KR20140006835A - Methods and systems for producing silane - Google Patents

Abstract

Described are methods and systems for the production of silanes using electrolysis to regenerate reactive components. The method and system may be substantially closed loop for halogen, alkali metal or alkaline earth metal and / or hydrogen.

Description

METHODS AND SYSTEMS FOR PRODUCING SILANE

FIELD OF THE INVENTION The field of the present disclosure relates to methods of making silanes, particularly those involving the use of electrolysis to regenerate reactive components. Some specific embodiments relate to a method wherein the preparation of the silane is substantially "closed-loop" to halogen and / or alkali or alkaline earth metals.

Silanes are multipurpose compounds with numerous industrial uses. In the semiconductor industry, silanes can be used for the deposition of epitaxial silicon layers on semiconductor wafers and for the production of polycrystalline silicon. Polycrystalline silicon is an essential raw material used in the manufacture of various commodities including, for example, integrated circuits and photovoltaic cells (i.e. solar cells), which can be produced by pyrolysis into silicon particles of silane in a fluidized bed reactor. to be.

Silanes are incorporated into the reaction of silicon tetrafluoride with alkali or alkaline earth metal aluminum hydrides, such as sodium aluminum tetrahydride, as disclosed in US Pat. No. 4,632,816, which is incorporated herein by reference for all relevant and consistent purposes. It can manufacture. The method is characterized by high energy efficiency; Starting material costs can adversely affect the economy of these systems.

Alternatively, silanes are incorporated herein by Mueller et al. For all relevant and consistent purposes. in "Development and Economic Evaluation of a Reactive Distillation Process for Silane Production," Distillation and Adsorption: Integrated Processes, 2002, the so-called "metallurgical silicon reacts with hydrogen and silicon tetrachloride to produce trichlorosilane. Union Carbide Process ". Trichlorosilane is subsequently subjected to a series of disproportionation and distillation steps to produce the silane final product. The method requires not only initial plant costs, but also a large number of large recycle streams that increase operating costs.

Therefore, there is a continuing need for methods that are closed loops for economical methods for producing silanes and for certain materials used in the production methods. There is also a need for a system for performing such a method that includes a substantially closed loop system.

One aspect of the disclosure relates to a method of making silane from an alkali metal or alkaline earth metal halide salt source. The method includes the alkali metal or alkaline earth metal halide salt being electrolyzed to produce metallic alkali or alkaline earth metal and halogen gas. Metallic alkali or alkaline earth metals are contacted with hydrogen to produce alkali or alkaline earth metal hydrides. Halogenated silicon feed gas containing at least one halosilane selected from the group consisting of silicon tetrahalides, trihalosilanes, dihalosilanes and monohalosilanes produces halogen gases and (1) silicon tetrahalides. And (2) at least one contact of hydrogen to produce hydrogen halide, where the hydrogen halide is further contacted with silicon to produce a mixture containing silicon tetrahalide and trihalosilane. The halogenated feed gas is contacted with an alkali metal or alkaline earth metal hydride to produce silane and alkali metal or alkaline earth metal hydride salts.

Another aspect of the disclosure relates to a method of making silane in a substantially closed loop system for alkali metals or alkaline earth metals. The halogenated silicon feed gas is contacted with an alkali metal or alkaline earth metal hydride to produce silane and alkali metal or alkaline earth metal halide salts. Halide salts are electrolyzed to produce metallic alkali or alkaline earth metals and halogen gases. Metallic alkali or alkaline earth metals are contacted with hydrogen to produce alkali or alkaline earth metal hydrides. Alkali or alkaline earth metal hydrides produced by the contact of metallic alkali or alkaline earth metals and hydrogen are contacted with the halogenated silicon feed gas to produce silane and alkali or alkaline earth metal halide salts.

Another aspect of the disclosure relates to a method of making silane in a substantially closed loop system for halogen. Halogenated silicon feed gases containing one or more halosilanes selected from the group consisting of silicon tetrahalides, trihalosilanes, dihalosilanes and monohalosilanes are contacted with alkali metal or alkaline earth metal hydrides to give silane and alkali Produces metal or alkaline earth metal halide salts. Halide salts are electrolyzed to produce metallic alkali or alkaline earth metals and halogen gases. Halogenated silicon feed gas containing at least one halosilane selected from the group consisting of silicon tetrahalides, trihalosilanes, dihalosilanes and monohalosilanes produces halogen gases and (1) silicon tetrahalides. And (2) at least one contact of hydrogen to produce hydrogen halide, where the hydrogen halide is further contacted with silicon to produce a mixture comprising silicon tetrahalide and trihalosilane. The halogenated silicon feed gas is contacted with an alkali metal or alkaline earth metal hydride to produce silane and alkali metal or alkaline earth metal halide salts.

In another aspect of the present disclosure, a method for making a closed loop of polycrystalline silicon is halogenated containing at least one halosilane selected from the group consisting of silicon tetrahalide, trihalosilane, dihalosilane and monohalosilane. The silicon feed gas is contacted with an alkali metal or alkaline earth metal hydride to produce silane and an alkali metal or alkaline earth metal halide salt. Silanes are pyrolyzed to produce polycrystalline silicon and hydrogen. Halide salts are electrolyzed to produce metallic alkali or alkaline earth metals and halogen gases. Halogenated silicon feed gas containing at least one halosilane selected from the group consisting of silicon tetrahalides, trihalosilanes, dihalosilanes and monohalosilanes is produced by the electrolysis of alkali or alkaline earth metal halides. Produced by contact of at least one of halogen gas with (1) silicon to produce silicon tetrahalide and (2) hydrogen to produce hydrogen halide, wherein the hydrogen halide is further contacted with silicon to form silicon tetrahalide and trihalo A mixture containing silane is produced. Metallic alkali or alkaline earth metals are contacted with hydrogen generated from pyrolysis of silanes to produce alkali or alkaline earth metal hydrides. The halogenated silicon feed gas produced by the contact of halogen gas or hydrogen halide with silicon is brought into contact with the alkali metal or alkaline earth metal hydride produced by the contact of metallic alkali metal or alkaline earth metal with hydrogen to form silane and alkali metal or alkali. Produces earth metal halide salts.

In another aspect of the present disclosure, a system for producing silanes in a substantially closed loop method includes a vessel wherein an alkali metal or alkaline earth metal halide salt is electrolyzed to produce metallic alkali metal or alkaline earth metal and halogen gas. The system comprises (1) silicon tetrahalide and (2) by reaction of at least one of silicon with (1) halogen gas released from the vessel and (2) hydrogen halide generated by contact of hydrogen with halogen gas emitted from the vessel. ) Halogenated reactors producing at least one of trihalosilanes. The system includes a hydride reactor in which hydrogen reacts with a metallic alkali or alkaline earth metal released from the vessel to produce an alkali or alkaline earth metal hydride. The system includes a silane reactor in which at least one of (1) silicon tetrahalide and (2) trihalosilane reacts with an alkali metal or alkaline earth metal hydride to produce silane and alkali metal or alkaline earth metal halide salts.

The specified features in connection with the above-mentioned aspects of the present disclosure are variously improved. Additional features can also be included in the aforementioned aspects of the disclosure. These improvements and additional features may be present individually or in any combination. For example, various features discussed below in connection with any of the illustrated embodiments of the present disclosure may be included alone or in any combination in any of the aspects described above of the present disclosure.

1 is a schematic diagram of a silane preparation system comprising electrolysis of a halide salt, in accordance with an embodiment of the present disclosure;
2 is a cross-sectional view of a Down's cell suitable for the electrolysis of halide salts;
3 is a schematic diagram of a halogenated silicon feed gas preparation system containing silicon tetrahalide and trihalosilane;
4 is a schematic diagram of a substantially closed loop system for making silanes, in accordance with embodiments of the present disclosure;
5 is a schematic diagram of a substantially closed loop system for producing polycrystalline silicon, in accordance with embodiments of the present disclosure.
Corresponding reference characters indicate corresponding parts throughout the drawings.

The method of embodiments of the present disclosure uses electrolysis in the silane manufacturing process to regenerate the reactive components. Electrolysis allows the silane manufacturing method to be a substantially closed loop system, optionally for certain compounds used in the system, such as halogens (eg chlorine) and / or alkali or alkaline earth metals (eg sodium). . As used herein, the expression “substantially closed loop method” or “substantially closed loop system” is not recovered by the system or method unless the compound or system in which the system or method is a closed loop is an impurity for the compound, and is also an impurity system. The system or method for purposes other than supplementing the amount of the compound lost (e.g., the amount of the compound to be supplemented is less than about 5% of the total circulating in the system, as described in more detail below). Refers to a method or system that is not supplied to.

In one or more embodiments of the present disclosure, the silane is prepared by electrolysis of an alkali metal or alkaline earth metal halide salt that produces a metallic alkali metal or alkaline earth metal and a halogen gas. The metallic alkali or alkaline earth metal reacts with hydrogen to produce hydrides, and the halogen gas reacts with silicon (also in some embodiments, additionally hydrogen) to contain silicon tetrahalides and, in some embodiments, trihalosilanes. Produces a halogenated silicon feed gas. The feed gas reacts to produce silane and halide salts. In embodiments where the process is substantially closed loop for at least one of alkali metal or alkaline earth metal and halogen gas, the halide salt by-product is recycled by electrolysis of the halide salt to produce metallic alkali metal or alkaline earth metal and halogen gas.

Silane  Use of electrolysis to manufacture

Referring here to FIG. 1, halide salt 3 is introduced into vessel 4, where the halide salt is electrolyzed to halogen gas (eg Cl ₂ ) and metal (eg metallic alkali metal or alkali). Earth metals). As used herein, a "halide salt" contains an alkali metal or alkaline earth metal and a halogen. The halide salt may have a formula of MX _y where M is an alkali metal or alkaline earth metal, X is halogen, y is 1 when M is an alkali metal, and 2 when M is an alkaline earth metal. The alkali metal or alkaline earth metal (also recycled in a closed loop system in certain embodiments described below) may be selected from the group consisting of lithium, sodium, potassium, magnesium, barium, calcium and mixtures thereof. Halogen may be selected from fluorine, chlorine, bromine, iodine and mixtures thereof. Given the wide availability of sodium chloride and the fact that sodium chloride can be more easily separated into its constituent parts (eg, chloride gas and sodium metal) compared to other halide salts, sodium is the preferred alkali or alkaline earth metal. Chloride is the preferred halogen. In this regard, in particular in embodiments where the method and system for producing silanes are closed loops for alkali or alkaline earth metals, as described below, any alkali or alkaline earth metal may be used, and any halogen may also be used. You should know that

One suitable vessel 4 in which the halide salt is electrolyzed is a Downs cell. An example of a downs cell is shown in FIG. 2 and is generally referred to by the numeral “20”. Downs cell 20 includes at least one halide salt 15 therein and contains an anode 14 and a cathode 16. The anode 14 may be composed of carbon (eg graphite), for example, and the cathode 16 may be composed of steel or iron, for example. At anode 14, chlorine ions are oxidized to form a halogen gas (eg Cl ₂ ). At the cathode 16, alkali metal or alkaline earth metal ions are reduced to form metallic alkali metal or alkaline earth metal. In this regard, it is to be understood that the term "metallic" as used herein refers to an alkali or alkaline earth metal with zero oxidation number. The halogen gas and the metallic alkali or alkaline earth metal formed are divided by the separator 19. Separator 19 may be a screen or gauze made of steel or iron. In this regard, it should be appreciated that electrolysis cells other than Downs cells, such as the electrolysis cells disclosed in US Pat. No. 5,904,821, incorporated herein by reference for all relevant and consistent purposes, may be used.

The resulting metallic alkali or alkaline earth metal is lower in concentration than the halide salt, which causes such alkali or alkaline earth metal to rise in the cell. Halogen gas also rises, and both halogen gas 18 and metallic alkali metal or alkaline earth metal 17 are removed from the downs cell. A second alkali metal or alkaline earth metal salt is added to the downs cell to form a eutectic mixture and to suppress the melting point of the electrolyzed halide salt to melt the halide salt and / or to keep the halide salt molten. Energy costs can be reduced. For example, when sodium chloride is electrolyzed in the Downs cell 20, a certain amount of calcium chloride, aluminum chloride or sodium carbonate can be added to suppress the melting point of sodium chloride. For example, a mixture containing 53.2 mol% calcium chloride and 46.8 mol% sodium chloride has a melting point of 494 ° C., while the melting point of sodium chloride alone is 801 ° C., and an exemplary mixture containing 23.1 mol% sodium carbonate and 76.9 mol% sodium chloride. Has a melting point of 634 ° C. Preferably, the alkali metal or alkaline earth metal of the second salt is the same as the alkali metal or alkaline earth metal of the halide salt, or is a weaker oxidant than the alkali metal or alkaline earth metal of the halide salt so as not to affect the reduction of the alkali metal or alkaline earth metal of the halide salt.

Referring again to FIG. 1, a halogen gas 18 is introduced into a halogenation reactor 8, where the halogen gas is in contact with silicon 6 to contain a halogenated silicon tetrahalide (eg, SiCl ₄ ). Generates water gas 21. The reaction is explained as follows.

Si + 2X ₂ → SiX ₄ (1)

The source of silicon 6 can be silicon for metallurgy; It should be appreciated that other sources of silicon can be used, such as sand (ie, SiO ₂ ), quartz, chief, diatomaceous earth, silicate minerals, fluorosilicates and mixtures thereof. In this regard, as used herein, "contacting" two or more reactive compounds generally results in a reaction of the components, and the terms "contacting" and "reaction" have the same meaning as if they were derivatives of these terms, It should be understood that these terms and their derivatives should not be considered in a limiting sense.

As shown in FIG. 3 as an alternative to direct reaction with silicon, halogen gas 18 is hydrogen in a hydrogen halide burner 25 (synonymous hydrogen halide “oven” or “furnace”). React with (28) to form hydrogen halide (26; HX). Hydrogen halide 26 reacts with silicon 6 in a halogenation reactor 8 to form a halogenated silicon feed gas 21 'containing trihalosilane and silicon tetrahalide. Can be.

Si + 3HX → SiHX ₃ + H ₂ (2)

Si + 4HX → SiX ₄ + 2H ₂ (3)

The molar ratio of silicon tetrahalide to trihalosilane in the halogenated silicon feed gas 21 'may vary, and in various embodiments is about 1: 7 to about 1: 2 or about 1: 6 to about 1: 3 days Can be. In this regard, it should be appreciated that the reaction of silicon 6 with hydrogen halide 26 may also produce, without limitation, an amount of dihalosilane and / or monohalosilane.

In certain embodiments, halogen gas 18 reacts with hydrogen 28 to form hydrogen halide followed by silicon to form a mixture comprising trihalosilane and silicon tetrahalide (FIG. 3) Compared to the direct halogenation of (FIG. 1), it is preferred because the production of silanes from trihalosilanes uses less hydride than silicon tetrahalides, as shown in reactions 5-6ii below. In addition, direct halogenation reactions may require higher temperatures and may be more difficult to control than the reaction of hydrogen halides with silicon.

The source of hydrogen 28 may be selected from the sources described below in connection with the hydrogen feed 31. Optionally, the source of hydrogen 28 can be hydrogen that is recycled from the halogenated feed gas 21 'or hydrogen separated from the halogenated silicon feed gas 21'. Hydrogen can be separated from the halogenated silicon feed gas 21 'by the use of a vapor-liquid separator (not shown). Examples of such vapor-liquid separators include reduced pressure and / or temperature of the incoming gas such that low-boiling gases (eg, silicon tetrahalides and / or trihalosilanes) condense to high-boiling gases (eg, A vessel to allow separation from the hydrogen). Suitable containers include those commonly known in the art as "knock-out drums." Optionally, the vessel can be cooled to promote separation of the gas. Alternatively, hydrogen may be separated by one or more distillation columns.

As an alternative to the subsequent reaction of hydrogen halide and silicon in a halogenation reactor, following the reaction of hydrogen and halogen in a hydrogen halide burner as shown in FIG. It is possible to produce a mixture comprising rosilane and silicon tetrahalide. In this regard, although the preparation of hydrogen halides has been generally described in connection with anhydrous hydrogen halide gas, in some embodiments it reacts with silicon in a manner known to those skilled in the art to produce a mixture comprising trihalosilane and silicon tetrahalide. It should be noted that aqueous hydrogen halide and especially aqueous HF can be produced. Further in this regard, although the reaction product of hydrogen halide and silicon has been described as a mixture comprising trihalosilane and silicon tetrahalide, the reaction parameters are limited to silicon tetrahalide and only trace amounts of trihalosilane (eg, about Control to produce less than 5% by volume or less than about 1% by volume) or trihalosilane with trace amounts of silicon tetrahalide (eg, less than about 5% by volume or less than about 1% by volume). You should know that

The halogenation reactor 8 can operate as a fluidized bed suspended in a gas into which silicon is introduced (eg, halogen 18 (FIG. 1) or hydrogen halide 26 (FIG. 3)). The halogenation reactor 8 can operate at room temperature (eg, about 20 ° C.), especially when fluorine is selected as halogen. More generally, the reactor is at least about 20 ° C., at least about 75 ° C., at least about 150 ° C., at least about 250 ° C., at least about 500 ° C., at least about 750 ° C., at least about 1000 ° C. or at least about 1150 ° C. (eg, About 20 ° C. to about 1200 ° C., about 250 ° C. to about 1200 ° C., or about 500 ° C. to about 1200 ° C.). Reactor 8 may be operated at a pressure of at least about 1 bar, at least about 3 bar, or at least about 6 bar (eg, about 1 bar to about 8 bar or about 3 bar to about 8 bar).

In this regard, the halogenated silicon feed stream 21 shown in FIG. 1 and the halogenated silicon feed stream 21 'shown in FIG. 3 are halosilanes other than silicon tetrahalide or trihalosilane, such as an amount. It should be appreciated that it may contain monohalosilanes and / or dihalosilanes. In addition, halogenated silicon feed stream 21 or halogenated silicon feed stream 21 ′ is introduced into a disproportionation system (not shown) to provide an amount of trihalosilane, dihalosilane and / or monohalo. Lossilane can be produced. As used herein, “halogenated silicon feed gas” refers to any gas containing any amount of one or more halosilanes (ie, silicon tetrahalide, trihalosilane, dihalosilane, or monohalosilane). It is to be understood that the present invention includes both a gas not introduced into the disproportionation system and a gas introduced into the disproportionation system.

Referring again to FIG. 1, halogenated silicon feed stream 21 (or halogenated silicon feed stream 21 ′ as in FIG. 3) is introduced into silane reactor 30 to produce silane 35. Before being introduced into the silane reactor 30, the halogenated silicon feed gas 21 (or feed gas 21 ′ containing both silicon tetrahalide and trihalosilane) may contain impurities such as aluminum halides or iron halides. (Eg AlCl ₃ and / or FeCl ₃ if the halide is chlorine) and / or silicone polymer (eg Si _n Cl _m polymer if the halide is chlorine). These impurities can be removed by cooling the gas to precipitate the impurities from the system. Precipitated impurities can be removed by introducing a gas into a particulate separator, such as a bag filter or a cyclonic separator. In order to precipitate impurities (eg, metal halides and / or silicone polymers), the halogenated silicon feed gas 21 (or silicon tetrahalide and / or trihalosilane mixture 21 ') is about 200 ° C. Or less than about 175 ° C., less than about 150 ° C. or less than about 125 ° C. (eg, about 100 ° C. to about 200 ° C. or about 125 ° C. to about 175 ° C.) as in other embodiments. The gas may be cooled by heat exchange with cooling water or cooling oil in a heat exchange device and / or a cooling device. After impurity removal, the halogenated silicon feed gas 21 (or silicon tetrahalide and / or trihalosilane mixture 21 ') may contain less than 10% by volume of impurities (ie, compounds other than halosilanes) or about 5 Contain less than about 1% by volume, less than about 1% by volume, less than about 0.1% by volume or less than about 0.01% by volume of impurities (eg, 0.001% to about 10% by volume or about 0.001% to about 1% by volume). Can be.

The metallic alkali or alkaline earth metal 17 produced as the electrolysis product is introduced into the hydride reactor 9. An amount of hydrogen 31 is also introduced into the hydride reactor 9. The reaction between the metallic alkali metal or alkaline earth metal and hydrogen produces an alkali metal or alkaline earth metal hydride 32 as shown by the following reaction.

(2 / y) M + H ₂ → (2 / y) MH _y (4)

In the above scheme, y is 1 when M is an alkali metal, and 2 when M is an alkaline earth metal. For example, when M is Na, the reaction proceeds as follows.

2Na + H ₂ → 2NaH (4i)

When M is Ca, the reaction proceeds as follows.

Ca + H ₂ → CaH ₂ (4ii)

Reaction 4 may occur in the presence of a solvent in the hydride reactor 9. Suitable solvents include various hydrocarbon compounds such as toluene, dimethyl ether, diglyme and ionic liquids such as NaAlCl ₄ . In embodiments in which NaAlCl ₄ is used, the hydride reactor 9 may comprise an electrode. When the supply amount of alkali metal or alkaline earth metal hydride is depleted, energy can be supplied to the electrode to regenerate the hydride compound so that sodium (including a certain amount of Na from NaAlCl ₄ ) and H ₂ react. In embodiments where NaAlCl ₄ is used as the solvent, other ionic compounds may be added to form eutectic mixtures, which are disclosed in US Pat. No. 6,482,381, incorporated herein for all related and consistent purposes.

The hydride reactor 9 can be a stirred tank reactor, to which an amount of solvent (not shown) and metallic alkali metal or alkaline earth metal 17 are added. Hydrogen 31 may bubble through the reaction mixture to form alkali or alkaline earth metal hydrides 32 in a batch or semi-continuous or continuous process. Suitable sources of hydrogen 31 include hydrogen obtained from commercially available hydrogen or other process streams. For example, hydrogen can be separated from the trihalosilane and silicon tetrahalide mixture 21 'in embodiments where hydrogen halide reacts with silicon (eg, the vapor-liquid separator described above). Alternatively or additionally, hydrogen released from the silane may be used during the downstream preparation of the polycrystalline silicon. The amount of solvent, hydrogen 31 and metallic alkali metal or alkaline earth metal 17 added to the reactor 9 may have a weight ratio of hydride to solvent amount in the reactor 9 of at least about 1:20, and in other embodiments About 1:10 or more, about 1: 5 or more, about 1: 3 or more, about 2: 3 or more or about 1: 1 or more (eg, about 1:20 to about 1: 1 or about 1:10 to about 2: 3).

In one or more embodiments, the reaction mixture in reactor 9 is well mixed using, for example, one or more relatively high speed stirred mixers having one or more impellers. Relatively high speed agitation ensures that the hydrogen is well dispersed throughout the reaction mixture to maximize the rate of hydrogen dissolution, and that any solid alkali or alkaline earth metal hydride can be used continuously for reaction with dissolved hydrogen in the liquid alkali or alkaline earth metal. The ride is sheared from metallic alkali metal or alkaline earth metal. Without wishing to be bound by a particular theory in this regard, mass transfer in the hydride reactor depends on liquid lateral resistance, and the volumetric gas-liquid mass transfer coefficient (K _L a _G ) is about 100 to about 1000000. s ⁻¹ , more typically about 1,000 to about 10,000 s ⁻¹ . It should be noted that the specific volumetric gas-liquid mass transfer coefficient (K _L a _G ) may vary depending on the particular hydride and solvent selected for use in the reactor (9). The value can be readily determined by one of skill in the art according to known methodologies (eg measuring hydrogen utilization as a function of time).

In many embodiments of the present disclosure, the hydride reactor 9 is subjected to high pressure conditions, such as at least about 50 bar, at least about 125 bar, at least about 200 bar, at least about 275 bar or at least about 350 bar (eg, Operating at a pressure of about 50 bar to about 350 bar or about 50 bar to about 200 bar). The hydride reactor 9 is at a temperature lower than the pyrolysis of the alkali metal or alkaline earth metal halide, such as less than about 160 ° C., less than about 145 ° C. or less than about 130 ° C. (eg, from about 120 ° C. to about 160 ° C.). Can work.

Alkali metal or alkaline earth metal hydrides 32 are typically solids in organic solvents. A slurry containing an alkali metal or alkaline earth metal hydride 32 suspended in a solvent can be introduced into the silane reactor 30 to produce the silane 35. In this regard, in another particular embodiment of the present disclosure, alkali metal or alkaline earth metal hydride 32 may be introduced into the silane reactor 30 as a solid or caked solid containing a smaller amount of solvent. You should know that The alkali metal or alkaline earth metal may be separated from the solvent by centrifugation or filtration or any other suitable method available to those skilled in the art. In this regard, it should be appreciated that solvents other than organic solvents (eg, NaAlCl ₄ ) may be used without limitation.

As described above, silicon tetrahalides and alkali metal or alkaline earth metal hydrides from hydrogenated silicon feed gas 21 (or mixture 21 ′ comprising silicon tetrahalide and trihalosilane as in FIG. 3) (32) is introduced into the silane reactor (30) to produce silane (35) and halide salt (37) in accordance with the reaction shown below.

(4 / y) MH _y + SiX ₄ → (4 / y) MX _y + SiH ₄ (5)

3MH _y + ySiHX ₃ → 3MX _y + ySiH ₄ (6)

In the above scheme, y is 1 when M is an alkali metal, and 2 when M is an alkaline earth metal. For example, when M is Na and X is Cl, the reaction proceeds as follows.

4NaH + SiCl ₄ → 4NaCl + SiH ₄ (5i)

3NaH + SiHCl ₃ → 3NaCl + SiH ₄ (6i)

When M is Ba and X is Cl, the reaction proceeds as follows.

2BaH ₂ + SiCl ₄ → 2BaCl ₂ + SiH ₄ (5ii)

3BaH ₂ + 2SiHCl ₃ → 3BaCl ₂ + 2SiH ₄ (6ii)

The silane reactor 30 may be a stirred tank reactor (eg, impeller stirred). The alkali metal or alkaline earth metal hydride 32 added to the reactor 30 is suspended in an amount of solvent (eg toluene) from which it is produced (eg by reaction of an alkali metal or alkaline earth metal with hydrogen). Can be. The silicon tetrahalides and / or trihalosilanes 31 may form bubbles through the hydride slurry and preferably in a countercurrent relationship. The weight ratio of the amount of hydride 32 added to the reactor 30 to the amount of solvent added to the reactor is at least about 1:20, and in other embodiments at least about 1:10 or at least about 1: 5 (eg, about 1:20 to about 1: 5 or about 1:20 to about 2:10). Silicon tetrahalide from halogenated silicon feed gas 21 (FIG. 1) or silicon tetrahalide and trihalosilane from halogenated silicon feed gas 21 ′ (FIG. 3) is added to hydride 32. Can be added in substantial stoichiometric ratios, and such molar ratios are shown in reactions 5-6ii above.

An amount of catalyst such as triethyl aluminum, various Lewis acids or trace alkali metals (eg impurity Lewis acids such as metal chlorides) can be added to the reactor 30. Such catalysts can lower the temperature at which reactions 5 and 6 achieve sufficient conversion and reduce the amount of heat input to the system. In embodiments in which no catalyst is used, reactor 30 may operate at a temperature of at least about 120 ° C. (eg, from about 120 ° C. to about 225 ° C. or from about 140 ° C. to about 200 ° C.); In embodiments in which a catalyst is used, reactor 30 operates at relatively low temperatures of at least about 30 ° C. (eg, from about 30 ° C. to about 125 ° C., from about 40 ° C. to about 100 ° C. or from about 40 ° C. to about 80 ° C.). can do. The average residence time of the materials added to the reactor 30 can be from about 5 minutes to about 60 minutes.

Silane gas 35 may be relatively pure (eg, containing less than about 5% or less than about 2% by volume of compounds other than silane). After the silane gas 35 is removed from the reactor 30, the silane gas 35 can be applied for further processing. For example, silane 35 may be used to remove impurities as disclosed in US Pat. No. 5,211,931, US Pat. No. 4,554,141 or US Pat. No. 5,206,004, each incorporated herein by reference for all relevant and consistent purposes. It may be introduced into one or more distillation columns and / or molecular sieves or purified by other known methods available to those skilled in the art (eg to remove compounds such as boron halides or phosphorus halides).

Silane gas 35 may be used to produce polycrystalline silicon (eg, granular or agglomerate polycrystalline silicon) or may be used to produce one or more epitaxial layers on a silicon wafer. Silane gas may be stored and / or transported prior to use, as will be appreciated by those skilled in the art.

The reaction of the alkali metal or alkaline earth metal hydride with silicon tetrahalide in the halogenated silicon feed gas 21 (or the mixture 21 'comprising trihalosilane and silicon tetrahalide) is an alkali metal or alkaline earth metal as a by-product. To produce a halide salt (37). Halide salt 37 may be dissolved in a solvent (eg, toluene) and also more typically suspended in embodiments in which a solvent is used. The halide salt (37) can be commercially available separately from the solvent, or can be recycled as further described below.

Silane  substantial Closed loop  Manufacturing method

The method described above can be included in a method for producing substantially closed loops of silane. The method may be a closed loop for alkali metal or alkaline earth metal and / or halogen. Referring here to FIG. 4, the halide salt 37 can be separated from the solvent using the separator 40. Separator 40 may be an evaporator, or other suitable equipment, including crystallization apparatus, filters, and / or gravity-based separators (eg, centrifuges) may be used with or instead of the evaporator. Suitable evaporators include wiped-film evaporators. After separation, the dried halide salt can be heated (eg to 500 ° C.) to remove traces of solvent.

The solvent 43 may be condensed and reintroduced into the hydride reactor 9 and / or silane reactor 30. The separated halide salt (3) is used as feed (3) for electrolysis so that the alkali metal or alkaline earth metal and / or halide is substantially recycled through the system.

In this regard, the substantial closed loop method shown in FIG. 4 can be modified to include a hydrogen halide burner 25 that produces a gas 21 'containing silicon tetrahalide and trihalosilane as in FIG. You should know

As shown in FIG. 4, the process does not include alkali metal or alkaline earth metal or halogens (ie, alone or as alkali metal or alkaline earth metal or halogen containing compounds) anywhere in the injection stream 6, 31, and It is also substantially closed to alkali metal or alkaline earth metals and halogens in that alkali metal or alkaline earth metals and halogens are not removed into the outlet stream 35. In this regard, it should be appreciated that alkali or alkaline earth metals and / or halogens may be removed from the system as impurities or may be included in a purge stream and fed to the system or method as a supplemental stream. Any replenishment of alkali or alkaline earth metals and / or halogens can be achieved by the addition of compounds containing respective elements to the system, and in certain embodiments by the respective hydride salts themselves. In various embodiments, the amount of alkali metal or alkaline earth metal and / or halogen gas (which may be added as an alkali metal or alkaline earth metal salt) supplemented to the system is less than about 5% of the total circulation in the system, and in other embodiments Less than about 2% of the total circulation in the system (eg, about 0.5% to about 5%).

In some embodiments of the present disclosure, the systems and methods can be substantially closed loop for hydrogen. For example, as shown in FIG. 5, the silane 35 exiting the silane reactor 30 is preferably a trace silane, carbon compound, trace metal and any dopant boron, phosphorus or aluminum compound. May be introduced into the polycrystalline reactor 50 after purification (e.g., purification with cryogenic activated carbon adsorbent). Polycrystalline reactor 50 may be a fluidized bed (e.g., granulated polycrystalline silicon) or a Siemens reactor (e.g., agglomerated polycrystalline silicon), or any suitable for polycrystalline silicon production. And other reactor designs. The silane is pyrolyzed according to the following reaction to produce polycrystalline silicon.

SiH ₄ → Si + 2H ₂ (7)

The silane may be subjected to further processing, such as various purification steps as described above, before being added to the polycrystalline reactor 50. The reaction product of reactor 50 comprises polycrystalline silicon 52 and hydrogen 31. As shown in FIG. 5, hydrogen 31 is introduced into the hydride reactor 9. Hydrogen 31 may be further processed by separation and purification of silicon dust (eg distillation) before it is introduced into hydride reactor 9. As shown in FIG. 5, the only input to the system is silicon 6 and the only discharge is polycrystalline silicon 52. The system is substantially closed loop to hydrogen in that hydrogen is only removed as an impurity or as a purge stream (not shown) and also only added as a supplemental stream (not shown).

Silane  substantial Closed loop  Manufacturing system

The method of the invention can be carried out in any of the systems for producing silanes, such as the systems illustrated in FIGS. The system may be substantially closed loop for at least one of halogen, alkali metal or alkaline earth metal and hydrogen.

Referring to FIG. 1, the system may include a vessel 4 (eg, a downs cell) in which the halide salt is electrolyzed to produce metallic alkali or alkaline earth metals and halogen gas. Halogen gas is carried by a conveying device to (1) hydrogen halide burners 25 (FIG. 3) and (2) silicon (which is conveyed from the silicon reservoir by the conveying device to the halogenation reactor 8) ) And is delivered to at least one of the halogenation reactors 8 to produce silicon tetrahalides. In embodiments in which the halogen gas reacts to produce hydrogen halide, the hydrogen halide may then be delivered to the halogenation reactor 8 by a conveying device to produce a mixture comprising silicon tetrahalide and trihalosilane. Any silicon tetrahalide and / or trihalosilane gas produced is conveyed to the silane reactor 30 by a conveying device.

The system also includes a hydride reactor 9 (eg, a stirred tank reactor). Metallic alkali or alkaline earth metals are conveyed from the vessel to the hydride reactor 9 by means of a conveying device. Hydrogen gas is also conveyed by the conveying device to the hydride reactor 9 to react with the metallic alkali metal or alkaline earth metal to produce an alkali metal or alkaline earth metal hydride. The system includes a silane reactor 30 (eg, a stirred tank reactor) in which the hydride (any solvent, if present) is carried by the conveying device. The hydrides react in the silane reactor 30 with silicon tetrahalide and / or trihalosilane gas, optionally in the presence of a solvent, to form halide salts.

In various embodiments, as shown in FIG. 4, the solvent and halide salt can be conveyed to separator 40 for separating the solvent from the halide salt by a conveying device. The solvent can be conveyed to the hydride reactor 9 by means of a conveying device, and the halide salt can be recycled by the conveying device to complete a substantially closed loop system for halogen and alkali or alkaline earth metals. For example, a downs cell).

In many further embodiments, the system also includes a polycrystalline reactor 50, which may be a Siemens type reactor or a fluidized bed reactor. Silane is conveyed from the silane reactor 30 to the polycrystalline reactor 50 by a conveying device to produce hydrogen and polycrystalline silicon. Hydrogen can be conveyed from the polycrystalline reactor 50 to the hydride reactor 9 by a conveying device so that the hydrogen can be recycled to complete a substantially closed loop system for the hydrogen.

Suitable conveying devices are conventional and are well known in the art. Transport devices suitable for the delivery of gases include, for example, compressors or blowers, and transport devices suitable for delivery of solids, for example, include drags, screws, belts and pneumatic conveyors. Included. In this regard, the use of the expression "carrying device" herein is not intended to mean direct delivery from one unit of the system to another, but merely that the substance is directed to any number of indirect delivery members and / or mechanisms. It is to be understood that this means passing from one unit to another unit. For example, material from one unit may be delivered to a second processing unit (eg, a purification unit or a storage unit used to provide buffer between continuous or batch processes) and then to a second unit. Can be. In the above example, each conveying unit including the intermediate processing facility itself may be considered to be a "carrying device" and the expression "carrying device" should not be considered in a limiting sense.

Preferably, all equipment used in the silane production system is corrosion resistant in an environment that includes exposure to the compounds used and produced in the system. Suitable constituent materials are conventional and well known in the art, for example, carbon steel, stainless steel, MONEL alloys, INCONEL alloys, HASTELLOY alloys, nickel and nonmetallic materials, for example, it includes quartz (i.e., glass), and fluorinated polymers such as TEFLON (TEFLON), kelp (KEL-F), Viton (VITON), knife grease (KALREZ) and ill Ras (AFLAS).

Without departing from the scope of the present disclosure, the methods and systems described above may include more than any of the mentioned units (eg, reactors and / or separation units), and several units may be continuous It should be appreciated that it may also work in conjunction with and / or simultaneously. Further in this regard, it should be understood that the methods and systems described are exemplary and that the methods and systems may include additional units that perform additional functions without limitation.

When introducing elements of the present disclosure or preferred embodiment (s) thereof, the articles "a", "an", "the" and "the" are intended to mean that one or more elements are present. The terms "comprising", "including" and "having" are intended to be inclusive and mean that there may be additional elements other than the listed elements.

As various changes may be made in the above apparatus and methods without departing from the scope of the disclosure, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Claims (95)

A process for preparing silanes from a source of alkali metal or alkaline earth metal halide salts,
Electrolyzing the alkali metal or alkaline earth metal halide salt to produce metallic alkali metal or alkaline earth metal and halogen gas;
Contacting the metallic alkali metal or alkaline earth metal with hydrogen to produce an alkali metal or alkaline earth metal hydride;
With the halogen gas
(1) silicon to produce silicon tetrahalides; And
(2) hydrogen to produce hydrogen halides, wherein the hydrogen halides are further contacted with silicon to produce a mixture comprising silicon tetrahalide and trihalosilane;
Contacting at least one of the following to produce a halogenated silicon feed gas comprising at least one halosilane selected from the group consisting of silicon tetrahalide, trihalosilane, dihalosilane and monohalosilane; And
Contacting the halogenated silicon feed gas with the alkali metal or alkaline earth metal hydride to produce silane and alkali metal or alkaline earth metal hydride salts, wherein the halogenated silicon feed gas is combined with the halogenated silicon feed gas. Introduced into the disproportionation system prior to contacting the alkali metal or alkaline earth metal hydride-
≪ / RTI > A process for preparing silanes from a source of alkali metal or alkaline earth metal halide salts,
Electrolyzing the alkali metal or alkaline earth metal halide salt to produce metallic alkali metal or alkaline earth metal and halogen gas;
Contacting the metallic alkali metal or alkaline earth metal with hydrogen in a solvent to produce an alkali metal or alkaline earth metal hydride;
With the halogen gas
(1) silicon to produce silicon tetrahalides; And
(2) hydrogen to produce hydrogen halides, wherein the hydrogen halides are further contacted with silicon to produce a mixture comprising silicon tetrahalide and trihalosilane;
Contacting at least one of the following to produce a halogenated silicon feed gas comprising at least one halosilane selected from the group consisting of silicon tetrahalide, trihalosilane, dihalosilane and monohalosilane; And
Contacting the halogenated silicon feed gas with the alkali metal or alkaline earth metal hydride to produce silane and alkali metal or alkaline earth metal hydride salts
≪ / RTI > The method of claim 2, wherein the solvent is selected from the group consisting of toluene, dimethyl ether, diglyme, NaAlCl _4, and mixtures thereof. The method of claim 2, wherein the metallic alkali metal or alkaline earth metal is added to a reaction vessel comprising the solvent to form a reaction mixture, and hydrogen gas forms bubbles through the reaction mixture. The halogenated silicon feed of claim 2, wherein the alkali or alkaline earth metal hydride is selected from a solvent selected from the group consisting of toluene, dimethyl ether, diglyme, NaAlCl ₄ and mixtures thereof. Contacting the gas. The method of claim 5 wherein said solvent contains a catalyst. The method of claim 6, wherein the catalyst is selected from the group consisting of triethyl aluminum, various Lewis acids, trace alkali metals, and mixtures thereof. 8. The spent solvent according to claim 2, wherein the spent solvent comprising the halide salt and the solvent is produced upon contact of the alkali metal or alkaline earth metal hydride with the halogenated silicon feed gas, The method includes the step of regenerating the solvent by separation of the halide salt and the solvent. The method of claim 8, wherein the halide salt and the solvent are separated by evaporating the solvent from the salt and condensing the solvent after evaporation. The method of claim 1, wherein the halogenated silicon feed gas comprises one or more metal halide impurities, and the method cools the halogenated silicon feed gas to remove the metal halide impurities. Depositing a method. The halide salt of claim 1, wherein the halide salt is
Introducing the salt into a vessel comprising a cathode, an anode disposed within the cathode, and a separator disposed between the cathode and the anode;
Current is applied to the cathode and the anode to produce a halogen gas and a metallic alkali or alkaline earth metal;
Electrolysis by releasing halogen gas and metallic alkali metal or alkaline earth metal from the vessel. 12. The method of claim 11, wherein at least one compound selected from the group consisting of calcium chloride, aluminum chloride and sodium carbonate is added to the vessel to lower the melting point of the halide salt. 13. The method according to any one of claims 1 to 12, wherein granular silicon and at least one of halogen gas and hydrogen halide are introduced into a fluidized bed reactor and the halogen gas or hydrogen halide is introduced in the reactor. Fluidizing the granular silicone. The alkali metal or alkaline earth metal salt produced by contacting the halogenated silicon feed gas with the alkali metal or alkaline earth metal hydride is electrolyzed to form a metallic alkali metal. Or alkaline earth metal and halogen gas. The method of claim 1, wherein the alkali or alkaline earth metal is selected from the group consisting of lithium, sodium, potassium, magnesium, barium, calcium and mixtures thereof. The method according to any one of claims 1 to 14, wherein the alkali metal or alkaline earth metal is sodium. The method according to claim 1, wherein the alkali metal or alkaline earth metal halide salt comprises a halogen selected from the group consisting of fluorine, chlorine, bromine, iodine and mixtures thereof. The method according to claim 1, wherein the alkali metal or alkaline earth metal halide salt comprises chlorine. A process for producing silanes in a substantially closed loop system for alkali or alkaline earth metals,
Contacting a halogenated silicon feed gas with an alkali metal or alkaline earth metal hydride to produce a silane and an alkali or alkaline earth metal halide salt, wherein the halogenated silicon feed gas comprises the halogenated silicon feed gas and the alkali metal Or introduced into the disproportionation system prior to contacting the alkaline earth metal hydride;
Electrolyzing the halide salt to produce metallic alkali or alkaline earth metals and halogen gas;
Contacting the metallic alkali metal or alkaline earth metal with hydrogen to produce an alkali metal or alkaline earth metal hydride; And
Contacting said alkali metal or alkaline earth metal hydride produced by contacting said metallic alkali metal or alkaline earth metal with hydrogen to said halogenated silicon feed gas to produce silane and alkali metal or alkaline earth metal halide salts
≪ / RTI > A process for producing silanes in a substantially closed loop system for alkali or alkaline earth metals,
Contacting the halogenated silicon feed gas with an alkali metal or alkaline earth metal hydride to produce silane and an alkali metal or alkaline earth metal halide salt;
Electrolyzing the halide salt to produce metallic alkali or alkaline earth metals and halogen gas;
Contacting the metallic alkali metal or alkaline earth metal with hydrogen in a solvent to produce an alkali metal or alkaline earth metal hydride; And
Contacting said alkali metal or alkaline earth metal hydride produced by contacting said metallic alkali metal or alkaline earth metal with hydrogen to said halogenated silicon feed gas to produce silane and alkali metal or alkaline earth metal halide salts
≪ / RTI > The method of claim 20, wherein the solvent is selected from the group consisting of toluene, dimethyl ether, diglyme, NaAlCl _4, and mixtures thereof. The method of claim 20, wherein the metallic alkali metal or alkaline earth metal is added to a reaction vessel comprising the solvent to form a reaction mixture, and hydrogen gas forms bubbles through the reaction mixture. 23. The halogenated silicon feed of claim 20, wherein the alkali or alkaline earth metal hydride is in a solvent selected from the group consisting of toluene, dimethyl ether, diglyme, NaAlCl ₄ and mixtures thereof. Contacting the gas. The method of claim 23, wherein the solvent contains a catalyst. The method of claim 24, wherein the catalyst is selected from the group consisting of triethyl aluminum, various Lewis acids, trace alkali metals, and mixtures thereof. The spent solvent according to any one of claims 20 to 25, wherein the spent solvent comprising the halide salt and the solvent is produced upon contact of the alkali metal or alkaline earth metal hydride with the halogenated silicon feed gas, The method includes the step of regenerating the solvent by separation of the halide salt and the solvent. 27. The method of claim 26, wherein the halide salt and the solvent are separated by evaporating the solvent from the halide salt and condensing the solvent after evaporation. The method of claim 19, wherein the halogenated silicon feed gas comprises at least one metal halide impurity, and the method cools the halogenated silicon feed gas to remove the metal halide impurity. Depositing a method. 29. The halide salt of any of claims 19-28, wherein the halide salt is
Introducing the salt into a vessel comprising a cathode, an anode disposed within the cathode, and a separator disposed between the cathode and the anode;
Current is applied to the cathode and the anode to produce a halogen gas and a metallic alkali or alkaline earth metal;
Electrolysis by releasing halogen gas and metallic alkali metal or alkaline earth metal from the vessel. 30. The method of claim 29, wherein at least one compound selected from the group consisting of calcium chloride, aluminum chloride and sodium carbonate is added to the vessel to lower the melting point of the halide salt. 31. The granular silicone according to any one of claims 19 to 30, wherein granular silicone and at least one of halogen gas and hydrogen halide are introduced into a fluidized bed reactor and the halogen gas or hydrogen halide is introduced into the granular silicone in the reactor. To fluidize. 32. The method of any one of claims 19-31, wherein the alkali or alkaline earth metal is selected from the group consisting of lithium, sodium, potassium, magnesium, barium, calcium and mixtures thereof. 32. The method of any one of claims 19-31, wherein the alkali metal or alkaline earth metal is sodium. 34. The method of any one of claims 19-33, wherein the alkali or alkaline earth metal halide salt comprises a halogen selected from the group consisting of fluorine, chlorine, bromine, iodine and mixtures thereof. 34. The method of any of claims 19-33, wherein the alkali metal or alkaline earth metal halide salt comprises chlorine. A process for producing silanes in a substantially closed loop system for halogens,
Halogenated silicon feed gas comprising at least one halosilane selected from the group consisting of silicon tetrahalides, trihalosilanes, dihalosilanes and monohalosilanes is contacted with alkali metal or alkaline earth metal hydrides to give silane and alkali Producing a metal or alkaline earth metal halide salt;
Electrolyzing the halide salt to produce metallic alkali or alkaline earth metals and halogen gas;
With the halogen gas
(1) silicon to produce silicon tetrahalides; And
(2) hydrogen to produce hydrogen halides, wherein the hydrogen halides are further contacted with silicon to produce a mixture comprising silicon tetrahalide and trihalosilane;
Contacting at least one of the following to produce a halogenated silicon feed gas comprising at least one halosilane selected from the group consisting of silicon tetrahalide, trihalosilane, dihalosilane and monohalosilane; And
Contacting the halogenated silicon feed gas with an alkali metal or alkaline earth metal hydride to produce silane and alkali metal or alkaline earth metal halide salts, wherein the halogenated silicon feed gas comprises the halogenated silicon feed gas and the alkali Introduced into the disproportionation system before contact with the metal or alkaline earth metal hydride-
≪ / RTI > The method of claim 36, wherein the halogenated silicon feed gas comprises one or more metal halide impurities. 38. The method of claim 37, wherein the halogenated silicon feed gas is cooled to precipitate the metal halide impurities. The halide salt of any one of claims 36-38, wherein the halide salt is
Introducing the salt into a vessel comprising a cathode, an anode disposed within the cathode, and a separator disposed between the cathode and the anode;
Current is applied to the cathode and the anode to produce a halogen gas and a metallic alkali or alkaline earth metal;
Electrolysis by releasing halogen gas and metallic alkali metal or alkaline earth metal from the vessel. 40. The method of claim 39, wherein at least one compound selected from the group consisting of calcium chloride, aluminum chloride and sodium carbonate is added to the vessel to lower the melting point of the halide salt. 41. The granular silicone of any of claims 36-40, wherein granular silicon and one or more of halogen gas and hydrogen halide are introduced into a fluidized bed reactor, and the halogen gas or hydrogen halide is introduced into the granular silicon in the reactor. To fluidize. The alkali metal or alkaline earth metal salt produced by contacting said halogenated silicon feed gas with said alkali metal or alkaline earth metal hydride is electrolyzed to form a metallic alkali metal. Or alkaline earth metal and halogen gas. 43. The method of any of claims 36 to 42, wherein the alkali or alkaline earth metal is selected from the group consisting of lithium, sodium, potassium, magnesium, barium, calcium and mixtures thereof. 43. The method of any of claims 36 to 42, wherein the alkali metal or alkaline earth metal is sodium. 45. The method of any one of claims 36 to 44, wherein the alkali or alkaline earth metal halide salt comprises a halogen selected from the group consisting of fluorine, chlorine, bromine, iodine and mixtures thereof. 45. The method of any one of claims 36-44, wherein the alkali metal or alkaline earth metal halide salt comprises chlorine. As a closed loop manufacturing method of polycrystalline silicon,
Halogenated silicon feed gas comprising at least one halosilane selected from the group consisting of silicon tetrahalides, trihalosilanes, dihalosilanes and monohalosilanes is contacted with alkali metal or alkaline earth metal hydrides to give silane and alkali Producing a metal or alkaline earth metal halide salt;
Pyrolysis of the silane to produce polycrystalline silicon and hydrogen;
Electrolyzing the halide salt to produce metallic alkali or alkaline earth metals and halogen gas;
The halogen gas generated by electrolysis of the alkali metal or alkaline earth metal halide
(1) silicon to produce silicon tetrahalides; And
(2) hydrogen to produce hydrogen halides, wherein the hydrogen halides are further contacted with silicon to produce a mixture comprising silicon tetrahalide and trihalosilane;
Contacting at least one of the following to produce a halogenated silicon feed gas comprising at least one halosilane selected from the group consisting of silicon tetrahalide, trihalosilane, dihalosilane and monohalosilane;
Contacting the metallic alkali metal or alkaline earth metal with hydrogen generated from pyrolysis of silane to produce an alkali metal or alkaline earth metal hydride; And
The halogenated silicon feed gas produced by the contact of halogen gas or hydrogen halide with silicon is brought into contact with the alkali metal or alkaline earth metal hydride produced by the contact of hydrogen with the metallic alkali or alkaline earth metal to form silane and alkali. Producing a metal or alkaline earth metal halide salt
Closed loop manufacturing method comprising a. 48. The method of claim 47 wherein silane is introduced into the fluidized bed reactor to deposit silicon onto the silicon seed particles fluidized therein. 49. The closed loop preparation of claim 47 or 48 comprising introducing said halogenated silicon feed gas into a disproportionation system prior to contacting said halogenated silicon feed gas with said alkali metal or alkaline earth metal hydride. Way. 50. The waste of any one of claims 47 to 49 wherein the metallic alkali or alkaline earth metal is contacted with hydrogen in a solvent selected from the group consisting of toluene, dimethyl ether, diglyme, NaAlCl ₄ and mixtures thereof. Loop manufacturing method. 51. The method of claim 50, wherein the metallic alkali metal or alkaline earth metal is added to a reaction vessel comprising the solvent to form a reaction mixture, and hydrogen gas forms bubbles through the reaction mixture. 52. The halogenated silicone feed of any of claims 47-51, wherein the alkali or alkaline earth metal hydride is in a solvent selected from the group consisting of toluene, dimethyl ether, diglyme, NaAlCl ₄ and mixtures thereof. Closed loop manufacturing method in contact with the gas. 53. The method of claim 52 wherein the solvent contains a catalyst. 54. The method of claim 53 wherein the catalyst is selected from the group consisting of triethyl aluminum, various Lewis acids, trace alkali metals, and mixtures thereof. 55. The process of any one of claims 50-54, wherein the spent solvent comprising the halide salt and the solvent is produced upon contact of the alkali metal or alkaline earth metal hydride with the halogenated silicon feed gas, The method comprises the step of regenerating the solvent by separation of the halide salt and the solvent. 56. The method of claim 55 wherein the halide salt and the solvent are separated by evaporating the solvent from the halide salt and condensing the solvent after evaporation. The method of claim 47, wherein the halogenated silicon feed gas comprises at least one metal halide impurity, and the method cools the halogenated silicon feed gas to remove the metal halide impurity. A closed loop manufacturing method comprising the step of depositing. 58. The halide salt of any one of claims 47-57, wherein the halide salt is
Introducing the salt into a vessel comprising a cathode, an anode disposed within the cathode, and a separator disposed between the cathode and the anode;
Current is applied to the cathode and the anode to produce a halogen gas and a metallic alkali or alkaline earth metal;
A process for producing a closed loop, wherein said gas is electrolyzed by releasing halogen gas and metallic alkali metal or alkaline earth metal from said vessel. 59. The method of claim 58 wherein at least one compound selected from the group consisting of calcium chloride, aluminum chloride and sodium carbonate is added to the vessel to lower the melting point of the halide salt. 60. The granular silicone according to any one of claims 47 to 59, wherein granular silicone and at least one of halogen gas and hydrogen halide are introduced into a fluidized bed reactor, and the halogen gas or hydrogen halide is introduced into the granular silicone in the reactor. Closed loop manufacturing method. 61. The method of claim 47, wherein the alkali or alkaline earth metal is selected from the group consisting of lithium, sodium, potassium, magnesium, barium, calcium and mixtures thereof. 61. The closed loop production method according to any one of claims 47 to 60, wherein the alkali metal or alkaline earth metal is sodium. 63. The method of any of claims 47-62, wherein the alkali or alkaline earth metal halide salt comprises a halogen selected from the group consisting of fluorine, chlorine, bromine, iodine and mixtures thereof. 63. The method of claim 47, wherein the alkali metal or alkaline earth metal halide salt comprises chlorine. A system for producing silanes in a substantially closed loop method,
A vessel for electrolyzing an alkali metal or alkaline earth metal halide salt to produce a metallic alkali metal or alkaline earth metal and a halogen gas;
With silicone
(1) halogen gas released from the vessel; And
(2) hydrogen halides produced by contact of hydrogen with halogen gas emitted from the vessel;
By at least one reaction
(1) silicon tetrahalide, and
(2) trihalosilane
Halogenated reactors producing at least one of;
A hydride reactor wherein hydrogen reacts with a metallic alkali metal or alkaline earth metal discharged from the vessel to produce an alkali metal or alkaline earth metal hydride, wherein the hydride reactor is a reaction mixture in which hydrogen contains a solvent and a metallic alkali metal or alkaline earth metal A stirred tank reactor for generating bubbles through and producing alkali or alkaline earth metal hydrides suspended in the solvent; And
A silane reactor in which at least one of (1) silicon tetrahalide and (2) trihalosilane reacts with the alkali metal or alkaline earth metal hydride to produce silane and alkali metal or alkaline earth metal halide salts.
/ RTI > A system for producing silanes in a substantially closed loop method,
A vessel for electrolyzing an alkali metal or alkaline earth metal halide salt to produce a metallic alkali metal or alkaline earth metal and a halogen gas;
With silicone
(1) halogen gas released from the vessel; And
(2) hydrogen halides produced by contact of hydrogen with halogen gas emitted from the vessel;
By at least one reaction
(1) silicon tetrahalide, and
(2) trihalosilane
Halogenated reactors producing at least one of;
Disproportionation systems for producing monohalosilanes or dihalosilanes from at least one of (1) silicon tetrahalide and (2) trihalosilane;
A hydride reactor in which the metallic alkali metal or alkaline earth metal released from the vessel reacts with hydrogen to produce an alkali metal or alkaline earth metal hydride; And
Silane reactor in which at least one of (1) silicon tetrahalide and (2) trihalosilane reacts with alkali metal or alkaline earth metal hydride to produce silane and alkali metal or alkaline earth metal halide salts
/ RTI > 67. The system of claim 65 or 66, wherein said vessel is an electrolysis cell. 68. The apparatus of any of claims 65 to 67, comprising a conveying device for conveying the alkali metal or alkaline earth metal halide salt released from the silane reactor to the vessel for electrolyzing the alkali metal or alkaline earth metal halide salt. system. 69. The halogenation of claim 65, wherein the silane reactor comprises at least one halosilane selected from the group consisting of silicon tetrahalide, trihalosilane, dihalosilane, and monohalosilane. The stirred silicon feed gas is a stirred tank reactor that forms bubbles through a reaction mixture containing a solvent and an alkali metal or alkaline earth metal hydride dispersed in the solvent, and the alkali metal or alkaline earth metal halide salt produced is the solvent System dissolved or suspended in the air. 70. The system of claim 69, comprising a separator for separating the solvent and the alkali metal or alkaline earth metal halide salt. 71. The apparatus of claim 70, wherein a conveying apparatus for conveying the solvent and the alkali metal or alkaline earth metal halide salts discharged from the silane reactor and the separated alkali metal or alkaline earth metal halide salt is transferred to an alkali metal or alkaline earth metal halide. A conveying device for conveying salt to said vessel for electrolysis. 72. The system of claim 70 or 71, comprising a conveying device for conveying the separated solvent to the hydride reactor. The halogenated reactor of claim 65, wherein the halogenation reactor comprises at least one halosilane wherein the silicon is selected from the group consisting of silicon tetrahalide, trihalosilane, dihalosilane, and monohalosilane. A fluidized bed reactor suspended in a halogenated silicon feed gas. 74. The system of claim 73 comprising a conveying device for conveying an alkali metal or alkaline earth metal hydride and a solvent from said hydride reactor to said silane reactor. 75. The system of any of claims 65-74, wherein the silane comprises a polycrystalline silicon reactor that decomposes to produce hydrogen and polycrystalline silicon. 77. The system of claim 75, wherein said polycrystalline silicon reactor is a Siemens reactor. 76. The system of claim 75, wherein the polycrystalline reactor is a fluidized bed reactor in which silane fluidizes polycrystalline silicon particles. 78. The system of any one of claims 75-77 comprising a conveying device for conveying hydrogen from said polycrystalline reactor to said hydride reactor. 79. The system of any one of claims 75 to 78 comprising a conveying device for conveying silane from the silane reactor to the polycrystalline reactor. 80. A device according to any of claims 65 to 79, comprising a conveying device for conveying the metallic alkali or alkaline earth metal released from the vessel for electrolyzing an alkali metal or alkaline earth metal halide salt to the hydride reactor. system. 81. The system of any of claims 65-80, comprising a conveying device for conveying halogen gas released from said vessel electrolyzing an alkali metal or alkaline earth metal salt to said halogenation reactor. 82. The system of any one of claims 65-81, comprising a conveying device for conveying at least one of (1) silicon tetrahalides and (2) trihalosilanes from the halogenation reactor to the silane reactor. . 82. The system of any of claims 65-81, wherein the hydrogen comprises a hydrogen halide burner that reacts with a halogen gas to produce hydrogen halide. 84. The system of claim 83, comprising a conveying device for conveying hydrogen halide to said halogenation reactor. 85. The system of claim 82 or 84, comprising a conveying device for conveying halogen gas from said vessel for electrolyzing an alkali metal or alkaline earth metal salt to said hydrogen halide burner. 86. The system of any of claims 65-85, comprising a silicon reservoir and a conveying device for conveying silicon to the halogenation reactor. 87. The system of any of claims 65-86, which is substantially closed loop for hydrogen. 88. The system of claim 87, wherein the system does not include an input stream containing hydrogen other than the hydrogen make-up stream. 89. The system of claim 87 or 88, wherein the system does not comprise an outlet stream containing hydrogen, if not as an impurity. 90. The system of any of claims 65-89, which is substantially closed loop with respect to halogen. 91. The system of claim 90, wherein the system does not include an input stream containing halogen other than the halogen make up stream. 92. The system of claim 90 or 91, wherein the system does not comprise an effluent stream containing halogen if not as an impurity. 97. The system of any of claims 65-92, which is substantially closed loop with respect to alkali metal or alkaline earth metal. 95. The system of claim 93, wherein the system does not include an input stream containing alkali metal or alkaline earth metal other than the alkali metal or alkaline earth metal make-up stream. 95. The system of claim 93 or 94, wherein the system does not include an effluent stream containing alkali metal or alkaline earth metal, if not as impurities.

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