DOI: https://doi.org/10.55373/mjchem.v28i2.153

Keywords: SiO₂ Extraction, high-purity silica, Coprecipitation Method

Abstract

Using a coprecipitation method, SiO₂ was extracted from river sand samples obtained from the Silau River, Indonesia. The phase of each sample was determined by X-ray Fluorescence (XRF) and X-ray Diffraction (XRD). Chemical characterization was performed with Fourier Transform Infrared Spectroscopy (FTIR), while microanalysis and elemental mapping were carried out with a Scanning Electron Microscope (SEM) equipped with an Energy Dispersive Spectrometer (EDS). The thermal characteristics of the samples were examined using Differential Scanning Calorimetry (DSC). XRF data showed that after the extraction process, the concentration of SiO₂ in the river sand increased from 80.91 wt% to 99.41 wt%, demonstrating successful SiO₂ extraction. SEM images revealed that the particles were more uniform after extraction compared to those found in the river sand before the extraction process. FTIR data showed substantial changes in peak positions and intensities after extraction, indicating that the impurities had been removed and pure SiO₂ had been synthesized. The XRD results indicated that the primary component of the extracted SiO₂ was quartz, although there were some minor amorphous components. The DSC results indicated that the thermal profile of the extracted SiO₂ was nearly flat, indicating good thermal stability. In summary, the precipitation method was effective in isolating SiO₂ from Silau River sand, and the resulting product should have a variety of applications. The extracted SiO₂ was found to be of high purity.