CN116062758A - A boron, phosphorus impurity adsorption device - Google Patents

Abstract

The present invention relates to a boron and phosphorus impurity adsorption device. The adsorption device comprises: a cylinder, a baffle is arranged inside the cylinder; a first filling chamber, a second filling chamber, the first filling chamber and the second The filling chambers are arranged in the cylinder and are respectively located at both ends of the baffle; wherein, the first filling chamber is filled with a first adsorbent for removing boron impurities, and the second filling chamber is filled with an adsorbent for removing phosphorus impurities. Secondary adsorbent for impurities. The boron and phosphorus impurity adsorption device of this technical solution is provided with a separated first filling cavity and a second filling cavity in the cylinder, and the first filling cavity and the second filling cavity are respectively filled with the first adsorbent for removing boron impurities, The second adsorbent for removing phosphorus impurities enables the device to adsorb and remove boron and phosphorus impurities in the gas at the same time, increasing the types of impurities removed by the device and making the device applicable to a wider range.

Description

A boron, phosphorus impurity adsorption device

technical field

The invention relates to the technical field of polysilicon, in particular to a boron and phosphorus impurity adsorption device.

Background technique

Chlorosilane is used as a raw material for the production of polysilicon. Before it enters the reduction furnace and reacts with hydrogen to produce polysilicon, it must undergo a strict purification process. The initial raw material chlorosilane contains many types and contents of impurities. . However, the purification of chlorosilane refined materials is mainly to remove the B and P compound impurities. For the boron and phosphorus impurities that are difficult to remove in chlorosilane refined materials, they mainly exist in various forms such as PCl ₃ , BCl ₃ , and PCl ₅ .

At present, most polysilicon production enterprises in China usually use rectification to remove impurities. The general process flow is primary fractionation-crude distillation-rectification and multi-column coupling to separate and purify trichlorosilane. Hydrogen silicon and tetrachlorosilane are basically separated, which can remove most of the impurities and bring them down to lower concentrations. In addition, some enterprises convert impurities into high boiling substances by adding organic matter (aromatic aldehydes, solid alkali, etc.) as rectification aids, and separate impurities in silicon tetrachloride through multi-stage rectification to achieve efficient removal such as copper, Iron, manganese and other metal impurities. However, the properties such as the boiling point of boron and phosphorus compound impurities are similar to those of silicon tetrachloride and SiHCl ₃ , the separation coefficient is small, the relative volatility with SiHCl ₃ is close to 1.0, and the boiling point of the chlorosilane system is very close, so it is difficult to pass simple rectification method to remove. Therefore, it is necessary to continue to use methods such as complex adsorption to remove impurities such as boron and phosphorus.

Chinese patent CN202110038842.6 discloses a method based on ultra-fine nitride conversion-purification of impurity boron in metallurgical silicon. The nitride powder with a particle size of nanometer is added to the silicon melt. Adsorption and nitriding treatment are carried out, and then the above-mentioned silicon melt after the reaction is subjected to electromagnetic purification treatment, and then the polycrystalline silicon rich in nitride particles obtained after electromagnetic purification is separated; the nitrides used are nano-scale powders with The excellent characteristics of relatively large area can effectively adsorb B impurities and realize the nitriding of B impurities to form nitride particles; electromagnetic purification can enrich nitride particles around the silicon melt, so as to realize the effective separation of nitride and silicon melt Separation, that is, the removal of boron impurities from silicon.

The above-mentioned patent involves the method of metallurgical boron impurity in silicon. This method realizes the removal of boron impurity in silicon by adsorbing B impurity and realizing the nitriding of B impurity, forming nitride particles and separating them. However, this method uses a single complex adsorbent to adsorb boron impurities, which can only achieve a single boron removal effect.

In addition, Chinese patent CN202111143137.9 discloses a low-pollution, high-purity electronic-grade polysilicon purification method. By installing a 4A molecular sieve adsorption column between the first rectification tower and the second rectification tower, most of the ethylene can be removed. At the same time, a small part of the unremoved ethylene is converted into ethyl silane, which is removed through the second rectification tower, which reduces the need for subsequent rectification towers, reduces production costs and energy consumption, and is subsequently filled by molecular sieve mixing and combination The adsorption column completely removes subsequent hydrides and organic macromolecules.

Similarly, the low-pollution, high-purity electronic-grade polysilicon purification method involved in the above-mentioned patent completely removes subsequent hydrides and organic macromolecular substances through molecular sieve mixing and packing adsorption columns. This method realizes hydrogen impurity adsorption through a single complexed adsorbent, which can only achieve a single impurity removal effect.

To sum up, at present, the existing complex adsorption is packed in a fixed bed device through a single complex adsorbent, so as to realize the adsorption of impurities, which can only achieve a single boron or phosphorus removal effect.

Contents of the invention

The purpose of the present invention is to propose a boron and phosphorus impurity adsorption device, aiming to solve the technical problem that the existing complex adsorption device can only remove boron impurities or phosphorus impurities alone, and the product has a single effect of removing impurities.

In order to achieve the above object, the present invention proposes a boron, phosphorus impurity adsorption device, comprising:

A cylinder, the cylinder is provided with a baffle;

A first filling cavity and a second filling cavity, the first filling cavity and the second filling cavity are arranged in the cylinder and are respectively located at both ends of the baffle; wherein,

The first filling chamber is filled with a first adsorbent for removing boron impurities, and the second filling chamber is filled with a second adsorbent for removing phosphorus impurities.

As a further improvement of the present invention: the first adsorbent includes a modified resin.

As a further improvement of the present invention: the modified resin is loaded with specific hydroxyl functional atomic groups capable of forming coordination compounds with boron impurity targets.

As a further improvement of the present invention: the modified resin uses 2-hydroxyethylamino-2,3-propanediol or iminodipropylene glycol as boron selective adsorption functional group, which is introduced into methacrylic acid Methyl ester or trimethylolpropane trimethacrylate to prepare boron-selective organic resins.

As a further improvement of the present invention: the active concentration of the modified resin is ≥3.3eq/L, and the load of the modified resin is 500kg/m ³ .

As a further improvement of the present invention: the first adsorbent includes one or more of activated carbon, silicate, oxide, molecular sieve, boron selective adsorption functional group loading, modified silica gel, and activated carbon.

As a further improvement of the present invention: the second adsorbent includes silica gel and active zeolite.

As a further improvement of the present invention: the volume ratio of the total capacity of the silica gel to the active zeolite ranges from 5:1 to 1:3.

As a further improvement of the present invention: the silica gel is loaded with CuCl ₂ metal salt.

As a further improvement of the present invention: the active zeolite adopts ZSM-5 type zeolite loaded with metal ions.

As a further improvement of the present invention: the cylinder is provided with an inlet and an outlet, the inlet is located at the end of the cylinder close to the first filling chamber, and the outlet is located at the end of the cylinder The other end of the body is close to the second filling cavity.

As a further improvement of the present invention: the barrel is connected with a plurality of filling conduits, and the plurality of filling conduits communicate with the first filling cavity and the second filling cavity respectively.

As a further improvement of the present invention: the barrel is connected with a measuring tube, and the measuring tube communicates with the first filling cavity and/or the second filling cavity.

As a further improvement of the present invention: the cylinder body is provided with lifting lugs, and the lifting lugs are connected to the outer surface of the cylinder body.

As a further improvement of the present invention: the baffle is provided with mesh holes for ventilation.

Compared with the prior art, the present invention has the following beneficial effects:

The boron and phosphorus impurity adsorption device of this technical solution is provided with a separated first filling cavity and a second filling cavity in the cylinder, and the first filling cavity and the second filling cavity are respectively filled with the first adsorbent for removing boron impurities, The second adsorbent for removing phosphorus impurities enables the device to adsorb and remove boron and phosphorus impurities in the gas at the same time, increasing the types of impurities removed by the device and making the device more applicable.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained according to the structures shown in these drawings without creative effort.

FIG. 1 is a schematic structural view of an embodiment of the boron and phosphorus impurity adsorption device of the present application.

Explanation of reference numbers:

The realization of the purpose of the present invention, functional characteristics and advantages will be further described in conjunction with the embodiments and with reference to the accompanying drawings.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

It should be noted that if there is a directional indication (such as up, down, left, right, front, back...) in the embodiment of the present invention, the directional indication is only used to explain the relationship between the components in a certain posture. If the specific posture changes, the directional indication will also change accordingly.

In addition, if there are descriptions involving "first", "second" and so on in the embodiments of the present invention, the descriptions of "first", "second" and so on are only for descriptive purposes, and should not be interpreted as indicating or implying Its relative importance or implicitly indicates the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include at least one of these features. In addition, if "and/or" or "and/or" appears throughout the text, its meaning includes three parallel plans, taking "A and/or B" as an example, including plan A, or plan B, or A and B is a solution that is satisfied at the same time. In addition, the technical solutions of the various embodiments can be combined with each other, but it must be based on the realization of those skilled in the art. When the combination of technical solutions is contradictory or cannot be realized, it should be considered that the combination of technical solutions does not exist , nor within the scope of protection required by the present invention.

At present, the existing complex adsorption is to pack a single complex adsorbent in a fixed bed device to achieve adsorption of impurities, which can only achieve a single boron or phosphorus removal effect.

The purpose of the present invention is to propose a boron and phosphorus impurity adsorption device, aiming to solve the technical problem that the existing complex adsorption device can only remove boron impurities or phosphorus impurities alone, and the product has a single effect of removing impurities.

Example 1

Please refer to Fig. 1, the boron, phosphorus impurity adsorption device of the present embodiment comprises:

A cylinder 1, the cylinder 1 is provided with a baffle 8;

The first filling cavity 21 and the second filling cavity 22, the first filling cavity 21 and the second filling cavity 22 are arranged in the cylinder body 1 and are respectively located at both ends of the baffle plate 8; wherein,

The first filling chamber 21 is filled with a first adsorbent for removing boron impurities, and the second filling chamber 22 is filled with a second adsorbent for removing phosphorus impurities.

Specifically, in this embodiment, the cylinder body 1 has a cylindrical structure, and the baffle plate 8 inside it is placed horizontally, and divides the cylinder body 1 into a first filling cavity 21 and a second filling cavity 22 . Since the first filling chamber 21 is filled with the first adsorbent for removing boron impurities, and the second filling chamber 22 is filled with the second adsorbent for removing phosphorus impurities, when the chlorosilane gas to be purified flows into the adsorption device, the chlorosilane The gas is in contact with the first adsorbent and the second adsorbent in the first filling chamber 21 and the second filling chamber 22 respectively, and a physical adsorption reaction occurs, and the boron and phosphorus impurities in the chlorosilane gas are adsorbed by the first adsorbent and the second adsorbent. Removal by adsorption.

The boron and phosphorus impurity adsorption device of this embodiment is provided with a separated first filling cavity 21 and a second filling cavity 22 in the cylinder body 1, and the first filling cavity 21 and the second filling cavity 22 are respectively filled with a material for removing boron impurities. The first adsorbent and the second adsorbent used to remove phosphorus impurities allow the device to simultaneously adsorb and remove boron and phosphorus impurities in chlorosilane gas, increasing the types of impurities removed by the device and making the device more applicable.

Further, in this embodiment, the cylinder body 1 is provided with a feed port 2 and a discharge port 3, and the feed port 2 is located at one end of the cylinder body 1 close to the first filling cavity 21, so The discharge port 3 is located at the other end of the barrel 1 close to the second filling cavity 22 . The barrel 1 is connected with a plurality of filling conduits 6 , and the plurality of filling conduits 6 communicate with the first filling cavity 21 and the second filling cavity 22 respectively. The cylinder body 1 is connected with a measuring tube 12 , and the measuring tube 12 communicates with the first filling cavity 21 and/or the second filling cavity 22 . The baffle plate 8 is provided with mesh holes for ventilation.

Specifically, the feed port 2 and the discharge port 3 provided on the cylinder body 1 are respectively used for introducing chlorosilane gas and discharging chlorosilane gas. A screen tube 4 is arranged on one side of the discharge port 3, and the screen tube 4 is used for filtering impurities in the chlorosilane gas. The discharge port 3 is located at one end of the cylinder body 1 close to the second filling chamber 22, and the feed port 2 is located at the other end of the cylinder body 1 close to the first filling chamber 21. Therefore, the chlorosilane gas flowing into the adsorption device first passes through the first filling chamber. Chamber 21, the chlorosilane gas first reacts with the first adsorbent to remove boron impurities; then, the chlorosilane gas flows through the baffle 8 and enters the second filling chamber 22 to react with the second adsorbent, thereby removing phosphorus in the chlorosilane gas Impurities, and finally chlorosilane gas are discharged out of the device through the outlet 3.

In addition, the cylinder body 1 is connected with a filling conduit 6, and the filling conduit 6 is provided with two pieces, which communicate with the first filling cavity 21 and the second filling cavity 22 respectively, and one end of the filling conduit 6 communicating with the first filling cavity 21 is provided with a The adsorbent addition port 9 of the first filling chamber is provided with an adsorbent addition port 10 of the second filling chamber at one end of the filler conduit communicating with the second filling chamber 22 . Therefore, the operator can fill the first adsorbent and the second adsorbent into the first filling cavity 21 and the second filling cavity 22 through the filling conduit 6 . The barrel 1 is also connected with a measuring tube 12 , which communicates with the first filling cavity 21 and the second filling cavity 22 , and the operator can measure the air pressure and temperature inside the barrel 1 through the measuring tube 12 . The bottom of the cylinder body 1 is also provided with a discharge pipe 11 for discharging the adsorbent, and a discharge pipe valve 7 for switching is arranged in the discharge pipe 11 .

In addition, the cylinder 1 is provided with lifting lugs 5, which are connected to the outer surface of the cylinder 1, and external equipment can be connected to the lifting lugs 5 to drive the adsorption device to move; The sieve hole and the baffle plate 8 can isolate the adsorbents in the first filling chamber 21 and the second filling chamber 22, but do not hinder the passage of chlorosilane gas.

Further, in this embodiment, the first adsorbent includes a modified resin.

Specifically, the modified resin is used to adsorb boron impurities, and the modified resin is loaded with specific hydroxyl functional atomic groups that can form coordination compounds with boron impurity targets. In this example, the modified resin uses 2-hydroxyethylamino-2,3-propanediol or iminodipropylene glycol as boron selective adsorption functional groups, which are introduced into methyl methacrylate or Preparation of boron-selective organic resins on trimethylolpropane trimethacrylate. The active concentration of the modified resin is ≥3.3eq/L, and the load of the modified resin is 500kg/m ³ .

It is worth noting that, in other embodiments, the first adsorbent also includes one or more of activated carbon, silicate, oxide, molecular sieve, boron selective adsorption functional group loading, modified silica gel, activated carbon . The aforementioned components can all adsorb and remove boron impurities, so they can all be filled into the first filling chamber 21 as the first adsorbent.

Further, in this embodiment, the second adsorbent includes silica gel and active zeolite. The volume ratio of the total capacity of the silica gel to the active zeolite ranges from 5:1 to 1:3. In this embodiment, the volume ratio range of the total volume of silica gel to active zeolite is 2:1. Wherein, the silica gel supports a metal salt with a strong ability to complex phosphorus, and in this embodiment, the metal salt is _CuCl2 metal salt. The active zeolite adopts ZSM-5 type zeolite supported by metal ions, which can effectively selectively adsorb phosphine (PH3) in silane tail gas impurities.

It should be noted that, in other embodiments, the second adsorbent further includes one or more of activated carbon, silicate, oxide, and molecular sieve. All the above-mentioned components can adsorb and remove phosphorus impurities, so all the above-mentioned components can be filled into the second filling chamber 22 as the second adsorbent.

In the actual application scene of the boron and phosphorus impurity adsorption device in this embodiment, the working steps are as follows:

Pass a stream of chlorosilane gas with a boron impurity content of about 8ppbw and a phosphorus impurity content of about 20ppbw into the boron and phosphorus impurity adsorption device at a flow rate of 40kg/min;

(1) The first filling chamber 21 mainly adsorbing boron is filled with methyl methacrylate resin loaded with 2-hydroxyethylamino-2,3-propanediol. The mechanism is that functional atoms on the resin undergo a coordination reaction with target B ions to form a stable structure similar to small molecules, thereby removing boron impurities in chlorosilane gas;

(2) The second filling chamber 22 based on adsorption of phosphorus is filled with CuCl ₂ metal salt-loaded silica gel, and metal-loaded Al ₂ 0 ₃ adsorbent (activated zeolite), wherein the silica gel and the adsorbent of activated aluminum sesquioxide The filling and mixing of the silica gel and the active zeolite total capacity volume ratio range is 2:1. Among them, silica gel rich in hydroxyl groups on the surface can not only effectively re-adsorb boron (Si-OH+BCl ₃ →Si-OBCl ₂ +HCl), but also support CuCl ₂ metal salt with strong phosphorus complexing ability (mass fraction 1%), which can greatly increase the adsorption of phosphorus impurities; and the modified Al ₂ 0 ₃ is specifically the Al ₂ 0 ₃ supported by metal Pt and Cu ions, so that the physical adsorption of the original Al ₂ 0 ₃ on PH ₃ is transformed into a chemical Adsorption (3CuO+2PH ₃ →Cu ₃ P ₂ +3H ₂ O) can effectively selectively adsorb P impurities such as phosphine (PH ₃ ) in silane tail gas impurities.

(3) The purified chlorosilane gas passes through the impurity evaluation device to evaluate the impurity content. The average content of boron in TCS is ≤1ppbw, and the average content of phosphorus is ≤3ppbw.

Comparative example 1

Different from Example 1, this comparative example changes the adsorbent in step (2), does not fill the phosphorus adsorbent, and the first filling chamber 21 and the second filling chamber 22 procedures are all equipped with the same load 2-hydroxyethylamine The methyl methacrylate resin based on 2,3-propanediol was not filled with other adsorbents, and the rest of the steps and parameters were the same.

The purified chlorosilane gas passes through the impurity evaluation device to evaluate the impurity content. In the obtained TCS, the boron content is ≤1.2ppbw, and the phosphorus content is ≤5.2ppbw.

It can be seen that in the absence of phosphorus adsorbents: silica gel supported by CuCl ₂ metal salts, and Al ₂ 0 ₃ adsorbent (activated zeolite) supported by metals, the phosphorus impurities in chlorosilane gas have not been filtered and purified.

Comparative example 2

The difference from Example 1 is that in this comparative example, the phosphorus adsorbent in step (2) is changed to silica gel without metal salt and Al ₂ 0 ₃ without metal, and the rest of the steps and parameters are the same.

The purified chlorosilane gas was evaluated by the impurity evaluation device for impurity content. In the obtained TCS, the boron content was 1.7 ppbw, and the phosphorus content was 6.6 ppbw.

It can be seen that silica _gel without _{CuCl2 metal} salt, phosphorus adsorbent without metal-loaded _Al203 adsorbent, phosphorus adsorption of metal- _{loaded Al203} adsorbent relative to silica gel loaded with CuCl2 metal salt The performance of phosphorus absorption and phosphorus filtration of the former is even worse, and the phosphorus impurities in the chlorosilane gas have not been filtered and purified.

Comparative example 3

The difference from Example 1 is that in this comparative example, in step (2), the order in which trichlorosilane enters the integrated device is first passed through the second filling chamber 22 mainly adsorbing P, and then through the second filling chamber 22 mainly adsorbing B. The first filling cavity 21, the rest of the steps and parameters are the same.

The purified chlorosilane gas is evaluated by the impurity evaluation device for impurity content. In the obtained TCS, the boron content is 0.8 ppbw, and the phosphorus content is 2.2 ppbw.

It can be seen that even if the order of adsorption P and adsorption B is reversed, the boron and phosphorus impurity adsorption device can maintain good adsorption and filtration performance, and the phosphorus impurities and boron impurities in the chlorosilane gas can be filtered and purified.

In summary, the boron and phosphorus impurity adsorption device of this technical solution is provided with separated first filling chamber 21 and second filling chamber 22 in the cylinder body 1, and the first filling chamber 21 and the second filling chamber 22 are filled with useful The first adsorbent for removing boron impurities and the second adsorbent for removing phosphorus impurities make this device can simultaneously adsorb and remove boron and phosphorus impurities in chlorosilane gas, and can give full play to the biggest advantages of the adsorption complexing agents. Avoid the short board of the impurity removal effect of an adsorbent; in addition, this device greatly simplifies the subsequent repeated purification process of tail gas chlorosilane, effectively reduces the energy consumption required to remove impurities, and improves the economy of the entire production process and efficiency.

The above descriptions are only optional embodiments of the present invention, and do not limit the patent scope of the present invention. Under the inventive concept of the present invention, the equivalent structural transformation made by using the description of the present invention and the contents of the accompanying drawings, or direct/indirect Application in other related technical fields is included in the patent protection scope of the present invention.

Claims (10)

1. A boron and phosphorus impurity adsorbing device, comprising:

the cylinder body is internally provided with a baffle;

the first filling cavity and the second filling cavity are arranged in the cylinder body and are respectively positioned at two ends of the baffle plate; wherein,,

the first filling cavity is filled with a first adsorbent for removing boron impurities, and the second filling cavity is filled with a second adsorbent for removing phosphorus impurities.

2. The boron, phosphorus impurity adsorbing device according to claim 1, wherein said first adsorbent comprises a modified resin carrying a group of specific hydroxyl functional atoms capable of forming a complex with the boron impurity target.

3. The boron and phosphorus impurity adsorbing device according to claim 2, wherein the modified resin is prepared by introducing 2-hydroxyethylamino-2, 3-propanediol or iminodipropyleneglycol as a boron selective adsorption functional group onto methyl methacrylate or trimethylolpropane trimethacrylate.

4. The boron and phosphorus impurity adsorbing device according to claim 2, wherein the active concentration of the modified resin is not less than 3.3eq/L, and the load of the modified resin is 500kg/m ³ 。

5. The boron and phosphorus impurity adsorbing device according to claim 1, wherein said first adsorbent comprises one or more of activated carbon, silicate, oxide, molecular sieve, boron selective adsorption functional group loading, modified silica gel, activated carbon.

6. The boron, phosphorus impurity adsorbing device according to claim 1, wherein said second adsorbent comprises silica gel and active zeolite.

7. The boron, phosphorus impurity adsorbing device according to claim 6, wherein the total volume ratio of silica gel to active zeolite is in the range of 5:1-1:3.

8. the boron and phosphorus impurity adsorbing device according to claim 6, wherein said silica gel is loaded with CuCl ₂ A metal salt.

9. The boron and phosphorus impurity adsorbing device according to claim 6, wherein said active zeolite is a metal ion-supported ZSM-5 type zeolite.

10. The boron and phosphorus impurity adsorbing device according to claim 1, wherein the cylinder is provided with a feed inlet and a discharge outlet, the feed inlet is positioned at one end of the cylinder close to the first filling cavity, and the discharge outlet is positioned at the other end of the cylinder close to the second filling cavity.

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