ICP-AES Determination of Aluminium in Rare Earth Products and the Intermediate Control Samples

After the rare earth product samples were dissolved with hydrochloric acid or nitric acid, or the appropriate amount of the intermediate control samples in the production process was taken, oxalic acid was added into the solution to precipitate the rare earth elements. Then perchloric acid was added into the solution to eliminate the excessive oxalic acid and aluminium in the solution was determined by ICP-AES with Al 396.153 nm or Al 237.373 nm as the analytical spectral line dependent on the matrix. The linearity range of aluminium was 0.10-5.0 mg·L-1, with detection limits in the range of 3.1-3.5 mg·kg-1, and the lower limits of determination in the range of 15.5-17.5 mg·kg-1. Recovery rates obtained by standard addition method were in the range of 85.0%-110% and RSDs (n=11) were less than 9.0%. The proposed method was used to determine aluminium in rare earth products and the intermediate control samples, giving results in consistent with those obtained by ICP-MS and spectrophotometry.