摘要
研究高铁铝土矿还原熟料中单质铁颗粒聚集体的形成过程和金相组织结构。研究表明:原生的微细粒单质铁是实心颗粒,直接还原铁中常见的孔洞结构是呈空间网状结构的细颗粒集合体,而不是含铁矿物还原后失氧造成的孔洞,传统的原位还原机理不能完全概括直接还原反应的实质;还原熟料中原生单质铁的赋存形态与原矿中赤铁矿的赋存形态相关;原矿中赤铁矿的粒度决定还原后的原生微细粒铁单质铁粒度,各粒级的颗粒均能烧结成为次生空间网状单质铁集合体,但细颗粒表面能较高,更容易相互烧结;碳化物主要分布在单质铁颗粒的烧结颈处,表明单质铁颗粒间的烧结受到表面渗碳的影响。
The formation of iron grain aggregates in reduction clinkers and the micro structures of iron powder were investigated. The results show the primary iron grain is solid, so the common porous structure in direct reduced iron consists of the holes and grains in iron aggregates with 3-dimension network structure, but not the vacancy produced by oxygen loss in direct reduction reaction. So, the essence of direct reduction reaction can not be covered by traditional in-situ reduction theory entirely. The combined forms of original iron grain in reductive clinkers is determined by the combined forms of hematite in ferric bauxite ore, and both large and fine grains can be a component unit of secondary iron grain aggregates. Since the surface energy of fine iron grains is higher than large ones, they are easier to form larger aggregates with 3-dimension network structure. The carbide in iron mainly distributed in the sintering necks of grains, which indicates the sintering of grains was promoted by surface carburization.
出处
《中南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2013年第10期3971-3976,共6页
Journal of Central South University:Science and Technology
基金
国家自然科学基金资助项目(51304012)
中国博士后科学基金资助项目(2013M530529)
关键词
高铁铝土矿
铁
直接还原
金相组织
ferric bauxite
iron
direct reduction
metallographic structure
