Decomposition of SiO_2(gel) with mixed HF and HNO₃ acid

Decomposition SiO_2(gel) with a mixture of HF and HNO₃ acids have been done. The objective of this research is to purify of SiO_2(gel) by decomposition process using HF and HNO₃ acid mixture, and characteristic test product by XRD and Fourier Transform Infra Red (FTIR) were done. The decomposition process was used teflon bomb digaster with various of temperature, contact time and concentration of HNO₃ and HF. The sample SiO_2(gel) from local producted of the zirconium process technology (TPZ) in PSTA-BATAN. The results showed that as longer as contact time will affected of decomposition result and at 10 hours. Result processed decomposition were optimum at HNO₃ 1N, HF 5 %, 100 °C and result of decomposition 36 %. Characterization product was done by XRD shows that the product pattern is not significantly different from the standard silica. This mean that at an angle of 2ϴ 20°-22° were indicated the presence of illite or quartz minerals. With so many other peaks at a 2ϴ angle at 40°-60° it is likely still not pure. While the FTIR characteristics of the Si-O-Si and Si-O groups are present at a wavelength of 1096.32 cm^-1 in the form of asymmetric stretching vibrations. The 800 cm^-1 region will strengthen the vibration of the symmetry of the silonol and siloxane groups. (author)