CN105271246A - Method for preparing chlorinated disilane by utilization of polysilicon byproducts - Google Patents

Abstract

The invention relates to a method for preparing chlorodisilane by using polysilicon by-products, which comprises the following steps: 1. Insulating high-boilers containing aluminum trichloride produced in the polysilicon production process to form crystals and separating the crystals ; 2. Add additives to the high boiler from which crystals have been removed in step 1 to form a mixed system; 3. Heat the temperature of the mixed system in step 2 to 30°C to 120°C and keep it warm to form a non-volatile aluminum Compound mixed system; 4. Distill the mixed system in step 3 under normal pressure or absolute pressure less than 0.2MPa to obtain mixed chlorodisilane without aluminum trichloride; 5. Mix the mixed chlorodisilane obtained in step 4 Disilane rectification yields single-component chlorodisilane. The present invention has the following effects: 1. Efficient removal of metal chlorides in high boilers; 2. The photochlorination method is selected to carry out chlorination in the liquid phase, which can make the process safer.

Description

A kind of method utilizing polysilicon by-product to prepare chlorodisilane

technical field

The invention belongs to the field of chemical industry and relates to a method for preparing chlorodisilane, in particular to a method for preparing chlorodisilane by using polysilicon by-products.

Background technique

Chlorodisilane, especially hexachlorodisilane, is an important silicon source material in the field of modern electronics manufacturing. For example, in the patent CN200480028369 of Tokyo Yili Technology Co., Ltd., silicon-containing films are deposited with hexachlorodisilane; SMIC Integrated Circuit Manufacturing (Beijing) Co., Ltd. used a mixed gas containing hexachlorodisilane as a silicon source in its patent CN200810113992; Canon Co., Ltd. used hexachlorodisilane as a raw material gas in its patent CN201210375335 to form by low-pressure chemical vapor deposition Silicon nitride film. With the rapid development of high-precision electronic devices, the demand for hexachlorodisilane in the electronics industry is increasing rapidly.

Regarding the manufacture of hexachlorodisilane, Mitsubishi Materials Polysilicon Co., Ltd. discloses a method for producing hexachlorodisilane in its patent CN01803007. The process condenses off-gases from furnaces that produce polysilicon with chlorosilanes and hydrogen to separate hydrogen, distills the resulting condensate to separate unreacted chlorosilanes and by-product silicon tetrachloride, and then distills further to recover hexachloro Disilane and disilicon tetrachloride. The purity of recovered hexachlorodisilane is much higher than that of conventional products produced from metal silicon. At the same time, chlorine gas is introduced in this process. The purpose of introducing chlorine gas is to make tetrachlorodisilane Disiliconization or conversion to hexachlorodisilane to increase the yield of hexachlorodisilane. This method actually uses a series of separation processes to recover traces of hexachlorodisilane in the mixed gas discharged from the polysilicon deposition furnace. Since the content of hexachlorodisilane in the mixed gas discharged from the polysilicon deposition furnace is extremely low, the process consumes a lot of energy High and inefficient. The advantage of this method is that the processed process does not contain metal impurities such as aluminum chloride, so that it is possible to purify hexachlorodisilane by rectification. The patent explains in its background of the invention that the hexachlorodisilane prepared by the existing method contains chlorides such as aluminum chloride and titanium chloride. The boiling point of aluminum chloride and titanium chloride is close to that of hexachlorodisilane, so it is usually difficult to Refining hexachlorodisilane by rectification. However, this patent uses metal chloride-free raw materials to prepare hexachlorodisilane, so it is feasible to use rectification to prepare hexachlorodisilane.

Japan's Denki Chemical Industry Co., Ltd. disclosed in its patent CN200980158582 the recovery method of hexachlorodisilane generated as a by-product when producing trichlorosilane from silicon tetrachloride and hydrogen. The process flow of the method is to make tetrachlorosilane React with hydrogen at a temperature ranging from 700 to 1400 ° C, and the gas generated by the reaction is cooled to a temperature range of 30 to 60 ° C to obtain a condensate containing hexachlorodisilane, which is then concentrated and recovered from the condensate containing hexachlorodisilane Process for high boilers of silanes. The method actually uses the mixed gas containing hexachlorodisilane which is excluded from the hydrogenation furnace for preparing trichlorosilane by thermal hydrogenation reduction of silicon tetrachloride as a raw material, and obtains hexachlorodisilane through a series of separation processes. Its essence and patent CN01803007 Consistently, the raw materials used also do not contain metal chlorides, so it can be easily realized by rectification.

Wacker Chemie AG disclosed in its patent CN200880108573 a method for preparing hexachlorodisilane by rectifying a mixture containing hexachlorodisilane. The industrial waste gas, that is, the raw materials used are produced by the polysilicon deposition process, which is consistent with all the raw materials in the patent CN01803007, that is, the raw materials do not contain metal chlorides.

The patent CN201310059040 of Tianjin University discloses a batch operation method and device for recovering and purifying hexachlorodisilane from chlorosilane raffinate. The method and device mainly include a primary fractionation tower and a batch rectification tower. The invention can recover and obtain hexachlorodisilane with a purity of more than 98%.

The by-products in the production process of polysilicon enterprises in my country are mainly silicon tetrachloride and chlorodisilane, as well as high-boilers containing metal chlorides such as aluminum chloride. The existing public information and our many years of practice have confirmed that the metal chlorides in the high boilers, especially the aluminum chloride, will form hard solid crystals on the inner wall of the separation equipment or on the surface contacting the chlorosilane medium, eventually making the The device fails. Therefore, the existing high-purity hexachlorodisilane preparation technology generally uses mixed chlorosilanes that do not contain metal impurities, especially aluminum trichloride impurities, as raw materials. One of the purposes of the present invention is to use the by-products of polysilicon manufacturers in my country that contain higher metal chlorides, especially high-boilers that contain higher aluminum chloride, as raw materials, and realize further utilization of high-boilers by removing aluminum trichloride .

Most of the prior art simply separates hexachlorodisilane from a mixture of chlorodisilanes by rectification. Patent CN01803007 simultaneously separates hexachlorodisilane and tetrachlorodisilane, and in the rectification process or in the rectification The yield of hexachlorodisilane is improved by introducing chlorine into the distillate raffinate.

Our research found that the high boilers produced by polysilicon manufacturers in my country contain chlorodisilanes such as hexachlorodisilane, pentachlorodisilane, tetrachlorodisilane, trichlorodisilane and dichlorodisilane. Hydrochlorodisilanes can be transformed into molecules containing more chlorine atoms by chlorination. However, existing knowledge tells us that the mixture of hydrochlorodisilane and gaseous oxidant will form an explosive reaction. Therefore, the behavior of introducing chlorine in the rectification process described in the patent CN01803007 is extremely dangerous. Special measures must be taken to eliminate the hazards of the chlorination process.

The present invention intends to provide a method for preparing chlorodisilane, which can overcome the deficiencies of the prior art, and separate aluminum trichloride from the high-boiler raffinate, and then chlorinate the hydrogen-containing Chlorodisilane is selectively chlorinated to obtain a desired chlorodisilane mixture, and the mixture is separated by existing rectification technology to obtain single-component chlorodisilane.

Contents of the invention

Purpose of the invention: the present invention makes improvements to the problems existing in the above-mentioned prior art, that is, the present invention discloses a method for preparing chlorodisilane by using polysilicon by-products.

Technical solution: a method for preparing chlorodisilane by polysilicon by-products, comprising the following steps:

(1) 100 parts of high boilers containing aluminum trichloride, which are by-produced in the polysilicon production process, are kept at -5°C to -50°C for 10 to 80 hours to form crystals, and the crystals are separated by precision filtration ;

(2) Add 0.01 to 0.1 parts of N'-[5-[[4-[[5-(acetylhydroxylamino)pentyl]ammonia]-1 ,4-Dioxybutyl]hydroxylamine]pentyl]-N-(5-aminopentyl)-N-hydroxysuccinamide (CAS No. 70-51-9) or add 0.01~0.1 parts of 1,2-dimethyl Base-3-hydroxy-4-pyridone (CAS No. 30652-11-0) or add 0.01 to 0.1 parts of 7-iodo-8-hydroxyquinoline-5-sulfonic acid (CAS No. 547-91-1) to form a mixture system;

(3) Heating to raise the temperature of the mixing system in step (2) to 30°C to 120°C, and keeping the temperature at 30°C to 120°C for 5 to 10 hours to form a mixing system containing non-volatile aluminum compounds;

(4), the mixed system in the step (3) is distilled under the situation of normal pressure or absolute pressure less than 0.2MPa to obtain 90～98 parts of mixed chlorodisilanes not containing aluminum trichloride;

(5) Rectifying the mixed chlorodisilane obtained in step (4) to obtain single-component chlorodisilane.

As a preferred solution of the method for preparing chlorodisilane by using polysilicon by-products in the present invention: the condition of precision filtration in step (1) is: the filtration precision of the precision filter used is 0.1-10 microns.

As a preferred version of the method for preparing chlorodisilane by polysilicon by-products in the present invention: the single-component chlorodisilane described in step (5) includes hexachlorodisilane, pentachlorodisilane, tetrachlorodisilane Disilane and Trichlorodisilane.

A method utilizing polysilicon by-products to prepare chlorodisilane, comprising the following steps:

(1) 100 parts of high boilers containing aluminum trichloride, which are by-produced in the polysilicon production process, are kept at -5°C to -50°C for 10 to 80 hours to form crystals, and the crystals are separated by precision filtration ;

(2) Add 0.01 to 0.1 parts of N'-[5-[[4-[[5-(acetylhydroxylamino)pentyl]ammonia]-1 ,4-Dioxybutyl]hydroxylamine]pentyl]-N-(5-aminopentyl)-N-hydroxysuccinamide (CAS No. 70-51-9) or add 0.01~0.1 parts of 1,2-dimethyl Base-3-hydroxy-4-pyridone (CAS No. 30652-11-0) or add 0.01 to 0.1 parts of 7-iodo-8-hydroxyquinoline-5-sulfonic acid (CAS No. 547-91-1) to form a mixture system;

(3) Heating to raise the temperature of the mixed system in step (2) to 30°C-120°C, and keeping it warm at 30°C-120°C for 5-10 hours to form a mixed system containing non-volatile aluminum compounds;

(4), the mixed system in the step (3) is distilled under the situation of normal pressure or absolute pressure less than 0.2MPa to obtain 90～98 parts of mixed chlorodisilanes not containing aluminum trichloride;

(5), the mixed chlorodisilane in the step (4) is chlorinated in a photochlorination reactor to obtain an intermediate product, and the conditions for chlorination are: chlorine gas is passed into the mixed chlorodisilane liquid phase, The quality of chlorine gas is not higher than 50% of the mixed chlorodisilane obtained in step (4), using 254nm light as the light source, and the reaction temperature is controlled at -10°C to 0°C;

(6) Rectifying the intermediate product obtained in step (5) to obtain single-component chlorodisilane.

As a preferred method for preparing chlorodisilane by polysilicon by-products in the present invention: the single-component chlorodisilane described in step (6) includes hexachlorodisilane, pentachlorodisilane, tetrachlorodisilane Disilane and Trichlorodisilane.

As a preferred solution of the method for preparing chlorodisilane by using polysilicon by-products in the present invention: the condition of precision filtration in step (1) is: the filtration precision of the precision filter used is 0.1-10 microns.

Beneficial effects: the invention discloses a method for preparing chlorodisilane by using polysilicon by-products, which has the following beneficial effects:

1. Efficiently remove metal chlorides represented by aluminum chloride in high boilers, which provides convenience for subsequent processes;

2. Use the photochlorination method to carry out chlorination in the liquid phase, which can make the process safer.

detailed description:

Specific embodiments of the present invention will be described in detail below.

Specific embodiment 1

A method utilizing polysilicon by-products to prepare chlorodisilane, comprising the following steps:

(1) 100 parts of the by-product high boilers containing aluminum trichloride in the polysilicon production process were kept at -5°C for 80 hours to form crystals, and the crystals were separated by precision filtration;

(2), add 0.01 part of N'-[5-[[4-[[5-(acetylhydroxylamino)pentyl]ammonia]-1,4 -Dioxybutyl]hydroxylamine]pentyl]-N-(5-aminopentyl)-N-hydroxysuccinamide (CAS No. 70-51-9) to form a mixed system;

(3), heating to raise the temperature of the mixing system in step (2) to 30° C., and keeping the temperature at 30° C. for 10 hours to form a mixing system containing non-volatile aluminum compounds;

(4), the mixed system in the step (3) is distilled under normal pressure to obtain 90 parts of mixed chlorodisilanes not containing aluminum trichloride;

(5) Rectifying the mixed chlorodisilane obtained in step (4) to obtain single-component chlorodisilane.

In this embodiment, the condition of precision filtration in step (1) is: the filtration precision of the precision filter used is 0.1 micron.

In this embodiment, the one-component chlorodisilane in step (5) includes hexachlorodisilane, pentachlorodisilane, tetrachlorodisilane and trichlorodisilane.

Specific embodiment 2

A method utilizing polysilicon by-products to prepare chlorodisilane, comprising the following steps:

(1) 100 parts of high boilers containing aluminum trichloride, which are by-produced in the polysilicon production process, are kept at -50°C for 10 hours to form crystals, and the crystals are separated by precision filtration;

(2) Add 0.1 part of 1,2-dimethyl-3-hydroxy-4-pyridone (CAS No. 30652-11-0) to the high boiler from which crystals have been removed in step (1) to form a mixed system ;

(3), heating to raise the temperature of the mixed system in step (2) to 120° C., and keeping the temperature at 120° C. for 5 hours to form a mixed system containing non-volatile aluminum compounds;

(4), the mixed system in step (3) is distilled under the situation of absolute pressure 0.2MPa to obtain 98 parts of mixed chlorodisilanes not containing aluminum trichloride;

(5) Rectifying the mixed chlorodisilane obtained in step (4) to obtain single-component chlorodisilane.

In the present embodiment, the condition of precision filtration in step (1) is: the filtration precision of the precision filter used is 10 microns.

In this embodiment, the one-component chlorodisilane in step (5) includes hexachlorodisilane, pentachlorodisilane, tetrachlorodisilane and trichlorodisilane.

Specific embodiment 3

A method utilizing polysilicon by-products to prepare chlorodisilane, comprising the following steps:

(1) 100 parts of high boilers containing aluminum trichloride, which are by-produced in the polysilicon production process, are kept at -25°C for 40 hours to form crystals, and the crystals are separated by precision filtration;

(2), adding 0.05 parts of 7-iodo-8-hydroxyquinoline-5-sulfonic acid (CAS No. 547-91-1) to the high boiler from which crystals have been removed in step (1) to form a mixed system;

(3), heating to raise the temperature of the mixed system in step (2) to 70° C., and keeping the temperature at 70° C. for 8 hours to form a mixed system containing non-volatile aluminum compounds;

(4), the mixed system in step (3) is distilled under the situation of 7 absolute pressure 0.1MPa to obtain 95 parts of mixed chlorodisilanes not containing aluminum trichloride;

(5) Rectifying the mixed chlorodisilane obtained in step (4) to obtain single-component chlorodisilane.

In the present embodiment, the condition of precision filtration in step (1) is: the filtration precision of the precision filter used is 5 microns.

In this embodiment, the one-component chlorodisilane in step (5) includes hexachlorodisilane, pentachlorodisilane, tetrachlorodisilane and trichlorodisilane.

Specific embodiment 4

A method utilizing polysilicon by-products to prepare chlorodisilane, comprising the following steps:

(1) 100 parts of the by-product high boilers containing aluminum trichloride in the polysilicon production process were kept at -5°C for 80 hours to form crystals, and the crystals were separated by precision filtration;

(2), add 0.01 part of N'-[5-[[4-[[5-(acetylhydroxylamino)pentyl]ammonia]-1,4 -Dioxybutyl]hydroxylamine]pentyl]-N-(5-aminopentyl)-N-hydroxysuccinamide (CAS No. 70-51-9) to form a mixed system;

(3), heating to raise the temperature of the mixed system in step (2) to 30°C, and keeping the temperature at 30°C for 10 hours to form a mixed system containing non-volatile aluminum compounds;

(4), the mixed system in step (3) is distilled under normal pressure to obtain 90 parts of mixed chlorodisilanes not containing aluminum trichloride;

(5), the mixed chlorodisilane in the step (4) is chlorinated in a photochlorination reactor to obtain an intermediate product, and the conditions for chlorination are: chlorine gas is passed into the mixed chlorodisilane liquid phase, The mass of chlorine gas is 40% of the mass of the mixed chlorodisilane obtained in step (4), using 254nm light as the light source, and the reaction temperature is controlled at -10°C;

(6) Rectifying the intermediate product obtained in step (5) to obtain single-component chlorodisilane.

In this embodiment, the one-component chlorodisilane in step (6) includes hexachlorodisilane, pentachlorodisilane, tetrachlorodisilane and trichlorodisilane.

In this embodiment, the condition of precision filtration in step (1) is: the filtration precision of the precision filter used is 0.1 micron.

Specific embodiment 5

A method utilizing polysilicon by-products to prepare chlorodisilane, comprising the following steps:

(1) 100 parts of high boilers containing aluminum trichloride, which are by-produced in the polysilicon production process, are kept at -50°C for 10 hours to form crystals, and the crystals are separated by precision filtration;

(2) Add 0.1 part of 1,2-dimethyl-3-hydroxy-4-pyridone (CAS No. 30652-11-0) to the high boiler from which crystals have been removed in step (1) to form a mixed system ;

(3), heating to raise the temperature of the mixed system in step (2) to 120° C., and keeping the temperature at 120° C. for 5 hours to form a mixed system containing non-volatile aluminum compounds;

(4), the mixed system in step (3) is distilled under the absolute pressure of 0.2MPa to obtain 98 parts of mixed chlorodisilanes not containing aluminum trichloride;

(5), the mixed chlorodisilane in the step (4) is chlorinated in a photochlorination reactor to obtain an intermediate product, and the conditions for chlorination are: chlorine gas is passed into the mixed chlorodisilane liquid phase, The quality of chlorine gas is 50% of the mass of the mixed chlorodisilane obtained in step (4), using 254nm light as the light source, and the reaction temperature is controlled at 0°C;

(6) Rectifying the intermediate product obtained in step (5) to obtain single-component chlorodisilane.

In this embodiment, the one-component chlorodisilane in step (6) includes hexachlorodisilane, pentachlorodisilane, tetrachlorodisilane and trichlorodisilane.

In the present embodiment, the condition of precision filtration in step (1) is: the filtration precision of the precision filter used is 10 microns.

Specific embodiment 6

A method utilizing polysilicon by-products to prepare chlorodisilane, comprising the following steps:

(1) 100 parts of the by-product high boilers containing aluminum trichloride in the polysilicon production process were kept at -30°C for 50 hours to form crystals, and the crystals were separated by precision filtration;

(2) Add 0.05 parts of 7-iodo-8-hydroxyquinoline-5-sulfonic acid (CAS No. 547-91-1) to the high boiler from which crystals have been removed in step (1) to form a mixed system;

(3), heating to raise the temperature of the mixed system in step (2) to 60° C., and keeping the temperature at 60° C. for 8 hours to form a mixed system containing non-volatile aluminum compounds;

(4), the mixed system in step (3) is distilled under the absolute pressure of 0.1MPa to obtain 95 parts of mixed chlorodisilanes not containing aluminum trichloride;

(5), the mixed chlorodisilane in the step (4) is chlorinated in a photochlorination reactor to obtain an intermediate product, and the conditions for chlorination are: chlorine gas is passed into the mixed chlorodisilane liquid phase, The mass of chlorine gas is 10% of the mass of the mixed chlorodisilane obtained in step (4), using 254nm light as the light source, and the reaction temperature is controlled at -5°C;

(6) Rectifying the intermediate product obtained in step (5) to obtain single-component chlorodisilane.

In this embodiment, the one-component chlorodisilane in step (6) includes hexachlorodisilane, pentachlorodisilane, tetrachlorodisilane and trichlorodisilane.

In the present embodiment, the condition of precision filtration in step (1) is: the filtration precision of the precision filter used is 5 microns.

Specific embodiment 7

The high boilers produced by the polysilicon factory, the content of aluminum trichloride is 0.5% according to ICP analysis; the composition analysis of gas chromatography is as follows, hexachlorodisilane 35%, pentachlorodisilane 20%, tetrachlorodisilane 30%, trichloroethyl Silane 10%, dichlorodisilane 5%.

2.1 kg of the high boiling matter was kept at -10°C for 80 hours, and the crystals were separated with a filter with a filtration accuracy of 10 microns. Add 2.05 g of 7-iodo-8-hydroxyquinoline-5-sulfonic acid to 2.05 kg of high boilers from which crystals have been removed, raise the temperature to 30° C., and keep at this temperature for 10 hours. Atmospheric distillation obtained 2kg of distillate (mixed chlorodisilane), which was detected by ICP with an aluminum content of 1.5ppbw. For the distillate, a 254nm ultraviolet lamp was used as a light source, and 0.9kg of chlorine gas was passed into the bottom of the photochlorination reactor, and the reaction temperature was maintained at 0°C. The reaction product obtained 2.5 kg of hexachlorodisilane, 0.5 kg of pentachlorodisilane and 0.12 kg of tetrachlorodisilane by rectification.

Specific embodiment 8

Using 2.1 kg of the raw material used in Example 1, the raw material was kept at -35° C. for 10 hours, and the crystals were separated with a filter having a filtration accuracy of 2 μm. 0.21 g of 1,2-dimethyl-3-hydroxy-4-pyridone was added to 2.06 kg of high boilers from which crystals were removed, the temperature was raised to 90° C., and the temperature was maintained at this temperature for 5 hours. Atmospheric distillation obtained 2kg of distillate (mixed chlorodisilane), which was detected by ICP with an aluminum content of 1.0ppbw. The distillate uses a 254nm ultraviolet lamp as the light source, and 0.5kg of chlorine gas is passed into the bottom of the photochlorination reactor, and the reaction temperature is maintained at -10°C. The reaction product was obtained by rectification to obtain 0.75 kg of hexachlorodisilane, 0.6 kg of pentachlorodisilane and 0.88 kg of tetrachlorodisilane.

Specific embodiment 9

Using 2.1 kg of the raw material used in Example 1, the raw material was kept at -45° C. for 12 hours, and the crystals were separated with a filter having a filtration accuracy of 0.1 μm. Add 1.1g N'-[5-[[4-[[5-(acetylhydroxylamino)pentyl]ammonia]-1,4-dioxobutyl]hydroxylamine] in 2.05kg of high boilers from which crystals have been removed Pentyl]-N-(5-aminopentyl)-N-hydroxysuccinamide, the temperature was raised to 60°C and kept at this temperature for 7 hours. Atmospheric distillation obtained 2kg of distillate (mixed chlorodisilane), which was detected by ICP with an aluminum content of 0.8ppbw. The distillate was not chlorinated, and directly distilled to obtain 0.62kg of hexachlorodisilane, 0.32kg of pentachlorodisilane, 0.55kg of tetrachlorodisilane, 0.18kg of trichlorodisilane, and dichlorodisilane was not collected as the front fraction .

The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above-mentioned embodiments, and various changes can be made within the scope of knowledge of those skilled in the art without departing from the gist of the present invention.

Claims (6)

1. utilize polysilicon by-product prepare chloro silicoethane a method, it is characterized in that, comprise the following steps:

(1) at-5 DEG C ~-50 DEG C, by the high boiling material containing aluminum chloride of by-product in 100 parts of polysilicon production process be incubated 10 ~ 80 hours formation crystallisates, isolate crystallisate by the mode of secondary filter;

(2), eliminate in the high boiling material of crystallisate in step (1) and add 0.01 ~ 0.1 part of N'-[5-[[4-[[5-(acetyl hydroxyl base) amyl group] ammonia]-1,4-bis-oxygen-butyl] azanol] amyl group]-N-(5-Aminopentyl)-N-hydroxysuccinimide or add 0.01 ~ 0.1 part of 1,2-Dimethyl-3-hydroxypyrid-4-one or add 0.01 ~ 0.1 part of 7-iodo-8-hydroxy-quinoline-5-sulfonic acid and form mixed system;

(3), heating makes the temperature of the mixed system in step (2) rise to 30 DEG C ~ 120 DEG C, and be incubated 5 ~ 10 hours at 30 DEG C ~ 120 DEG C, the mixed system of formation containing nonvolatile aluminum compound;

(4), the mixed system in step (3) is distilled when normal pressure or absolute pressure are less than 0.2MPa obtain 90 ~ 98 parts not containing the mixing chloro silicoethane of aluminum chloride;

(5) the mixing chloro silicoethane rectifying, step (4) obtained obtains the chloro silicoethane of single component.

2. as claimed in claim 1 a kind of utilize polysilicon by-product prepare chloro silicoethane method, it is characterized in that, the condition of secondary filter is in step (1): the filtering accuracy of accurate filter used is 0.1 ~ 10 micron.

3. as claimed in claim 1 a kind of utilize polysilicon by-product prepare chloro silicoethane method, it is characterized in that, the chloro silicoethane of step (5) described single component comprise disilicone hexachloride, pentachloro-silicoethane, four silicon hexachlorides and trichloroethyl silane.

4. utilize polysilicon by-product prepare chloro silicoethane a method, it is characterized in that, comprise the following steps:

(1) at-5 DEG C ~-50 DEG C, by the high boiling material containing aluminum chloride of by-product in 100 parts of polysilicon production process be incubated 10 ~ 80 hours formation crystallisates, isolate crystallisate by the mode of secondary filter;

(2), eliminate in the high boiling material of crystallisate in step (1) and add 0.01 ~ 0.1 part of N'-[5-[[4-[[5-(acetyl hydroxyl base) amyl group] ammonia]-1,4-bis-oxygen-butyl] azanol] amyl group]-N-(5-Aminopentyl)-N-hydroxysuccinimide or add 0.01 ~ 0.1 part of 1,2-Dimethyl-3-hydroxypyrid-4-one or add 0.01 ~ 0.1 part of 7-iodo-8-hydroxy-quinoline-5-sulfonic acid and form mixed system;

(3), heating makes the temperature of the mixed system in step (2) rise to 30 DEG C ~ 120 DEG C, and at 30 DEG C ~ 120 DEG C, is incubated the mixed system formed for 5 ~ 10 hours containing nonvolatile aluminum compound;

(4), the mixed system in step (3) is distilled when normal pressure or absolute pressure are less than 0.2MPa obtain 90 ~ 98 parts not containing the mixing chloro silicoethane of aluminum chloride;

(5), the mixing chloro silicoethane in step (4) is carried out chlorination in optical chlorinating reaction device and obtain intermediate product, the condition of chlorination is: chlorine is passed in mixing chloro silicoethane liquid phase, pass into quality of chlorine gas not higher than 50% of step (4) gained mixing chloro silicoethane quality, use 254nm light as light source, temperature of reaction controls at-10 DEG C ~ 0 DEG C;

(6), the intermediate product rectifying that step (5) obtains is obtained the chloro silicoethane of single component.

5. as claimed in claim 4 a kind of utilize polysilicon by-product prepare chloro silicoethane method, it is characterized in that, the chloro silicoethane of step (6) described single component comprise disilicone hexachloride, pentachloro-silicoethane, four silicon hexachlorides and trichloroethyl silane.

6. as claimed in claim 4 a kind of utilize polysilicon by-product prepare chloro silicoethane method, it is characterized in that, the condition of secondary filter is in step (1): the filtering accuracy of accurate filter used is 0.1 ~ 10 micron.