Investigating the Potential for Producing Ultrapure Silica: A Case Study on Bonab Silica Samples

This study investigates the potential for producing ultrapure silica from Bonab silica samples to meet the stringent purity requirements of strategic industries such as glassmaking, semiconductors, and photovoltaic. The raw silica underwent multi-stage processing, including crushing, grinding, and magnetic separation, acid leaching, and flotation, to remove impurities such as iron oxides and aluminosilicate. Magnetic separation tests revealed that dry high-intensity magnetic separation (۱.۷ Tesla) outperformed methods, achieving a silica grade of ۹۸.۸۶% with iron and aluminum oxide contents of ۲۲۱ ppm and ۰.۵۸%, respectively. Acid leaching experiments, conducted with sulfuric acid and a ۱:۱ mixture of sulfuric and oxalic acids, further reduced impurities. The optimized leaching conditions included a temperature range of ۸۵-۹۰°C, a dosage of ۱۰۰ kg/t, and a retention time of ۲ hours. Heat treatment at ۶۵۰°C was found to destabilize aluminosilicate structures, improving the efficiency of subsequent leaching processes. However, the economic viability of industrial-scale heat treatment remains questionable. Flotation was evaluated as an auxiliary method for aluminosilicate removal but showed minimal impact on reducing iron impurities. The combination of magnetic separation and acid leaching proved effective in reducing iron and aluminum oxide contents to below ۲۰۰ ppm and ۰.۲۱%, respectively, on a laboratory scale. This research provides a practical framework for silica purification, emphasizing the integration of cost-effective and sustainable methods. The findings lay the groundwork for pilot-scale studies and potential industrial applications in producing high-purity silica.

کلیدواژه ها:

Ultrapure silica ، Magnetic separation ، Acid leaching ، Aluminosilicate removal ، Silica beneficiation