Technical evaluation and beneficiation of Ugandan silica sands for solar glass and photovoltaic-grade silicon production.
| dc.contributor.author | Omuria, Godfrey | |
| dc.date.accessioned | 2026-10-15T10:01:26Z | |
| dc.date.available | 2026-10-15T10:01:26Z | |
| dc.date.issued | 2026 | |
| dc.description | Dissertation | |
| dc.description.abstract | The growing demand for high-purity silica in photovoltaic applications has created a need to evaluate local silica resources for solar glass and silicon feedstock production. This study assessed the suitability of selected Ugandan silica sand deposits for these applications through systematic chemical, mineralogical, and physical characterization combined with sequential beneficiation. The specific objectives were to determine the chemical composition of the silica sand, quantify improvements in silica purity and iron removal after beneficiation, analyse mineralogical characteristics, and evaluate particle size distribution and morphological properties. Silica sand samples were subjected to physical beneficiation involving washing, sieving, and magnetic separation, followed by chemical beneficiation using hydrochloric, sulfuric, nitric, and oxalic acids. Chemical composition was determined using X-ray fluorescence (XRF), while mineralogical analysis was conducted using X-ray diffraction (XRD). Particle size distribution and morphological characteristics were evaluated using optical microscopy and ImageJ software. The results indicated that raw silica sand contained up to 96.696% 𝑆𝑖𝑂₂ and 0.338% 𝐹𝑒₂𝑂₃. Beneficiation significantly enhanced silica purity and reduced impurity concentrations across all samples. The highest silica purity of 99.815% and the lowest 𝐹𝑒₂𝑂₃ content of 0.00976% were achieved after oxalic acid leaching. XRD results confirmed quartz as the dominant mineral phase in all samples, with the crystallinity index increasing from 57.5% in the raw sample to 90.3% after magnetic separation and remaining above 84% after acid leaching. Particle size analysis showed progressive reductions in particle area, perimeter, and Ferret diameter, indicating improved liberation and impurity removal. Morphological analysis revealed that particles remained predominantly sub-angular to moderately rounded throughout processing. The study concludes that Ugandan silica sand can be successfully upgraded through sequential beneficiation to produce high-purity silica suitable for high-quality solar glass production and with strong potential as a feedstock for metallurgical-grade silicon and photovoltaic applications. The final product (99.815% 𝑆𝑖𝑂₂) with extremely low 𝐹𝑒₂𝑂₃ (0.00976%) meets quality requirements for solar glass and has a promising potential as an upgraded feedstock precursor for carbothermic reduction to MG-Si, rather than direct semiconductor-grade silicon. Further studies should focus on pilot-scale processing and industrial application of the beneficiated silica. | |
| dc.description.sponsorship | Assoc. Prof. Tumutegyereize Peter ; Eng. Dr. Joseph Ddumba Lwanyaga ; Busitema University | |
| dc.identifier.citation | Omuria, G. (2026). Technical evaluation and beneficiation of Ugandan silica sands for solar glass and photovoltaic-grade silicon production. [Unpublished dissertation]. Busitema University. | |
| dc.identifier.uri | https://bdears.busitema.ac.ug/handle/123456789/10979 | |
| dc.language.iso | en | |
| dc.publisher | Busitema University | |
| dc.title | Technical evaluation and beneficiation of Ugandan silica sands for solar glass and photovoltaic-grade silicon production. | |
| dc.type | Other |