STUDY OF THE DISSOLUTION BEHAVIOR OF NICKEL, COBALT, IRON, AND MAGNESIUM FROM LIMONITIC NICKEL ORES AS A FUNCTION OF TEMPERATURE AT ATMOSPHERIC AND HIGH PRESSURE

• Main Author: Annisa, Nur
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/69277
• Institution: Institut Teknologi Bandung

Nickel is a transition metal that has widespread applications, one of them being as a component in the production of vehicle electric batteries that can be obtained through hydrometallurgical processing. Indonesia is one of the countries with the largest nickel reserve and nickel ore as nickel laterite ore. Technology processing lateritic nickel ore among them that is through leaching in sulphuric acid (H2SO4) processes such as high-pressure acid leaching (HPAL) and atmospheric agitation leaching (AL) processes. Iron is the main impurity element in nickel limonite ore that comes dissolved during the leaching process. This research was done to study the dissolution and precipitation behavior of nickel, cobalt, iron, and magnesium on limonite ore from Halmahera Island, Indonesia, for HPAL and AL processes in H2SO4 solution. The nickel laterite ore nickel was prepared by homogenization, drying, sieving, and sampling. Ore characterization was carried out using X-ray diffraction (XRD) and X-ray fluorescence (XRF). HPAL experiment was carried out with variation temperature in the range of 180-240 ° C and variations time in the range of 1-4 hours with level addition of H2SO4 300 kg/ton of ore. AL experiment was carried out with variation temperature in the range of 70-100 ° C and variations time in the range of 1-12 hours with level addition of H2SO4 900 kg/ton ore. The concentration of iron, nickel, cobalt, and magnesium dissolved in the filtrate and residue, after conducted digestion, was measured using atomic absorption spectroscopy (AAS) for calculation of percent extraction metal as well as selectivity leaching. The kinetic model used is the shrinking core model (SCM). The percent extraction of iron in the AL process tends to increase with the increased temperature while the HPAL process tends to decrease. The percent extraction of iron in the AL process is higher compared to the HPAL process with the highest score of 89.31% in the AL process and 15.47% in the HPAL process. The consumption of H2SO4 in the HPAL process is 66.74% used for reacting with nickel while in the AL process as much as 88% is used for reacting with iron. Analysis of kinetics leaching with SCM through linear regression of every equality controller rate reaction with experimental data shows that kinetics leaching controlled by diffusion through an inert layer with score energy activation of 41.02 kJ/mol and 28.74 kJ/mol for two different sample nickel laterite ore. XRD leaching residue analysis showed that there was an increase in the hematite diffraction peak as the leaching temperature increased.