Extraction Behavior of Nickel and Cobalt From Serpentine-Rich Ore Through Sulfation–Roasting–Leaching Process

The demand for nickel has been steadily increasing in the 21st century, primarily driven by the rising demand for electric vehicle batteries. Nickel in laterite is associated within silicate in saprolite ore and hydroxide/oxide in limonite ore. Recently, the sulfation–roasting–leaching process has been developed to address the challenges of extracting nickel from laterite ores. It involves the formation of sulfates through the sulfation process using sulfuric acid. During the roasting process, iron sulfates decompose to produce SO₃ gas. The SO₃ gas then reacts with oxides, leading to the formation of soluble nickel and cobalt sulfates during the water leaching process. However, most of the previous researches focus on limonite-type ore resulted in limited understanding on saprolite-type ore. The focus of this study is to observe the behavior of nickel and cobalt extraction, from saprolite-type ores through sulfation–roasting–leaching process. It was found in this research that addition of sulfuric acid up to 0.8 ml/g with moisture 40 wt pct followed by roasting process at 700 °C for 30 minutes and leaching process at 80 °C for 30 minutes resulted in the extraction of 70 pct of nickel and 68 pct of cobalt in the derived optimal conditions. It was also found in the evidence that the presence of magnesium oxide in the ore posed a challenge as it thermodynamically favored reacting with the SO₃ gas over the nickel and cobalt oxides. Additionally, the presence of SiO₂ originating from serpentine minerals affected the recovery of nickel and cobalt due to their adsorption onto amorphous silica during the leaching process. These factors may have contributed to the lower recovery observed in the results of this study.