Heat flow in copper converters

Abstract

A mathematical heat flow model has been developed to quantify the influence of out-of-stack time and other variables on the temperature distribution in the refractory wall of copper converters. Factors such as diameter of the converter, size and position of the converter mouth, and the use of a mouth cover have been studied with the model, in order to relate converting practice to operating problems. The results of the model indicate that when the converter is out of the stack, heat losses through the mouth of the converter cause the internal refractory surface to cool rapidly which may lead to freezing at the tuyere line and tuyere blockage when blowing is resumed. The temperature gradient, localized to within 60 to 80 mm of the refractory inside wall, changes markedly within the first minutes of the converter being out of the stack. This may generate thermal stresses in the converter wall and contribute to refractory erosion at the tuyere line. Covering the converter mouth during out-of-stack periods significantly reduces the change in temperature gradient at the inside wall as well as heat losses from the converter.