Estimation of Spectral Emissivity and S/Cu Ratio From Emissions of Copper Concentrates at the Flash Smelting Process

Abstract

The project focused on the investigation of new sensing techniques in the copper production industry, specifically in the flash smelting of copper concentrate process. In this paper, we report a direct relationship between the visible and near-infrared emission spectra in the combustion of copper concentrates by changing some operating conditions such as the sulfur-copper and the oxygen ratios provided to the reaction zone. Spectral processing techniques are applied to the measured spectra. The first one aims to separate both continuous radiations mainly associated to incandescent particles and heating walls with discontinuous emissions associated with some emitting atoms and molecules. This goal was carried out using airPLS baseline estimation algorithm. The second processing technique aims to find the continuous emission only associated with the combustion of copper concentrate particles, eliminating the background spectra associated with the smelter walls. This goal was carried out by directly measuring walls emission at operating temperature and in the absence of flame. The most relevant results show that the estimation of the total radiation associated with each measured spectra is an intrinsic parameter of the process that can provide useful information to the operator that supervises the industrial process. It allows estimate quantitatively the sulfur-copper ratio in order to online monitor the mineral characteristics of the copper concentrate that is entering the process. On the other hand, the approach of a first prototype of the emissivity model for the copper concentrate particles, which validated with measurements, becomes a promising tool that will allow increasing the development of optoelectronic applications around this industry process.

Sensors and Process Control in Copper Smelters: A Review of Current Systems and Some Opportunities

“…The algorithms are based on principal component analysis (PCA) applied on the spectral data showing high correlation features among species with similar elemental compositions or the same type of concentrate. Classifica- In the same scope and analyzing data from the same set-up for combustion of concentrates, Arias at all [21] reported exploratory results depicted some spectral features related to the presence of Cu x O emissions at 606 nm and 616 nm.…”

“…This combustion test is very representative due to the possibility to produce Fe 3 O 4 in the laboratory furnace according to the control of oxygen potential in the combustion chamber. In the same scope and analyzing data from the same set-up for combustion of concentrates, Arias at all [21] reported exploratory results depicted some spectral features related to the presence of CuxO emissions at 606 nm and 616 nm.…”

A Radiometric Technique for Monitoring the Desulfurization Process of Blister Copper

“…Specifically, among the factors that must be considered there are multiple chemical reactions, changes in the temperature, and the formation of gases and other intermediate species. In order to overcome these issues, many techniques have been proposed for characterizing and monitoring pyrometallurgical processes based on the measurement of optical properties such as the visible-near-infrared (VIS-NIR) spectral emissions [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ]. On the one hand, in the iron and steel industry, several optical studies based on radiometry and spectral imaging have measured molten-phase temperature, the steel emissivity, and the slag absorption and reflection coefficients.…”

“…[ 17 , 18 , 19 , 20 , 21 ]. On the other hand, only few developments based on optical technology for control and monitoring of copper pyrometallurgical processes have been reported [ 10 , 11 , 12 , 13 , 14 , 15 , 22 ]. Nowadays, there is only one instrument [ 22 ] commercially available for this industry, and it is only intended for monitoring the first stage of the process through the measurement of exhaust gases concentration such as PbS, PbO, and CuOH.…”

“…Nowadays, there is only one instrument [ 22 ] commercially available for this industry, and it is only intended for monitoring the first stage of the process through the measurement of exhaust gases concentration such as PbS, PbO, and CuOH. As a consequence, many of the methods used to control and monitor the processes in this industry are still qualitative, lack of accuracy, and, in many cases, depend on the decisions taken by an operator [ 10 , 11 , 13 , 15 ].…”