Characterization Study of Iron Sand and Silica Deposits Based on Mineralogical-Geochemical Data

Abstract

Iron sand and silica sand are strategic commodities for raw materials in the metal, cement, glass, and functional materials industries. However, the quality and economic viability of deposits are largely determined by mineral composition and elemental content. Variations in mineralogical-geochemical characteristics that are not well mapped often lead to inaccuracies in determining quality, beneficiation routes, and industrial utilization directions. Therefore, preliminary characterization is necessary to ensure the most appropriate processing potential and recommendations. This study aims to identify the main minerals carrying Fe and SiO₂ and determine the geochemical composition of both deposits. The research was conducted by taking representative samples at several locations, such as the Jenne Berang River, Burungintia River, and Tanjung Bayang Beach, followed by preparation (drying, sieving, fraction separation). Next, mineralogical and chemical characterization was carried out using X-Ray Diffraction (XRD) and X-Ray Fluorescence (XRF) to determine the mineral and chemical composition. Samples from Tanjung Bayang Beach showed the presence of several main crystalline phases dominated by iron oxides such as Magnetite with a content of 31.5% and Maghemite with 30.4%. In addition, a Quartz phase of 24.7% was identified, representing the dominant gangue mineral in the sand fraction. Another minor phase was Hematite with 13.4%. These samples are iron sand with magnetic iron oxide as the main component. Geochemical analysis of the iron sand samples found Fe₂O₃ at a level of 54.7%, SiO2 at 36.8%, 2.7%, and CaO at 2.3%. The sample from the Jenne Berang River is dominated by the aluminosilicate phase in the form of Albite (plagioclase feldspar, Na-rich) with a fraction of around 84.1%, while the minor phase identified is Fe₃O₄ (magnetite/iron oxide) at around 15.9%. This sample is silica sand with aluminosilicate as its main component. Geochemical analysis of silica sand samples from the Jenne Berang River showed SiO₂ content of 40.3%, Fe₂O₃ 18.7%, Al₂O₃ 30.7%, and CaO 4.50%. The sample from the Burungintia River is dominated by the Albite phase (NaAlSi₃O₈; feldspar/aluminosilicate) with a fraction of approximately 90.2%, while the minor phase detected is Fe₃O₄ (magnetite/iron oxide) at approximately 9.8%. The sample is silica sand with aluminosilicate as the main component. Geochemical analysis of silica sand samples from the Burungintia River showed SiO₂ content of 45.5%, Fe₂O₃ 11.6%, Al₂O₃ 33.0%, and CaO 4.0%.