Characterization and Beneficiation of Gold Mining By-products as Source of High-Quality Silica for High Technical Applications; Response Surface Studies and Optimization

This paper aims to evaluate and upgrade the quality of quartz mining by-products through acid leaching process. The quartz samples were collected as gold mine by-products from El Sid- Fawakhir gold mine, Qift-Quseir, Eastern Desert, Egypt and characterized using XRF and polarized transmitted optical microscope. The present magnetic mineral impurities were detected using Frantz Isodynamic Tester. Suitability of acid leaching utilizing oxalic acid as an efficient technique for considerable reduction of the associated impurities was evaluated based on Response Surface methodology and face centered central composite design (CCD). The quartz sample was classified as low-quality quartz with low silica content (99.3%) which can’t match the requirements of wide range of applications. The main detected impurities are muscovite, biotite, sericite, pyrite and iron oxide. The present magnetic impurities represent about 2.72% of the total sample. The leaching process at the optimum conditions of temperature, time and oxalic acid concentration removes \(\sim \) 36% of the iron. This associated with a clear reduction of other magnetic impurities and noticeable enhancing in the silica content to about 99.56%. Magnetic purification followed by oxalic acid leaching for the quartz samples give better results as the iron content was reduced to about 0.001% and the silica content increased to about 99.9% which match the specifications of most of the typical high technical applications.