Yuan Lei told you | what are the characteristics of ores that can produce high purity quartz?

Release time:

2024-01-29 09:35


Yuan Lei told you | what are the characteristics of ores that can produce high purity quartz?


There is not a simple correspondence between the quality of high-purity quartz and the content of impurity elements in raw materials. It is closely related to the impurity selectability determined by the mineralogical characteristics of the raw material process. There are obvious differences in the mineralogical characteristics of different types of quartz ore, and a detailed analysis of the mineralogical characteristics of quartz raw materials is the basis for determining the nature of quartz raw ore, beneficiation and purification process and product direction.

1. Chemical composition and occurrence state of impurity elements

The chemical composition only reflects the type and content of the elements contained in quartz, but it is difficult to make a correct judgment on whether the quartz raw material has the potential to be processed into high purity quartz. There are many kinds of impurity elements, high content and diversified occurrence states in quartz raw materials. The common occurrence states are shown in the table below.

2. Mineral composition and embedding characteristics

Chemical composition is only to obtain information such as the type and content of impurities in quartz raw materials, and to select the correct high purity quartz raw materials and formulate the best quartz purification scheme, it is necessary to clarify the occurrence state of impurity elements in quartz. Associated independent gangue minerals (such as mica, feldspar, hematite, tourmaline, chlorite and clay minerals, etc.) are the main carrier minerals of impurity elements in quartz, and it is easy to become mineral inclusions in quartz in the process of geological mineralization, which is one of the important factors restricting the quality of the final quartz products.

The distribution characteristics of quartz and gangue minerals directly affect the dissociation degree of quartz monomer, and then affect the effect of mineral processing and purification. The greater the intensity of quartz transformation by diagenesis and metamorphism, the more obvious the difference between quartz and gangue mineral inlay, and the inlay characteristics gradually change from adjacent type to slit-like or even wrapped type, and the difficulty of monomer dissociation increases in turn during the crushing process, which is added. The possibility of working as high-purity quartz is also gradually decreasing.

(a) Granitic pegmatite rock topography in Spruce Pine, USA; (B) Microscopic topography of a vein quartz in Qinghai;(c) Profile topography of mineral inclusions in quartz after beneficiation purification, roasting and water quenching-mixed acid leaching of a vein quartz


Mineral composition Even very complex quartz raw materials have the potential to be processed into high purity quartz As shown in the above figure (a), the mineral composition of granite pegmatite in Spruce Pine area of the United States is complex, and a large amount of black impurities are obviously observed by naked eyes. The main minerals are plagioclase and potassium feldspar, Shi Ying only accounts for 25% ~ 35%, and there are also a small amount of biotite, garnet and epidote, with an average particle size of about 1.3cm, and no mineral and fluid inclusions.

Vein quartz with mineral impurities in the quartz grain gaps and intergrain boundaries may also be processed to high purity quartz. As shown in the above figure (B), a vein of Shi Ying in Qinghai has coarse grains, pure texture, associated with a small amount of muscovite, and is mostly distributed in the gaps and grain boundaries of Shi Ying, which is easy to dissociate from Shi Ying monomer. SiO can also be obtained through purification and processing.2Content of 99.99, Al content of less than 10ppm of high purity quartz.

Under the current technical conditions, mineral inclusions can not be effectively separated from quartz As shown in the above figure (c), the quartz raw ore has coarse grains, and high purity quartz products with the total amount of main impurity elements less than 40ppm can be obtained through purification and processing, but the mineral inclusions in quartz have not disappeared.

Under the existing technical conditions, it is not easy to dissociate from the gangue mineral monomer, and the quartz ore, which generally contains a large number of inclusions, is difficult to be processed into high-purity quartz.

3. Fluid inclusions

Fluid inclusions are widely present in minerals or rocks, and the number of fluid inclusions per cubic centimeter is about 102 to 109, and the diameter is generally less than 50 m. The type, size and content of fluid inclusions have a significant effect on the quality of high purity quartz.

Fluid inclusions in quartz can be divided into pure gas, pure liquid, gas-liquid mixed inclusions and three-phase inclusions according to the state of the inclusions. Fluid inclusions in the formation process of the capture of the fluid is supersaturated solution, when the temperature decreases will be crystallized from the solution, including the formation of rock salt, potassium salt and some silicate minerals, so the fluid inclusions contain Na, K, Ca and other impurities, is one of the main sources of impurities in high purity quartz products.

Fluid inclusions have serious adverse effects on the melting behavior of high purity quartz. Compared to the impurity elements,Fluid inclusions are more difficult to remove and are one of the key factors affecting the quality of the final quartz product..

Although the research on how to reduce the content of fluid inclusions in quartz has been carried out for a long time, good progress has not been made in the removal of rich gas phase and small size fluid inclusions.

Therefore,Selecting quartz with little or no fluid inclusions as the raw material of high purity quartz is the key to processing high purity quartz.

4. Lattice impurities

In the formation process of quartz crystal, some elements will replace the silicon element into the quartz crystal, forming the structural impurities of quartz. Although the content of these impurities is very low, it is difficult to separate them from quartz, which is the most critical factor restricting the quality of high purity quartz.

There are three main ways of trace elements in quartz lattice:
(1) Equivalent substitution, such as Ti4 、Ge4 and Si.4 The substitution of the same quality of the class;
(2) Ion group substitution, such as Al3 and adjacent P5 Substitute for Si4 ;
(3) Charge compensation substitution, such as Al3 , Fe3 Substitute for Si4 formed [AlO4/M+0or [FeO4/M+0Structural Center, M+acts as an electrovalency compensation ion to balance the charge.

Among the quartz structural impurities, the Al impurity element content is generally the highest. Because Al is Al.3 Substitute for Si4 The form of the existence of the quartz lattice caused by the internal charge imbalance, when there are a large number of Al impurities in the quartz, Li, K, Na and other impurity elements will increase. Therefore,The content of Al in natural quartz can be used to judge the quality of the quartz raw material.

Under current processing techniques, the crystal lattice impurities in the quartz raw material can hardly be removed. Although the content of Al element in the form of lattice impurities is very low, it is very difficult to remove it, which is the key to restrict the final quality of high purity quartz.

Generally speaking, under the existing technical conditions, natural quartz minerals that can be used for processing high-purity quartz should have the following mineralogical characteristics:The quartz grains have pure chemical composition, little or no lattice impurities, large embedded grain size, few mineral inclusions and fluid inclusions, and few associated gangue minerals..

Quartz, impurity, parcel, mineral, fluid, content, element, processing, presence

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