Vein quartz is not a mineralogical name, but a vein-like aggregate of quartz. Therefore, vein quartz is essentially quartz, which has the same physicochemical properties as common Xingying. Generally colorless, Milky white, grease or glass gloss, transparent or translucent, hardness is 7, density is 2.65 g/cm3. Vein quartz is chemically stable, insoluble in any acid except hydrofluoric acid, but soluble in alkaline solution.
The chemical composition of vein quartz is mainly Si02. The content of vein quartz is usually over 99%. Other components, such as A1203, Fe203, S03, CT, etc.
1) As metallurgical flux.
2) As raw material of high purity quartz sand. Vein quartz can be purified by physical and chemical methods to produce high purity quartz sand. High-purity quartz sand products are widely used in large-scale integrated circuits, optical fibers, lasers, aerospace and military fields. They are also used in plastic materials. They are combined with epoxy resin, curing agent and various additives to save packaging costs. It can also be used as an electronic substrate material for making extruded silicon and polycrystalline dolls.
3) As raw material of special glass. Quartz glass has a series of excellent physical and chemical properties, such as high temperature resistance of 1100~200zhang, 800 Yu higher than ordinary glass, transparent refractory, low thermal expansion coefficient, only 5.5x10_7/q, equivalent to 1/20 of ordinary glass. Quartz glass has excellent light transmittance, ultraviolet and visible light transmittance, good electrical insulation, 2 (resistivity at T_is 1018 n cm). The insulation strength is 25 kV/cm.
4) Because vein quartz is vein, and its texture is hard, the mining cost is based on quartz sand, quartz sandstone and quartzite, so it is seldom used in making flat glass.
IV. GEOLOGICAL CHARACTERISTICS
The geotectonic environment of vein quartz deposit is near suture zone, back arc magma zone and inheritance area, and ore-bearing hydrothermal filling is formed. Vein quartz is widely distributed and occurs in almost all strata, but few ore deposits can be formed, which is common in ancient metamorphic rock series, and the ore-bearing wall is mainly gneiss. Pegmatite veins occur mostly in granite. Ore bodies occur as veins, with veins ranging from tens of meters to several W meters in length and from several meters to tens of meters in thickness. They occur as single ore veins or multiple ore veins. The geological characteristics of the deposit are illustrated by two examples below.
The Xinjihami Weigai vein quartz deposit occurs in the Paleozoic intrusive body with a length of 620 m, a thickness of 15-60 m and an extension of more than 50 m. Samamoto is bare on the surface. The roof of the orebody is diorite and the floor is granodiorite. The joints are well developed and there are fine crystal caves. The mineral composition is mainly quartz, with a content of more than 98%, feldspar, chromite, bornite, secondary sericite, kaolin and so on. The chemical composition of $05 contains the maximum of 98.9%, Al203 0.87% and Fe2O 30.1%. The ore has high hardness, brittleness and good fragmentation. The deposit is of medium scale with good quality piers and has been exploited and utilized.
The Quartz Deposit of Qian Lingyan Mountain in Hubei Province is located 13 km north-west of Qianchun County. It belongs to high-temperature hydrothermal vein quartz deposit. The ore bodies occur in vein and gentle porphyry in metamorphic rocks with a length of 250-280 m, a thickness of 13-40.8 m and a width of 200 m. Chemical constituents Si02 99.35%, A120,
0.22%, Fe20, 0.03%. The ore has high hardness, brittleness, developed joints and fissures, and can be mined in open pit. The brief characteristics of some vein quartz deposits are listed in Table 2-47-1.