Implementation of sulfuric acid leaching for aluminum and iron removal for improvement of low-grade silica from quartz sand of Sukabumi, Indonesia

Abstract

Indonesia has very abundant reserves of silica, but progressive studies on the deposition of this material are very few, resulting in limited applications of silica. This work refers to the purification of silica from quartz sand originated from Sukabumi, Indonesia to obtain high-purity silica, which can be applied as important raw materials for special purposes. The aim of our research is to improve low-grade silica from quartz sand by removing impurities, especially aluminum and iron removal, using sulfuric acid leaching. In order to achieve the aim, the effect of reaction time and sulfuric acid concentration on the leaching process was investigated. The effectiveness of sulfuric acid for the impurities removal was observed. The chemical composition of the samples before and after leaching was studied using X-ray fluorescence. The mineralogical analysis of the starting materials and the products was conducted using X-ray diffraction. Microstructure analysis was performed using a scanning electron microscope, and EDS test was used to show the element composition at different points. The experimental results show that the optimum condition of the leaching process occurs at a reaction time of 5 hours with a sulfuric acid concentration of 10 N. The silica levels increase from 93.702 % to 96.438 %. Aluminum and iron impurities reduced from 4.691 % to 2.712 % and from 0.641 % to 0.094 %, respectively. At this optimum point, sulfuric acid is very effective to remove aluminum and iron impurities up to 42 % and 85 %, respectively. The results of this research can be a very significant opportunity to increase the value added of quartz sand from Sukabumi, which can enhance the quality of low-grade silica to provide better raw materials for glass industries.

Development of high purity amorphous silica from emulsifier silicon by pyrolysis process at temperature of 700 oC

“…Products from silica processing are widely used for ceramics, cement, paper, rubber, glass, foundry, oil and mining industries as well as refractories [1][2][3]. In the current technological era, silica with high purity in the form of amorphous phase and nano size, has been utilizing for the electronics industry, bitumen, composite industry, polymers, insulators, catalysts, solar cells, absorbent materials, battery industry, special optics and other special materials [4][5][6][7][8][9][10].…”