
  • Contact: Qingshan Zhu
  • Supported by:
    The authors wish to gratefully acknowledge the financial support from the National Natural Science Foundation of China (Grant No. 21878305). The authors would like to thank the raw materials support provided Huamao Tungsten Materials Co. Ltd.

Abstract: Ultrafine or nano-sized of tungsten carbide (WC) is the key material to prepare ultrafine grained cemented carbides. In this paper, nano-sized WC powders were directly prepared by using industrial nano-needle violet tungsten oxide (WO2.72) as the raw material, a fluidized bed as the reactor, and CO as the carbonization gas. The relationship between particle sizes and reaction temperatures, residence times, atmospheres has been investigated systematically. In addition, the physical-chemical indexes (such as residual oxygen, total carbon and free carbon) of the products were measured. The results indicated that the particle size of WC increased with the increase of temperature from 800 to 950 ℃. As the residence time increased, the particle size decreased gradually, and then increased due to slight sintering. The introduction of hydrogen reduced the carbonization rate, and is not beneficial to obtaining nano-sized WC. Products that satisfy the standard were obtained when WO2.72 reacted with CO at 850 ℃, 900 ℃ and 950 ℃ for 3.0 h, 2.5 h and 2.0 h, respectively. The particle sizes of the three samples calculated from the specific surface area were 46.4 nm, 53.2 nm and 52.1 nm, respectively.

Key words: Nanoparticles, Violet tungsten oxide, Nano tungsten carbide, Fluidized-bed, Reduction-carbonization, Process control