Rapid electrochemical determination of dissolved sulphur in liquid copper by solid-sulphide electrolytes

The application of solid-sulphide electrolyte sulphur sensing cells to measure directly dissolved sulphur in molten copper has been investigated using an immersion probe with the Cas-2wt% ZrS₂ solid solution electrolyte and the Mo+Mo₂S₃ two-phase mixture reference electrode. The emf measurements were carried out at 1473 K for the liquid copper with sulphur concentrations from 0.43 to 2.20 at %. Steady potentials were attained within ≈10 min after dipping the probe. The equilibrium partial pressures of sulphur in molten copper calculated from the observed emfs were in agreement with those from the H₂-H₂S gas equilibrium investigations.