Determination of Mn in Black Tungsten Concentration and Middling Products by Inductively Coupled Plasma-Atomic Emission Spectrometry

A simple, rapid and interference-free method of Na₂O₂ ore fusion and complexometric extraction with tartaric acid is proposed for the determination of manganese (Mn) in black tungsten concentration and middling by Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES). The precipitation of tungstic acid was successfully avoided by this preparation method, which resolved problems such as incomplete ore digestion and encapsulation/adsorption of the target elements. Under the optimized conditions, the detection limit (LOD) for this method was 0.019 g/mL with relative standard deviations (RSD, n=11) in the range of 0.92%-1.50%. Moreover, good recoveries were obtained (97.5%-104.0%). The deviation between a single determination result and a certification result was much lower than the allowable deviation of national standards with ferrous ammonium sulfate (GB/T 6150.14—2008) between laboratories. This method met the requirements of national standards for the accurate determination of Mn in black tungsten concentration and middling.