Yankuang ceshi (Mar 2020)
Determination of Antimony in Antimony Ores by Inductively Coupled Plasma-Optical Emission Spectrometry with Microwave Digestion
Abstract
BACKGROUND The dissolution of antimony ore by aqua regia is often incomplete and antimony is easy to hydrolyze in the process of extraction, which leads to inaccurate results. Although atomic fluorescence spectrometry has been widely used in the determination of antimony, it is easy to introduce large dilution error for the determination of high-content antimony (>5%) due to the narrow linear range of the instrument. OBJECTIVES To solve the problem of incomplete dissolution of antimony ores and hydrolysis of antimony in the extraction process, and establish a new method with wider linear range for determination of antimony in antimony ores. METHODS Based on inductively coupled plasma-optical emission spectrometry (ICP-OES), the antimony ore was fully dissolved by hydrofluoric acid, nitric acid and hydrochloric acid, and the hydrolysis of antimony was fully inhibited by the complexation of tartaric acid and antimony. RESULTS The results showed that the solution of the mixed hydrofluoric acid, nitric acid and hydrochloric acid can effectively decompose the silicate components in antimony ores, which can make antimony ores dissolve more completely. The determination result of antimony was better than that of aqua regia, and the detection limit was lower (1.10μg/g). The determination result of antimony obtained by the mixed extraction method of tartaric acid and hydrochloric acid was better than that of aqua regia. The precision of the method was 0.11%-1.11%, which was more stable than that of hydrochloric acid or aqua regia. By using an inductively coupled plasma emission spectrometer, a wider linear range can be obtained by optimizing the spectrum of antimony element analysis, therefore realizing the accurate determination of high-content antimony. CONCLUSIONS This method can dissolve antimony ore quickly and effectively, and avoid the hydrolysis of antimony. The method is confirmed by national first grade standard materials, and the result is in agreement with the certified values. This method is suitable for the analysis of 0.7%-40% antimony in antimony ores.
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