Selective reduction of nickel from lateritic ore using Na₂SO₄ in an NH₃ atmosphere

All sectors, including the ferronickel industry, are being encouraged by governments and campaigners to reduce CO₂ emissions due to their effect on the global climate. Compared to using reductants that contain carbon, free-carbon reductants are an alternative solution in decarbonizing the ferronickel industry, known as a CO₂-intensive industry. This study uses NH₃, one of the H₂ carriers, for the selective reduction process of nickel laterite ore, with Na₂SO₄ serving as a selectivity additive. This study aims to investigate the selective reduction process of nickel laterite ore using Na₂SO₄ in an NH₃ atmosphere. A Na₂SO₄ variation of 0–20 % by mass was used to study this. For all Na₂SO₄ addition variations, a fixed temperature and duration of 900 °C and 4 hours were used respectively. Based on X-ray diffractometer analysis, all variations of the Na₂SO₄ mixture (0–20 %) can form metallic phases. The more Na₂SO₄ is used, the reduction reaction extent increases and then decreases. Using a 900 °C, 4 hours, and 15 % Na₂SO₄ additive mixture can achieve the highest reduction reaction extent of 81.6 ± 1.17 %. Morphologically, using 10 % Na₂SO₄ or higher has been able to separate nickel- and iron-rich areas from impurities. Smelting experiments at 1600 °C also proved that ferronickel metal had formed. This early indication suggests that an NH₃ atmosphere can also facilitate the selective reduction of lateritic ores.