How Is Sodium Tungstate Produced?

Sodium tungstate can be produced through several methods, including the reaction of tungsten ores with sodium hydroxide or sodium carbonate, as well as the reaction of tungstic acid with sodium hydroxide. In one common method, scheelite (CaWO4), a tungsten-containing mineral, is roasted with sodium carbonate to produce sodium tungstate:

CaWO4 + Na2CO3 → Na2WO4 + CaCO3

The resulting sodium tungstate can then be purified through precipitation and filtration. Alternatively, ammonium paratungstate (APT) can be reacted with sodium hydroxide to yield sodium tungstate:

(NH4)10[H2W12O42] + 22 NaOH → 10 Na2WO4 + 21 H2O + 5 N2

This method is preferred when high-purity sodium tungstate is required.