Design of Experimental (DOE) Analysis of Silica Sand Processing Using Spiral Concentrator

The main aim of this study on silica sand using a spiral concentrator using the design of experiments DOE) approach is to improve the silica content of the tailing sand for the glassmaking process. Three significant operational parameters of the spiral concentrator, namely feed rate (t/h), solid feed (wt.%), and splitter position (cm), were investigated to observe their effects on the SiO2 grade (%) and recovery of SiO2 (%) in the middlings using Design of Experiments (DOE). The raw sample was sieved to prepare the feed sample in the size range of -600+75µm, which was the suitable particle size range for the glassmaking process. The SiO2 grade (%) of each middling fraction from 33 test runs was determined from XRF analysis. The analysis determined that the feed rate and weight of the solid feed (wt.%) significantly affected the separation, while the splitter position in the investigated range (4.5-5.5cm) showed a negligible effect on the percentage and recovery of SiO2 in the middling fraction. It was observed that a maximum SiO2 grade of 94.98% was achieved at a solid feed of 25%, feed rate of 0.63 t/h, and splitter position of 5.5cm. The highest SiO2 recovery of 89.74% was achieved at the solid feed of 15%, feed rate of 0.45t/h, and splitter position of 5.0cm. A trade-off between the optimized results for SiO2 Grade (%) and recovery of SiO2 (%) responses using overlaid contour plots suggested a feed rate of 0.58 t/h of feed rate and 25 wt. % solid feed regardless of the splitter position. The customized range of parameters is expected to produce 94.51% SiO2 grade (%) and 80.11% recovery of SiO2 in the middling fraction.