Modeling of flash smelter operations at the Chagres Smelter

摘要

Chagres has operated a Flash Smelting Furnace (FSF) since 1995. Smelter capacity is presently restricted by the Flash Furnace - Waste Heat Boiler (WHB) -Electrostatic Precipitator system. These processes were modeled to assess the factors constituting bottlenecks and predict capacity increases through process and equipment modifications. From a heat balance point of view, the challenge in Flash Furnace operation is to balance heat production of the process and heat extraction capacities of units such as reaction shaft, settler, uptake shaft and waste heat boiler, to achieve adequate operating and product temperatures. The main variables involved are smelting rate, oxygen enrichment, matte grade and supplementary fuel, subject to restrictions. Heat production depends on feed sulfur and iron contents, from several mineralogical species in the concentrate. This paper compares the thermal behavior of the most usual sulfide minerals in the FSF. The interplay between furnace and WHB heat balances is analyzed. To obtain gas temperatures adequate for electrostatic precipitator operation, restriction of heat production in the reaction shaft is the usual solution. However, uncompensated heat losses in the FSF settler may require higher fuel usage, with higher heat loads on the WHB. The present modeling work addresses the study of these effects.