Crystal structure transformation and lattice impurities migration of quartz during chlorine roasting

Abstract

To investigate the effect of chlorine roasting on the migration and removal of trace elements in quartz lattice, firstly, an efficient pretreatment process, grinding–HCl washing–flotation–HF and HCl leaching, was used to remove the gangue minerals in quartz ore to obtain purified quartz for the preparation of high-purity quartz and the investigation of lattice impurities migration. The results showed that the high-purity quartz with total impurities less than 50 μg/g could be obtained from purified quartz after being treated with chlorine at 1200 °C. The variation of crystal structure and the lattice impurities migration of quartz during chlorine roasting were studied through in-situ XRD, TGA, SEM-EDS, ICP-MS, FT-IR and XPS analysis. It revealed that the decomposable impurities H₂O, −OH, and residual collectors in the crystal of purified quartz could be effectively removed through chlorine roasting above 900 °C, which also had an obvious effect on the removal of low-valence trace elements Li, Na and K in the crystal of quartz but didn’t affect the multivalent trace elements Al and Ti. This study revealed the removal and migration mechanism of the trace elements in quartz crystal during chlorine roasting.