电位滴定法测定铜镁合金中镁  

Determination of magnesium in Cu–Mg intermediate alloys by potentiometric titration

作　　者：张金娥 苏玉龙 贺铭兰 孙海峰 ZHANG Jin’e;SU Yulong;HE Minglan;SUN Haifeng(Chinalco Materials Application Research Institute Co.,Ltd,Beijing 102209,China;Guobiao(Beijing)Testing&Certification Co.,Ltd.,Beijing 100088,China)

机构地区：[1]中铝材料应用研究院有限公司,北京102209 [2]国标(北京)检验认证有限公司,北京100088

出　　处：《化学分析计量》2022年第2期34-39,共6页Chemical Analysis And Meterage

摘　　要：建立电位滴定法测定铜镁合金中的镁含量。以光度电极为指示电极,乙二胺四乙酸二钠溶液为滴定剂。试料用王水溶解,在pH 4.0~4.5时,用硫化钠和铜试剂将大量基体铜和杂质元素沉淀分离。在pH约为10的环境下,以铬黑T为指示剂,用乙二胺四乙酸二钠溶液滴定至电位突跃记为终点,计算镁含量。考察滴定参数的影响,确定了滴定波长为610 nm,每次最大滴定体积为200 μL,最小滴定体积为10 μL,最大时间间隔为20 s,设定阈值为20。铜镁合金中镁测定结果的相对标准偏差为0.12%~0.37%(n=11),加标回收率为99.9%~100.1%。该方法满足铜镁合金中镁的质量分数在10%~30%之间的测定。A potentiometric titration method for the determination of magnesium in Cu–Mg intermediate alloys was established.The photometric electrode was used as the indicator electrode and Na;EDTA solution was used as the titrant.The samples were dissolved in aqua regia.At pH 4.0–4.5,a large amount of matrix copper and impurity elements were precipitated and separated with sodium sulfide and copper reagent.In the environment with about pH 10,take chrome black T as the indicator,titrate with disodium ethylenediamine tetraacetic acid to the end point of potential jump,and calculate the magnesium content.The influence of titration parameters was investigated.The titration wavelength was 610 nm and the maximum titration volume was 200 μL.The minimum titration volume was 10 μL.The maximum time interval was 20 s and the threshold was set to 20.The relative standard deviation of magnesium in copper magnesium alloy was 0.12%–0.37%(n=11),and the recovery was 99.9%~100.1%.The method can meet the determination of magnesium content in copper magnesium alloy between 10%–30%.

关 键 词：电位滴定法 铜镁合金 硫化钠 铜试剂 乙二胺四乙酸二钠 

分 类 号：O657.3[理学—分析化学]