Effects of Basicity and Al2O3 Content on the Crystal Structure of Silico-ferrite of Calcium and Aluminum

Junwoo Park, Eunju Kim, In Kook Suh, Joonho Lee

Research output: Contribution to journalArticlepeer-review

Abstract

Silico-ferrite of calcium and aluminum (SFCA) is the primary bonding phase of iron ore sinter, the world's most popular artificial feed material for ironmaking. However, fundamental questions about its crystal structure and the atomic occupancy at each site remain unanswered. To date, the quantitative phase analysis (QPA) of SFCA has mostly been conducted using two-dimensional information and only provided information regarding phase fractions. In contrast, Rietveld analysis uses bulk data and provides lattice information in addition to phase fraction information. This study investigates the effects of basicity and Al2O3 concentration on the crystal structure and atomic site occupancy of SFCA through Rietveld analysis of the X-ray diffraction patterns. Raman spectroscopy and micro-Vickers hardness tests are used to verify the analytical results. Changes in the chemical composition affect the atomic occupancies at sites Si1 (Si-Al), Ca2 (Ca-Fe), Ca3 (Ca-Fe), Fe4 (Fe-Al), Fe5 (Fe-Al), and Fe7 (Fe-Al). With increasing basicity or Al2O3 content, the microhardness increases linearly, which can be attributed to the modification of atomic site occupancies. The crystalline structure obtained in this study is essential for developing a thermodynamic model of SFCA that can be used to predict its phase stability. This information can then be used to design a novel high-performance iron ore sinter.

Original languageEnglish
Pages (from-to)235-243
Number of pages9
JournalISIJ International
Volume63
Issue number2
DOIs
Publication statusPublished - 2023

Bibliographical note

Funding Information:
Foundation of China-the joint research fund of China Bao-Wu Iron and Steel Group Co., Ltd. (Grant No. U1860108, U1860203), the National Natural Science Foundation of China (Nos. 52022054; 51974181), the Shanghai Rising-Star Program (19QA1403600), and the Program for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher Learning (TP2019041) for financial support.

Funding Information:
This work was supported by the Industrial Strategic Technology Development Program (20212010100040, Development of hybrid ironmaking process for lower CO2 emission) funded by the Ministry of Trade, Industry, and Energy of the Republic of Korea. JP and EK were supported by the Competency Development Program for Industry Specialists of the Korea Institute for Advancement of Technology (Grant No. P0002019) of the Republic of Korea.

Publisher Copyright:
© 2023 The Iron and Steel Institute of Japan.

Keywords

  • hardness
  • iron ore sinter
  • Rietveld analysis
  • site occupancy
  • x-ray diffraction

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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