高温热水解-离子色谱法测定铬矿中氟含量

建立了一种快速、准确的离子色谱法测定铬矿中氟含量的方法,将铬矿与石英砂混合,控制氧气和水蒸气的流量,于1 100℃高温下热水解30min,水解液经吸收后,选用Dionex AS11-HC阴离子分析柱,以KOH(20mmol/L)作淋洗液,自动再生抑制型电导检测器检测,离子色谱法测定铬矿中氟的含量。方法的检出限为0.022μg/mL,定量限为0.073μg/mL,方法的检测范围为0.0015%~0.20%,加标回收率在92%~101%。应用于实际样品的测定结果表明,铬矿中氟含量的测定值与标准方法的测定值一致。方法简单快速、检出限低、精密度高、准确度好。能满足铬矿中氟含量的快速准确检测要求。

Determination of Fluorine in Chrome Ore by Ion Chromatography Combined with Pyrohydrolysis

A new method that can quickly and accurately determine the fluorine in chrome ore using pyro hydrolysis for sample digestion and ion chromatography(IC) for the determination was proposed.The major parameters that influenced pyrohydrolysis were investigated.Based on experimental results,the optimal conditions were established.Firstly,chrome ore samples were blended with quartz sand,and then the mixture were pyrohydrolyzed at 1 100 ℃ for 30 min with the controlled oxygen and water vapor flow rate.After the pyro hydrolyzed solution was absorbed,the fluorine from the solution was separated on a Dionex AS11-HC column with 20 mmol/L KOH as the eluent and detected by automatically renewable inhibitory conductance detector.The limit of detection (LOD) was 0.022 μg/mL and the limit of quantitation (LOQ) was 0.073 μg/mL.The fluorine ion concentrations that could be analyzed were in the range of 0.0015% to 0.20%.The recovery rates were 92%-101%.The real samples were tested for fluorine content,and the results were consistent with the those obtained using standard testing method.The method is simple,fast,and has low detection limit,high precision and good accuracy,which meet the requirement for fast and accurately testing fluorine content in chrome ore.