Abstract: According to a new idea of the metallurgy with controlled oxygen flow, the unpolluted short circuit electrochemical reduction technique for molten oxide slags was developed. The electrochemical reduction principle of direct extraction of metal from molten oxide slags using oxygen ionic conductor as separate membrane was analysed. By means of equivalent circuit, oxygen ionic current characteristics in the open circuit mode and short circuit mode were compared; the effects on oxygen ionic current in electrochemical reduction process were discussed. The results show that oxygen ionic current may get large and the electrochemical reduction reaction rate will increase when the external circuit has a short circuit, total resistance of the circuit decreases, a stronger reducing agent was selected, the cathode-alloying is employed, and so on. In the present experiment the carbon saturated iron melt is used as the reducing agent and the following galvanic cells were assembled: graphite rod |［O］Fe-C saturated |ZrO₂(MgO)|(FeO)_(slag)| iron rod, graphite rod |［O］Fe-C saturated |ZrO₂ (MgO)|Cu_(l)+(FeO)_(slag)|Mo wire. Pure iron and carbon-free ferroalloy were obtained respectively from CaO-SiO₂-Al₂O₃-FeO molten slags by means of the above cells mentioned.

Key words: metallurgy with controlled oxygen flow; electrochemical reduction; molten oxide slags; oxygen ionic conductor; zirconia; pollution-free