Honglei New Material

High purity quartz sand generally refers to quartz powder with SiO2 content higher than 99.99%, which is the main raw material of quartz glass and quartz crucible.Its high-end products are widely used in large-scale and ultra-large scale integrated circuits, optical fiber, solar cells, laser, aerospace, military and other industries.

Because these industries are related to the long-term development of the country, is a national high-tech sustainable development of the necessary conditions, so the strategic position of high purity quartz sand is very important, its high-end product preparation technology is monopolized by the United States, Germany and other countries, and limited technology and exports.

At present, the purification and large-scale mining of quartz sand in China is still in a difficult stage of exploration.High purity quartz sand has unique physical and chemical properties, especially its internal crystal structure, crystal shape and lattice change law, so that it has high temperature resistance, low thermal expansion coefficient, high insulation, corrosion resistance, piezoelectric effect, resonance effect and unique optical properties.

The quality requirements of quartz sand products are generally directly related to their actual industrial use.If used for electronic materials, quartz crucible and other fine, high-performance materials, the quality of raw materials is strict, the need for high purity and ultra-pure quartz sand, the total content of impurities should be low.Specifically, the quality requirements of quartz sand are mainly reflected in the chemical composition and particle size composition :① the appearance is white, no visible mechanical impurities;Purity requirements: silica content is greater than 99.99%;③ According to the requirements of different industries, it can be processed into a series of products of different specifications and models to meet user requirements.

Application of high purity quartz sand

High purity quartz sand is also the main raw material of quartz glass.Quartz glass is known as "glass mesh", because it has a series of excellent physical and chemical properties, such as temperature resistance up to 1100~1200℃, 800℃ higher than ordinary glass;Is a transparent refractory material;The coefficient of thermal expansion is small, only 5.5×10-7/ C, equivalent to 1/20 of ordinary glass, which can theoretically reach zero expansion;With light transmission performance, ultraviolet, visible light, infrared can be well penetrated;It has good electrical insulation, the resistivity is 1018Ω/cm at 20℃, the insulation strength is 250kV/cm, and the vacuum degree can reach 10-6Pa;Good chemical stability, except hydrofluoric acid, insoluble in any other acid.Quartz glass is a brittle material, the compressive strength is very good, but the tensile strength is smaller, quartz glass is not resistant to hydrofluoric acid, high temperature conditions (above 1000℃) will be transformed into quartz, which is its two shortcomings.

The main products of quartz glass include: high purity and high temperature resistant quartz glass tube for large-scale integrated circuit, quartz crucible for arc method (solar level and semiconductor level), quartz glass for optical communication, quartz glass for electric light source.The varieties and uses of quartz glass are closely related, and users can manufacture different quartz glass according to the characteristics and requirements of quartz glass.

Research and development status of high purity quartz sand in China

Since the end of the 1980s, China began to study the ordinary quartz raw materials of quartz glass, and has made certain progress, the products studied can reach the level of two, three and four crystals, but only suitable for middle and low grade quartz glass, and the technical difficulties of high purity and low hydroxyl quartz raw materials have not been completely overcome.The purity of industrial production of quartz glass raw materials can not meet the requirements of high purity quartz sand glass raw materials, high-quality quartz glass raw materials are mainly imported, restricting the development of China's quartz sand glass industry, which has attracted the attention of domestic quartz glass and raw material production enterprises and relevant scientific research units.

China is one of the countries with rich quartz reserves. At present, there are good areas for the exploitation and utilization of quartz ore in Donghai, Jiangsu, Fengyang, Anhui, Hongan, Jiangxi, Xiushui, Wuhai and other places. The quartz ore reserves in these areas are large, with high grade and easy to exploit, but due to the backward processing and utilization technology of quartz sand in China,Most of the quartz ore mined is only used as low-end quartz products with low economic added value, such as silicon powder, glass, refractory materials, ferrosilicon, silicon carbide, fused quartz and so on.

In fact, there are many mineral sources that can be used to produce high-purity quartz sand in China, but due to backward processing methods and the lack of basic research in earth sciences such as mineralogy and geological origin related to quartz glass raw materials, the products can not meet the requirements of high-purity quartz raw materials.At present, the middle and low grade high purity quartz sand used in quartz glass in China is mostly made from crystal.The reserves of crystal in China are limited, the price is expensive, the texture is uneven, and some mineral impurities and mixed substances in the process are impossible to get rid of, resulting in a small batch of ultra-pure quartz sand produced by crystal and unstable quality.

Future development trend of high purity quartz sand

With the depletion of high-quality crystal resources, the solution to the problem of insufficient self-sufficiency of high-end quartz sand in China is mainly focused on the improvement of geological prospecting, process mineralogy and mineral processing technologies.First of all, it is necessary to find the ore with relatively pure crystals, in-phase substitution of similar substances and less inclusions in gas liquid. Secondly, it is necessary to use modern advanced physical and chemical processing and purification technology and equipment to develop high-efficiency and stable high-purity quartz processing and purification technology.High purity quartz raw material sand has become a strategic product of national economy.

Efforts to seek the progress of China's high-purity quartz sand purification technology and industrial development, to achieve high-end (high-purity and ultra-high-purity) quartz sand self-sufficiency is an urgent need for the development of China's quartz glass industry, and is of great significance for the development of China's related high-tech industries.