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Method and equipment for efficiently purifying polysilicon powder by utilizing electron beams

A technology of polysilicon and electron beams, applied in chemical instruments and methods, silicon compounds, inorganic chemistry, etc., can solve problems such as uneven distribution of impurities, achieve rapid removal of impurities, achieve phosphorus and metal removal, and achieve the effect of simple methods

Inactive Publication Date: 2011-07-20
DALIAN LONGTIAN TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The known invention patent with the application number of 200810011631.8 uses induction heating and electron beams to achieve the purpose of removing phosphorus and metal impurities in polycrystalline silicon, but the disadvantage of this method is that bulk silicon material is smelted and purified, and the distribution of impurities is similar to that of powdered silicon material. relatively uneven

Method used

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  • Method and equipment for efficiently purifying polysilicon powder by utilizing electron beams
  • Method and equipment for efficiently purifying polysilicon powder by utilizing electron beams

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] A method for efficiently purifying polysilicon powder with electron beams. The carrier high-purity silicon material forms a high-purity silicon molten pool under electron beam heating, and then continuously adds silicon powder to be purified, and electron beams melt the silicon powder to quickly remove impurities in the silicon powder. Phosphorus, low-phosphorus silicon liquid overflows into the ingot pulling mechanism to pull the ingot to achieve the directional solidification effect. The steps are as follows:

[0020] The first step of material preparation: put the high-purity silicon material with low phosphorus and low metal into the smelting crucible with cooling at the bottom, open the powder loading cover 1 and add the high phosphorus and high metal silicon powder 24 to be purified into the powder loading bucket 25, Close the powder loading cover 1, close the vacuum cover 5;

[0021] The second step of pretreatment: vacuumize the vacuum chamber 3, and use vacuum ...

Embodiment 2

[0024] like figure 1 The described equipment for efficiently purifying polysilicon powder by electron beams comprises vacuum equipment consisting of a vacuum cover 5, a furnace wall 4 and a powder loading cover 1. The inner cavity of the vacuum equipment is a vacuum chamber 3; the upper part of the vacuum chamber is equipped with a powder loading bucket , the top of the powder loading barrel has a powder loading cover, the powder loading cover is located on the wall of the vacuum furnace, the bottom of the powder loading bucket has a discharge port, and the discharge port is equipped with an external drive powder baffle 22, an external drive powder baffle 22 It is an L-shaped powder baffle. One end of the powder baffle is rotated and installed in the rotating mechanism 23. The rotating mechanism 23 is installed outside the vacuum furnace wall. A melting crucible is installed at the bottom of the outlet of the powder loading barrel. The bottom of the crucible is fixed on the bo...

Embodiment 3

[0026]The equipment described in Example 2 is used to efficiently purify polysilicon powder with electron beams. The first step is to prepare materials: put high-purity silicon materials with a phosphorus content of 0.00004% and a total metal content of 0.0002% into a water-cooled copper crucible 17, low in phosphorus, The amount of low-metal high-purity silicon material is three-quarters of the height of the water-cooled copper crucible 17, and the powder baffle 22 is rotated to the bottom of the powder loading bucket 25 by the rotating mechanism 23 to block the bottom of the powder loading bucket 25 Tribe the powder hole, open the powder loading cover 1 and add high phosphorus and high metal silicon powder 24 in the powder loading bucket 25, the high phosphorus and high metal silicon powder 24 loading is slightly lower than the position on the upper edge of the powder loading bucket 25, close the loading Powder cover 1, close vacuum cover 5;

[0027] The second step of pretr...

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PUM

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Abstract

The invention belongs to the technical field of purifying polysilicon by using a physical metallurgy technology. The invention provides a method for efficiently purifying polysilicon powder by utilizing electron beams. The method comprises the following steps: 1. material preparation: putting low-phosphorous and low-metal highly pure silicon materials into a smelting crucible with a cooling function at the bottom and adding the high-phosphorous and high-metal silicon powder needing to be purified into a powder loading barrel; 2. pretreatment: vacuumizing a vacuum chamber; cooling the smelting crucible and an ingot pulling mechanism to 25-45 DEG C; and preheating an electron gun; and 3. purification: opening the electron gun to carry out smelting so as to remove the volatile impurity phosphorous; directionally solidifying the low-phosphorous liquid silicon obtained after smelting so as to ensure the metal impurities to be gathered on the upper part of a silicon ingot; and closing the electron gun, continuing vacuumizing for 15-30 minutes, opening an air escape valve for air escape, opening a vacuum cover, taking out the silicon ingot and cutting off the part, which contains more metal impurities, on the upper part of the silicon ingot. The method has the beneficial effects of simultaneously achieving the double effects of removing phosphorous from the silicon powder smelted by the electron beams and removing metals through directional solidification and achieving the purposes of efficiently smelting the silicon powder and rapidly removing the impurities.

Description

technical field [0001] The invention belongs to the technical field of purifying polysilicon by physical metallurgy technology, in particular relates to a method for removing phosphorus and metal impurities in polysilicon, and also relates to its equipment. Background technique [0002] In a society where energy is scarce and low-carbon environmental protection is advocated, solar energy, as an environmentally friendly new energy, has great application value. Solar cells can convert solar energy into electrical energy, and solar-grade polycrystalline silicon materials are important raw materials for solar cells. Therefore, the preparation technology of solar grade polysilicon material is particularly important. At present, the main technical routes for preparing solar-grade polysilicon materials worldwide include: improved Siemens method, silane method, and metallurgical method. The principle of the improved Siemens method is to use high-purity hydrogen to reduce high-puri...

Claims

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Application Information

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IPC IPC(8): C01B33/037
Inventor 谭毅姜大川战丽姝
Owner DALIAN LONGTIAN TECH