| Title |
Acidimetric Determination of Tungsten |
| Abstract |
The reaction between wolframate ion, WO₄^=, H^+ and mannitol has been studied at 25℃. The reaction was found to be: 2H^+＋2WO₄^=＋C_6H_(14)O_6=W₂O_7·C_6H_(14)O_6^=＋H₂O with the equilibrium constant. logk=20.24±0.04. Acidimetric determination of wolframate in the presence of mannitol has been studied potentiometrically. Mixed indicator made of bromcresol green: methyl red=3:2 was found to be best indicator for this titration. Effect of mannitol concentration and influences of molybdate, silicate, and carbonate have been studied. Analytical procedure was described for the determination of wolframate in pregnant solution obtained by pressure leaching of Scheelite. |