Abstract
Good results were obtained by applying the following method on the determination of tungsten in wolframite and ferro-tungsten. The procedure:-
0·5g of the finely pulverized sample of wolframite or ferro-tungsten was weighed and fused with an alkaline fusion mixture (K2CO3 7g+KOH2g+KNO3 0·2g)in a nickel crueible. After the melt had been leached with the warm water, a little quantity of H2O2 was added by dropping to precipitate the soluble permanganate. Then (NH4)2CO3 was added and the solution warmed to precipitate the greater portion of the soluble silicate. The precipitate was filtered off and the filter was made slightly acid. The hydrochloric acid solution of cinchonine was added to the filterate to precipitate tungsten practically perfect. The precipitate was filtered again, ignited and finally weighed as WO3.
