Trace metals analysis in molybdenite mineral sample

Abstract

DC polarography and other related techniques, viz., DPP and DPASV have been sucessfully used for the simultaneous determination of trace metals in. molybdenite mineral sample. The

polarograms and voltammograms of sample solution have been recorded in 0.1 <i>M </i>(NH₄)₂ tartrate supporting electrolyte at two different <i>p</i>H values i.e., 2.7 ±0.1 and 9.0 ± 0.1. The results indicate the presence of Cu²⁺, Mo⁶⁺,Cd²⁺ Ni²⁺ ,In³⁺, Fe³⁺ and W⁶⁺ metal ions in

the sample. For the determination of tungsten(VI), 11 <i>M </i>HCl has been used as supporting electrolyte. Tungsten(VI) produces a well defined wave/peak with <i>E</i>_1/2<i>/E</i>_P<i>=-</i>0.42V/-0.48V<i> </i>vs SCE in 11 <i>M </i>HCl. The quantitative analysis by the method of standard addition shows

the mineral sample to have the following composition, Cu²⁺ (14.83), Mo⁶⁺ (253.70), Cd²⁺ (41.36), Ni²⁺ (16.08), In³⁺(3.06), Fe³⁺ (83.00) and W⁶⁺ (4.14 )mg/g of the sample. Statistical treatment of the observed voltammetric data reveals high accuracy and good precision of determination. The observed voltammetric results are comparable with those obtained using AAS method.