PURIFICATION OF ARTIFICIAL SOLUTION SIMULATING FERRONICKEL LEACH SOLUTION TO SYNTHESIS NICKEL SULFATE FOR LITHIUM-ION BATTERY CATHODE PRECURSOR

• Main Author: Asisiansion Ritonga, Mark
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/75161
• Institution: Institut Teknologi Bandung

The battery industry has been rapidly growing in recent years due to the significant increase in global demand for electric vehicles. Nickel sulfate hexahydrate (NiSO4.6H2O) is one of the main raw materials for lithium battery cathodes commonly used in electric vehicles today. To meet the growing future demand for nickel (Ni), ferronickel (FeNi) and nickel pig iron (NPI), which has large production capacity in Indonesia, can serve as a potential source of raw material for nickel sulfate production. The focus of this research is on the purification of nickel from the leach solution of FeNi after iron (Fe) precipitation as iron phosphate, to separate nickel from the remaining impurity metals, namely Fe, Co, Mn, and Cr. A series of purification experiments on artificial solutions simulating the leaching of FeNi were carried out to determine the optimum conditions for the purification process using the selective precipitation and solvent extraction (SX) methods. The experiment began with an analysis of the composition of the FeNi sample which became the basis for determining the composition of the artificial solution in this study with a certain metal dissolution percentage determined based on previous studies. The artificial solution underwent a precipitation step to separate iron (Fe) and chromium (Cr). The composition of the filtrate obtained from the optimum precipitation conditions was then used as the sample for the SX experiments using bis(2,4,4-trimethylpentyl) phosphinic acid (Cyanex 272) as the extractant. The SX experiments with Cyanex 272 were conducted by varying the equilibrium pH, extractant concentration, and O/A ratio. The raffinate obtained under the optimum SX conditions underwent further SX experiments using neodecanoic acid (Versatic 10) as the extractant to separate nickel from monovalent ions. The loaded organic from this stage was subsequently subjected to a stripping process to obtain a loaded stripped solution, which was further crystallized to obtain nickel sulfate crystals. The results of this study revealed that the optimum conditions for selective precipitation of Fe and Ce were achieved at pH 4.4. At this pH, the precipitation of Fe and Cr reached 97.85% and 100%, respectively. Meanwhile, the co-precipitation of Ni, Co, and Mn was 26.83%, 55.87%, and 46.51% respectively. The optimum conditions for Cyanex 272 solvent extraction (SX) were achieved at an equilibrium pH of 4.5, an extractant concentration of 20%, an O/A ratio of 1, and a temperature of 40 ºC. The metal extraction percentages were 100% for Fe, 99.48% for Co, and 98.86% for Mn, while the co-extraction of Ni was 9.95%. The extraction of Ni using Versatic 10 from the Ni-rich raffinate achieved an extraction percentage of 99.31%, and the stripping process resulted in a 99.82% recovery of Ni. The nickel sulfate crystal product obtained showed a Ni content of 22.28% which meets the purity for lithium-ion battery raw materials.