This standard specifies a neutralized Titrimetric method for the determination of free bases in sodium stannate. This method is suitable for sodium stannate samples with free base content between 0.50% and 10.00%. After the sample is dissolved with water, barium stannate is formed by the reaction of barium chloride and sodium stannate to settle, thereby separating free bases. Phenolphthalein is used as an indicator and muriatic acid standard titration solution is used for titration to determine the content of free bases. The standard describes the preparation of the required reagents and the calibration method in detail, which ensures the accuracy and Reliability of the determination process.