Characteristics on process mineralogy of a granitic pegmatite−type high purity quartz resource in Altai region, Xinjiang

A detailed process mineralogical study was conducted on a granitic pegmatite−type quartz sample from the Altai region of Xinjiang, by means of optical microscopy, chemical analysis, and mineral liberation analyser (MLA). The material composition and content, textural and structural characteristics, grain size distribution of major minerals, content of main impurity elements, and characteristics of inclusions in quartz were determined, aiming to service for the comprehensive utilization of granitic pegmatite−type quartz resources in the region. The results showed that the mineral content of quartz in the sample was 36.38%. The main gangue mineral is albite, followed by muscovite. The grain size distribution of albite is very similar to that of quartz, so it is the main mineral that needs to be separated and removed in subsequent beneficiation operations. The grain size distribution of muscovite is finer than that of quartz, thus they are difficult to separate from quartz in subsequent beneficiation. Therefore, necessary separation methods need to be designed for targeted removal. Fluid inclusions and a small amount of mineral inclusions can be observed inside the quartz, and the fluid inclusions are mainly of gas−liquid two−phase type. After mineral processing and purification, the product with a SiO₂ content of 99.9978% (4N7) can be obtained, which meets the requirement in purity for high−purity quartz ore. The main impurity elements are Al, Ti, and Na, followed by Li, B, Ca, and K.