碘酸钾滴定法测定分银渣中的锡含量

Determination of Tin Content in Silver Separating Residue by Potassium Iodate Titration

采用碘酸钾滴定法测定分银渣中的锡含量。试样用过氧化钠熔融，水浸酸化，加铁粉过滤除杂质；加铝片还原，待反应平静后加热煮沸至冒大泡，冷却至室温；以淀粉为指示剂，碘酸钾滴定至淡蓝色为终点。对试样进行11次平行测定，相对标准偏差（RSD）小于1．2％，加标回收率在99％～101％。方法流程短，除杂质效果好，结果准确。

The potassium iodate titration method was used for determination of tin content in silver separating residue. After samples were fused by sodium peroxide, they were dipped into water and acidified with hydrochloric acid. Iron powder was added into the acidified solution and the impurities were removed by filtration. Aluminum flaks were added into the solution which caused reduction reaction. When reaction finished, the solution was heated to boiling and generating some big bubbles, then cooled down to room temperature. Potassium iodate was used to titrate the solution with starch as an indicator and light blue color as finished point. The method has a short process, good impurities removal efficiency and accurate results. The samples were parallelly detected for 11 times, and the relative standard deviation （RSD） was less than 1.2%. The accuracy of the method was confirmed by the standard addition method with the recoveries of 99%- 101 %.