Tungsten determination in iron-manganese concretion

Certification of two photometric methods for determining tungsten in iron-manganese concretions (IMC) in order to reveal comparative possibilities of their practical application is performed. The first determination method is a thiocyanate one, the second one makes use of bromopyrogallol red in the presence of cetylpirydine. it is shown that tungsten determination in IMC is possible using the first method if tungsten content is no less than 0.02% and using the second one, if tungsten quantity is less than 0.02% (Sr=0.04-0.05). In both cases it is advisable to perform sample transfer into solution by alkaline melting method