Extension of Lance Life by Change of Height of Lances in the Smelting Furnace of Mitsubishi Process

A Mitsubishi process, which pertains to continuous Cu production, involves a smelting furnace, cleaning furnace, and converting furnace connected in series. One of the main issues pertaining to the smelting furnace is the frequent interruption of operations required to allow the inspection and replacement of lances, because lances are frequently fractured. The present study was aimed at modifying the operating conditions of the smelting furnace to suppress lance fractures. A numerical model was developed to simulate the transport phenomena in the furnace, including multi-phase behaviors. The simulation results showed that the lances were exposed to a severely erosive atmosphere with high temperatures. Further calculation indicated that raising the positions of the lances could lower the temperature of the lances, and reducing the occurrence of splashed melt, which contains erosive sulfides. The smelting furnace was operated under the conditions of the raised lance height and attentively monitored for several months. It was confirmed that by implementing such a change of the lance heights, the occurrence of lance failures has been considerably reduced without notably affecting the reaction ability of the smelting furnace. These slides can be retrieved under Electronic Supplementary Material.