The Research On Enrichment Of Ferronickel By Reduction-Magnetic Separation From Serpentine

This paper is focus on comprehensive utilization of nickel and iron from Huili serpentine with the concentration of0.617%nickel and10.21%iron. The technical scheme of enrichment of ferronickel by reduction-magnetic separation from serpentine is established based on the process mineralogy and phase analysis. A new technical route and parameters for enrichment of ferronickel by reduction-magnetic separation from serpentine were obtained. The ferronickel products with high quality and high recovery rate are obtained. Therefore, the comprehensive utilization of nickel and iron is achieved by this method.The main phase of Huili serpentine was obtained by phase analysis. The results show that it is composed of chrysotile (Mg3[Si2-xO5](OH)4-4x), some spinel with iron and magnesium (MgFe2O4) and quartz (SiO2). The thermal decomposition products for serpentine were forsterite and enstatite by calcination. At the same time, the nickel and magnesium turn into forsterite and enstatite phase. Therefore, it is diffcult to separate nickel by physical method.The optimization paratemeter was obtained by systematically study the process of reduction-magnetic separation technology of Huili serpentine. The results are shown as follow, the dosage for activated carbon was5%, the mixture of anhydrous sodium carbonate and anhydrous sodium sulphate was15%, reduction temperature at1100℃for120minutes. The grinding fineness of roasting mineral was passing0.074mm; the intensity of magnetic field was1000Gs. The recovery rate of nickel and iron can reach to83.58%and73.39%respectively for ferronickel with4.044%nickel and52.28%iron under these conditions.It is better for separation serpentine by continuous magnetic separation after throughing roasting reduction, the grade for nickel can reached to9.737%under500Gs magnetic field intensity, and the grade for ferronickel was62.20%under1500Gs magnetic field intensity. The total nickel and iron recovery rate of contentration mineral were90.47%and85.35% after grade separation, respectively. Therefore, the nickel and iron in ferronickel contentration mineral under these conditions were concentrated more than15times and6times respectively.