Abstract
Usually, dust generated during the copper smelting process by the Teniente Converter and the Flash Smelting Furnaces in Chile, contains high concentrations of copper, zinc, arsenic, antimony and other metals. In general, the dust is recirculated to the smelting process or it is directed to hydrometallurgical process for recovery and stabilization. However, in recent years the generation of dust has increased because of the degradation of the quality of the concentrate. In addition, the environmental regulations have become stricter. It is therefore desirable to understand the behavior of those elements, when the smelting process operates with recirculation of dust. In this study, the effect of dust recirculation to smelting process on the distribution among the matte, slag and gas phases was evaluated, as a function of matte grade, amount of recirculated dust, oxygen enrichment and temperature. It was found that the concentration in thematte of the impurities such as arsenic, antimony and bismuth, increased slightly with recirculation of dust. On the other hand, the concentration of lead and zinc depend of the direct recirculation of dust to the process. Additionally, it was found that high concentrations of arsenic and antimony in the dust may lead to the formation and precipitation of copper arsenates and other metals (speiss), which may generates important operational problems.
Highlights
Usualmente, el polvo generado durante el proceso de fusión de concentrado de cobre por el Convertidor Teniente y el Horno Flash en Chile, contienen altos contenidos de cobre, zinc, arsénico y antimonio, entre otros metales
Dust generated during the copper smelting process by the Teniente Converter and the Flash Smelting Furnaces in Chile, contains high concentrations of copper, zinc, arsenic, antimony and other metals
The dust is recirculated to the smelting process or it is directed to hydrometallurgical process for recovery and stabilization
Summary
Actualmente, las emisiones de polvos representan un problema serio en la metalurgia mundial, especialmente en Chile, donde el concentrado de cobre contiene metales peligrosos para el organismo humano. Las grandes cantidades de polvo generado requieren ser reducidas y recuperar los elementos de interés económico que están contenidos. Usualmente, las mayores impurezas en el polvo son arsénico (As), plomo (Pb), zinc (Zn), bismuto (Bi) y antimonio (Sb), además de con un contenido importante de cobre. Zn genera problemas operacionales ya que juega un importante rol en la creación de acreciones en hornos y trenes de gases, especialmente en el proceso de fusión flash. Adicionalmente, las impurezas presentes en el proceso, tales como As y Sb, requieren un control especial en la refinería electrolítica para mantener los estándares de calidad[4,5]. Las distribuciones de los elementos menores permiten determinar su efecto en la calidad de los productos y a los procesos posteriores de conversión y refinación de cobre
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