The effect of the carbonaceous materials properties on the energy consumption of silicon production in the submerged arc furnace

The objective of this study was to use a statistical approach to determine the correlation of fixed carbon, volatile matters and moisture with the specific electrical consumption and exergy efficiency by collecting and analyzing an abundance of actual production data generated in silicon plants during the melting process of silicon produced in the submerged arc furnace (SAF). A high positive correlation (the r maximum value of 0.82) between the fixed carbon composition and the specific electrical consumption, as well as the perfect negative correlation (the r maximum value of −0.92) between the fixed carbon and the exergy efficiency were found, especially when the carbon materials contained a very high amount of graphitized carbon. Compared with the carbon materials without woodchips, the high correlation among the volatile matters, the specific electrical consumption and exergy efficiency was observed when using the carbon materials with woodchips. The influence of the proximate composition on the electrical consumption and exergy efficiency becomes stronger with the increase of the graphitized carbon content in the carbon materials. The analysis results can be used to support decisions when optimizing the proximate composition of the carbonaceous reductants in order to increase exergy efficiency and decrease electrical consumption costs, which is one of the biggest operating costs in the silicon furnace.