电感耦合等离子体质谱法测定钨钼矿中锗

Determination of germanium in tungsten molybdenum ore by inductively coupled plasma mass spectrometry

钨钼矿石组分较为复杂,通常含有多种矿物,包括硅酸盐、硫化物、氧化物等,通常情况下较难溶解。实验发现,先采用氢氟酸微波消解样品,再加入硝酸-高氯酸-硫酸于高温电热板上加热继续溶解样品,至高温发烟形成湿盐后再用硝酸复溶,可使样品完全溶解。待样品溶液澄清后,以45.0ng/mL铼为内标,采用电感耦合等离子体质谱法(ICP-MS)对上清液中锗进行测定,可实现对钨钼矿中锗的测定。实验表明,锗的质量浓度在5~100ng/mL范围内与锗的信号强度和内标元素信号强度的比值呈线性关系,相关系数为0.999 5,方法的检出限为0.006ng/mL。将实验方法应用于钼矿石标准物质、钨矿石标准物质以及实际钨钼矿石样品中锗的测定,标准物质测定值与认定值基本一致,测得结果的相对标准偏差(RSD,n=6)为0.30%~2.8%,根据DZ/T 0130—2006《地质矿产实验室测试质量管理规范》,计算出的重复分析相对偏差小于限值。在上述样品中加入锗标准溶液进行加标回收试验,回收率在93%~106%之间。

The composition of tungsten molybdenum ore is relatively complex,and it usually contains several types of minerals including silicate,sulfides,oxide,and so on.Generally,the tungsten molybdenum ore is hardly dissolved.The sample was decomposed with hydrofluoric acid by microwave digestion.After adding nitric acid-perchloric acid-sulfuric acid,the solution was heated on high-temperature electric hot plate to further dissolve the sample.The wet salt formed after fuming at high temperature was redissolved with nitric acid.It was found that the sample could be completely dissolved.When the sample solution was clarified,the content of germanium in supernatant liquor was determined by inductively coupled plasma mass spectrometry（ICP-MS）using 45 ng/mL rhenium as the internal standard.Thus the determination method of germanium in tungsten molybdenum ore was established.The experiments showed that the mass concentration of germanium in range of 5-100 ng/mL had a linear relationship with the ratio of signal intensity between germanium and internal standard.The correlation coefficient was 0.999 5,and the detection limit of method was 0.006 ng/mL.The experimental method was applied for the determination of germanium in the certified reference material of molybdenum ore,the certified reference material of tungsten ore and the actual sample of tungsten molybdenum ore.The found results of certified reference materials were basically consistent with the certified values.The relative standard deviations（RSD,n=6）of determination results ranged from 0.30% to 2.8%.According to DZ/T 0130-2006（The Specification of Testing Quality Management for Geological Laboratories）,the calculated relative deviation of repeated analysis was less than the limit value.The standard solution of germanium was added into sample above for recovery test.The recoveries were between 93% and 106%.