*Article* **Copper Oxide Spectral Emission Detection in Chalcopyrite and Copper Concentrate Combustion**

**Gonzalo Reyes 1,\*, Walter Diaz 1, Carlos Toro 2, Eduardo Balladares 1, Sergio Torres 3, Roberto Parra 1 and Alejandro <sup>V</sup>ásquez 1**


**Abstract:** In this research, the spectral detection of copper oxide is reported from different combustion tests of chalcopyrite particles and copper concentrates. Combustion experiments were performed in a bench reactor. In all the tests, the radiation emitted from the sulfide particle reactions was captured in the VIS–NIR range. The obtained spectral data were processed by using the airPLS (adaptive iteratively reweighted penalized least squares) algorithm to remove their baseline, and principal component analysis (PCA) and the multivariate curve resolution method alternate least squares (MCR-ALS) methods were applied to identify the emission lines or spectral bands of copper oxides. The extracted spectral pattern is directly correlated with the emission profile reported in the literature, evidencing the potential of using spectral analysis techniques on copper sulfide combustion spectra.

**Citation:** Reyes, G.; Diaz, W.; Toro, C.; Balladares, E.; Torres, S.; Parra, R.; Vásquez, A. Copper Oxide Spectral Emission Detection in Chalcopyrite and Copper Concentrate Combustion. *Processes* **2021**, *9*, 188. https:// doi.org/10.3390/pr9020188

Received: 21 December 2020 Accepted: 16 January 2021 Published: 20 January 2021

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**Keywords:** combustion; optical sensors; spectroscopy measurements; signal detection; digital processing; principal component analysis; multivariate data analysis; curve resolution
