STUDY OF THE EFFECT OF VARIATION OF TEMPERATURE AND ACID CONCENTRATION ON NICKEL LEACHING PERFORMANCE IN SULFURIC ACID SOLUTION AT HIGH TEMPERATURE AND PRESSURE
Nickel is one of the most widely used metals for various applications. Indonesia has low-grade (limonite) laterite nickel reserves which have not been processed. One of the techniques for processing low grade nickel laterite ore that has been applied in industrial scale is High Pressure Acid Leac...
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| Format: | Final Project |
| Language: | Indonesia |
| Online Access: | https://digilib.itb.ac.id/gdl/view/49087 |
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| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | Nickel is one of the most widely used metals for various applications. Indonesia has
low-grade (limonite) laterite nickel reserves which have not been processed. One of the
techniques for processing low grade nickel laterite ore that has been applied in
industrial scale is High Pressure Acid Leaching (HPAL) in sulfuric acid solution. The
HPAL process provides high nickel and cobalt yields and produces a leach solution
with relatively low iron concentration due to the precipitation of dissolved iron ions
into hematite at high temperatures. Leaching at high temperatures and pressures of
laterite nickel ore in Indonesia has not yet been frequently carried out. In this research,
the behavior of limonite ore leaching from Mandiodo, Southeast Sulawesi at high
temperature and pressure in an autoclave with a reactor volume of 500 mL was studied.
Samples of laterite nickel ore from Mandiodo, Konawe Utara Regency, Southeast
Sulawesi received from PT Antam were initially prepared. The ore preparation consists
drying, sampling, comminution, and sieving. Thedominant mineral in the ore sample
was identified by X-Ray Diffraction (XRD) and their chemical composition was
determined with X-Ray Fluorescence (XRF). The ore sample used in the experiment
has particle size fraction of -65+100# (149-208 µm). Measurement of the concentration
of dissolved nickel, iron, and magnesium was carried out by using Atomic Absorption
Spectroscopy (AAS) to determine the extraction percentages of these three metals. The
leached residue which has been separated from the solution was the dried in an oven
for 24 hours and the dominant phase within the residu was identified by XRD analysis.
Variables varied in the experiment are leaching temperature, sulfuric acid
concentration, solid percentage, and leaching duration.
Experimental results show that an increase in leaching temperature and concentrations
of sulfuric acid increases extraction percentage of nickel, while increasing the solid
percentage of ore decreases extraction percentage of nickel. An increase in extraction
percentage of nickel was also followed by a decrease in extraction percentage of Fe.
The best condition was obtained at leaching temperature of 180?, 2M sulfuric acid
concentration, solid percentage of 5%, and leaching duration of 4 hour which resulted
in 88.47% extraction percentages of Ni. The XRD analysis results of leached residues
showed that the dominant compounds detected in the leach residu are goethite and
hematite. |
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