Direct temperature measurement of melts in continuous copper converter with expendable immersion optical fiber thermometer

Newly developed expendable immersion optical fiber thermometer is a possible choice for the temperature measurement of the melts in copper pyrometallurgy. With this method the radiation is collected directly from inside the melt and transmitted to the pyrometer through the fiber, so that the measurement accuracy is hardly influenced by the surface condition and emissivity change of the melts, diffused reflection on the melt surface, and atmosphere, i.e. burner flame, combustion gases, dust etc. Since the fiber is expendable, this method is free from accretion problem as well. A series of plant tests were carried out in order to develop its application to the molten blister copper at the outlet of the continuous converter. The immersion time required for each measurement was less than 5 seconds, and the degree of accuracy was within +/-2 similar to 5K. Consumption of the fiber was less than 0.01m for each measurement on average. Based on the obtained results, an automated temperature measurement system for molten blister copper was designed and installed at Naoshima Smelter & Refinery of Mitsubishi Materials Corporation.