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

The different acid systems of aqua regia, HF+HClO₄ and HCl were chosen for dissolving tests for Ni-bearing laterite samples. Results indicated that using aqua regia to dissolve samples with the support of HF acid and adding HClO₄ acid to remove HF, is an ideal method for Ni-bearing laterite. The sample solution was dissolved by HCl before loading to determine Ni, Cr, Mg, Al and Co by inductively coupled plasma emission spectrometry (ICP-MS). The right analytical spectral lines were chosen after studying the spectral interferences for the selected elements. Test results demonstrated that Fe can increased the background intensity of the selected elements' spectral lines. The addition of the same amount of Fe with samples in mixed standard solution can eliminate matrix interference. Experimental results show that the recovery factors of Ni, Mg, Al and Co were 96.83%-105.23% with a relative standard deviation(RSD) of less than 3.3%, except Cr. The element determination results (except Cr) were in good agreement with certified values of standard materials. A further study is necessary for the low recovery of Cr.