To understand the three types of quartz raw materials used in photovoltaics, first let's take a look at the panoramic view of the photovoltaic new energy industry chain?

Photovoltaic power generation plays an increasingly important role in the energy supply system, and the photovoltaic related industry has also become stronger. It has formed a complete industrial chain from high-purity silicon materials, silicon ingots/rods/wafers, battery cells/modules, photovoltaic auxiliary materials, photovoltaic production equipment to system integration and photovoltaic product applications. The photovoltaic industry chain includes links such as silicon materials, silicon wafers, battery cells, modules, and photovoltaic power plants. Specifically, the upstream of the photovoltaic industry chain includes the production of high-purity polycrystalline silicon materials, monocrystalline silicon and polycrystalline silicon, and silicon wafers; The midstream includes photovoltaic cells, photovoltaic modules, and inverter links; Downstream are photovoltaic power station application

Now let's talk in detail about the three types of quartz raw materials used in photovoltaic: upstream raw materials for solar polycrystalline silicon: industrial silicon, core raw materials for quartz crucibles: high-purity quartz sand, and raw materials for photovoltaic ultra white glass: low iron quartz sand.

Polycrystalline silicon is purified from industrial silicon. Industrial silicon, also known as metallic silicon, is produced by reducing silicon dioxide from crushed silica (quartz stone) and carbon reducing agents (mainly composed of clean coal, petroleum coke, charcoal, wood chips, etc.) in an electric furnace. Its silicon content is generally above 99%, and it is the upstream raw material of polycrystalline silicon. Silica is a general term for vein quartz, quartzite, quartz sandstone, etc. China has abundant reserves of silica resources, and quartz sand is a quartz particle formed by crushing and processing quartz minerals.

Crystal silicon products mainly include solar cells and chips, mainly used in the photovoltaic and semiconductor industries. From the perspective of production capacity and output, the global industrial silicon production capacity grew slowly from 2014 to 2021, with a global industrial silicon production capacity of 6.32 million as of 2021.

Quartz crucible is a container made of high-purity quartz, which is an indispensable and important supporting material in the photovoltaic industry. It is a necessary quartz container for the production of solar products such as single crystal and polycrystalline silicon, and is also the basic equipment for the semiconductor industry and silicon solar cells. Quartz crucibles can undergo crystallization, expansion, and mechanical stress rupture during use, making them consumable utensils. With the continuous expansion of China's production capacity of monocrystalline silicon, especially silicon ingots for solar energy, the demand for quartz crucibles is increasing day by day.

The mineral resources directly affect the product quality of high-purity quartz sand, and overseas quartz sand enterprises have few plans to expand production. Sibico in the United States and TQC in Norway basically rely on the Spruspin deposit in the United States. This deposit belongs to granite pegmatite (granite), which has advantages such as large reserves, low impurities, good bubble performance, and stable ore quality. However, the quartz content is low, and mining will be accompanied by a large number of other by-products. Considering the economic benefits of mining, overseas enterprises have a low willingness to expand production. Domestic enterprises such as Quartz Corporation use vein quartz ore sources from India and other regions, with slightly poor quality stability. There are still some differences in impurity content, stability, and other aspects compared to imported products. Currently, most domestic sand can only be used for the outer layer of crucibles, and only some products of Quartz Corporation can be used for the inner layer of crucibles.

The iron content in ultra-white glass is below 0.015%, and high-quality ultra-white glass for photovoltaic glass for clean energy solar-thermal power generation requires higher transmittance and lower requirements for iron content, which puts forward higher requirements for glass raw materials.

In the mix of ultra white glass, quartz sand generally accounts for over 60% by weight, which is the main factor affecting the size of glass iron content. Moreover, the high melting temperature of quartz sand determines the rate of glass melting and formation. For most glass production, Fe2O3 in various raw materials is a harmful component, and the lower the content, the better. However, some raw materials cannot meet the low iron requirements, such as feldspar and dolomite raw materials used in ordinary glass production. In order to reduce the iron content, maximum selection can be carried out. Therefore, it is very important to improve the grade of quartz sand and reduce the content of iron elements in the production process of quartz sand.