Abstract：Abstract:The sample is dissolved by nitric acid, and the nitric acid system is used for fluorination. Rare earth and fluorine form fluorinated rare earth precipitation while iron and hydrofluoric acid react to form iron hexafluoride complex, which is left in the solution, realizing the separation of interfering elements iron and rare earth elements. Nitric acid and perchloric acid were dissolved and precipitated, acetylacetone solution was used to cover a small amount of residual iron interference elements, the acidity pH of the test solution was adjusted to 5.5, dichlorophenol orange was used as indicator, and the EDTA standard solution was used to titrate the solution until the solution changed from purple to bright yellow, which was the end point. An EDTA titration method was established to determine the total amount of rare earth in rare earth ferroalloy. A uniform sample covering light rare earth, medium rare earth and heavy rare earth as well as the determination range of methods was selected to conduct precision and accuracy tests. The relative standard deviation (RSD,n=11) of the results was 0.17 ~ 0.80% and %, and the standard recovery was 98.94 ~ 101.1%. The method was compared with GB/T26416.1-1010 oxalate gravimetric method, and the results were basically consistent. The method was used to determine the total amount of rare earth in rare earth ferroalloy, and the detection range was 10% ~ 90%.
2022, Vol. 29 