Extraction of Nickel from Garnierite Laterite Ore Using Roasting and Magnetic Separation with Calcium Chloride and Iron Concentrate

Abstract

In this study, segregation roasting and magnetic separation are used to extract nickel from a garnierite laterite ore. The garnierite laterite ore containing 0.72% Ni, 0.029% Co, 8.65% Fe, 29.66% MgO, and 37.86% SiO2 was collected in the Mojiang area of China. Garnierite was the Ni-bearing mineral; the other main minerals were potash feldspar, forsterite, tremolite, halloysite, quartz, and kaolinite in the garnierite laterite ore. The iron phase transformations show that nickel is transformed from (Ni,Mg)O·SiO2·nH2O to a new nickel mineral phase dominated by [Ni]Fe solid solution; and iron changed from Fe2O3 and FeOOH to a new iron mineral phase dominated by metal Fe and Fe3O4 after segregation roasting. Ferronickel concentrate with Ni of 16.16%, Fe of 73.67%, and nickel recovery of 90.33% was obtained under the comprehensive conditions used: A roasting temperature of 1100 °C, a roasting time of 90 min, a calcium chloride dosage of 15%, an iron concentrate dosage of 30%, a coke dosage of 15%, a coke size of −1 + 0.5 mm, a magnetic separation grinding fineness of H = 0.10 T. The main minerals in ferronickel concentrate are Fe, [Ni]Fe, Fe3O4, and a small amount of gangue minerals, such as CaO·SiO2 and CaO·Al2O3·SiO2.

Keywords

• nickel
• garnierite laterite ore
• segregation roasting
• magnetic separation