SYNTHESIS OF FEPO4 FOR PRECURSOR OF LIFEPO4 BATTERY CATHODE FROM ARTIFICIAL SOLUTION SIMULATING NICKEL PIG IRON (NPI) PREGNANT LEACH SOLUTION

• Main Author: Esther Dameria P., Gabriella
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/69371
• Institution: Institut Teknologi Bandung

The battery industry for electric vehicle is growing due to the global commitment to suppress carbon emission. One battery type, LiFePO4, is continuously developed due to its high durability, safe, low raw material costs, light weight, high efficiency, and extreme temperature durability. Meanwhile, various research is being conducted on the recovery of Ni from class II nickel products through hydrometallurgical route to produce class I nickel products, which are the raw materials to produce nickel-based batteries. However, recent research shows high Fe concentration as impurity in the product. Therefore, this research is aimed to separate and utilize the Fe content in the pregnant solution obtained from leaching of class II nickel products, specifically NPI, to produce FePO4. The pregnant leach solution composition referred to that reported in recent research on NPI leaching, which contained Fe, Ni, and Co. Series of FePO4 precipitation experiments were conducted using 24 factorial experimental design to study the effect of pH, temperature, P/Fe mole ratio, and %seed on the precipitation of Fe, Ni, and Co. The process was followed by solvent extraction of the filtrate from optimum conditions of precipitation using Cyanex 272 extractant at a pH of 5, temperature of 40 oC, O/A ratio of 1, and extractant concentration of 10% (v/v). The loaded organic was then stripped with 1 M H2SO4 at a temperature of 40 oC and O/A ratio of 1. Concentration of Fe in the precipitate, concentration of Ni and Co in the filtrate, and concentration of each metal in the solvent extraction (SX) product streams were analyzed by atomic absorption spectroscopy (AAS) to study the effect of each variable and to determine the optimum condition. After that, the mineralogy, structure and morphology of the optimum product was analyzed using scanning electron microscope (SEM) and particle size analysis (PSA). The result was then compared to a commercial FePO4 product. The results showed that the increase in the pH, P/Fe mole ratio, and %seed increased the Fe precipitation and Ni and Co co-precipitations. On the other hand, the increases in the temperature increased Fe precipitation and reduced the other metals co-precipitations. The optimum condition was reached at a pH of 5, temperature of 50 oC, P/Fe mole ratio of 1, and without the addition of seed, which resulted in 81.44% Fe precipitation, 10.51% Ni co-precipitation, and 8.59% Co coprecipitation. However, the structure and morphology of the products was observed to be a bulky aggregation that was not distributed evenly. Solvent extraction experiment using Cyanex 272 showed that high metals extraction, with 92.43% Ni and 99.69% Co extraction, can be achieved.