微波溶样-自动电位滴定法测定铬矿石中三氧化二铬

Determination of Chromium Oxide in Chrome Ores by Automatic Potentiometric Titrimetry with Microwave Digestion Sample Preparation

样品经硫酸-磷酸-氟硼酸分解,在30～60 kPa条件下进行微波溶样,用自动电位滴定仪测定铬矿石中三氧化二铬的含量。对两个不同三氧化二铬含量的铬矿石国家一级标准物质测定20次,测定的平均值与标准值的相对误差为0.015%～0.021%,相对标准偏差为0.09%～0.10%。选取主要进口国的不同含量的铬矿石进行主含量的测定,与经典法对比,分析结果均在合理允差范围之内。方法具有简便、快速、低耗、污染小等优点,可应用于大批铬矿石样品的分析及检测。

A method for the determination of Cr2O3 in chrome ores by automatic potentiometric titrimetry technology coupled with microwave digestion under high-pressure was developed.The method has been tested by determination of Cr2O3 in 2 National Standard Reference chrome ore samples with wide range of Cr2O3 contents.The results were in agreement with certified values with relative error of 0.015%~0.021% and the precision of 0.089%~0.102% RSD（n=20）.Six imported inspection samples were also tested by the method and the results were in accordance with those from classical method.The method provides the advantages of low energy consumption,low labor intensity,high efficiency and is suitable for the daily inspection work.