温度滴定法测定复合肥中钾离子浓度的研究

复合肥中钾元素的检测可有效控制复合肥产品的质量。本研究选取合适的前处理方法,并应用温度滴定法对复合肥中的钾离子进行了定量研究。该法测定复合肥中的钾离子以四苯硼钠与钾离子生成沉淀反应为基础,由于反应是放热反应,当滴定到等当点时,反应室的温度变化率最大,指示终点的到达。该方法具有操作简便、快速、灵敏度高等优点,非常适合对复合肥中钾离子含量的监控。研究结果表明,使用温度滴定法和离子色谱法及四苯硼酸钾重量法测得的复合肥中钾离子含量一致,该方法准确度高,重现性好,回收率可达97%以上。

Study on the determination of potassium in compound fertilizer by thermometric titration

Determination of potassium can control the quality of compound fertilizer effectively.In this research,under suitable pretreatment,we established a quantitative method to determine potassium in the compound fertilizer by thermometric titration.The method to determine potassium was based on the precipitation reaction of sodium tetraphenylborate and potassium.Because of the exothermal reaction,the temperature changed obviously in the reaction chamber when equivalent point reached.The method which had the advantages of easy operation,fast and good sensitivity was feasible to supervise potassium in compound fertilizer.The conclusion showed that the result of thermometric titration was consistent with ion chromatography and potassium tetraphenylborate gravimetric method.The method had good accuracy and repeatability,and the recovery was above 97%.