Abstract

More than 50% of the world primary copper is produced by Flash Smelting technology [1], which partially burns copper concentrate particles. It has proved to be superior to other processes because of its low fuel consumption, reduced fugitive-emissions and high production rate. Despite of all these advantages, Flash Smelting presents some operational problems, the most important being the control of magnetite formation and dust loss in the off-gases. The control of these variables is difficult due to poor understanding of the complex interactions between the processes involved, such as thermodynamics, chemical kinetics, mass and heat transfer, local distribution of oxygen concentration, and fluid-flow conditions. One practical tool to understand these complex interactions is the study of flame propagation in the Copper Concentrate (CC) cloud. In this work we developed an experimental method to estimate the velocity of the flame propagation in a CC cloud. We performed measurements in a vertical burner using rich mixtures, which showed that flame speed is inversely proportional to particle size and CC concentration. Also, the flame speed is mainly a function CC/oxygen mass ratio, independent of the oxygen dilution in the gas. In this moment, as a second part of this investigation, we are developing a mathematical model to predict flame speeds of the same order of magnitude and trend as the ones measured experimentally. The model includes heat generation and all modes of heat transfer i.e. conduction, convection, and radiation