CN-121988251-A - Chlorosilane purification device and method

CN121988251ACN 121988251 ACN121988251 ACN 121988251ACN-121988251-A

Abstract

The invention discloses a chlorosilane purification device and method, relates to the technical field of polysilicon production, and mainly aims to reduce the cost of chlorosilane purification and improve the impurity removal efficiency. The chlorosilane purifying device comprises a stirring tank, a filter, a buffer tank, a conveying pump and a siloxane separating tower which are sequentially connected, wherein a side collecting pipe, a complexing agent storage tank, a first feeding pump and the upper end of a reaction kettle of the siloxane separating tower are sequentially connected, the chlorosilane storage tank, a second feeding pump and the upper end of the reaction kettle are sequentially connected, the lower end of the reaction kettle is connected with a feed inlet of the first rectifying tower, the upper end of the first rectifying tower, a first cooler and a refined chlorosilane tank are sequentially connected, the lower end of the first rectifying tower is connected with a feed inlet of the second rectifying tower, and the upper end of the second rectifying tower, the second cooler and the complexing agent storage tank are sequentially connected.

Inventors

HE FEIFEI
MA WEICHUN
WANG ZHICHAO
Qiu Zhengke
HUANG WEI
DAI LU
LIU JINLIANG

Assignees

新疆大全新能源股份有限公司

Dates

Publication Date: 20260508
Application Date: 20260306

Claims (10)

1. A chlorosilane purifying device, characterized by comprising the following steps: The pretreatment part comprises a stirring tank, a filter, a buffer tank, a delivery pump and a siloxane separation tower which are connected in sequence; The reaction part comprises a complexing agent storage tank, a first feeding pump, a second feeding pump, a chlorosilane storage tank and a reaction kettle, wherein a side sampling pipe of the siloxane separation tower, the complexing agent storage tank, the first feeding pump and the upper end of the reaction kettle are sequentially connected, and the chlorosilane storage tank, the second feeding pump and the upper end of the reaction kettle are sequentially connected; The separation part comprises a first rectifying tower, a second rectifying tower, a first cooler, a refined chlorosilane tank and a second cooler, wherein the lower end of the reaction kettle is connected with a feed inlet of the first rectifying tower, the upper end of the first rectifying tower, the first cooler and the refined chlorosilane tank are sequentially connected, the lower end of the first rectifying tower is connected with the feed inlet of the second rectifying tower, and the upper end of the second rectifying tower, the second cooler and the complexing agent storage tank are sequentially connected.
2. The chlorosilane purification apparatus as claimed in claim 1, wherein, The middle part of the side wall of the stirring tank is connected with the inlet of the filter.
3. The chlorosilane purification apparatus as claimed in claim 1, wherein, Still include first flowmeter and second flowmeter, the export of first charge pump pass through first charging tube connect in reation kettle, first flowmeter install in first charging tube, the export of second charge pump pass through the second charging tube connect in reation kettle, the second flowmeter install in the second charging tube.
4. A chlorosilane purification apparatus as claimed in claim 3 wherein, The outlet of the first feed pump is connected to the upper end side of the siloxane separation column through a first return pipe.
5. The chlorosilane purification apparatus as claimed in claim 4, wherein, The device further comprises an output pump, wherein an inlet of the output pump is connected with the refined chlorosilane tank, an outlet of the output pump is connected with the rectifying unit through a discharging pipe, and an outlet of the output pump is connected with the upper end side of the first rectifying tower through a second return pipe.
6. The chlorosilane purification apparatus as claimed in claim 2, wherein, The lower extreme of agitator tank is connected in first row material pipe, first row material pipe installs first row material valve.
7. The chlorosilane purification apparatus as claimed in claim 1, wherein, The outlet of the second cooler is respectively connected with one end of a return pipe and a discharging pipe, the other end of the return pipe is connected with the complexing agent storage tank, the return pipe is provided with a first control valve, and the second discharging pipe is provided with a second control valve.
8. The chlorosilane purification apparatus as claimed in claim 2, wherein, The lower extreme of filter is connected to the second row material pipe, the second row material pipe is installed the second and is arranged the material valve.
9. A method for purifying chlorosilane, characterized by using the chlorosilane purification apparatus as claimed in claim 2, comprising the steps of: Adding high-boiling substances generated in the production process of polycrystalline silicon into the stirring tank, stopping stirring by the stirring tank when the liquid level of the stirring tank reaches the upper limit, and sequentially discharging supernatant materials into the filter and the buffer tank after standing for 3 to 5 hours, wherein the temperature in the buffer tank is controlled at 50 to 60 ℃; Step two, a conveying pump is started to convey the materials in the buffer tank to a siloxane separation tower, the pressure in the tower is 90-110 KPa, the temperature of the tower bottom is controlled to be 150-170 ℃, the temperature of the tower top is controlled to be 60-80 ℃, and a siloxane complexing agent in the siloxane separation tower reaches the complexing agent storage tank through a side mining pipe; Step three, starting the first feeding pump and the second feeding pump, conveying the siloxane complexing agent in the complexing agent storage tank and the chlorosilane containing impurities in the chlorosilane storage tank to the reaction kettle according to a specific mass ratio, controlling the temperature of materials in the reaction kettle to be 40-60 ℃, starting a stirrer of the reaction kettle, wherein the stirring speed is 150-250r/min, and the reaction time is 1-2h; Step four, materials after reaction in the reaction kettle enter the first rectifying tower, the pressure in the first rectifying tower is 70-90 KPa, the temperature of the tower bottom of the first rectifying tower is 70-90 ℃, the temperature of the tower top of the first rectifying tower is 50-75 ℃, the distillate at the tower top of the first rectifying tower enters the refined chlorosilane tank after being condensed by the first cooler, the liquid in the tower bottom of the first rectifying tower enters the second rectifying tower, the vacuum degree in the second rectifying tower is controlled to be-9-9.5 KPa, the temperature of the tower bottom of the second rectifying tower is 110-130 ℃, the temperature of the tower top of the second rectifying tower is 90-105 ℃, and the distillate at the tower top of the second rectifying tower returns to the complexing agent tank after being condensed by the second cooler.
10. The method for purifying chlorosilane as claimed in claim 9, wherein, In the third step, the mass ratio of the siloxane complexing agent to the impurity-containing chlorosilane is 1:5 to 1:20.

Description

Chlorosilane purification device and method Technical Field The invention relates to the technical field of polysilicon production, in particular to a chlorosilane purification device and method. Background Polysilicon is used as a core raw material in the photovoltaic, semiconductor industry, and its purity directly determines downstream product performance. The current mainstream polysilicon production process is an improved siemens method, which takes high-purity trichlorosilane as a raw material and generates polysilicon through reduction reaction. Along with the improvement of the efficiency of the photovoltaic component and the refinement of the manufacturing process of the semiconductor chip, the requirements on the impurity content in the polysilicon are more severe, and the impurities of boron (B) and phosphorus (P) are required to be controlled below ppb level. Trichlorosilane purification is a key link of polysilicon production, and the existing chlorosilane purification technology mainly comprises the following two types: (1) The conventional rectification technology generally adopts three-stage rectification of a light component removal tower-heavy component removal tower-refining tower or five-stage rectification flow of the light component removal tower-heavy component removal tower-light component removal tower-refining tower, and low-boiling impurities (such as PCl 3、BCl3) and high-boiling impurities (such as high-boiling chlorosilane) in the chlorosilane are removed by controlling parameters such as temperature, pressure and the like of each tower. Wherein the temperature of the top of the light component removing tower is controlled at 60-80 ℃, low-boiling components such as PCl 3、BCl3 and the like are removed, the temperature of the bottom of the heavy component removing tower is controlled at 80-100 ℃, high-boiling chlorosilane is removed, and the chlorosilane with the purity of more than 99.999% is finally obtained by further purification of a refining tower. However, the technology has limited effect on B, P impurity separation, and because BCl3 (boiling point 12.5 ℃) and trichlorosilane (boiling point 31.8 ℃) have close boiling points, the relative volatility is small, and the conventional rectification can only reduce B impurity to 20-50ppb, so that the requirement of electronic grade polysilicon is difficult to meet. The complex rectification technology is a core means of a complex method in the chlorosilane reaction purification process, and based on Lewis acid-base theory, electron donor impurities such as boron, phosphorus and the like in a system and a complexing agent (electron acceptor) form a high-boiling point complex, and the complex is subjected to rectification separation, so that the energy consumption is lower than that of simple rectification, and the separation effect is better. The complexing agent commonly used in the method comprises metal/alkaline earth metal compounds, amines containing N/P/O/S, heterocyclic compounds, ethers, benzene ring derivatives and the like, and part of the scheme can remove impurities to ppb level. However, the process has the defects of easiness in decomposition of the complexing agent, easiness in introduction of new impurities, insufficient continuity and the like, and the actual application needs to be optimized by combining other methods. Meanwhile, a large amount of high-boiling substances (accounting for 1% -5% of the yield of the polysilicon) are generated in the production process of the polysilicon, the main components comprise Si 2OCl6 (boiling point 138 ℃) and Si 2HOCL5 (boiling point 145 ℃) siloxane substances, the existing treatment mode generally adopts an atomization incineration-quenching-acid absorption process, the high-boiling substances are incinerated into products such as SiO 2 and HCl, the HCl is recycled after being absorbed, and SiO 2 is used as solid waste for treatment. The treatment mode not only wastes silicon resources in the high-boiling residues, but also consumes a large amount of fuel (such as natural gas), and the incineration process can produce pollutants such as dioxin, so that the environmental protection pressure is high. Disclosure of Invention In view of the above, the present invention provides a chlorosilane purification apparatus and method, which mainly aims to reduce the cost of chlorosilane purification and improve the impurity removal efficiency. In order to achieve the above purpose, the present invention mainly provides the following technical solutions: in one aspect, the invention provides a chlorosilane purification device, which comprises a pretreatment part, a reaction part and a separation part; The pretreatment part comprises a stirring tank, a filter, a buffer tank, a delivery pump and a siloxane separation tower which are connected in sequence; The reaction part comprises a complexing agent storage tank, a first feeding pump, a second feeding pump, a chlorosilane storage tank a