The temperature of the flame of copper concentrates was determined through spectral measurements by using an optical and infrared spectrometer, where the experimental data were adequately processed by the two-colour pyrometer method. Experiments were carried out in a drop-tube, and the furnace temperature was 773 K ensuring the ignition of
concentrates. This technique allowed an in-situ evaluation to be made of the effect of the oxygen content in the feed gas and the sulphur in the concentrate. Two intense peaks at 750 nm wavelength from spectral measurements may be explained by the oxidation of labile sulphur in concentrates. The flame temperature was between 1600 and 2100 K and
this increased with both oxygen concentration and S/Cu ratio. The direct study of emission spectra through unique measurement probes can help to have a more profound vision of what is happening with the concentrated particles subjected to flash combustion conditions. This work has special interests in the pyrometallurgical industry, presenting a critical lack of non-invasive techniques for monitoring and controlling the process.