Pengaruh Variasi Penambahan Aditif Na2so4 Dan Waktu Tahan Pada Proses Reduksi Selektif Bijih Nikel Lateritik Menggunakan Gas Nh3

Ramadhan, Dolph Raikhan Shahrukh (2025) Pengaruh Variasi Penambahan Aditif Na2so4 Dan Waktu Tahan Pada Proses Reduksi Selektif Bijih Nikel Lateritik Menggunakan Gas Nh3. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Indonesia memiliki cadangan nikel terbesar di dunia, menjadikannya sebagai komoditas strategis yang mendukung pertumbuhan ekonomi nasional dan transisi energi global. Namun, proses pengolahan bijih nikel laterit, khususnya metode pirometalurgi, masih bergantung pada bahan bakar fosil dan menghasilkan emisi CO2 yang tinggi 18 ton CO₂-eq/ton nikel. Salah satu metode alternatif yang dapat menurunkan emisi CO2 adalah penggunaan reduktan non-karbon, seperti gas amonia (NH₃) dan natrium sulfat (Na₂SO₄) sebagai aditif selektif dalam proses reduksi bijih nikel laterit. Penelitian ini bertujuan untuk menganalisis pengaruh variasi penambahan Na₂SO₄ serta waktu tahan terhadap derajat reduksi, kandungan Ni morfologi, produk reduksi bijih nikel laterit menggunakan NH₃. Selain itu, potensi pengurangan emisi CO₂ secara teoritis juga dianalisis untuk mengkaji efektivitas metode ini dalam mendukung teknologi pengolahan nikel yang lebih ramah lingkungan. Reduktan yang digunakan adalah Gas NH3 yang akan dialirkan ke dalam tube furnace dengan laju alir 0.3 L/min. Variasi yang digunakan yaitu penambahan aditif Na2SO4 sebesar 5, 10, 15, 20% massa dan waktu tahan 0.5, 1, 2, dan 3 jam. Setelah seluruh proses reduksi selesai, pengujian X-Ray Diffractometer (XRD), Scanning Electron Microscope-Energy Dispersive X-Ray (SEM-EDX), dan Atomic Absoprtion Spectrophotometer (AAS) dilakukan untuk menganalisis produk hasil reduksi. Dari hasil penelitian diperoleh hasil bahwa penambahan Na₂SO₄ dan peningkatan waktu tahan terbukti meningkatkan derajat reduksi, kadar Ni dan Fe, serta memperbaiki mineralogi dan morfologi produk reduksi bijih nikel laterit menggunakan gas NH₃. Derajat reduksi tertinggi sebesar 82,74% diperoleh pada 15 wt% Na₂SO₄ dan waktu tahan 2 jam. Waktu tahan yang lebih lama memungkinkan lebih banyak oksida nikel dan besi tereduksi, membentuk fasa logam yang lebih stabil. Kandungan logam tertinggi tercapai pada 10 wt% Na₂SO₄ dan waktu tahan 120 menit, dengan kadar Ni dan Fe masing-masing 1,21% dan 12,28%. Na₂SO₄ memfasilitasi pembentukan fasa troilit (FeS) dan feronikel (FeNi), memperbesar partikel logam, serta menurunkan titik leleh slag agar mudah terpisah dari logam. Penggunaan NH₃ sebagai reduktan juga menghasilkan emisi CO₂ yang lebih rendah (4,77 kg CO₂-eq/kg FeNi) dibandingkan proses konvensional, karena tidak menghasilkan CO₂ langsung selama proses reduksi.
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Indonesia holds the largest nickel reserves in the world, positioning it as a strategic commodity in supporting national economic development and the global energy transition. However, the processing of lateritic nickel ore, particularly through pyrometallurgical methods, still relies heavily on fossil fuels and contributes to high CO₂ emissions, reaching up to 18 tons CO₂-eq per ton of nickel. One promising alternative to reduce CO₂ emissions is the application of non-carbon reductants such as ammonia gas (NH₃), along with sodium sulfate (Na₂SO₄) as a selective additive during the reduction of lateritic nickel ore. This study aims to analyze the effect of varying Na₂SO₄ additions and holding times on the reduction degree, Ni content, mineralogy, morphology, and overall characteristics of the reduced product using NH₃ gas. Additionally, the theoretical potential for CO₂ emission reduction is assessed to evaluate the effectiveness of this method in supporting more environmentally friendly nickel processing technologies. NH₃ gas was used as the reductant and introduced into a tube furnace at a flow rate of 0.3 L/min. The experimental variations included Na₂SO₄ additions of 5, 10, 15, and 20 wt% and holding times of 0.5, 1, 2, and 3 hours. After the reduction process, X-Ray Diffraction (XRD), Scanning Electron Microscope with Energy Dispersive X-Ray Spectroscopy (SEM-EDX), and Atomic Absorption Spectrophotometry (AAS) were conducted to analyze the reduced products. The results showed that increasing Na₂SO₄ addition and holding time significantly enhanced the reduction degree, Ni and Fe content, and improved the mineralogy and morphology of the reduced lateritic nickel ore. The highest reduction degree of 82.74% was achieved at 15 wt% Na₂SO₄ with a holding time of 2 hours. A longer holding time enabled more NiO and FeO to be reduced into stable metallic phases. The highest metal content was obtained at 10 wt% Na₂SO₄ and 120 minutes, yielding Ni and Fe concentrations of 1.21% and 12.28%, respectively. Na₂SO₄ facilitated the formation of troilite (FeS) and ferronickel (FeNi) phases, enlarged the metallic particles, and lowered the slag melting point, allowing easier separation from the metal that shown improved the morphology. Moreover, the use of NH₃ as a reductant led to significantly lower CO₂ emissions (4.77 kg CO₂-eq/kg FeNi) compared to conventional processes, as no direct CO₂ generation occurs during reduction.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Amonia, Nikel laterit, Na2SO4, Reduksi selektif, Waktu tahan, Ammonia, Laterite nickel, Na2SO4, Selective reduction, Holding time
Subjects:	Q Science Q Science > QC Physics > QC151 Fluid dynamics Q Science > QC Physics > QC320 Heat transfer Q Science > QC Physics > QC 611.97.T46 Temperature effects. Including transition temperature Q Science > QC Physics > QC765 Magnetic materials Q Science > QC Physics > QC912.3 Greenhouse gases Q Science > QD Chemistry > QD117 Absorption Q Science > QD Chemistry > QD63.S4 Separation (Technology) Q Science > QD Chemistry > QD75.2 Chemistry, Analytic
Divisions:	Faculty of Industrial Technology and Systems Engineering (INDSYS) > Material & Metallurgical Engineering > 28201-(S1) Undergraduate Thesis
Depositing User:	Dolph Raikhan Shahrukh Ramadhan
Date Deposited:	31 Jul 2025 06:50
Last Modified:	31 Jul 2025 06:50
URI:	http://repository.its.ac.id/id/eprint/124577

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