Extraction of silica from Bangka quartz sand using the alkaline digestion method

Abstract Bangka quartz sand is a strategic mineral that contains relatively high levels of silicon compared to other sources of silicon minerals. The silicon content in a mineral greatly determines the feasibility of processing its derivative products, one of which is very well known, namely silica. Silica is a functional material that is widely applied in various fields including energy, environment, food and medicine. In this research, the silica extraction process has been carried out from Bangka quartz sand using the alkaline digestion method. The main extraction process stages include preparation, digestion using NaOH, water leaching, and calcination. The effect of varying calcination temperatures: 600, 800, and 1000°C on the silica phase and content of Si element was studied comprehensively. Based on the research results, it shows that at a temperature of 600°C, amorphous silica is formed, while at temperatures of 800 and 1000°C, crystalline silica with a quartz phase is formed with the element content of Si at 800°C reaching 98.87%.