Determination of Dispersed Elements in Metal Sulfide Ores by Inductively Coupled Plasma-Mass Spectrometry Using Microwave Digestion

BACKGROUND Copper nickel and zinc concentrates all belong to metal sulfide minerals and are import commodities. The rapid and accurate analysis of dispersed elements in these samples is beneficial to the comprehensive utilization of mineral. However, the content of rare elements in such minerals is extremely low, and the properties of each element are different. In particular, Ge and Se cannot be precisely determined due to volatilization loss in wet digestion, and it is difficult to simultaneously measure various elements. OBJECTIVES To simultaneously determine the various elements in the sample. METHODS Copper, zinc and nickel concentrates were used as representative sulfide minerals. The sample was pre-sealed by microwave digestion, and the content of rare elements was determined by inductively coupled plasma-mass spectrometry (ICP-MS). Simultaneous determination of various elements was realized. The experimental conditions of total solid solution, internal standard, mass spectrum interference elimination and pretreatment acid selection were compared. RESULTS During determination of Ga, Ge, Se, Cd, In, Te, La and Tl by microwave digestion in ICP-MS analysis, total amount of solid solution, internal standard, and mass spectrum interference elimination conditions was consistent in three types of metal sulfide ores. Unfortunately, the acid types were not the same. HNO3-HCl-HF-H2O2 system was more suitable for measuring Ga, Ge, Se, Cd, In, Te, La and Tl in nickel and zinc concentrates, and Ga, Ge, Se, Cd, In, La and Tl in copper concentrate. The recoveries of these elements ranged from 85.5% to 116.6%. The HCl-HNO3 (3:1) system was more suitable for detecting Te in copper concentrate. CONCLUSIONS The method is simple, and the simultaneous determination of multiple elements is realized. Other factors of the method are the same, the acid digestion system is the key to selection.