TRANSPORT PHENOMENA IN ELECTRIC SMELTING OF NICKEL MATTE - PART I - ELECTRIC-POTENTIAL DISTRIBUTION

An electric potential probe was constructed so that simultaneous, mult iple measurements of electric potential could be made in a six-in-line electric furnace for smelting nickel calcine having a maximum transfo rmer capacity of 36 MVA. When the electric potential distributions wer e compared with those calculated from the solution of the Laplace equa tion, it was evident that there was significant electric potential dro p at the electrode surface, 100 to 120 V for an applied potential of 1 80 to 230 V and currents of 20 to 30 kA. The Soderberg electrodes were continuously oxidized in the slag, likely creating carbon monoxide. T he electric potential drop at the surface was attributed to arcing thr ough the carbon monoxide. Thus, heat was released in the immediate vic inity of the electrode due to arcing, as well as in the bulk of the sl ag by Joule heating. The proper distribution of heat dissipation is re quired for the transport model, developed in Part II of this series.