化工学报 ›› 2022, Vol. 73 ›› Issue (12): 5592-5604.DOI: 10.11949/0438-1157.20221018

• 材料化学工程与纳米技术 • 上一篇    下一篇

Co对WO3-Co3O4预还原的影响及其产物碳化性能

尚慧俊1,2(), 黎亨利2,3, 刘家义2, 潘锋2(), 杜占2(), 孙林兵1   

  1. 1.南京工业大学化工学院,江苏 南京?210009
    2.中国科学院过程工程研究所多相复杂系统国家重点实验室,北京? 100190
    3.石河子大学化学化工学院,新疆 石河子 832003
  • 收稿日期:2022-07-16 修回日期:2022-11-26 出版日期:2022-12-05 发布日期:2023-01-17
  • 通讯作者: 潘锋,杜占
  • 作者简介:尚慧俊(1996—),男,硕士研究生, 1293287496@qq.com
  • 基金资助:
    国家自然科学基金项目(22078326)

Effect of Co on the pre-reduction process of WO3-Co3O4 and carbonization performance of its product

Huijun SHANG1,2(), Hengli LI2,3, Jiayi LIU2, Feng PAN2(), Zhan DU2(), Linbing SUN1   

  1. 1.College of Chemical Engineering, Nanjing Tech University, Nanjing 210009, Jiangsu, China
    2.State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
    3.School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832003, Xinjiang, China
  • Received:2022-07-16 Revised:2022-11-26 Online:2022-12-05 Published:2023-01-17
  • Contact: Feng PAN, Zhan DU

摘要:

为避免超细WC-Co粉体制备过程中形成对烧结过程及其产物带来不利影响的η相(Co6W6C或Co3W3C),提出了WO3-Co3O4预还原至WO2-Co,再深度还原碳化至WC-Co的技术路线。主要考察了600℃,H2-C2H4-Ar气氛条件下,Co含量及钴源粒径对WO3-Co3O4预还原过程的影响规律,并对预还原产物进行了深度还原碳化性能测试。结果表明,Co的存在可催化C2H4裂解析出H2和C,显著加快WO3预还原速率,且随着Co含量增加其预还原速率显著增加;乙烯析碳速率和析碳量也随Co含量增加而增加。钴源粒径对WO3还原速率和C2H4析碳速率有显著影响,本实验体系下,纳米钴源体系中C2H4析碳速率大约是微米钴源体系的2倍;同时,纳米钴源体系中WO3也具有较快的还原速率。8%Co含量的预还原产物在950℃、甲烷分压1.25%条件下焙烧60 min,可获得无η相的WC-Co复合粉体。

关键词: WO3-Co3O4体系, 流化床, 还原, 粉体

Abstract:

In order to avoid the formation of η phase (Co6W6C or Co3W3C) that adversely affect the sintering process and its products in the preparation process ultra-fine WC-Co powder, we propose a technical route of pre-reduction of WO3-Co3O4 to WO2-Co and then deep reduction carbonization to WC-Co. The influence of Co content and cobalt source particle size on the pre-reduction process of WO3-Co3O4 was investigated at 600℃ H2-C2H4-Ar atmosphere in a fluidized-bed reactor, and the deep reduction and carbonization properties of the pre-reduced products were tested. The results show that the presence of Co can catalyze the splitting of C2H4 to separate H2 and C, significantly accelerate the pre-reduction rate of WO3, and the pre-reduction rate increases significantly with the increase of Co content. The carbon evolution rate and carbon evolution amount of ethylene also increase with the increase of Co content. Cobalt source particle size has a significant effect on the pre-reduction rate of WO3 and carbon evolution rate of C2H4. In this experimental system, the carbon evolution rate of C2H4 in nano cobalt source system is about twice that of micron cobalt source system. Meanwhile, WO3 in nano cobalt source system also has faster reduction rate. The pre-reduced product was calcined with methane partial pressure of 1.25% at 950℃ for 60 min, and fine WC-Co composite powder without η could be obtained.

Key words: WO3-Co3O4 system, fluidized-bed, reduction, powder

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