Reduction Of Solid Oxides Research Articles

Fused salt electrolytic reduction of solid oxides and oxide mixtures for green production of metals and alloys

In this work, a fused salt electrochemical process was investigated experimentally for production of metals and alloys directly from respective solid oxides by electro-deoxidation. Direct electrochemical reduction of the oxides was carried out in molten CaCl2-based chlorides in an electrolytic cell, incorporating an oxygen-evolving inert anode, over the temperature range of 850–950°C. The technical viability of the process was demonstrated by the electro-deoxidation of pure oxides and oxide mixtures including NiO, Nb2O5, Nb2O5/TiO2 and Nb2O5/SnO2 to produce nickel metal, niobium metal, NbTi alloys and the intermetallic compound, Nb3Sn. Compared with the conventional metallurgical processes for producing these metals and alloys, this new electrochemical process appears to be much less energy intensive, with lower costs and no direct greenhouse gas emissions from the electrolytic reduction process. The present electrolytic reduction process has the potential to be scaled up for the green extraction of a number of non-ferrous base metals and processing of many advanced alloys.

Lead electrocrystallization during reduction of solid oxides

On the basis of data concerning the dependence of the value of the limiting current of the reduction of PbO 2 to PbO 1·34 on alkali concentration, the change of active component of impedance, R s in course of PbO 2 reduction and the dependence of R s on ω − 1 2 , it is concluded that the process starts at the PbO 2/electrolyte interface and proceeds in the solid oxide phase. The suggestion is made that the localization of the reduction process depends on the distribution of defects of different type in the crystal lattice. A system of lead dendrites arises when PbO 2 is reduced.