Pengaruh Variasi Holding Time terhadap Perubahan Mikrostruktur Refraktori Magnesia Spinel Akibat Interaksi Calcine pada Temperatur 1200°C

Addhuha, Nurul Latifah (2026) Pengaruh Variasi Holding Time terhadap Perubahan Mikrostruktur Refraktori Magnesia Spinel Akibat Interaksi Calcine pada Temperatur 1200°C. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Refraktori magnesia–spinel digunakan pada lingkungan temperatur tinggi karena memiliki stabilitas termal dan ketahanan kimia yang baik, tetapi interaksinya dengan material proses dapat menyebabkan perubahan komposisi, mikrostruktur, dan fase penyusun. Penelitian ini bertujuan menganalisis pengaruh interaksi calcine terhadap komposisi unsur, perubahan mikrostruktur akibat variasi holding time, serta kemungkinan pembentukan fase baru pada refraktori magnesia–spinel. Pengujian dilakukan pada temperatur 1200°C dengan variasi waktu penahanan 2, 4, dan 8 jam. Karakterisasi material dilakukan menggunakan X-Ray Fluorescence (XRF), X-Ray Diffraction (XRD), serta Scanning Electron Microscopy–Energy Dispersive X-ray Spectroscopy (SEM–EDX). Hasil XRF menunjukkan bahwa refraktori didominasi MgO sebesar 81,455% dan Al₂O₃ sebesar 14,728%, sedangkan calcine didominasi Fe₂O₃ sebesar 37,377%, SiO₂ sebesar 33,221%, dan MgO sebesar 19,191%. Setelah interaksi, unsur Fe, Si, Ni, dan Ca dari calcine terdeteksi secara lokal pada permukaan, pori, celah, dan batas butir refraktori. Peningkatan holding time menyebabkan perubahan mikrostruktur secara bertahap, yaitu terbentuknya deposit awal pada 2 jam, pemadatan dan pengisian sebagian pori pada 4 jam, serta peningkatan keterikatan deposit dengan permukaan pada 8 jam. Meskipun demikian, mikrostruktur tetap heterogen dan masih menunjukkan pori serta retakan mikro. Hasil XRD pada seluruh variasi waktu mengidentifikasi MgO atau periclase dan MgAl₂O₄ atau spinel sebagai fase utama. Fase MgFe₂O₄, (Mg,Fe)O, dan Mg₂SiO₄ belum terbentuk. Dengan demikian, interaksi refraktori dengan calcine pada 1200°C lebih dominan menyebabkan perubahan morfologi dan komposisi kimia lokal daripada transformasi fase kristalin secara menyeluruh.
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Magnesia–spinel refractories are widely used in high-temperature environments because of their good thermal stability and chemical resistance. However, interaction with process materials may alter their elemental composition, microstructure, and constituent phases. This study aimed to investigate the effect of calcine interaction on the elemental composition of magnesia–spinel refractories, the influence of holding time on microstructural evolution, and the possible formation of new phases. The interaction test was conducted at 1200°C with holding times of 2, 4, and 8 hours. Material characterization was performed using X-ray fluorescence (XRF), X-ray diffraction (XRD), and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDX). XRF results showed that the refractory was primarily composed of 81.455% MgO and 14.728% Al₂O₃, whereas the calcine was dominated by 37.377% Fe₂O₃, 33.221% SiO₂, and 19.191% MgO. Following interaction, Fe, Si, Ni, and Ca originating from the calcine were locally detected on the refractory surface, particularly within deposits, pores, gaps, and grain boundaries. Increasing the holding time resulted in gradual microstructural changes, including initial deposit formation after 2 hours, denser deposits and partial pore filling after 4 hours, and stronger integration of deposits with the refractory surface after 8 hours. Nevertheless, the microstructure remained heterogeneous, with pores and microcracks still present. XRD analysis identified MgO, or periclase, and MgAl₂O₄ spinel as the main crystalline phases at all holding times. The formation of MgFe₂O₄, (Mg,Fe)O, and Mg₂SiO₄ was not clearly detected. Therefore, the interaction between the refractory and calcine at 1200°C predominantly caused local changes in morphology and chemical composition rather than an extensive crystalline phase transformation

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Calcine, Holding Time, Magnesia-Spinel Refractory
Subjects:	T Technology > TN Mining engineering. Metallurgy > TN687 Electric furnaces.
Divisions:	Faculty of Industrial Technology > Material & Metallurgical Engineering > 28201-(S1) Undergraduate Thesis
Depositing User:	Nurul Latifah Addhuha
Date Deposited:	28 Jul 2026 04:30
Last Modified:	28 Jul 2026 04:30
URI:	http://repository.its.ac.id/id/eprint/137408

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