Pengaruh Rasio Fluks High Kalsium Hidroksida (Ca(OH)2) Dan Fluks Kalsium Karbonat (CaCO3) Terhadap Penurunan Persentase Mangan Pada Peleburan Campuran Skrap Baja

Cahyono, Galang Tri (2025) Pengaruh Rasio Fluks High Kalsium Hidroksida (Ca(OH)2) Dan Fluks Kalsium Karbonat (CaCO3) Terhadap Penurunan Persentase Mangan Pada Peleburan Campuran Skrap Baja. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Penggunaan baja dengan kandungan mangan (Mn) yang tinggi pada komponen otomotif dapat meningkatkan kekerasan material, namun berdampak pada penurunan ketangguhan dan sifat mekanik lainnya yang penting untuk keandalan dan keamanan struktur. Kandungan Mn yang terlalu tinggi, khususnya dalam rentang 0,70–0,71% berat, melebihi batas maksimum yang ditetapkan sebesar 0,2% berat, sehingga perlu dikurangi melalui proses peleburan. Penelitian ini bertujuan untuk mengevaluasi efektivitas penambahan fluks kalsium hidroksida (Ca(OH)2) dan kalsium karbonat (CaCO3) dalam menurunkan kadar Mn melalui proses peleburan scrap baja menggunakan tungku induksi. Proses dilakukan dengan memanfaatkan kombinasi scrap baja berkandungan Mn tinggi dan Mn rendah sebanyak 250 gram, serta variasi penambahan fluks sebesar 2 wt%, 4 wt%, dan 6 wt% dengan komposisi 75% kalsium hidroksida dan 25% kalsium karbonat. Selama proses peleburan, fluks mengalami dekomposisi termal menjadi kalsium oksida (CaO), uap air (H2O), dan karbon dioksida (CO2). Kalsium oksida (CaO) yang terbentuk kemudian bereaksi dengan unsur mangan (Mn) yang terlarut dalam logam cair, membentuk senyawa stabil yang dapat membentuk slag. Karakterisasi hasil slag menggunakan X-Ray Diffraction (XRD) menunjukkan terbentuknya senyawa seperti kalsium manganat (CaMnO3), CaMn14O24Si, kalsium besi oksida (CaFe4O7), dan senyawa kompleks CaFe0.2Mn0.8Si2, yang mengindikasikan keberhasilan pengikatan unsur Mn ke dalam fasa slag melalui reaksi oksidasi. Berdasarkan hasil pengujian, penambahan fluks sebesar 4 wt% menghasilkan penurunan kadar Mn paling signifikan dan mendekati standar PT. AT Indonesia. Namun demikian, dari sisi efisiensi energi dan biaya produksi, penambahan fluks sebesar 2 wt% dinilai lebih ekonomis dan layak diterapkan dalam skala industri tanpa menurunkan efektivitas proses secara signifikan. Penelitian ini membuktikan bahwa kombinasi fluks kalsium hidroksida dan kalsium karbonat mampu meningkatkan efisiensi proses penurunan kadar mangan pada skrap baja.
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The use of steel with high manganese (Mn) content in automotive components can increase material hardness, but it also reduces toughness and other mechanical properties that are important for structural reliability and safety. Excessively high Mn content, particularly in the range of 0.70–0.71% by weight, exceeds the maximum limit of 0.2% by weight, so it needs to be reduced through the smelting process. This study aims to evaluate the effectiveness of adding calcium hydroxide (Ca(OH)2) and calcium carbonate (CaCO3) fluxes in reducing Mn content through the melting process of steel scrap using an induction furnace. The process was carried out using a combination of 250 grams of high-Mn and low-Mn steel scrap, with variations in flux addition of 2 wt%, 4 wt%, and 6 wt% with a composition of 75% calcium hydroxide and 25% calcium carbonate. During the melting process, the flux undergoes thermal decomposition into calcium oxide (CaO), water vapor (H2O), and carbon dioxide (CO2). The formed calcium oxide (CaO) then reacts with the dissolved manganese (Mn) in the molten metal, forming a stable compound that can form slag. Characterization of the slag using X-Ray Diffraction (XRD) shows the formation of compounds such as calcium manganate (CaMnO3), CaMn14O24Si, calcium iron oxide (CaFe4O7), and the complex compound CaFe0.2Mn0.8Si2, indicating the successful incorporation of Mn into the slag phase through oxidation reactions. Based on the test results, adding 4 wt% flux resulted in the most significant reduction in Mn content, approaching the standards of PT. AT Indonesia. However, from the perspective of energy efficiency and production costs, the addition of 2 wt% flux is considered more economical and feasible for industrial-scale application without significantly reducing process effectiveness. This study demonstrates that the combination of calcium hydroxide and calcium carbonate flux can enhance the efficiency of the manganese reduction process in steel scrap.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Fluks Ca(OH)2, Fluks (CaCO3), Penurunan Mangan, Peleburan Baja, Steel Scrap, Slag.Ca(OH)2 Flux, CaCO3 Flux, Manganese Reduction, Steel Melting, Steel Scrap, Slag.
Subjects:	T Technology > TS Manufactures > TS253 Die-Casting T Technology > TS Manufactures > TS320 Steel--Metallurgy.
Divisions:	Faculty of Industrial Technology > Material & Metallurgical Engineering > 28201-(S1) Undergraduate Thesis
Depositing User:	Galang Tri Cahyono
Date Deposited:	30 Jul 2025 09:19
Last Modified:	30 Jul 2025 09:19
URI:	http://repository.its.ac.id/id/eprint/123927

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