Beneficiation of dune sands from the Ighil-Ali deposit (Ouargla, Algeria) toward high-purity silica for glass and ceramic applications

The valorization of desert silica sands represents an important opportunity for developing alternative sources of high-quality raw materials for industrial applications. This study investigates the beneficiation of dune sands from the Ighil-Ali deposit (Ouargla Province, Algerian Sahara) to produce a high-purity silica concentrate suitable for glass and ceramic applications. The raw sand was characterized using X-ray fluorescence (XRF), Raman spectroscopy, scanning electron microscopy (SEM), and optical microscopy to determine its chemical, mineralogical, and morphological characteristics. The results revealed quartz as the major mineral phase, associated with minor iron-bearing minerals, clay minerals, and aluminosilicate impurities that affect its industrial suitability. An integrated beneficiation flowsheet combining attrition, hydrocycloning, and reverse flotation was developed to enhance quartz liberation and remove undesirable mineral phases. The attrition step was optimized at 70 wt% solids and pH 11, followed by a two-stage reverse flotation process using dodecylamine (300 g/t) and AERO-801/825 collectors. The proposed treatment effectively reduced impurity levels and produced a silica concentrate containing 99.28 wt% SiO₂ with an overall purification mass recovery of 89.7%. These findings demonstrate the potential of Ighil-Ali dune sands as a valuable silica resource and confirm the efficiency of the proposed beneficiation strategy. Further pilot-scale studies are required to validate process performance and assess industrial feasibility.