Effect of pH on Precipitation of Ferronickel Leaching Solution by Using MgO for Mixed Sulfate Precipitate Synthesis

The increasing demand for electric vehicles affects the high demand for nickel-based batteries, including Nickel Manganese Cobalt (NMC) batteries. Generally, NMC is processed from high-quality ore (sulfide ore) to produce nickel (II) sulfate hexahydrate or NiSO 4 .6H 2 O. But sulfide ore face scarcity due to a long history of mining and exploitation. Thus, laterite-type nickel ore can be an alternative to nickel resources. This study aims to produce mixed sulfate precipitates from a ferronickel leaching solution that can be utilized further to produce NiSO 4 .6H 2 O. Also, this research will study the pH effect of the precipitation process on the product's elemental composition, recovery, and compounds formed. The precipitation process was conducted using 5% MgO (weight basis) with a pH range of 2.5 to 6.5 with one increment. The mixed sulfate precipitates were characterized using AAS, EDX, and XRD. When using a pH of 3.5, a nickel concentration of 1473.00 ppm, nickel recovery of 23.02%, and Nickel grade of 3.18% could be obtained. As a result, the phase of NiSO 4 .6H 2 O was formed. Also, the other phases were formed after precipitation, such as CoSO 4 , FeSO 4 , and MgSO 4 .