PURIFICATION OF NICKEL SULFATE SOLUTIONS RESULTED FROM THE LEACHING OF MIXED HYDROXIDE PRECIPITATE (MHP) BY SOLVENT EXTRACTION USING VERSATIC 10 AND NICKEL-LOADED CYANEX 272

• Main Author: Putra Rianto, Anugrah
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/66550
• Institution: Institut Teknologi Bandung

The demand for nickel sulfate is predicted to increase along with the growing market of electric vehicles as one of the precursor materials for the cathode of lithium-ion battery, which is currently the first choice battery for electric vehicles. The precursor material is used in the form of nickel sulfate hexahydrate, which can be obtained from the crystallization of nickel-rich sulfate solutions. These solutions can be obtained from mixed nickel-cobalt hydroxide precipitate (MHP) by leaching the MHP and purifying the pregnant leach solution (PLS) by solvent extraction (SX). In this study, purification of the PLS solution was carried out by SX using Versatic 10 and nickel-loaded Cyanex 272 (Ni-Cyanex 272), which was used to reduce the amount of sodium in the final nickel sulfate solution to increase the purity of the nickel sulfate solution. This study is focused on studying the effect of various operating parameters during pre-loading stage of Cyanex 272 with nickel to form Ni-Cyanex 272 and at SX stage using Ni-Cyanex 272 on the metals extraction and the separation factor between nickel and other metal ions. The pre-loading experiments were carried out at varying temperature, ratio of organic/aqueous volume (O/A), pH, and extractant concentration. The SX experiments using Ni-Cyanex 272 were carried out at varying O/A ratio, Ni-loading, temperature, and mixing time using loaded strip solutions from SX experiments using Versatic 10. The experiments using Versatic 10 performed using the optimum operating parameters reported in the literatures. The experimental results of the Cyanex 272 pre-loading stage showed that increasing temperature, O/A ratio, pH, and extractant concentration generally increased the nickel extraction. The optimum conditions for the pre-loading stage were found to be at a temperature of 40 oC, O/A ratio of 2, pH of 7.5 and extractant concentration of 25% (v/v). The experimental results using Ni-Cyanex 272 showed that O/A ratio had no significant effect on the metal extraction and the separation factor of sodium over nickel. Increases in the Ni-loading and temperature were found to decreased sodium extraction, but it had no significant effect on the nickel, cobalt, and magnesium extractions. Meanwhile, increases in the extraction time was found to increased the extraction of all the observed metal ions. The optimum conditions of SX stage using Ni-Cyanex 272 were obtained at an O/A ratio of 0.5, Ni-loading of 2.23 g/L, temperature of 30 oC, and extraction time of 15 minutes. An additional SX process using Versatic 10 after the SX stage using Ni-Cyanex 272 could separate 99,74% sodium from feed solution so that the sodium content in the final nickel sulfate solution down to 37 mg/L could be obtained.