氧化亚氮-乙炔火焰原子吸收光谱法测定钒钛高炉渣中二氧化钛

钒钛高炉渣具有反应活性差、样品溶解困难的特点,采用硫酸-硝酸-氢氟酸三元混酸体系(体积比为1∶2.5∶1)在90~100℃温度下加热溶解钒钛高炉渣样品。为避免钛离子水解,用盐酸调节溶液酸度为1.0mol/L,并以氯化钾抑制高温下钛的电离,建立了氧化亚氮-乙炔火焰原子吸收光谱法测定钒钛高炉渣中二氧化钛的方法。实验对溶解方法及测定条件进行了优化。结果表明,钛的质量浓度在4~30μg/mL范围内符合朗伯-比尔定律,线性相关系数为0.999 1,方法检出限为1.7mg/g。将实验方法应用于钒钛高炉渣标准物质和实际样品中二氧化钛的测定,测得结果与认定值基本一致,相对标准偏差(n=5)小于0.4%。

Determination of titanium dioxide in blast furnace slag containing vanadium and titanium by nitrous oxide-acetylene flame atomic absorption spectrometry

Blast furnace slag containing vanadium and titanium has low reaction activity and the sample is hardly dissolved. The blast furnace slag containing vanadium and titanium was dissolved with sulfuric acid-nitric acid-hydrofluoric acid system (volume ratio of 1∶2.5∶1) by heating at 90-100 ℃. The solution acidity was adjusted to 1.0 mol/L with hydrochloric acid in order to avoid the hydrolysis of titanium ion. Potassium chloride was added to inhibit the ionization of titanium at high temperature. Consequently, a determination method of titanium dioxide in blast furnace slag containing vanadium and titanium was established by nitrous oxide-acetylene flame atomic absorption spectrometry. The dissolution and determination condition was optimized. The results showed that Lambert-Beer′s law was obeyed for mass concentration of titanium in range of 4-30 μg/mL. The linear correlation coefficient was 0.999 1. The detection limit was 1.7 mg/g. The proposed method was applied to the determination of titanium dioxide in certified reference material and actual sample of blast furnace slag containing vanadium and titanium. The results were consistent with the certified values. The relative standard deviations (RSD, n=5) were less than 0.4%.