A study of Wilson's determination of ferrous iron in silicates

The chemical factors affecting the accuracy of Wilson's procedure for determination of ferrous iron in silicates have been investigated. This procedure utilizes pentavalent vanadium to oxidize ferrous iron as it is set free from the silicate by hydrofluoric acid. The quadrivalent vanadium produced is more resistant to oxidation by oxygen than ferrous iron, and conserves the reducing power of the silicate. The procedure is done at room temperature.Recovery of ferrous iron under various conditions has been studied to elucidate the chemical mechanisms of loss in the procedure. Some improvements have been made. The studies indicate that the procedure is of high accuracy.An effect resulting in loss of ferrous iron titre has been found, involving the chemical attack of solids by solutions containing oxygen and pentavalent vanadium. This loss does not appear to take place if all ion species are in solution.