THE MEASUREMENT OF HYDROGEN ACTIVITIES IN MOLTEN COPPER USING AN OXIDE PROTONIC CONDUCTOR

We have developed a hydrogen sensor for in situ measurements of hydrog en activities in molten copper. The sensor consists of a concentration cell utilizing a proton conductor, CaZr0.9In0.1O3-delta, as the solid electrolyte. The electromotive force (emf) of the cell was generated by both hydrogen and oxygen activity gradients across the cell in a hi gh-temperature region simulating the fire refining processes of copper . However, accurate hydrogen activity in molten copper could be evalua ted from the emf if oxygen activity in molten copper was determined si multaneously by another concentration cell and if the hydrogen and the oxygen activities at the reference electrode were known. The performa nce of the sensor was studied under various conditions. The observed g ood response and reliability of the sensor show that it should be a po werful tool for improvement of the fire refining process of the molten copper. Theoretical treatment of the calculation of the emf of the co ncentration cells using a mixed ionic conductor, i.e., protonic and ox ide ionic conductor, as solid electrolytes is also discussed briefly.