Kristanto, Christophorus Amabel (2026) Analisis Pengaruh Variasi Rasio Slag:NaOH Dan Waktu Tahan Alkali Fusion Terhadap Efektivitas Aktivasi Nickel Matte Slag Untuk Aplikasi Carbon Capture. Other thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Industri pengolahan nikel laterit melalui jalur pirometalurgi menghasilkan emisi CO2 tinggi serta limbah padat berupa nickel matte slag dalam jumlah besar. Slag ini masih mengandung magnesium yang berpotensi dimanfaatkan sebagai material penangkap CO2 melalui mineral carbonation, tetapi magnesium umumnya masih terikat dalam struktur silikat kompleks sehingga reaktivitasnya rendah. Oleh karena itu, penelitian ini dilakukan untuk menganalisis pengaruh variasi rasio slag:NaOH dan waktu tahan pada aktivasi nickel matte slag melalui metode alkali fusion untuk aplikasi carbon capture. Proses alkali fusion dilakukan pada temperatur 800oC dengan variasi rasio slag 1:1, 1:2, 1:3, dan 1:4 serta waktu tahan 1, 2, dan 4 jam. Produk hasil aktivasi dikarakterisasi menggunakan XRF, XRD, dan SEM-EDX, sedangkan efektivitas aktivasi dievaluasi melalui Si removal sebagai indikator utama dan Mg/Si ratio sebagai indikator pendukung. Evaluasi performa carbon capture difokuskan pada sampel waktu tahan 2 jam melalui aqueous-pressurized carbonation, perhitungan carbonation efficiency (CE) berbasis penurunan tekanan CO2, serta XRD pascakarbonasi. Hasil penelitian menunjukkan bahwa nickel matte slag didominasi Fe, Si, dan Mg dengan fasa yaitu olivine ((Mg,Fe)2SiO4), cristobalite (SiO2), fayalite (Fe2SiO4), dan forsterite (Mg2SiO4). Proses alkali fusion mampu menurunkan kandungan Si dan menghasilkan produk yang lebih kaya Mg secara relatif, dengan Si removal tertinggi sebesar 86,87% pada rasio slag 1:4 selama 2 jam. Hasil XRD produk aktivasi menunjukkan terbentuknya periclase (MgO), magnesioferrite (MgFe2O4), dan sodium iron oxide (NaFeO2), sementara SEM-EDX menunjukkan morfologi yang lebih kasar, tidak beraturan, dan berpori. Evaluasi karbonasi menunjukkan CE tertinggi sebesar 19,365% pada rasio slag 1:4 dengan waktu tahan 2 jam, sejalan dengan nilai Si removal tertinggi. XRD pascakarbonasi juga mengindikasikan terbentuknya magnesite (MgCO3) dan hydromagnesite (Mg5(CO3)4(OH)2·4H2O). Berdasarkan hasil tersebut, aktivasi nickel matte slag melalui alkali fusion berpotensi menghasilkan material kaya Mg sebagai material yang mampu menangkap karbon dan menyimpannya secara stabil.
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The processing of laterite nickel via pyrometallurgical methods generates high levels of CO2 emissions and large quantities of solid waste in the form of nickel matte slag. This slag still contains magnesium, which has the potential to be utilised as a CO2 capture material through mineral carbonation; however, the magnesium is generally bound within a complex silicate structure, resulting in low reactivity. Therefore, this study was conducted to analyse the effect of varying the slag:NaOH ratio and holding time on the activation of nickel matte slag via the alkali fusion method for carbon capture applications. The alkali fusion process was carried out at a temperature of 800°C with slag ratios of 1:1, 1:2, 1:3 and 1:4, and holding times of 1, 2 and 4 hours. The activation products were characterised using XRF, XRD and SEM-EDX, whilst the effectiveness of the activation was evaluated using Si removal as the primary indicator and the Mg/Si ratio as a supporting indicator. The evaluation of carbon capture performance focused on the 2-hour holding time sample via aqueous-pressurised carbonation, calculation of carbonation efficiency (CE) based on the reduction in CO2 pressure, and post-carbonation XRD analysis. The results of the study show that nickel matte slag is dominated by Fe, Si and Mg, with phases including olivine ((Mg,Fe)2SiO4), cristobalite (SiO2), fayalite (Fe2SiO4) and forsterite (Mg2SiO4). The alkali fusion process was able to reduce the Si content and produce a product that was relatively richer in Mg, with the highest Si removal of 86.87% at a slag ratio of 1:4 during 2 hours. XRD results of the activated product indicate the formation of periclase (MgO), magnesioferrite (MgFe2O4) and sodium iron oxide (NaFeO2), whilst SEM-EDX reveals a coarser, irregular and porous morphology. Carbonation evaluation showed the highest CE of 19.365% at a slag ratio of 1:4 with a holding time of 2 hours, consistent with the highest Si removal value. Post-carbonation XRD also indicated the formation of magnesite (MgCO3) and hydromagnesite (Mg5(CO3)4(OH)2·4H2O). Based on these results, the activation of nickel matte slag via alkali fusion has the potential to produce a Mg-rich material capable of capturing carbon and storing it stably.
| Item Type: | Thesis (Other) |
|---|---|
| Uncontrolled Keywords: | Alkali Fusion; Carbon Capture; Mineral Carbonation; Nickel Matte Slag Alkali Fusion; Carbon Capture; Mineral Carbonation; Nickel Matte Slag |
| Subjects: | Q Science Q Science > Q Science (General) |
| Divisions: | Faculty of Industrial Technology and Systems Engineering (INDSYS) > Material & Metallurgical Engineering > 28201-(S1) Undergraduate Thesis |
| Depositing User: | Christophorus Amabel Kristanto |
| Date Deposited: | 24 Jul 2026 01:23 |
| Last Modified: | 24 Jul 2026 01:23 |
| URI: | http://repository.its.ac.id/id/eprint/136920 |
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