Determination of 10 Elements in Antimony Ore by Inductively Coupled Plasma Atom Emission Spectrometry with Sealed Acid Digestion at High Pressure

Sealed acid digestion at high pressure was used to decompose antimony ore, and the contents of 10 elements, including arsenic, antimony, aluminum, iron, calcium, magnesium, potassium, sodium, titanium and manganese in antimony ore were determined by inductively coupled plasma atom emission spectrometry (ICP-AES). Mixed solution (1 mL) consisted of hydrochloric acid-nitric acid with volume ratio of 3:1 and 2 mL of hydrofluoric acid were added into the digestion inner tank containing 0.10 g sample, and the mixture was heated at 150 ℃ for 24 h in the oven. The inner tank was taken out and the mixture was evaporated to near-dryness at 150 ℃ on the electric hot plate. Mixed solution (0.5 mL) consisted of hydrochloric acid-nitric acid with volume ratio of 3:1 was added and the mixture was evaporated to near-dryness again, and the operation was repeated once more. Mixed solution (5 mL) consisted of nitric acid-hydrochloric acid-water with volume ratio of 1:3:4 was added and the mixture was heated in a 130 ℃ oven for 3 h. The volume of the sample solution obtained was made up to 100 mL by mixed solution consisted of nitric acid-hydrochloric acid-water with volume ratio of 1:3:36, and the content of target elements were determined at the optimized ICP-AES instrument working conditions. The results showed that the mass concentrations of the 10 elements were linearly related to their corresponding spectral response values within certain ranges, with detection limits (3s) in the range of 1.98-77.20 μg·g^-1. Four reference materials were analyzed by the prescribed method, giving relative errors ranged from -2.8% to 10%; two reference materials were analyzed 12 times in parallel, with RSDs of the determined values in the range of 0.25%-6.6%.