ORIGINAL PAPER
The effect of sulfur, temperature, the duration of the process and reductant on the selective reduction of limonite ore
 
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1
Research Unit for Mineral Technology, National Research and Innovation Agency of Indonesia, Jalan Ir. Sutami Km 15 South Lampung, Lampung, Indonesia 35361
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Agency for Rembang Regional Planning and Development, Rembang Local Government
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Department of Physic-University of Lampung,Jl. Prof. Dr. Ir. Sumantri Brojonegoro No.1, Gedong Meneng, Kec. Rajabasa, Kota Bandar Lampung, Lampung 35141
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Chemical Engineering Department, University of Jenderal Achmad Yani, Jalan Terusan Jend. Sudirman, Cibeber, Kec. Cimahi Sel., Kota Cimahi, Jawa Barat 40531
CORRESPONDING AUTHOR
Fathan Bahfie   

Research Unit for Mineral Technology, National Research and Innovation Agency of Indonesia, Jalan Ir. Sutami Km 15 South Lampung, Lampung, Indonesia 35361
Submission date: 2021-09-17
Final revision date: 2021-11-30
Acceptance date: 2022-02-03
Publication date: 2022-03-23
 
Gospodarka Surowcami Mineralnymi – Mineral Resources Management 2022;38(1):123–135
 
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ABSTRACT
Lateritic nickel ore is used for producing of ferronickel. Nickel grade in ferronickel ranged from 20–40%. Ferronickel is commonly used to manufacture stainless steel. A new method that can increase the levels of nickel grade is selective reduction, which is a process to reduce the metal oxide to the metallic phase with the addition of additives. In this work, the selective reduction of limonitic nickel ore was carried out by add the 5 wt%, 10 wt%, and 15 wt% of reductant and the 10 wt% of sulfur as additive. The process of selective reduction is performed at temperatures of 950, 1050, and 1150°C with the duration of processs of 60, 90, and 120 minutes, followed by magnetic separation to separate between the concentrate and tailings. The characterization used AAS, XRD, and SEM-EDS for grade and recovery; phases transformation; and the microstructure analysis. The optimum of the grade and recovery of nickel was obtained at a temperature of 1050°C with the duration of process of 60 minutes and 5 wt% of reductant and 10 wt% of additive, which obtain 3.72 wt% and 95.67%. The metal grade and recovery was increase with the increasing of temperature reduction. Nevertheless, too long of the duration of process and too many reductant addition resulted in negative effect on selective reduction of lateritic nickel ore. Highest recovery could get more nickel in the process. And sulfur has the important rules when the selective reduction has been done on the increasing nickel content, the forming of FeS, and decreasing the grain size of ferronickel according to the microstructure in the SEM images around ~30 µm.
ACKNOWLEDGEMENTS
The authors would like to acknowledge the Indonesia Ministry of Education, Culture, Research, and Technology for providing funds to complete this work under the research project PTUPT Grant grants for the year 2021–2022 and thank LPPM-UNJANI for financial support through competitive research, and thank Mr. Fajar Nurjaman as the promotor of this research and the first author, and thank to the Research Unit for Mineral Technology-National Research and Innovation Agency of Indonesia for supporting this research.
METADATA IN OTHER LANGUAGES:
Polish
Wpływ siarki, temperatury, czasu trwania procesu i reduktora na selektywną redukcję rudy limonitu
limonit, siarka, redukcja selektywna, temperatura, czas trwania procesu
Ruda laterytowa niklu jest wykorzystywana do produkcji żelazoniklu. Zawartość niklu w żelazoniklu wahała się w przedziale 20–40%. Żelazonikiel jest powszechnie stosowany do produkcji stali nierdzewnej. Nową metodą, która może zwiększyć poziom niklu, jest redukcja selektywna, czyli proces redukcji tlenku metalu do fazy metalicznej z dodatkami. W niniejszej pracy prowadzono selektywną redukcję rudy limonitowej niklu przez dodanie 5, 10 i 15% wag. reduktora oraz 10% wag. siarki jako dodatku. Proces selektywnej redukcji odbywa się w temperaturach 950, 1050 i 1150°C z czasem trwania 60, 90 i 120 minut, po czym następuje separacja magnetyczna w celu oddzielenia koncentratu od odpadów. Zastosowano: AAS, XRD i SEM-EDS do oceny procesu, transformację faz oraz analizę mikrostruktury. Optimum stopnia odzysku niklu uzyskano w temperaturze 1050°C przy czasie trwania procesu 60 minut i 5% mas. reduktora i 10% mas. dodatku, co daje 3,72% mas. i 95,67%. Gatunek i odzysk metalu wzrastały wraz z obniżeniem temperatury. Niemniej jednak zbyt długi czas trwania procesu i zbyt częste dodawanie reduktora skutkowało negatywnym wpływem na selektywną redukcję laterytowej rudy niklu. Przy najwyższym odzysku można w tym procesie uzyskać więcej niklu. A siarka spełnia ważną rolę, gdy selektywna redukcja została przeprowadzona w celu zwiększenia zawartości niklu, tworzenia FeS i zmniejszenia wielkości ziarn żelazoniklu, zgodnie z mikrostrukturą na obrazach SEM około ~30 µm.
 
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