南秦岭安康地区高纯石英用脉石英矿特征及质量影响因素

南秦岭安康地区志留系梅子垭组千枚岩中赋存丰富的脉石英矿产资源, 但其作为高纯石英原料研究程度低, 尤其是对其中影响石英提纯的痕量杂质元素含量及其赋存状态缺乏系统认识, 很大程度制约了该区高纯石英原料的质量评价和进一步的找矿突破。本文在厘定安康地区脉石英地质发育特征的基础上, 对研究区产出的3件脉状石英样品(AK200、AK201、AK202)开展了样品杂质元素检测, 对样品矿物学特征、杂质赋存形式和可提纯性能进行了研究, 进而进行了提纯实验, 结果显示, 3件样品提纯后SiO₂含量分别为99.993 11%、99.997 66%和99.998 58%, 均达到高纯石英产品质量要求, 其中AK202样品提纯后达到4N8级。研究表明, 提纯后Al、Ti、Na、K为主要杂质元素, Al可能以杂质矿物、晶格杂质两种方式存在; Ti可能多以晶格杂质的方式存在; Na、K多以流体包裹体的方式存在; 杂质矿物、流体包裹体、晶格杂质对该区脉石英质量均产生不同程度影响, 其中流体包裹体为主要影响因素, 晶格杂质次之, 杂质矿物影响最小。这一结论对于评价该区的脉石英矿产资源质量、明确今后找矿目标体特征具有重要参考意义。

Characteristics and quality influencing factors of vein quartz deposit for high- purity quartz in Ankang area, South Qinling Mountains

There are abundant vein quartz mineral resources in the phyllite of the Silurian Meiziya Formation in the Ankang area of the South Qinling Mountains, but the research degree of the vein quartz as the raw material of high-purity quartz is low, especially the lack of systematic understanding of the content of trace impurity elements and their occurrence that affect the purification of quartz state, which greatly restricts the quality evaluation of the high-purity quartz raw material in this area and further exploration breakthrough. On the basis of determining the geological development characteristics of vein quartz, this paper has carried out sample impurity element detection on three vein quartz samples (AK200, AK201, AK202) produced in three regions, studied the mineralogical characteristics, impurity occurrence and purification performance of the samples, and then conducted purification experiments. The results show that the SiO₂ content of the three samples after purification is 99.993 11%, 99.997 66% and 99.998 58%, respectively, all of which reaches the quality of high-purity quartz products, in which the AK202 sample reaches 4N8 level after purification. The results show that after purification, Al, Ti, Na, K are the main impurity elements, and Al may exist in two ways: impurity minerals and lattice impurities; Ti may exist in the form of lattice impurities; Na and K mostly exist in fluid inclusions. Impurity mineral, fluid inclusion and lattice impurity all have varying degrees of influence on the quality of the vein quartz in this area, among which fluid inclusion is the main influencing factor, lattice impurity is the second, and impurity mineral has the least effect. This conclusion has an important reference significance for evaluating the quality of vein quartz mineral resources in this area and defining the prospecting target in the future.