电感耦合等离子体原子发射光谱法测定云南昆阳磷矿黑色页岩中钒钼镍

黑色页岩中碳含量较高,共存元素较多。碳质残渣因消解不完全会堵塞仪器进样系统,同时吸附钒、钼、镍,导致结果偏低。为了消除碳对钒、钼、镍测定的干扰,对黑色页岩进行了高温灼烧预处理试验。同时进行了不同酸度的盐酸介质对钒、钼、镍谱线强度的影响、共存元素的干扰等条件试验。确定采用在750℃马弗炉中灼烧除碳后,经硝酸-氢氟酸-高氯酸消解处理样品,盐酸酸化提取定容后,选择 V 311.071nm、Mo 202.031nm、Ni 231.604nm为分析谱线,选取耐氢氟酸雾化器进样,使用电感耦合等离子体原子发射光谱法(ICP-AES)测定钒、钼、镍,从而建立了云南昆阳磷矿黑色页岩中钒、钼、镍的分析方法。在仪器最佳工作条件下,各元素校准曲线的线性相关系数均大于0.9995;方法检出限为1.2~8.1μg/g。方法应用于云南昆阳磷矿黑色页岩样品中钒、钼、镍的测定,结果的相对标准偏差(RSD,n=11)为0.91%~5.1%,各元素的加标回收率为96%~102%。按照实验方法测定水系沉积物国家标准物质(GBW 07306、GBW 07311、GBW 07312)中钒、钼、镍,测定值与认定值基本一致。

Determination of vanadium,molybdenum and nickel in black shale of Kunyang phosphate mine in Yunnan by inductively coupled plasma atomic emission spectrometry

The black shale contained high content of carbon and many types of coexisting elements. Due to the incomplete digestion of carbon residue, the injection system of instrument was usually blocked. Meanwhile, vanadium, molybdenum and nickel could be also adsorbed, leading to the lower determination results. In order to eliminate the interference of carbon with the determination of vanadium, molybdenum and nickel, the black shale sample was pretreated by high-temperature burning. The influence of hydrochloric acid medium with different acidities on the spectral strength of vanadium, molybdenum and nickel was investigated. The interference tests of coexisting elements were also conducted. After removing carbon by burning in muffle furnace at 750℃, the sample was digested in nitric acid-hydrofluoric acid-perchloric acid system. After acidification by hydrochloric acid and dilution to constant volume, V 311.071nm, Mo 202.031nm and Ni 231.604nm were selected as the analytical lines for determination of vanadium, molybdenum and nickel by inductively coupled plasma atomic emission spectrometry (ICP-AES). The hydrofluoric acid resistant nebulizer was used for sample solution injection. Consequently, a determination method of vanadium, molybdenum and nickel in black shale of Kunyang phosphate mine in Yunan was established. Under the optimum working conditions of instrument, the linear correlation coefficients of calibration curves of elements were all higher than 0.9995. The detection limit of method was 1.2-8.1μg/g. The proposed method was applied for the determination of vanadium, molybdenum and nickel in black shale samples of Kunyang phosphate mine in Yunan. The relative standard deviations (RSD, n=11) of determination results were between 0.91% and 5.1%, and the recoveries of elements were between 96% and 102%. The content of vanadium, molybdenum and nickel in national certified reference materials of stream sediment (GBW 07306, GBW 07311 and GBW 07312) was determined according to the proposed method, and the results were basically consistent with the certified values.