Zinc-Ferriteに関する研究 (第5報)

加速酸溶解について

抄録

In the present experiment, an attempt to promote the acid dissolution of zinc-ferrite was made to obtain a high zinc extraction in the electrolytic zinc process, and the following results were obtained.
(1) By an addition of Fe powder in the leaching solution, the dissolution rate of zinc-ferrite increases markedly. The increase in dissolution rate of zinc-ferrite increases markedly. The increase in dissolution rate is, however, not due to the direct contact of Fe powder with zinc-ferrite particles, but due to the action of Fe²⁺which is produced by the dissolution of Fe powder.
(2) The dissolution rate is enhanced by the cathodic polarization, which is achieved by the contact of zinc-ferrite particles with cathodically polarized electrodes.
(3) The addition of Fe²⁺as FeSO₄·E7H₂O in the leaching solution gives an increase in dissolution rate of zinc-ferrite. The simultaneous addition of Fe³⁺with Fe²⁺lowers the dissolution rate considerably.
These results suggest that the increase in dissolution rate by the above methods would be caused by the increase in concentration of anion vacancy at the surface of zinc-ferrite. This agrees with the conclusion of the previous papers.
From the discussion on the dissolution mechanism of oxides, based on the results of our works and others', it is concluded that the dissolution of the oxides containing Fe₃₊would be promoted under reducing conditions.