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

Jingtao SUN   Xingmin GUO

doi:10.12034/j.issn.1009-606X.216325

The Chinese Journal of Process Engineering >

2017 , Vol. 17 >Issue 3: 565 - 570

DOI: https://doi.org/10.12034/j.issn.1009-606X.216325

Process & Technology

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

Jingtao SUN Xingmin GUO

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School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China

Received date: 2016-10-19

Revised date: 2016-11-11

Online published: 2017-06-14

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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 addedinto 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

Cite this article

Jingtao SUN Xingmin GUO . Formation of Cuspidine and Action with Calcium Ferrite in Sintering Process of Fluorine-containing Iron Ores[J]. The Chinese Journal of Process Engineering, 2017 , 17(3) : 565 -570 . DOI: 10.12034/j.issn.1009-606X.216325

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