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过程工程学报 ›› 2017, Vol. 17 ›› Issue (3): 565-570.DOI: 10.12034/j.issn.1009-606X.216325

• 过程与工艺 • 上一篇    下一篇

含氟铁矿石烧结过程中枪晶石的生成及其与铁酸钙的作用

孙敬焘， 郭兴敏*   

  1. 北京科技大学冶金与生态工程学院，北京 100083
  • 收稿日期:2016-10-19 修回日期:2016-11-11 出版日期:2017-06-20 发布日期:2017-06-14
  • 通讯作者: 郭兴敏 guoxm@ustb.edu.cn
  • 基金资助:
    利用XRD-XRF进行铁矿石矿物定量及表征方法的基础研究;氧化钐高温电解直接制备Sm2Fe17合金方法的研究

Formation of Cuspidine and Action with Calcium Ferrite in Sintering Process of  Fluorine-containing Iron Ores

Jingtao SUN,   Xingmin GUO *   

  1. School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China
  • Received:2016-10-19 Revised:2016-11-11 Online:2017-06-20 Published:2017-06-14
  • Contact: GUO Xingmin guoxm@ustb.edu.cn

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摘要：

通过CaO-SiO2-CaF2三元系的烧结实验，结合光学显微镜观察和X射线衍射分析，对含氟矿烧结过程中枪晶石(Ca4Si2O7F2)的生成及其与铁酸钙(CaFe2O4)的作用进行了研究. 结果表明，1050℃空气气氛下烧结时，CaO和SiO2先发生反应生成Ca2SiO4，再与SiO2和CaF2发生反应生成枪晶石；CaFe2O4和枪晶石在1220℃下烧结时，都可稳定存在，自由态SiO2是含氟矿烧结过程中CaFe2O4分解的关键因素，SiO2与CaFe2O4反应生成Ca2SiO4和中间产物Ca2Fe22O33，随SiO2含量增加，Ca2Fe22O33量逐渐减少，Fe2O3量逐渐增加；SiO2含量为6.0%(w)时，Ca2Fe22O33消失，最终产物为Ca2SiO4和Fe2O3；生成的Ca2SiO4会与SiO2和CaF2发生反应生成枪晶石，抑制CaFe2O4生成. CaFe2O4、枪晶石和CaF2在1200℃下烧结时三者不发生反应.

关键词: 枪晶石, 铁酸一钙, 硅酸二钙, X射线衍射, 矿相结构

Abstract:

Combining analysis of XRD and optical microscopy (OM), the experiments sintered in CaO-SiO2-CaF2 system were carried out to investigate the formation of cuspidine (Ca4Si2O7F2) and the action on calcium ferrite (CaFe2O4). The results showed that when the sample was sintered at 1050℃, Ca2SiO4 was generated first by the reaction of CaO and SiO2, then the Ca2SiO4 reacted with CaF2 and SiO2 to form the Ca4Si2O7F2. Ca4Si2O7F2 and CaFe2O4 both can coexist stably at 1200℃. The existence of free SiO2 is the key factor to degradation of CaFe2O4 during the sintering process of fluorine-containing ore. SiO2 reacted with CaFe2O4 to generate Ca2SiO4 and Ca2Fe22O33, but the amount of Ca2Fe22O33 decreased with increase of SiO2, up to disappearance of Ca2Fe22O33 when SiO2 was 6.0%(w), and then formed Ca2SiO4 and Fe2O3. Finally Ca2SiO4 reacted with CaF2 and SiO2 to form Ca4Si2O7F2. An interesting phenomenon is found that CaF2 was added into the equivalent amount mixture of Ca4Si2O7F2 and CaFe2O4, the three also coexisted stably at 1200℃.

Key words: cuspidine, calcium ferrite, dicalcium silicate, X ray diffraction, mineral phase structure