重量法测定氧化稀土中稀土总量的不确定度评定

Evaluation of Uncertainty for Determination of Total Rare Earth Contents in Rare Earth Oxide by Gravimetric Method

对重量法测定氧化稀土中稀土总量的不确定度进行了评定,测量不确定度主要来源于测量的重复性、样品称重及坩埚和沉淀灼烧的称重等,测量的重复性引入的不确定度对整个测量结果的不确定度贡献最大,其次是样品称重。因此,在实际操作过程中,应严格控制测量的重复性和样品称量的影响因素,以减少测量结果的不确定度。当氧化稀土中稀土总量为95.37%时,扩展不确定度为0.14%(k=2)。

The uncertainty for the determination of total rare earth contents in rare earth oxide by gravimetric？method was evaluated. The measurement uncertainties come from the measurement repeatability,the sample weighing,the weight of the crucible and precipitation calcination,and so on. The uncertainty introduced by measurement repeatability made the most contribution to the uncertainty of whole result,followed by the sample weighing. In the actual operation process,the influence of measurement repeatability and sample weighing should be strictly controlled to reduce the uncertainty of the measurement result. When total rare earth contents in rare earth oxide was 95. 37%,the expanded uncertainty was 0. 14%（ k = 2）.