Optimization and application of ferrous reduced ammonium vanadate titration method for the determination of uranium content in geological samples

The accurate determination of uranium content in geological samples is extremely important for the exploration and development of uranium resources. In this study, based on titration method for the determination of uranium content of the nuclear industry standard test, the pretreatment process such as sample dissolution, sample dissolution reagent and test method has been improved according to the characteristics of geological samples. The results showed that the sample was moistened with water before acid treatment, and the dissolving vessel was adjusted from 100 mL beaker to 150 mL triangle flask, which basically avoided the problem of sputtering during the boiling process. The amount of phosphoric acid added in the sample dissolution reagent was increased to ensure that the ferrous could completely reduce the hexavalent uranium in the sample at the appropriate phosphoric acid concentration, and the low measurement result caused by the low phosphoric acid concentration is avoided. In the test, the amount of reducing agent ferrous sulfate is changed to 1 mL, and the amount of sodium nitrite was changed to 3–4 drops, which improved the sensitivity of titration endpoint and realized clear determination of titration end point. The RSD of the improved test method is better than 2.5%, and the standard recovery is between 99 and 102%. The results are accurate and reliable, can meet the needs of scientific research and production. It can provide technical support for uranium exploration and natural uranium production.