Quartz is a frame-like structure oxide mineral, which has the advantages of high hardness, stable chemical properties, and good heat insulation. Quartz is widely used in optical fiber transmission and photovoltaic fields due to its high refractive index. At the same time, quartz has light transmission , can be made into quartz glass, known as “the crown of glass materials”.
High-purity quartz is used in high-tech fields, such as the production of semiconductor crystalline silicon, which is made into silica crucibles to contain high-temperature silicon melts. The excellent performance and wide application of quartz make it stand out in the era of high-tech development. Quartz resource is not only one of the key basic raw materials in the photovoltaic power generation industry, but also an important strategic non-metallic mineral resource.
There are three different types of quartz sand in the photovoltaic industry chain. They are the raw material of silicon metal — silica, the raw material of quartz crucible in the rod link — high-purity quartz sand, and the raw material of photovoltaic glass — ultra-white stone quartz sand. Today, let’s take a look at the differences between these three photovoltaic raw materials.
Raw material of silicon metal — silica (SiO2≥99%)
Silica generally refers to the general name of vein quartz, quartzite, and quartz sandstone. Silica is usually used in large quantities as the main raw material for building materials, and is also an important raw material for building materials used in the inorganic salt industry. Silica generally refers to natural quartz sand with high purity, that is, silicon dioxide, which is widely distributed in nature and has considerable reserves. my country has large-scale high-quality mineral resources. Silica is mainly used for acidic refractory bricks for metallurgical industry.
The raw material of the quartz crucible—high-purity quartz sand (SiO2≥99.99%, the total impurity content is less than 25ppm)
High-purity quartz is a mineral product purified from crystal, vein quartz, granite pegmatite and other ores as raw materials. It is the material basis of high-end products in the silicon industry and is widely used in strategic emerging industries.
Global high-purity quartz raw material deposits are mainly distributed in Brazil, the United States, Canada, Norway, Australia, Russia, and China. According to the statistics of the US Geological Survey, as of the end of 2019, the global mineral resources of high-purity quartz raw materials are about 73 million tons, of which Brazil is the country with the largest resource volume in the world, with a resource volume of 21.11 million tons, and the ore type is mainly natural crystal; The United States is the country with the second largest resource volume, with a resource volume of 18.22 million tons, and the ore type is mainly granite pegmatite quartz. Canada ranks third in the world, with resources of 10 million tons, and the ore type is mainly vein quartz.
Photovoltaic glass raw material—ultra white quartz sand (SiO2≥99.30%, Fe2O3≤60ppm)
Photovoltaic glass is different from ordinary glass. It is made of ultra-clear glass through deep processing. Ultra-clear glass is a kind of ultra-transparent low-iron glass, also known as low-iron glass and high-transparency glass, which has the advantages of low self-explosion rate, consistent color, high visible light transmittance, good permeability, and low ultraviolet transmittance.
At present, the most widely used solar tempered glass is low-iron ultra-clear glass. Low-iron ultra-clear glass usually requires the main elements in quartz sand, SiO2≥99.30%, Fe2O3≤60ppm, etc. The quartz resources used to make solar photovoltaic glass are mostly quartzite and quartz sandstone. , Binhai quartz sand and other resources are obtained through mineral processing and purification.