Advances in analysis for cobalt and nickel in geological materials

As early as the 20th century, chemists carried out colorimetric analysis of cobalt and nickel. Due to the low sensitivity and cumbersome operation of the colorimetric method, more efficient digestion methods, simpler operation, higher sensitivity, and high-precision became the development direction, and gradually two sets of sample decomposition systems were developed, namely acid digestion and alkali fusion. At the same time, more efficient and simple instrumental analysis technologies such as Atomic Absorption Spectrometry (AAS), Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES), X-ray Fluorescence spectroscopy (XRF), and Inductively Coupled Plasma Mass Spectrometry (ICP-MS)were also developed. With the development of geological science, Electron Microprobe Analysis (EMPA), and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS)for in-situ micro-analysis technology, as well as Multi-collector Inductively Coupled Plasma Mass Spectrometry (MC-ICP-MS)for nickel isotope analysis technology, have been developed. In terms of element analysis, AAS and ICP-OES / ICP-MS generally require acid or alkali to decompose samples into solution state, and the pretreatment process is cumbersome, whereas the XRF technology uses fused dicks or pressed powder pellet for sample preparation and is becoming popular due to its simple and efficient pretreatments. Nickel isotopes are gradually applied to the study of cobalt nickel deposits. In recent years, it is expected to clarify the behavior and fractionation mechanism of nickel isotopes in various mineralization processes, such as magma evolution, hydrothermal alteration, and weathering. Since it is still difficult to separate and quantitative recovery nickel from the rock matrix, innovation of nickel separation technique and testing method, and establishment of simplified analysis process are the focus of future development. In micro-analysis, LA-ICP-MS is simpler than EMPA in sample preparation, faster in analysis and lower in cost. In summary, this paper summarizes the achievements in the analysis of cobalt and nickel in geological samples domestic and overseas, compares the advantages and disadvantages of various methods, and looks forward to the development prospects of the analytical methods of cobalt and nickel in geological samples. © 2023 Science Press. All rights reserved.