ICP-AES Determination of Barium and Tungsten in Barium Concentrate

The sample (0.100 0 g) was mixed with 2.0 g of a mixed flux (m_Na2CO3:m_Na2O2=1:2) and fused at 750℃. After cooling, the melt was taken up with 50 mL of 2.0% (w) Na₂CO₃ solution by heating, and the mixture was filtered after cooling. The filtrate (containing the tungsten as tungstate) was made up its volume to 250 mL with water. An aliquot of 25.0 mL was taken, 5 mL of 2.5% (w) tartaric acid solution were added and after 2 min, 50 mL of HCl (1+9) solution were added, and the solution was diluted to 100 mL. The insolubles (containing the barium as BaCO₃ precipitate) were boiled with 15 mL of HNO₃ for 3 min, and made up its volume to 100 mL with water. After standing, an aliquot of 10.0 mL of the supernatant was taken and diluted to 100 mL with water. The above mentioned 2 solutions were used to determined tungsten and barium separately by ICP-AES. The proposed method was used to determined W and Ba in 2 CRMs (GBW 07284, GBW 07811), giving results of WO₃ and BaO in consistency with the certified values, and RSDs (n=6) of 1.6% for WO₃ and 0.24% for BaO.