北喜马拉雅马拉山二云母花岗岩的石英提纯实验和找矿前景OA

Objectives:High-purity quartz is a critical raw material for strategic emerging industries such as semiconductors and photovoltaics,yet the supply of its high-grade feedstock remains at risk.The North Himalayan Belt hosts the world's largest Cenozoic leucogranite belt,which holds theoretical potential for hosting alaskite—granite-type high-purity quartz deposits.However,systematic mineralogical studies and experimental validation of purification methods have been lacking.This study aims to clarify the mode of occurrence of impurities and the purification feasibility of quartz from the Malashan two-mica granite through detailed characterization and systematic experiments,and to evaluate its resource potential. Methods:Quartz from the Malashan two-mica granite was selected for investigation.Analytical techniques including polarized light microscopy,scanning electron microscopy(SEM),and Raman spectroscopy were employed for mineralogical and fluid inclusion analysis.A comprehensive purification process—"crushing,flotation,calcination—water quenching,mixed-acid leaching,and chlorination roasting"—was applied.The concentrations of 15 key impurity elements in quartz sand before and after purification were quantitatively analyzed using ICP-OES. Results:① The primary fluid inclusion content in quartz is extremely low,with secondary inclusions dominating,suggesting that parental magma evolution stagnated prior to extensive fluid exsolution;② systematic purification increased quartz SiO2 purity from 99.8969％to 99.9942％(4N4 grade).Flotation and acid leaching effectively removed mineral inclusions such as coexisting feldspar and mica,while chlorination roasting significantly reduced lattice-bound Li and Na;③ the main residual impurities in the final product—Al(43.3 × 10-6),Ti(8.03 ×10-6),and Li(1.69 ×10-6)—are present in the quartz lattice via isomorphism and are difficult to remove completely using conventional processes under current economic and technical conditions. Conclusions:The quartz from the Malashan two-mica granite possesses the mineralogical foundation for forming granite-type high-purity quartz.This study confirms that leucogranites within the North Himalayan Belt characterized by"high differentiation,low fluid exsolution,metamorphic—deformational overprinting,and absence of metallic mineralization"represent favorable targets for exploring this type of high-purity quartz resource.The findings provide a new prospecting direction for China to overcome bottlenecks in the supply of high-end quartz resources.