Production process of solar energy grade polysilicon

Abstract

The invention discloses a manufacturing method of solar grade polycrystalline silicon, which comprises the following steps: sintering graphite or carbon black or oil in the vacuum at 1500-2000 Deg C; purifying; adding the high-purity quartz and purified high-purity graphite or carbon black or oil with molar rate at 1: 2 in the reduced furnace; making silicon product with lower impurity; fusing the silicon in the vacuum; controlling temperature according to the fusing point of silicon; filtering to remove slag; removing carbon, silicon carbide and silica powder; pouring fused silicon in the mould; solidifying directionally to obtain 6N-grade solar grade polycrystalline silicon.

Description

technical field [0001] The invention relates to a production method of solar grade polysilicon. Background technique [0002] As the main raw material for the manufacture of integrated circuit substrates, solar cells and other products, polysilicon materials are an important cornerstone for the development of the information industry and new energy industries. There is a serious gap in the independent supply of polysilicon in my country, and more than 95% rely on imports. In recent years, the polysilicon market The skyrocketing price has endangered the normal operation of my country's polysilicon downstream industry, and has become a bottleneck restricting the development of my country's information industry and photovoltaic industry. [0003] The world's advanced polysilicon production technology has been monopolized by the United States, Japan, and Germany in the past. The product quality positioning of their production line technology is almost all electronic grade polysil...

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Problems solved by technology

But the key to this process is the preparation of high-purity silane. At present, there is no high-purity silane production process that has passed the customs in my country; moreover, silane is flammable and explosive, and the investment in its own production is very large. The raw materials are expensive to buy and difficult to transport, which is difficult for industrial production. bring some difficulties

[0008] The above polysilicon production methods all have problems such as large one-time investment, long construction period, low input-output rate, and high production cost.

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