CIESC Journal ›› 2019, Vol. 70 ›› Issue (11): 4143-4152.DOI: 10.11949/0438-1157.20190931

• Thermodynamics • Previous Articles     Next Articles

Thermodynamic studies on behavior of newly formed metallic iron on surface of particles

Zhan DU()   

  1. Information Research Institute of the Ministry of Emergency Management, Beijing 100029, China
  • Received:2019-08-13 Revised:2019-09-16 Online:2019-11-05 Published:2019-11-05
  • Contact: Zhan DU

颗粒表面金属铁析出规律的热力学研究

杜占()   

  1. 应急管理部信息研究院,北京 100029
  • 通讯作者: 杜占
  • 基金资助:
    国家自然科学基金项目(21908227)

Abstract:

The influence of reduction conditions on the morphology of newly formed metallic iron during high temperature gas-based reduction of iron ore are studied from the standpoint of thermodynamic analysis, and the solutions for controlling iron morphology through regulation of reduction conditions are proposed. Experimental results showed that addition of H2 in CO could not only accelerate the growth rate of iron grains, but also increase the amounts of iron nuclei, resulting in the transformation of fibrous iron into dense one, addition of CO2 in CO could transform the“sharp-pointed”iron whiskers into“cactus-like”ones, decrease of reduction temperature could lower the strength of fibrous iron.

Key words: precipitation behavior of iron, thermodynamics, regulation of iron morphology, reduction, granular materials

摘要:

从热力学角度出发,揭示了还原条件对高温气基还原过程中颗粒表面铁析出行为的影响规律,提出了通过改变还原气氛调控铁析出形貌的操控方法。研究表明在CO中混入H2可以加快铁晶粒的生长速率,同时增加还原初期矿粉表面的铁形核数量,导致矿粉表面新生成的金属铁由晶须状转变为致密状。随着CO-CO2中CO2含量的升高,矿粉表面新生成的金属铁会由“锋利”的晶须状转变为“仙人掌状”,并且表面铁的分布密度会变小。随着还原温度的降低,矿粉表面铁晶须的强度会变弱。

关键词: 铁析出规律, 热力学, 形貌调控, 还原, 颗粒物料

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