Aspects concerning the formation of flue dust in the primary copper industry

ABSTRACT In addition to the production of primary copper and ferro silicate slag, the formation of significant amounts of flue dust plays an increasingly important role in today’s copper industry. While valuable elements such as copper and precious metals primarily remain in the heavier, denser products, others such as zinc and lead preferably accumulate in the lighter dust fraction. The deteriorating ore concentrate quality also leads to the introduction of new elements to the copper production system which can cause problems in the process control as well as in the handling of environmentally toxic compounds [1]. This paper explains the formation of flue dust and sets a focus on the differentiation between a physical and a chemical fraction. While mechanically carried along particles form the first section, latter one can be explained in a different way. Due to the high process temperature in primary copper smelting furnaces, certain compounds evaporate and recondense in the following off-gas system. As a result, the chemical analysis of the accumulating flue dust displays a broad variety of different elements [2,3]. In order to determine the behavior of the various elements that can be found among the ore concentrate, vapor pressure calculations help to obtain better knowledge and to draw conclusions. Sulfidic and oxidic compounds of the mentioned elements are also taken into account. Other factors such as the grain size of the dust particles and the potential formation of new phases in the off-gas system therefore help to improve the understanding of the flue dust topic in the primary copper production [1].