Technology-Grade Silica for the Energy Transition in Colombia: Physical–Chemical Optimization and Mathematical Modeling for High-Value Applications

Silica sand is a strategic mineral for Colombia’s energy transition, but current processing in Boyacá yields only 95.16% SiO2, insufficient for high-value markets (>99%). This study optimizes beneficiation using DMAIC, integrating physical separation, acid leaching, and thermodynamic modeling. The method achieved 99.03% SiO2, classified as technology-grade but below the HPQ threshold (>99.99%). The nonlinear programming model identified 61.2 °C as optimal, raising profit margin from 1.7% to 38.8%. Experimental validation at 61.5 °C for 30 min confirmed 99.025% SiO2, statistically indistinguishable from 4-h leaching at 20 °C, demonstrating an 8-fold reduction in residence time. Validated by XRF, XRD, and SEM-EDS, these results confirm the technical and financial viability of transforming an underutilized local resource into a technology-grade material for the clean energy value chain.