Treatment process for residue slurry during polycrystalline silicon production

Abstract

The present invention relates to a treatment process for residue slurry during polycrystalline silicon production. Said treatment process comprises: carrying out solid-liquid separation on a solid-liquid mixed phase obtained after gas-liquid separation of residue slurry, so as to obtain a solid phase and a liquid phase; drying the solid phase, and performing acidic hydrolysis, filter pressing, drying and screening to obtain a solid phase containing silicon powder; reacting the solid phase containing silicon powder with hydrogen chloride, cooling same and recovering a cooled liquid phase; first performing light component removal on the liquid phase to recover trichlorosilane and silicon tetrachloride; then adding an auxiliary agent to the liquid phase obtained after the light component removal and reacting same; separating a liquid phase containing pentachlorodisilane, hexachlorodisilane, pentachlorodisiloxane and hexachlorodisiloxane; and subjecting the liquid phase obtained after the separation and hydrogen chloride to a cracking reaction, so as to generate trichlorosilane and silicon tetrachloride, and recovering same. The treatment process of the present invention can improve the material classified treatment capability and the amount of recovered materials of the residue slurry process.

Description

A treatment process of slag slurry in polysilicon production TECHNICAL FIELD

[0001] The present application belongs to the technical field of polysilicon, and particularly relates to a treatment process of slag slurry in polysilicon production. BACKGROUND

[0002] In the current polysilicon cold hydrogenation production process, a small amount of silicon powder is brought out by the fluidized bed, and is settled by washing in the post-system washing tower, so that a large amount of slag slurry containing high-boiling substances and silicon powder is discharged to the slag slurry treatment section. After gas-liquid separation, the gas phase is condensed and recovered, and the liquid phase is buffered in a receiving tank. After filtration and separation, the solid phase is hydrolyzed in an alkaline environment after drying, generating a large amount of acid gas, silicon dioxide, metal salt and sodium silicate, and the gas phase is neutralized and discharged after being washed with alkali.

[0003] Among them, after simple gas-solid-liquid three-phase separation, the solid phase and the liquid phase are dried by using a dryer, and by using the different boiling points of the material components, the light component liquid phase is recovered after heating, and a large amount of high-boiling (pentachloro, hexachloroethylsilane and ethylsiloxane) and metal chlorides are hydrolyzed. However, the slag slurry contains silicon powder, high-boiling substances (pentachloro, hexachloroethylsilane) and metal chlorides, the silicon powder has a certain recycling value, and the high-boiling substances (pentachloro, hexachloroethylsilane and ethylsiloxane) also contain a large amount of silicon and chlorine. After the part of the material is hydrolyzed and treated as waste, the system material consumption is high, the alkali consumption is high, and the production cost is high.

[0004] Therefore, the present application provides a new treatment process of slag slurry in polysilicon production, which can improve the material recycling rate of the slag slurry system. SUMMARY

[0005] The present application aims to provide a treatment process of slag slurry in polysilicon production, which can improve the material classification and processing capacity of the slag slurry process and the amount of material recycling.

[0006] In order to achieve the above-mentioned purpose, the technical scheme adopted is as follows:

[0007] A treatment process of slag slurry in polysilicon production, comprising the following steps:

[0008] After gas-liquid separation of the slag slurry, a solid-liquid mixed phase and a gas phase are obtained;

[0009] After solid-liquid separation of the solid-liquid mixed phase, a solid phase and a liquid phase are obtained;

[0010] The solid phase is dried, acid hydrolyzed, pressure filtered, dried, and sieved to obtain a solid phase containing silicon powder; the solid phase containing silicon powder is subjected to a synthesis reaction with hydrogen chloride, the gaseous phase after the reaction is cooled, and the liquid phase after cooling is recovered to a rectification system;

[0011] The liquid phase is first subjected to light component removal treatment to recover trichlorosilane and silicon tetrachloride; then, an auxiliary agent is added to the liquid phase after light component removal treatment, and a liquid phase containing pentachloroethysilane, hexachloroethysilane, pentachloroethyloxysilane, and hexachloroethyloxysilane is separated out; then, the separated liquid phase is subjected to a cracking reaction with hydrogen chloride to generate trichlorosilane and silicon tetrachloride, which are recovered, and the auxiliary agent that does not participate in the reaction is subjected to basic hydrolysis.

[0012] Further, the solid-liquid mixed phase is subjected to solid-liquid separation at a temperature lower than 15 DEG C.

[0013] Further, the solid-liquid mixed phase is subjected to solid-liquid separation at a temperature lower than 10 DEG C.

[0014] Further, the gaseous phase after cooling is recovered to a hydrogen system.

[0015] Further, the auxiliary agent is an organic ether or a chlorinated metal salt.

[0016] Further, the organic ether is at least one of 18-crown-6 ether and 15-crown-4 ether.

[0017] The chlorinated metal salt is sodium chloride, barium chloride, or potassium chloride.

[0018] Further, the catalyst for the cracking reaction is an amine salt or an amine salt resin.

[0019] Compared with the prior art, the present application has the following beneficial effects:

[0020] The slag slurry treatment process for polysilicon production can improve the slag slurry treatment capacity, and can recycle the gas, solid, and liquid in the slag slurry, recover the light components (trichlorosilane and silicon tetrachloride) in the liquid phase, crack the heavy components (pentachloroethysilane and hexachloroethysilane), and hydrolyze the components that cannot be cracked; the solid phase silicon powder is recovered, and then reacts with hydrogen chloride to produce trichlorosilane and silicon tetrachloride, which consumes hydrogen chloride, further reduces the material consumption in the polysilicon production process, and changes the hydrolysis of the solid phase silicon from an alkaline environment to an acidic environment, which can effectively reduce the amount of alkali liquor used, thereby reducing the production cost; the hydrolyzed waste slag is changed from solid waste to recyclable production raw materials, the waste liquid is fully recycled, the amount of solid waste and the treatment cost are reduced, and the production cost is further reduced. BRIEF DESCRIPTION OF DRAWINGS

[0021] Fig. 1 is a process flow diagram of the slag slurry treatment process for polysilicon production. DETAILED DESCRIPTION

[0022] In order to further illustrate the slag slurry treatment process in the production of polycrystalline silicon according to the present application, and achieve the intended purpose of the application, the slag slurry treatment process in the production of polycrystalline silicon according to the present application, its specific implementation, structure, features and functions are described in detail as follows. In the following description, different "an embodiment" or "embodiments" do not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0023] The slag slurry treatment process in the production of polycrystalline silicon according to the present application will be further described in detail below in conjunction with specific embodiments:

[0024] The technical solution of the present application can improve the material classification and processing capacity of the slag slurry process and the amount of material recycling. The gas, solid and liquid phases in the slag slurry system are all recycled, waste gas recovery, waste liquid recovery, waste liquid conversion, waste solid separation and utilization are achieved, the material recovery amount of the slag slurry process is improved, the alkali consumption of the slag slurry system is reduced, the amount of waste solid generated by the slag slurry system is reduced, and the cost is reduced through slurry treatment. The technical solution of the present application is:

[0025] A slag slurry treatment process in the production of polycrystalline silicon, comprising the following steps:

[0026] After the slag slurry is subjected to gas-liquid separation, a solid-liquid mixed phase and a gas phase are obtained;

[0027] The solid-liquid mixed phase is subjected to solid-liquid separation to obtain a solid phase and a liquid phase;

[0028] The solid phase is subjected to drying, acid hydrolysis, pressure filtration, drying and screening to obtain a solid phase containing silicon powder; the solid phase containing silicon powder is subjected to a synthesis reaction with hydrogen chloride, the gas phase after the reaction is cooled, and the liquid phase after cooling is recovered to a rectification system;

[0029] The liquid phase is first subjected to light removal treatment to recover trichlorosilane and silicon tetrachloride; then, an auxiliary agent is added to the liquid phase after light removal treatment, and a liquid phase containing pentachloroethyldisilane, hexachloroethyldisilane, pentachloroethyldisiloxane and hexachloroethyldisiloxane is separated out; thereafter, the separated liquid phase is subjected to a cracking reaction with hydrogen chloride to generate trichlorosilane and silicon tetrachloride, which are recovered, and the unreacted liquid phase is subjected to alkaline hydrolysis.

[0030] Preferably, the solid-liquid mixed phase is subjected to solid-liquid separation at a temperature lower than 15°C.

[0031] Further preferably, the solid-liquid mixed phase is subjected to solid-liquid separation at a temperature lower than 10°C.

[0032] The technical scheme limits the separation temperature of the solid-liquid mixture, so that a low-grade refrigerant can be selected and energy consumption is reduced.

[0033] Preferably, the cooled gas phase is recovered into a hydrogen system.

[0034] Preferably, the auxiliary agent is an organic ether or a chlorinated metal salt.

[0035] Further preferably, the organic ether is at least one of 18-crown-6 ether or 15-crown-4 ether.

[0036] The chlorinated metal salt is sodium chloride, barium chloride or potassium chloride.

[0037] Preferably, the catalyst for the cracking reaction is an amine salt or an amine salt resin.

[0038] Embodiment 1.

[0039] The present application re-establishes a slurry processing flow, the gas phase is recovered to a hydrogen system for recycling after condensation; the liquid phase is separated into light components and heavy components, the light components are recovered and treated, the heavy components are treated by removing metal ions, then are converted and cracked to obtain light components, which are recovered and treated by rectification, and unreacted components are treated by hydrolysis; the solid phase is hydrolyzed under certain conditions, then is filtered, the silicon residue is dried and recovered, and after screening, the silicon powder is obtained for use. The silicon powder is reacted with hydrogen chloride under certain conditions in a synthesis furnace to obtain trichlorosilane and silicon tetrachloride, the reaction gas phase is condensed and compressed, the liquid phase is recovered and purified in a rectification system for use, and the gas phase is compressed and returned to the cold hydrogen system for repeated use.

[0040] In combination with FIG. 1, the specific operation steps are as follows:

[0041] The residue slurry of the cold hydrogenation slurry is separated by a buffer tank, the gas phase is recovered to a hydrogen system for use. The solid-liquid mixture is separated by filtration under the condition that the temperature is not higher than 15℃, to obtain a solid phase and a liquid phase.

[0042] (1) Solid phase treatment

[0043] ① The solid phase is dried. A small amount of liquid phase in the solid phase is dried into a gas phase, which is treated as waste gas.

[0044] ② Acid hydrolysis: after drying, hydrolysis is performed under acidic conditions (hydrochloric acid).

[0045] In the prior art, the solid phase is generally subjected to alkaline hydrolysis. However, alkaline hydrolysis is prone to generate alkaline metal precipitates such as aluminum hydroxide and iron hydroxide, and silicon is also prone to react to generate sodium silicate dissolved in water, so that the impurity content of the solid phase recovered after hydrolysis is increased and the content of effective component silicon is reduced.

[0046] The acid hydrolysis is adopted in the present application, so that most of the metal salts need to be dissolved in water, and the reaction of elemental silicon with other substances is reduced. The silicon powder does not react with water under the acid condition, so the content of silicon in the solid-phase impurities can be effectively ensured. Meanwhile, a large amount of metal impurities react with water to generate metal salts and hydrogen chloride, and the discharge amount can be reduced, thereby reducing the production cost.

[0047] The hydrogen chloride is dissolved in water to form a hydrochloric acid solution system; the metal salt mainly exists in the form of chloride salt and can be dissolved in the hydrochloric acid solution system. After the hydrogen chloride is saturated, it is not dissolved in water, and the part of the hydrogen chloride gas not dissolved in water is eluted to the downstream section for further alkali elution. After the elution is qualified, the gas phase is vented.

[0048] ③Pressure filtration: the liquid phase rich in hydrochloric acid solution, chloride salt solution and silicon powder is subjected to pressure filtration through a pressure filter, and the silicon powder is in the form of silicon residue. The water after the pressure filtration is subjected to neutralization treatment and then reused.

[0049] ④Drying and screening: the silicon residue is dried to remove water, and part of the impurities in the silicon residue is discharged from the system through screening. The remaining residue contains about 70% of silicon. The rest is insoluble salt and part of silicon alloy.

[0050] ⑤Synthesis reaction, separation and cooling: the silicon powder after the screening is added to a synthesis furnace, and a synthesis reaction occurs again at about 300°C with the hydrogen chloride to generate trichlorosilane and silicon tetrachloride. The reaction gas phase is filtered and compressed and condensed, the liquid phase is recovered to a rectification system for purification and utilization, the unreacted gas phase and part of the byproduct hydrogen are recovered to a hydrogen system, and after multi-stage compression, they are returned to a hydrogen high-pressure system for repeated use of cold hydrogenation.

[0051] (2) Liquid phase treatment: the liquid phase after the solid-liquid separation is subjected to liquid phase treatment in a liquid phase treatment system. The liquid phase contains trichlorosilane, silicon tetrachloride, pentachloroethysilane, hexachloroethysilane, pentachloroethyloxysilane and hexachloroethyloxysilane. The treatment is as follows:

[0052] ①Light component removal: by taking advantage of the different boiling points of the components, the light components trichlorosilane and silicon tetrachloride are recovered and utilized through rectification. The condensed liquid phase is recovered to a cold hydrogenation treatment.

[0053] ②Metal impurity removal: the heavy components pentachloroethysilane, hexachloroethysilane, pentachloroethyloxysilane and hexachloroethyloxysilane are treated by adding an additive to remove metal impurities. The additive and the metal impurities can generate heavy component substances. After the removal of the metal impurities, the heavy components are treated by rectification again to remove the light components, so that the pentachloroethysilane, hexachloroethysilane, pentachloroethyloxysilane and hexachloroethyloxysilane are separated from the heavy components. The heavy component substances are subjected to residue discharge and alkaline hydrolysis treatment.

[0054] The additive for removing the metal impurities includes organic ether and chlorinated metal salt which can react with the chloride ion system.

[0055] The reaction mechanism of the organic ether: the most important property of crown ether is the ability to selectively complex metal ions. Under certain conditions, crown ether and some positively charged metal ions (such as alkali metals, alkaline earth lanthanide and actinide elements) and ammonium ions, etc. Form a certain stability of the host-guest complex. Whether the crown ether can complex with metal ions and the main factors affecting the stability of the complex are whether the diameter of the crown ether cavity is suitable for the diameter of the cation, and what type of bonding atoms in the crown ether.

[0056] The structure of the crown ether and metal ion complex is investigated according to the X-ray structure analysis of the crystalline complex. The results prove that:

[0057] 1) When the cation diameter and the crown ether ring cavity size match, the cation is located in the middle of the cavity, and the coordinated bonding atoms are equidistant from the cation, forming a 1:1 complex.

[0058] 2) When the crown ether cavity is smaller than the cation, it is found that the crown ether and the cation have a 2:1 or 3:2 complex, i.e. a 2:1 sandwich structure or a 3:2 double sandwich structure.

[0059] The diameters of the common crown ether cavities and the diameters of the alkali metal ions are shown in Table 1.

[0060] Table 1 Matching relationship between crown ether cavity diameter and alkali metal ion size

[0061]

[0062] The diameters of the common metal ions are shown in Table 2.

[0063] Table 2

[0064]

[0065] According to the above table, different ethers are selected to remove different metal ions; the metal ions removed in the present application are mainly iron ions, aluminum ions and calcium ions, and 18-crown-6 ether or 15-crown-4 ether can be selected according to the diameter of the crown ether cavity, or a 1:1 ratio of the two can be selected to remove metal ions. The specific addition ratio in the solution needs to be adjusted according to the reaction temperature and the composition of the material, according to the removal effect.

[0066] II Chlorinated metal salts that undergo complexation reactions in a chloride ion system:

[0067] Reaction mechanism: In the chlorosilane system, there are a large number of chloride ions, and part of the metal chloride salt reacts with the metal chloride in the liquid phase of the chlorosilane to form a coordination compound, i.e. the metal chloride salt and the metal impurities form a complex. The metal impurities to be removed are mainly iron, aluminum and calcium ions, which form a precipitated metal complex salt after the addition of part of the metal chloride salt. In this reaction system, iron, aluminum and calcium ions are central ions, and chloride ions act as ligands to form a coordination compound with the cations of the added metal chloride salt. The molar ratio of the added metal chloride salt to the metal chloride to be removed is 1:1, and the specific reaction mechanism is shown below (taking aluminum chloride as an example):

[0068] CL - +ALCL3——ALCL4 - That is, the chloride ion reacts with aluminum chloride to form tetrachloroaluminate ion.

[0069] To ensure the removal effect, the ratio of metal ions to metal salt in the chlorosilane solution is that the metal salt needs to be added in excess. Common metal chlorides include sodium chloride, barium chloride and potassium chloride.

[0070] ③ Cleavage conversion: hydrogen chloride is introduced into the liquid phase from which the heavy components are removed, and under the action of a catalyst, pentachloroethysilane and hexachloroethysilane are catalytically cracked into trichlorosilane and silicon tetrachloride. Part of the trichlorosilane and silicon tetrachloride are treated as light components and recovered by condensation for rectification treatment; pentachloroethysiloxane and hexachloroethysiloxane do not react with hydrogen chloride and are treated as heavy components and removed from the reaction system for alkaline hydrolysis treatment.

[0071] The catalyst for the cleavage reaction is an amine salt and a resin containing an amine salt functional group, which is a conventional catalyst in the art. The organic amine in the amine salt is n-tri-butyl tertiary amine, iso-tri-butyl tertiary amine, dimethyl aniline, aromatic tertiary amine, etc. The inorganic acid radical is sulfate ion. Various tertiary amines have different catalytic effects. The resin acts as a carrier and can achieve different effects when it is loaded with different functional groups. In this invention, the resin needs to be loaded with amine salt functional groups to achieve catalytic conversion effect.

[0072] Example 2.

[0073] The specific operation steps are as follows:

[0074] In combination with FIG. 1, the specific operation steps are as follows:

[0075] The residue slurry of the cold hydrogenation slurry is separated by a buffer tank for gas-liquid separation, and the gas phase is recovered to the hydrogen system for use. The solid-liquid mixed phase is intercepted by filtration under the condition that the temperature is not higher than 10℃, so as to realize solid-liquid separation and obtain solid phase and liquid phase.

[0076] (1) Solid phase treatment

[0077] ① Solid phase is subjected to drying treatment. After a small amount of liquid phase contained in the solid phase is dried into gas phase, waste gas treatment is performed.

[0078] ② Acid hydrolysis: after drying, hydrolysis is performed under acidic conditions (hydrochloric acid).

[0079] ③ Pressure filtration: after the liquid phase rich in hydrochloric acid solution, chloride salt solution and silicon powder is subjected to pressure filtration by a pressure filter, the silicon powder is in the form of silicon residue, and the water after pressure filtration is subjected to neutralization treatment and then is continuously used.

[0080] ④ Drying and screening: after the silicon residue is dried to remove water, part of the impurities inside the silicon residue is removed from the system through screening, and the remaining residue contains about 70% silicon. The rest is insoluble salt and part of silicon alloy.

[0081] ⑤ Synthesis reaction and separation cooling: the screened silicon powder is added into a synthesis furnace, and a synthesis reaction occurs again with hydrogen chloride at 300±20℃ to generate trichlorosilane and silicon tetrachloride. The reaction gas phase is compressed and condensed after filtration, the liquid phase is recovered to a rectification system for purification and utilization, the unreacted gas phase and part of the byproduct hydrogen are recovered to a hydrogen system, and after multi-stage compression, they are returned to a hydrogen high-pressure system for repeated use as cold hydrogen.

[0082] (2) Liquid phase treatment: the liquid phase after solid-liquid separation is sent to a liquid phase treatment system. The liquid phase contains trichlorosilane, silicon tetrachloride, pentachloroethysilane, hexachloroethysilane, pentachloroethyloxysilane and hexachloroethyloxysilane, and the treatment is as follows:

[0083] ① Removal of light components: by taking advantage of the different boiling points of the components, trichlorosilane and silicon tetrachloride are recovered and utilized first by rectification, and the condensed liquid phase is recovered to cold hydrogenation treatment.

[0084] ② Removal of metal impurities: the heavy components pentachloroethysilane, hexachloroethysilane, pentachloroethyloxysilane and hexachloroethyloxysilane are treated by adding an additive (18-crown-6 ether, 15-crown-4 ether, mass ratio 1:1) to remove metal impurities. The additive and the metal impurities can generate heavy component substances. After the removal of impurities, the heavy components are separated from the light components by rectification, and the heavy component substances are subjected to residue discharge and alkaline hydrolysis treatment.

[0085] ③ Cracking and conversion: hydrogen chloride is introduced into the liquid phase from which the heavy component substances have been removed, and under the action of a catalyst, pentachloroethysilane and hexachloroethysilane are catalytically cracked into trichlorosilane and silicon tetrachloride. The part of trichlorosilane and silicon tetrachloride are treated as light components, recovered by condensation and rectification treatment; pentachloroethyloxysilane and hexachloroethyloxysilane do not react with hydrogen chloride, and are treated as heavy components and subjected to alkaline hydrolysis treatment after being discharged from the reaction system.

[0086] The catalyst for the cracking reaction is a tertiary amine salt of n-tri-butylamine.

[0087] Example 3.

[0088] The operation steps of Example 3 are the same as those of Example 2, except that:

[0089] The auxiliary agent for removing metal impurities in the liquid phase treatment is a metal chloride salt, which is sodium chloride (the addition amount is 2.5 g / ml).

[0090] The catalyst for the cracking reaction is an amine salt of isobutyl tertiary amine.

[0091] Example 4.

[0092] The operation steps of Example 4 are the same as those of Example 2, except that:

[0093] The auxiliary agent for removing metal impurities in the liquid phase treatment is a metal chloride salt, which is potassium chloride (the addition amount is 1.25 g / ml).

[0094] The catalyst for the cracking reaction is an amine salt of nitrogen-nitrogen dimethyl aniline.

[0095] Example 5.

[0096] The operation steps of Example 5 are the same as those of Example 2, except that:

[0097] The auxiliary agent for removing metal impurities in the liquid phase treatment is a metal chloride salt, which is barium chloride (the addition amount is 0.625 g / ml).

[0098] The catalyst for the cracking reaction is an amine salt of aromatic tertiary amine.

[0099] The recovery effect of Examples 2-5 is determined. After using the process flow, the liquid phase recovery rate in the slag slurry system reaches more than 99%, among which the light components (trichlorosilane and silicon tetrachloride) in the liquid phase can reach 100% recovery, and the heavy components (pentachloroethysilane and hexachloroethysilane) can be cracked at 95%, and pentachloroethyloxysilane and hexachloroethyloxysilane can be effectively separated from the chlorosilane system; The recovery rate of the silicon powder in the slag slurry after pressure filtration recovery will reach 90%, and the remaining 10% of the silicon powder cannot be efficiently intercepted due to the small particle size, resulting in loss. The water content in 90% of the silicon powder is about 20-25%. After drying, about 75%-80% of the total silicon powder can be recovered and sieved. About 20% of the silicon powder in the sieving process is not suitable for use as raw material in the synthesis furnace due to the particle size screening problem. After sieving, about 55%-65% of the total silicon powder can be used as raw material in the synthesis furnace. The remaining silicon powder after drying can be treated as low-content silicon for sale.

[0100] The above is only the preferred embodiment of the present application, and does not limit the present application in any form. Any simple modification, equivalent change and modification of the above embodiment according to the technical essence of the present application are still within the scope of the technical solution of the present application.

Claims

1. A process for the treatment of slurry in polysilicon production, characterized in that, The method comprises the following steps: After gas-liquid separation of the slag slurry, a solid-liquid mixed phase and a gas phase are obtained; After solid-liquid separation of the solid-liquid mixed phase, a solid phase and a liquid phase are obtained; After drying, acid hydrolysis, pressure filtration, drying and sieving of the solid phase, a solid phase containing silicon powder is obtained; the solid phase containing silicon powder is subjected to a synthesis reaction with hydrogen chloride, the gas phase after the reaction is cooled, and the liquid phase after cooling is recovered to a rectification system; The liquid phase is first subjected to light removal treatment to recover trichlorosilane and silicon tetrachloride; then, an auxiliary agent is added to the liquid phase after light removal treatment, and a liquid phase containing pentachloroethysilane, hexachloroethysilane, pentachloroethyloxysilane and hexachloroethyloxysilane is separated out; then, the separated liquid phase is subjected to a cracking reaction with hydrogen chloride to generate and recover trichlorosilane and silicon tetrachloride, and the auxiliary agent that does not participate in the reaction is subjected to alkaline hydrolysis.

2. The treatment process according to claim 1, wherein The solid-liquid separation of the solid-liquid mixed phase is performed at a temperature lower than 15°C.

3. The treatment process according to claim 2, wherein The solid-liquid separation of the solid-liquid mixed phase is performed at a temperature lower than 10°C.

4. The treatment process according to claim 1, wherein The gas phase after cooling is recovered to a hydrogen system.

5. The treatment process according to claim 1, wherein The auxiliary agent is an organic ether or a chlorinated metal salt.

6. The treatment process according to claim 5, wherein The organic ether is at least one of 18-crown-6 ether and 15-crown-4 ether; and the chlorinated metal salt is sodium chloride, barium chloride or potassium chloride.

7. The treatment process according to claim 1, wherein The catalyst for the cracking reaction is an amine salt or an amine salt resin. ​

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