Hydrogen reduction of cassiterite concentrates

Synopsis

Hydrogen as a reducing agent shows, compared to carbon monoxide, some advantages both metallurgically and environmentally. A very precise adjustment of the reduction potential with hydrogen-steam mixtures allows reduction conditions under which it is possible to produce a low iron-containing tin with high tin yield, though the tin is not completely free of iron. The iron contents are between 0,4 and 1,6% at reduction temperatures between 700 and 900°C. With the use of B₂O₃ for stabilizing wustite and for conditions of liquid slag iron contents can be lowered to less than 0,05%.

The experiments prove that it is possible to reduce cassiterite to metal with a low iron content in a one-step process with a high reaction yield. The separation of metal from solid residue, however, is still an unsolved problem.