EDTA滴定法测定稀土铁合金中稀土总量  

Total amount of rare earth in rare earth ferroalloy was determined by EDTA titration

作　　者：高立红[1,2] 邢嵘嵘 朱悦然 赵文怡[1,2] GAO Lihong;XING Rongrong;ZHU Yueran;ZHAO Wenyi(Baotou Rare Earth Research Institute State Key Laboratory of Rare Earth Resources Research and Comprehensive Utilization,Baotou 014030,Nei Mongol,China;Ruike National Engineering Research Center for Rare Earth Metallurgy and Functional Materials,Baotou 014030,Nei Mongol,China)

机构地区：[1]包头稀土研究院白云鄂博稀土资源研究与综合利用国家重点实验室,内蒙古包头014030 [2]瑞科稀土冶金及功能材料国家工程研究中心,内蒙古包头014030

出　　处：《金属功能材料》2022年第4期98-102,共5页Metallic Functional Materials

摘　　要：试样用硝酸溶解,硝酸体系进行氟化分离,稀土与氟形成氟化稀土沉淀而铁与氢氟酸反应形成六氟化铁络合物留在溶液中,实现了干扰元素铁与稀土元素的分离;硝酸和高氯酸溶解沉淀,乙酰丙酮溶液掩蔽残留的少量铁、铝干扰元素,调节溶液酸度pH=5.5,以二甲酚橙作指示剂,用EDTA标准溶液滴定至溶液由红紫色变为亮黄色即为终点,建立了EDTA滴定法测定稀土铁合金中稀土总量的方法。条件试验选择具有代表性的轻稀土、中稀土和重稀土作为统一样,并进行了精密度和准确度试验,结果的相对标准偏差(RSD,n=11)为0.17%~0.80%,加标回收率为98.94%~101.1%。并与国标GB/T26416.1-2010草酸盐重量法进行方法比对试验,测定结果基本一致。方法用于稀土铁合金中稀土总量的测定,检测范围为10%~90%。The sample was dissolved by nitric acid,and the nitric acid system was used for fluorination.Rare earth and fluorine form fluorinated rare earth precipitation while iron and hydrofluoric acid reacted to form iron hexafluoride complex,which was left in the solution,realizing the separation of interfering elements iron and rare earth elements.Nitric acid and perchloric acid were dissolved and precipitated,acetylacetone solution was used to cover a small amount of residual iron interference elements,the acidity pH of the test solution was adjusted to 5.5,dichlorophenol orange was used as indicator,and the EDTA standard solution was used to titrate the solution until the solution changed from purple to bright yellow,which was the end point.An EDTA titration method was established to determine the total amount of rare earth in rare earth ferroalloy.A uniform sample covering light rare earth,medium rare earth and heavy rare earth as well as the determination range of methods was selected to conduct precision and accuracy tests.The relative standard deviation(RSD,n=11)of the results was 0.17%~0.80% and %,and the standard recovery was 98.94%~101.1%.The method was compared with GB/T26416.1-1010 oxalate gravimetric method,and the results were basically consistent.The method was used to determine the total amount of rare earth in rare earth ferroalloy,and the detection range was 10%~90%.

关 键 词：稀土铁合金 稀土总量 EDTA滴定法 

分 类 号：TG115.3[金属学及工艺—物理冶金]