Determination of Ni, Co, Mg, Al and Fe in Laterite Nickel Ore by Inductively Coupled Plasma-Atomic Emission Spectrometry

There is no uniform national assay standard for nickel laterite, and the industry standard has only recently been established in early 2013. The major elements of nickel laterite in the industry standard are tested by chemical analysis with a time-consuming, heavy workload and low efficiency which is unable to meet requirements in laterite nickel ore smelting production. A new analytical method has been established to determine Ni, Co, Mg, Al and Fe in laterite nickel ore by Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES). The samples were digested by aqua regia, hydrofluoric acid and perchloric acid, and heated until the perchloric acid fume was eliminated, then dissolved by hydrochloric acid. The optimum analytical spectral lines were chosen after studying the spectral interferences for the selected elements to eliminate interference. Experimental results show that the detection limits of the method are Ni 2.98 μg/g, Co 1.60 μg/g, Mg 1.68 μg/g, Al 3.79 μg/g and Fe 9.52 μg/g, , respectively. The relative standard deviations (RSD, n=11) are 1.5%-2.2%. The recovery rates of Ni,Co, Mg, Al and Fe are 96.0%-102.5%. The method was verified by the standard sample, and the measured value agrees well with the standard value. The method is simple and fast and can be widely used to guide the exploration and smelting process for laterite nickel ore.