岩石矿物中氧化铁电子探针价态定量分析方法的研究

Quantitative method of iron oxide in rock mineral by using EPMA chemical state analysis program

本文主要论述利用标准曲线法测定矿物中价态铁含量的电子探针定量分析方法。电子探针定量分析含氧化铁矿物时,氧化铁的成分只能以"FeO"形式给出全铁的含量,而不能准确地把"Fe2O3"和"FeO"各自的百分含量分开,这就给地质研究人员对于地质环境,矿物的成因,成岩作用及成岩后生作用等方面的研究带来很多困难。根据地质研究的需要,作者进行了此方法的研究及实验。利用天然菱铁矿和赤铁矿配制含有不同比例的FeO和Fe2 O3的标准样品。用电子探针测定这些标样中铁元素的Lα和Lβ的强度值,经过ZAF法修正,得到ILα/ILβ的强度比值,由Lα和Lβ线系的强度比和标样中价态铁的浓度比绘制成标准曲线。样品中铁元素的价态值,根据电子探针定量分析"FeO"数据及ILα/ILβ的比值,由此曲线求得FeO和Fe2O3的定量分析结果。

An EPMA quantitative method of different chemical state of Fe by using calibration curve was established in this paper.The composition of iron oxide can only be presented as＂FeO＂other than Fe2 O3 and FeO respectively when measuring the iron quantity in mineral oxide of iron by using EPMA.It will be very difficult to study geological environment,genetic reason of mineral,diagenesis and diagenesis after-born if the percentages of Fe2 O3 and FeO are not clear.A series of reference materials were confected using natural siderite and hematite,and the intensities of Fe Lα and Lβ from these materials were measured by using EPMA.The ratios of ILα /ILβ were calculated after ZAF correction,and then the calibration curves of these ratios against the Fe contents of different chemical states in these reference materials were plotted.The compositions of Fe2 O3 and FeO can be given from these calibration curves according to measured results of＂FeO＂from EPMA and the ratios of Fe Lα and Lβ.