High-purity quartz is the material basis for high-end products in the silicon industry

High-purity quartz is widely used in industries such as photovoltaics, electronic information, optical communications and electric light sources. High-purity quartz is the general term for quartz series products with a silica purity greater than 99.9%. Its product grades can be divided according to the purity of SiO2, that is, low-end w (SiO2) ≥ 99.9% (3N), mid-end w (SiO2) ≥ 99.99% (4N), high-end w (SiO2) ≥ 99.998 % (4N8); each grade of high-purity quartz can be divided into 40-80 mesh, 80-140 mesh, 80-200 mesh, 80-300 mesh and other varieties according to the particle size. my country's photovoltaic, electronic information and high-end electric light source industries have a great demand for high-purity quartz.

Quartz is a major rock-forming mineral that is widely distributed in nature. At present, there are seven genetic types of quartz mineral resources that can be used as industrial applications, and they are natural crystal, quartz sandstone, vein quartz, powder quartz, natural quartz sand and granite quartz.

High-purity quartz is initially made of primary and secondary natural crystals, and then processed through selection and purification. Natural crystals are usually formed in a geode environment under certain geological conditions, and the 

particularity of its origin determines that it has two congenital deficiencies:

1 The reserves are small and the mining conditions are poor. After years of development and utilization, resources will inevitably be scarce and expensive, making it difficult to meet the needs of large-scale industrial production.

2 Affected by changes in the crystallization environment, the chemical composition of mineral crystals is unstable. In a large number of industrial applications, the chemical composition of raw materials fluctuates greatly, and the standardization

of raw materials is difficult. It is difficult to meet the needs of the production of high-end high-purity quartz products. Start with resources and fundamentally solve the problem of high-purity quartz raw materials. This is the basic technical idea at home and abroad.

The result of the development of new energy industry

The wide application of high-purity quartz is the result of the continuous development of new materials and new energy industries in the last century, especially since the 1980s. In addition to natural crystals, among the other 6 origins of 

quartz mineral resources, vein quartz and granite quartz are ideal raw materials for replacing natural crystals and processing high-purity quartz mid-range and high-end products.

Practice has proved that according to the current level of processing technology, not all vein quartz and granite quartz can process high-purity quartz, and only a few, or even very few, can process high-end products. That is to say, the 

choice of vein quartz or granite quartz is only the right general direction, and cannot solve the key problem of specific raw material selection. The main reason is that not only vein quartz and granite have multiple subdivided genetic types, 

but also due to the influence of ore-forming geological conditions, the mineralogical, petrological and ore deposit characteristics of vein quartz and granite of the same genetic type are also quite different.

Top companies carefully select high-purity quartz raw materials and have very strict requirements. The main selection criteria are, first, quartz with the least impurities in the crystal structure, and second, quartz with less gas-liquid inclusions, 

such as pegmatite granite and crystal.

Generally speaking, the purity of SiO2 of high-purity quartz is extremely high, and the content of impurity elements is very low, but the content of impurity elements in raw materials is usually high, so it is difficult to correctly judge the quality 

of raw materials based on the detection data of chemical composition. Practice has shown that the content of impurity elements in raw materials and their quality are not a simple correspondence, but are related to the selectivity of impurities 

determined by the mineralogical characteristics of raw materials.

Blindness exists in China's high-purity quartz

At present, there is still a large blindness in the selection of high-purity quartz raw materials and its processing technology in China. For example, in the past, it was believed that high-purity quartz could be processed by using quartz mineral

 raw materials with a SiO2 purity of about 2N, and a large amount of manpower, material resources and resources were invested. time, resulting in a greater waste. This is one of the important reasons why China's high-purity quartz technology

 is relatively backward.

Obviously, the evaluation and selection of raw materials is the basis and premise of high-purity quartz, and it is the bottleneck that must be broken through in the development of high-purity quartz. For this reason, it is necessary to strengthen

 the mineralogical, petrological, and ore deposit studies of high-purity quartz mineral resources, focus on the chemical composition of raw materials, useful minerals (quartz) and other process mineralogy characteristics, and find out the 

distribution of raw material impurities and their occurrence status and Its influence and mechanism on the application of high-purity quartz, because in the absence of high-quality raw materials, it is difficult to process high-end products. 

This also provides a scientific basis for the selection of high-purity quartz raw materials.