Abstract
A methanolic bromine method for determination of beryllium oxide inclusion in Cu-Be alloy has been presented. In order to decide the optimum condition for extracting the inclusion, the effects of decomposition temperature, water in methanol, etc. on the solubility (recovery) of beryllium oxide have been studied by the use of synthesized pure beryllium oxides and internally oxidized Cu-Be alloys.
The solubilities of metallic copper, metallic beryllium, and beryllium oxide with ester-bromine or with acid have also been studied and the applicability of ester-bromine method or of acid decomposition method to the determination of beryllium oxide inclusion in Cu-Be alloy has been discussed.
The recommended procedure is as follows:25g of Cu-Be alloy is decomposed with methanolic bromine (methanol 100ml+bromine 10ml) in a decomposition flask at 4550°C for 5 hr or at 3035°C for 20hr. The solution is filtered by suction through Cella filter (CF, dense). The residue (beryllium oxide inclusion isolated) is washed with methanol, ignited in a platinum crucible, and fused with 58g of potassium pyrosulfate. The melt is leached with 40ml of 0.3N HCl and made up to 100ml with water. An aliquot of this solution containing 550 μg of beryllium is taken into a 100ml beaker, and 5ml of 4% KCN solution and 10ml of 0.1% Aresenazo-I solution are added. The pH of solution is adjusted to 12.5±0.1 by adding dropwise 20% NaOH solution. It is transferred into a 100ml volumetric flask and made up the volume with diluted NaOH solution (pH=12.5) The absorbance at 580 mμ is measured against the reagent blank and the amount of beryllium is determined from its calibration curve.
