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"Nikel merupakan logam penting yang banyak digunakan dalam paduan, misalnya baja tahan karat, paduan ruang angkasa, dan paduan khusus. Nikel ditambang dari dua jenis bijih: laterit dan sulfida. Laterit banyak ditemukan di daerah tropis seperti di Indonesia dan ditambang untuk memperoleh nikel dan kobalt. Pelindian bijih nikel laterit pada tekanan atmosfer saat ini banyak menarik perhatian karena biaya yang lebih rendah dibanding proses lainnya. Tujuan penelitian ini adalah untuk menentukan pengaruh waktu dan kecepatan agitasi pelindian atmosferik terhadap persentase perolehan nikel dari bijih laterit jenis saprolit. Bijih nikel saprolit dari Halmahera Timur digunakan dalam penelitian. Untuk mengetahui nilai perolehan nikel pada waktu dan kecepatan agitasi yang berbeda, pelindian teragitasi dilakukan selama 1, 3, dan 5 jam dengan kecepatan agitasi masing-masing 250 rpm, 500 rpm, dan 750 rpm. Selama penelitian, berat sampel yang telah dihaluskan (15 g), konsentrasi asam sulfat (5N (240.1 g/L)), volume asam sulfat (75 ml), dan suhu (100°C) dijaga konstan. Dapat dilihat bahwa dalam pelindian teragitasi, peningkatan waktu pelindian dari 1 jam hingga 5 hour memiliki pengaruh positif terhadap perolehan nikel. Peningkatan kecepatan agitasi dari 250 rpm hingga ke 750 rpm juga meningkatkan nilai perolehan nikel.

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Nickel is important metal that is mostly used in alloys, for example, in stainless steels, aerospace alloys and specialty steels. Nickel is mined from two types of ores: laterites and sulfides. Laterites are found mostly in tropical regions and are mined for their nickel and cobalt in countries like Indonesia. Leaching lateritic nickel ores with sulphuric acid at atmospheric pressure (AL) has been recently receiving more attention due to lower cost compared to other processes. The purpose of this study is to determine the effect of duration and agitation speed of atmospheric leaching to the recovery percentage of nickel from saprolitic type laterit ore. Saprolitic nickel ores from Eastern Halmahera were used during experiments. In order to study the recovery values at different time periods and different agitation speeds, agitative leaching experiments were carried out for 1, 3, and 5 hours with agitation speed 250 rpm, 500 rpm, and 750 rpm, respectively. During the experiments, weight of ground ore sample (15 g), concentrations of sulfuric acid (5N (240.1 g/L)), volume of sulfuric acid (75 ml), and temperature (100°C) were kept constant. It was shown that in agitative leaching, increasing leaching time from 1 hour to 5 hour had a positive effect on metal extractions. Increasing agitation speed from 250 rpm to 750 rpm also increased the recovery values of nickel."

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Indonesia merupakan negara yang kaya akan batuan mineral, salah satunya adalah bijih nikel laterit, dengan potensi cadangan sebanyak 1,391 milyar ton. Bijih nikel laterit merupakan batuan mineral yang mengandung senyawa oksida besi-nikel. Rendahnya penguasaan teknologi pengolahan bijih nikel laterit menyebabkan potensi sumber daya mineral tersebut belum dapat termanfaatkan secara optimal. Dalam penelitian ini akan dilakukan proses benefisiasi dari bijih limonit dan saprolit dengan proses selektif reduksi menggunakan penambahan aditif Na₂SO₄, reduktor grafit, dan dua tahap panas (pre-treatment dan reduksi) untuk menghasilkan konsentrat FeNi dengan kadar nikel diatas 5 %. Pemanasan 2 tahap adalah proses pre-treatment bijih nikel laterit agar didapatkan besi nikel yang memiliki kadar dan perolehan kembali logam nikel yang tinggi dengan penggunaan panas yang tidak terlalu tinggi (≤ 1000 ⁰C) seperti 250 ^oC, 300 ^oC, dan 350 ^oC selama 30, 60, dan 90 menit dan penambahan sulfur yang relatif sedikit (10 %). Teknologi pengolahan bijih nikel laterit kadar rendah menjadi FeNi banyak dilakukan. Namun, penelitian ini berfokus pada dua tahap panas dengan reduktor grafit kadar karbon 90-99 % berat sehingga kelak dapat digunakan sebagai pemodelan pengolahan bijih nikel laterit. Dalam penelitian ini bijih nikel laterit terlebih dahulu menjalani proses benefisiasi/pengkayaan dengan menggunakan metode reduksi selektif pada suhu rendah dan dilanjutkan pada suhu tinggi 1150 °C. Kemudian, dilanjutkan dengan proses pemisahan magnetik. Variasi berat grafit berdasarkan stoikiometri, konsentrasi sodium sulfat, jenis reduktor dan pre-treatment atau thermal upgrading akan dipelajari dalam proses peleburan reduced nickel ore menjadi konsentrat FeNi menggunakan mechanical chemical process. Luaran penelitian ini berupa suatu bagan untuk dijadikan pemodelan alternatif dalam pengolahan bijih nikel laterit jenis limonit dan saprolit menjadi konsentrat FeNi kedepannya dan konsentrat FeNi dengan persentase nikel di atas 5%.

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Indonesia is a country rich in mineral rocks, one of which is nickel laterite ore, with potential reserves of 1.391 billion tons. Laterite nickel ore is a mineral rock containing iron-nickel oxide compounds. The low mastery of laterite nickel ore processing technology causes the potential of these mineral resources to not be optimally utilized. In this research, the beneficiation process of limonite and saprolite ore will be carried out with a selective reduction process using the addition of Na2SO4 additives, graphite reducing agents, and two heat stages (pre-treatment and reduction) to produce FeNi concentrates with nickel content above 5%. 2-stage heating is a process of pre-treating laterite nickel ore in order to obtain nickel iron which has high levels and recoveries of nickel metal with the use of heat that is not too high (≤ 1000 ^oC) such as 250 ^oC, 300 ^oC, and 350 ^oC for 30, 60, and 90 minutes and the addition of relatively little sulfur (10%). The technology of processing low grade nickel laterite ore into FeNi is widely used. However, this research focuses on two heat stages with a graphite reducing agent with a carbon content of 90-99% by weight so that later it can be used as a modeling for laterite nickel ore processing. In this study, the laterite nickel ore first undergoes a beneficiation / enrichment process using a selective reduction method at low temperature and is continued at a high temperature of 1150 °C. Then, followed by the magnetic separation process. Graphite weight variations based on stoichiometry, sodium sulfate concentration, type of reducing agent and pre-treatment or thermal upgrading will be studied in the process of smelting reduced nickel ore into FeNi concentrate using a mechanical chemical process. The output of this research is in the form of a chart to be used as an alternative modeling in the processing of limonite and saprolite laterite nickel ore into FeNi concentrate in the future and FeNi concentrate with a nickel percentage above 5%.

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