Rebuild of a Flash Smelting Furnace Using Explosives

摘要

Kennecott Utah Copper (KUC) Smelter scheduled a rebuild of their flash smelting furnace forSeptember, 2014. KUC’s goal in this project was to reduce the rebuild time from 65 to 55 days by usingexplosives to break the matte and brick layers of the uptake shaft and hearth sections of the furnace.Previous rebuilds had employed the slower technique of mechanical breakers to remove the matte andbrick layers which took 22 days. KUC has many years of experience in removing slag from the uptakeshaft, but they had never used explosives to remove the hearth. As far as KUC was aware, no othersmelter operation had attempted a hearth removal in this way.For the explosive approach to be successful, the blasting in the furnace would need to commence duringthe cool down phase, after the furnace was off line and drained. This added another level of complexityto the blast design and explosive selection as the blast holes would be drilled and the explosives loadedin material that was upwards of 300° F (150° C). All the drilling and explosive loading would have tobe quickly and easily accomplished from outside of the furnace as the high internal temperaturesprevented entry of personnel into the furnace. In addition, the blasting would have to meet three criteria:1) no damage to the belly pan of the furnace, 2) no fly rock damage to the furnace interior, and 3) nobending of exterior structural supports.Given the importance of the blast results, it was undertaken to conduct tests with a mock-up of thefurnace with its liner to evaluate blast designs. These tests were necessary to ensure that the blast designcould adequately break up the matte and brick liner without damaging the furnace belly pan andsupporting structures.The blasting technique selected and applied to the furnace rebuild reduced the demolition time from 22to 5 days which exceeded the goal of 12 days. The drilling and blasting were conducted without anyincidents and provided the desired results.The following paper discusses the blast design concepts and reviews how each of the blasting criteriawere addressed. Details on how the blast design was applied for the furnace rebuild and the resultsachieved is provided.