RU2807187C1 - Combined production method and combined installation for producing zirconium oxide and methyl chlorosilane and/or polysilicon - Google Patents

Abstract

FIELD: production of zirconium oxide and silicone monomers.

SUBSTANCE: combined method for producing zirconium oxide and methyl chlorosilane is proposed, including: producing zirconium oxide using zircon sand, carbon, chlorine gas, silicon and hydrogen chloride as raw materials, and the products separated during the production of zirconium oxide include gas-phase products and liquid-phase products, while methylchlorosilane is obtained from gas-phase products separated during the preparation of zirconium oxide. A combined production method has also been proposed, which makes it possible to obtain polycrystalline silicon in addition to zirconium oxide and methylchlorosilane using liquid-phase products as raw materials, and corresponding installations.

EFFECT: use of carbon monoxide, hydrogen chloride and other waste gases formed during production of zirconium oxide as raw materials for production of methylchlorosilane, and the silicon tetrachloride formed as a by-product as a raw material for production of polycrystalline silicon allows the efficient reuse of waste gases and silicon tetrachloride, reducing processing costs waste gases and silicon tetrachloride and the costs of producing methylchlorosilane and polycrystalline silicon, and excluding environmental pollution.

31 cl, 3 dwg, 1 tbl, 27 ex

Description

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to Chinese Patent Application No. CN201811510146.5, filed on December 11, 2018, entitled “Combined Method for Producing Zirconium Oxide, Methylchlorosilane and/or Polycrystalline Silicon and Combination Plant,” which is incorporated herein by reference in its entirety.

Field of invention

The present invention relates to the technical field of producing zirconium oxide and silicone monomers, and, in particular, relates to a combined method for producing zirconium oxide, methylchlorosilane and/or polycrystalline silicon, as well as a combined installation.

BACKGROUND OF THE INVENTION

Zirconium dioxide (ZrO ₂ ) is an important ceramic material with excellent properties such as high temperature resistance, wear resistance and corrosion resistance. In addition to applications as refractory materials and ceramic pigments, it has become an important raw material for electronic ceramics, functional ceramics and artificial gemstones, and is increasingly used in high-tech fields. Zirconium tetrachloride is the base raw material for producing zirconium oxide, and the method for producing zirconium tetrachloride is also a key step in producing zirconium oxide. During the production of zirconium tetrachloride by the chlorination process, a large amount of CO-containing exhaust gas is generated. During the zirconium oxide production process, a large amount of waste acid solution will be generated, and the direct discharge will cause environmental pollution on the one hand and loss of valuable resources on the other hand.

The essence of the invention

To solve the above problems in the prior art, the present invention provides a combined method for producing zirconium oxide and methylchlorosilane and/or polycrystalline silicon and a combined plant, wherein the combined method can use off-gases such as carbon monoxide and hydrogen chloride generated during the production of zirconium oxide, in as a raw material for the production of methylchlorosilane, so as to enable the efficient reuse of off-gases with great profit, which further reduces the cost of off-gas treatment and the cost of producing methylchlorosilane. At the same time, the liquid-phase silicon tetrachloride product formed during the production of zirconium oxide can also be used as a raw material for the production of polycrystalline silicon.

In a first aspect, the present invention provides a combined process for producing zirconium oxide and methylchlorosilane, comprising:

producing zirconium oxide using zircon sand, carbon reducing agent, chlorine gas, silicon heat replenishing agent and hydrogen chloride as raw materials, and the products separated during the production of zirconium oxide include gas-phase products and liquid-phase products, and said gas-phase products include carbon monoxide, gas hydrogen and hydrogen chloride; And

producing methylchlorosilane using gas-phase products separated during the production of zirconium oxide as raw materials.

Preferably, the combined method particularly includes the following steps:

mixing and heating zircon sand, carbon reducing agent, chlorine gas, silicon heat replenishing agent and hydrogen chloride in the first reactor, the zircon sand, carbon reducing agent and chlorine gas reacting to form zirconium tetrachloride, silicon tetrachloride and carbon monoxide; the heat replenishing agent silicon, chlorine gas and hydrogen chloride react to form silicon tetrachloride and hydrogen gas so as to obtain a first gas-phase mixture;

removing hydrogen chloride and chlorine gas from the first gas-phase mixture by passing the first gas-phase mixture through silicon powder in a dechlorinator;

cooling the first gas-phase mixture from which hydrogen chloride and chlorine gas have been removed to separate the rough solid zirconium tetrachloride; hydrolyzing the rough solid zirconium tetrachloride to form zirconium oxychloride to obtain a hydrolyzate mixture; then subjecting the hydrolyzate mixture to evaporation, crystallization and solid-liquid separation to obtain solid zirconium oxychloride; and heating the solid zirconium oxychloride in a second reactor to produce zirconium oxide;

washing the first gas-phase mixture from which the crude solid zirconium tetrachloride has been removed using silicon tetrachloride as a washing solution to recover silicon tetrachloride therefrom so as to obtain a second gas-phase mixture containing carbon monoxide and hydrogen gas;

introducing a second gas-phase mixture into a third reactor; compressing and heating to react and form methanol so as to obtain a third gas-phase mixture;

introducing a third gas-phase mixture into a fourth reactor and introducing hydrogen chloride into the fourth reactor, heating to react methanol with hydrogen chloride to form chloromethane so as to obtain a fourth gas-phase mixture;

introducing a fourth gas-phase mixture into a fifth reactor; and introducing silicon powder into the fifth reactor, heating to react chloromethane with the silicon powder to form methylchlorosilane so as to obtain a fifth gas-phase mixture.

Preferably, the combination method further includes the following steps:

detecting the molar ratio of carbon to hydrogen in the gases introduced into the third reactor using a hydrocarbon detector, when the detected molar ratio of carbon to hydrogen is greater than the predetermined molar ratio of carbon to hydrogen, introducing hydrogen gas into the third reactor until the molar ratio of carbon to hydrogen in the gases introduced into the third reactor will not be equal to the predetermined molar ratio of carbon to hydrogen; when the detected molar ratio of carbon to hydrogen is less than the predetermined molar ratio of carbon to hydrogen, reduce the amount of hydrogen chloride introduced into the first reactor until the molar ratio of carbon to hydrogen in the gases introduced into the third reactor is equal to the predetermined molar ratio of carbon to hydrogen.

The predetermined molar ratio of carbon to hydrogen is from 1:4 to 1:5.

Preferably, the third reactor has a pressure of from 5.0 MPa to 6.0 MPa and a heating temperature of from 220ºC to 250ºC.

Preferably, the combination method further includes the following steps:

introducing one or more of the gas-phase products obtained by evaporating the hydrolyzate mixture and crystallizing the hydrolyzate mixture into a stripper column for stripping hydrogen chloride, and then using the stripped hydrogen chloride as a source of hydrogen chloride for introduction into the fourth reactor.

Preferably, said stripping column has a stripping temperature of 40°C to 60°C and a pressure of 0.1 MPa to 0.3 MPa.

Preferably, the combination method further includes the following steps:

introducing gas-phase products obtained by evaporating the hydrolyzate mixture into the heat exchanger as a heat source; introducing the hydrolyzate mixture into the heat exchanger to increase the temperature by heat exchange, then evaporating the hydrolyzate mixture after increasing the temperature by heat exchange; introducing the gas-phase products obtained by evaporating the hydrolyzate mixture into a heat exchanger to reduce the temperature due to heat exchange, followed by introducing the gas-phase products into a stripping column for stripping.

Preferably, the combination method further includes the following steps:

cooling the hydrogen chloride discharged from the gas-phase outlet of the stripping column to separate water therefrom; and introducing the hydrogen chloride from which the water has been removed into the fourth reactor.

Preferably, before subjecting the hydrolyzate mixture to evaporation, crystallization and solid-liquid separation to obtain solid zirconium oxychloride, the combination method further includes the following steps:

subjecting the hydrolyzate mixture to solid-liquid separation to remove solid impurities from it.

Preferably, before introducing the second gas-phase mixture into the third reactor, the combination method further includes the following steps:

cooling the second gas phase mixture to separate the liquid silicon tetrachloride so as to obtain purified products of the second gas phase.

Preferably, the combination method further includes the following steps:

using liquid silicon tetrachloride, separated by cooling the second gas-phase mixture, as a cold source for the cooling step and separating the crude solid zirconium tetrachloride from the first gas-phase mixture; and/or

using liquid silicon tetrachloride, separated by cooling the second gas-phase mixture, as a washing solution for the step of washing the first gas-phase mixture, from which silicon tetrachloride was separated, to remove silicon tetrachloride.

Preferably, before introducing the third gas-phase mixture into the fourth reactor, the combination method further includes the following steps:

cooling the third gas-phase mixture to obtain raw methanol and purifying the raw methanol by rectification to obtain purified products of the third gas phase.

Preferably, before introducing the fourth gas-phase mixture into the fifth reactor, the combination method further includes the following steps:

washing and cooling the fourth gas phase mixture using water as a wash solution to remove methanol and hydrogen chloride, and then drying to remove water so as to obtain purified fourth gas phase products.

Preferably, the first reactor has a heating temperature of from 1050°C to 1200°C, and/or the second reactor has a heating temperature of from 800°C to 1000°C.

Preferably, the fourth reactor has a heating temperature of from 130ºC to 150ºC.

Preferably, the fifth reactor has a heating temperature of from 280ºC to 320ºC.

Preferably, the combination method further includes the following steps:

returning the liquid obtained by evaporation, crystallization and solid-liquid separation of the hydrolyzate mixture into the hydrolyzate mixture, which is obtained by hydrolyzing the crude solid zirconium tetrachloride to form zirconium oxychloride, and then subjecting the hydrolyzate mixture to evaporation, crystallization and solid-liquid separation.

In a second aspect, the present invention also provides a combination process for producing zirconium oxide, methyl chlorosilane and polycrystalline silicon, wherein said liquid phase products separated during the above combined process for producing zirconium oxide and methyl chlorosilane include silicon tetrachloride, and said silicon tetrachloride is used as a raw material for producing polycrystalline silicon.

Preferably, according to the above combined method for producing zirconium oxide and methylchlorosilane, it further includes the following steps:

using liquid-phase silicon tetrachloride products separated during the production of zirconium oxide as a raw material for producing polycrystalline silicon, which includes first performing hydrochlorination of said silicon tetrachloride to produce trichlorosilane, and then carrying out a reduction reaction of trichlorosilane with hydrogen to produce polycrystalline silicon.

In a third aspect, the present invention also provides a combination plant for producing zirconium oxide and methylchlorosilane used in the above combination method, comprising:

zirconium oxide producing device, which is used to produce zirconium oxide using zircon sand, carbon reducing agent, chlorine gas, silicon heat replenishing agent and hydrogen chloride as raw materials, and is also used to separate the gas-phase products of carbon monoxide, hydrogen gas and hydrogen chloride obtained during obtaining zirconium oxide;

a methylchlorosilane producing device which is connected to said zirconium oxide producing device and which is used to produce methylchlorosilane using gas-phase products of carbon monoxide, hydrogen gas and hydrogen chloride separated from said zirconium oxide producing device as raw materials.

Preferably,

the zirconium oxide production device includes a first reactor, a dechlorinator, a first cooling separator, a hydrolysis tank, an evaporator, a crystallizer, a first solid-liquid separator, a second reactor and a washing column,

the methylchlorosilane producing apparatus includes a third reactor, a fourth reactor and a fifth reactor;

wherein said first reactor is used for mixing and heating the zircon sand, carbon reducing agent, chlorine gas, silicon heat replenishing agent and hydrogen chloride, causing the zircon sand, carbon reducing agent and chlorine gas to react to form zirconium tetrachloride, silicon tetrachloride and carbon monoxide; and causing the heat replenishing agent silicon, chlorine gas, hydrogen chloride to react to form silicon tetrachloride, hydrogen gas, so as to obtain a first gas-phase mixture;

said dechlorinator is disposed between said first reactor and said first cooling separator, and said dechlorinator is connected to said first reactor and said first cooling separator, respectively; alternatively, said dechlorinator is disposed in said first reactor and separates a first reaction chamber provided in the first reactor from the outlet of the first reactor, and the dechlorinator is used to remove chlorine gas, hydrogen chloride in the first gas phase mixture using silicon powder therein;

said first cooling separator is connected to said first reactor and is used to cool the introduced first gas-phase mixture from which hydrogen chloride and chlorine have been removed so as to separate rough solid zirconium tetrachloride and obtain a first gas-phase mixture without rough solid zirconium tetrachloride;

said hydrolysis tank is connected to said first cooling separator, and said crude solid zirconium tetrachloride is introduced into the hydrolysis tank and then hydrolyzed to form zirconium oxychloride so as to obtain a hydrolyzate mixture;

said evaporator is connected to said hydrolysis tank, and said hydrolyzate mixture is introduced into the evaporator for evaporation;

said crystallizer is connected to said evaporator, and the hydrolyzate mixture after evaporation is introduced into the crystallizer for crystallization;

said first solid-liquid separator is connected to said crystallizer, and the hydrolyzate mixture after crystallization is introduced into the first solid-liquid separator to separate the solid and liquid phases so as to obtain solid zirconium oxychloride;

said second reactor is connected to said first solid-liquid separator, and solid zirconium oxychloride is introduced into the second reactor and heated to produce zirconium oxide;

said washing column is connected to said first cooling separator, and the first gas-phase mixture from which the rough solid zirconium tetrachloride has been removed is washed using silicon tetrachloride as a washing solution to recover liquid silicon tetrachloride so as to obtain a second gas-phase mixture containing carbon monoxide and hydrogen gas;

said third reactor is connected to said washing column, and said second gas-phase mixture is introduced into the third reactor, compressed and heated to react the second gas-phase mixture and produce methanol so as to obtain a third gas-phase mixture;

said fourth reactor is connected to said third reactor, said third gas-phase mixture is introduced into the fourth reactor; hydrogen chloride is introduced into the fourth reactor; and both of them are heated to react methanol with hydrogen chloride to form chloromethane so as to obtain a fourth gas phase mixture;

said fifth reactor is connected to said fourth reactor, said fourth gas-phase mixture is introduced into the fifth reactor, silicon powder is introduced into the fifth reactor, and both of them are heated to react chloromethane with the silicon powder and form methylchlorosilane so as to obtain a fifth gas-phase mixture.

Preferably, the methylchlorosilane production apparatus further includes:

a hydrogen pipeline connected to the inlet of said third reactor, said hydrogen pipeline being used for introducing hydrogen into the third reactor, and said hydrogen pipeline being equipped with a first valve;

a hydrogen chloride pipeline connected to the inlet of said first reactor, wherein said hydrogen chloride pipeline is used for introducing hydrogen chloride into the first reactor, and said hydrogen chloride pipeline is equipped with a second valve;

a hydrocarbon detector for detecting the molar ratio of carbon to hydrogen in gases introduced into said third reactor;

a controller for receiving a value of a molar ratio of carbon to hydrogen in the gases in said third reactor detected by said hydrocarbon detector; when the molar ratio of carbon to hydrogen detected by the hydrocarbon detector becomes larger than a predetermined molar ratio of carbon to hydrogen, the controller opens the first valve to introduce hydrogen gas into the third reactor until the molar ratio of carbon to hydrogen in the gases introduced into the third reactor becomes equal to the predetermined molar ratio of carbon to hydrogen, and then the controller closes the first valve; when the molar ratio of carbon to hydrogen detected by the hydrocarbon detector becomes less than the predetermined molar ratio of carbon to hydrogen, the controller closes the second valve to reduce the amount of hydrogen chloride introduced into the first reactor until the molar ratio of carbon to hydrogen in the gases introduced into the third reactor is becomes equal to the preset molar ratio of carbon to hydrogen, and then the controller opens the second valve.

Preferably, the methylchlorosilane producing apparatus further includes:

a stripping column, and a gas outlet of said stripping column is connected to an inlet of said fourth reactor,

the inlet of said stripping column is connected to said evaporator, and gas-phase products evaporated in the evaporator are introduced into the stripping column for stripping hydrogen chloride, and the stripped hydrogen chloride is introduced into said fourth reactor as a source of hydrogen chloride; and/or

the inlet of said stripping column is connected to said crystallizer, and the gas phase crystallized in the crystallizer is introduced into the stripping column to strip off hydrogen chloride, and the stripped hydrogen chloride is introduced into said fourth reactor as a source of hydrogen chloride.

Preferably, the methylchlorosilane producing apparatus further includes:

a heat exchanger which is connected to said stripping column and also connected to said evaporator, and gas-phase products obtained by evaporating the hydrolyzate mixture by means of the evaporator are introduced into the heat exchanger as a heat source, and the hydrolyzate mixture is introduced into the heat exchanger to raise the temperature by heat exchange, and then gas-phase The products obtained by evaporation of the hydrolyzate mixture are introduced into the heat exchanger to reduce the temperature by heat exchange, after which the gas-phase products are introduced into the stripper column for stripping.

Preferably, the methylchlorosilane producing apparatus further includes:

a cooling separator at the top of the stripping column, wherein an inlet of the cooling separator at the top of the stripping column is connected to a gas outlet of the stripping column, a liquid outlet of the cooling separator at the top of the stripping column is connected to the inlet at the top of the stripping column, and a gas outlet of the cooling separator at the top of the stripping column is connected to said fourth reactor, and a cooling separator at the top of the stripper is used to cool and separate the water, and the cooled and separated water flows back into the stripper, and the hydrogen chloride from which the water has been removed flows into the fourth reactor.

Preferably, said zirconium oxide producing device further includes:

a second solid-liquid separator, wherein an inlet of said second solid-liquid separator is connected to an outlet of said hydrolysis tank, an outlet of the second solid-liquid separator is connected to an inlet of said evaporator, and the hydrolyzate mixture is introduced through the hydrolysis tank into the second solid-liquid separator to perform solid-liquid separation, removing solid impurities, and then flows into the evaporator.

Preferably, said zirconium oxide producing device further includes:

a first cooler disposed between said wash column and said third reactor, wherein an inlet of said first cooler is connected to a gas outlet of the wash column, a gas outlet of the first cooler is connected to an inlet of the third reactor, and the first cooler is used to cool the second gas-phase mixture to separate liquid silicon tetrachloride, in order to obtain purified products of the second gas phase.

Preferably, a liquid outlet of said first cooler is connected to an inlet of said first cooling separator, and liquid silicon tetrachloride separated from the second gas-phase mixture is introduced into the first cooling separator as a cold source for cooling the first gas-phase mixture to separate rough solid zirconium tetrachloride; and/or

a liquid outlet of said first cooler is connected to a wash solution inlet of the wash column, and liquid silicon tetrachloride separated by cooling the second gas-phase mixture is introduced into the wash column for washing to recover silicon tetrachloride.

Preferably, said methylchlorosilane producing apparatus further includes:

a second cooler connected to said third reactor, the third gas phase entering said second cooler for cooling to produce raw methanol;

a distillation column placed between said second cooler and said fourth reactor, wherein the distillation column is connected to the second cooler and the fourth reactor, respectively, and the raw methanol is introduced into the distillation column for purification to obtain purified third gas phase products.

Preferably, said methylchlorosilane producing apparatus further includes:

a washing and cooling column connected to said fourth reactor, the fourth gas-phase mixture entering said washing and cooling column, and washing and cooling water being used as a washing solution to remove methanol and hydrogen chloride;

a drying column placed between said washing and cooling column and said fifth reactor, the drying column being used for drying and removing dimethyl ether, a by-product during the reaction of water, methanol and hydrogen chloride to form methyl chlorosilane, so as to obtain purified products of the fourth gas phase .

Preferably, the liquid outlet of said first solid-liquid separator is connected to the inlet of said hydrolysis tank, and the liquid in the first solid-liquid separator flows into the hydrolysis tank.

In a fourth aspect, the present invention also provides a combination plant for producing zirconium oxide, methyl chlorosilane and polycrystalline silicon, and in addition to the plant used for the combined method for producing zirconium oxide and methyl chlorosilane used in the above method, it further includes:

a polycrystalline silicon producing device which is connected to said zirconium oxide producing device and is used to produce polycrystalline silicon using silicon tetrachloride separated by said zirconium oxide producing device as a raw material.

Compared with the prior art, the present invention provides the following advantageous results:

In the combined method for producing zirconium oxide, methylchlorosilane and polycrystalline silicon and the combination plant proposed in the present invention, not only carbon monoxide, hydrogen chloride and other waste gases generated during the production of zirconium oxide, but also silicon tetrachloride are used as raw materials for producing methylchlorosilane - the by-product generated during the production of zirconium oxide is also used as a raw material for the production of polycrystalline silicon, so that both the waste gases and silicon tetrachloride can be efficiently recycled with great benefit, which reduces the cost of treating the waste gases and silicon tetrachloride, eliminates environmental pollution, reduces the cost of producing methylchlorosilane and polycrystalline silicon and increases the technological level, as well as overall economic benefits.

Brief description of drawings

FIG. 1 is a schematic flow diagram of a combined plant for the production of zirconium oxide, methylchlorosilane and/or polycrystalline silicon shown in Example 2 of the present invention;

FIG. 2 is a schematic flow diagram of a combined plant for the production of zirconium oxide and methylchlorosilane and/or polycrystalline silicon shown in Example 3 of the present invention;

FIG. 3 is a flowchart of the combined process for producing zirconium oxide, methylchlorosilane and/or polycrystalline silicon shown in Example 2 of the present invention.

In the figures: 1 - first reactor; 2 - first cooling separator; 3 - hydrolysis tank (hydrolyzer); 4 - evaporator; 5 - crystallizer; 6 - first separator of solid and liquid phases; 7 - second reactor; 8 - washing column (scrubber); 9 - third reactor; 10 - fourth reactor; 11 - fifth reactor; 12 - third cooler; 13 - third storage tank; 14 - hydrogen pipeline; 15 - hydrocarbon detector; 16 - first valve; 17 - stripping column; 18 - heat exchanger; 19 - evaporation boiler of the stripping column; 20 - second separator of solid and liquid phases; 21 - first cooler; 22 - first storage tank; 23 - first transfer pump; 24 - compressor; 25 - second cooler; 26 - distillation column; 27 - second storage tank; 28 - second transfer pump; 29 - washing and cooling column; 30 - drying column; 31 - heater; 32 - mill; 33 - centrifugal separator; 34 - cooling separator at the top of the stripping column; 35 - dechlorinator; 36 - first reaction chamber; 37 - release of the first reactor; 38 - hydrogen chloride pipeline; 39 - inlet of the first reactor; 40 - second valve.

Detailed Description of Preferred Embodiments

To make the technical solutions of the present invention more understandable to those skilled in the art, the present invention will be further described below in more detail with reference to the accompanying drawings and examples.

Examples of the present invention are described in detail below, which examples are illustrated in the accompanying drawings, in which the same or similar reference numerals denote the same or similar elements, or elements having the same or similar functions throughout the description. The examples described below with reference to the accompanying drawings are illustrative and are used only to explain the present invention, but should not be construed as limiting the present invention.

Example 1

An example of the present invention is a combined plant for the production of zirconium oxide and methylchlorosilane, containing:

a zirconium oxide producing device which is used to produce zirconium oxide using zircon sand, carbon reducing agent, chlorine gas, silicon heat replenishing agent and hydrogen chloride as raw materials, and this zirconium oxide producing device is also used to separate the gas-phase products of carbon monoxide, hydrogen gas and hydrogen chloride formed during the production of zirconium oxide;

a methylchlorosilane producing device which is connected to the zirconium oxide producing device and which is used to produce methyl chlorosilane using separated gas-phase products of carbon monoxide, hydrogen gas and hydrogen chloride from the zirconium oxide producing device as raw materials.

An example of the present invention also provides a combined method for producing zirconium oxide and methyl chlorosilane using the above combined plant for producing zirconium oxide and methyl chlorosilane, comprising:

producing zirconium oxide using zircon sand, carbon reducing agent, chlorine gas, silicon heat replenishing agent and hydrogen chloride as raw materials, wherein the gas-phase products separated during the production of zirconium oxide include gas-phase products of carbon monoxide, hydrogen gas and hydrogen chloride; And

producing methylchlorosilane using gas-phase products separated during the production of zirconium oxide as raw materials.

In an example of the present invention, carbon monoxide and hydrogen chloride generated during the production of zirconium oxide are used as raw materials for the production of methyl chlorosilane, so that both off-gases and silicon tetrachloride can be efficiently recycled with great benefit, which reduces off-gas treatment costs and silicon tetrachloride, eliminates environmental pollution, reduces the cost of producing methylchlorosilane and polycrystalline silicon and increases the technological level, as well as overall economic benefits.

Example 2

As shown in FIG. 1, an example of the present invention represents a combined installation used for implementing a combined method for producing zirconium oxide and methylchlorosilane, containing:

a zirconium oxide producing device which is used to produce zirconium oxide using zircon sand, carbon reducing agent, chlorine gas, silicon heat replenishing agent and hydrogen chloride as raw materials, and this zirconium oxide producing device is also used to separate the gas-phase products of carbon monoxide, hydrogen gas and hydrogen chloride formed during the production of zirconium oxide;

a methylchlorosilane producing device which is connected to the zirconium oxide producing device and which is used to produce methyl chlorosilane using separated gas-phase products of carbon monoxide, hydrogen gas and hydrogen chloride from the zirconium oxide producing device as raw materials.

In addition, the device for producing zirconium oxide in this example includes: a first reactor 1, a dechlorinator 35, a first cooling separator 2, a hydrolysis tank 3, an evaporator 4, a crystallizer 5, a first solid-liquid separator 6, a second reactor 7 and a washing column 8.

Zircon sand, carbon reducing agent, chlorine gas, heat replenishing agent silicon and hydrogen chloride are mixed and heated in the first reactor 1, in which zircon sand, carbon reducing agent and chlorine gas react to form zirconium tetrachloride, silicon tetrachloride and carbon monoxide; the heat replenishing agent silicon, chlorine gas and hydrogen chloride react to form silicon tetrachloride and hydrogen gas, so that the first gas-phase mixture is obtained.

More specifically, the first reactor 1 is provided with one or more gas inlet(s) for introducing chlorine gas and hydrogen chloride. The first reactor 1 is also provided with one or more feed channel(s) for adding zircon sand, carbon reducing agent and silicon heat replenishing agent. In this example, the interior of the first reactor 1 includes a first reaction chamber 36, and this first reaction chamber 36 is preferably located at the lower part of the interior of the first reactor 1. The first reactor 1 should also have a heating function for heating the first reaction chamber 36, and has a heating temperature from 1050ºС to 1200ºС.

The dechlorinator 35 is located in the first reactor 1 and separates the first reaction chamber 36 provided in the first reactor 1 from the outlet 37 of the first reactor. The dechlorinator 35 is provided with silicon powder for removing chlorine gas and hydrogen chloride from the first gas phase mixture by passing the first gas phase mixture through the silicon powder in the dechlorinator 35.

The first cooling separator 2 is connected to the first reactor 1 and is used to cool the input of the first gas-phase mixture from which hydrogen chloride and chlorine gas have been removed so as to separate rough solid zirconium tetrachloride and obtain a first gas-phase mixture without rough solid zirconium tetrachloride; the top of the column of the first cooling separator 2 is equipped with a first temperature detection device and a first reflux wash solution flow control device, wherein the first temperature detection device and the first reflux wash solution flow control device are connected in a cascade circuit for controlling the first cooling separator to maintain a proper cooling temperature. In this example, the first cooling separator 2 preferably has a heating temperature of from 180ºC to 250ºC.

The hydrolysis tank 3 is connected to the first cooling separator 2, and the rough solid zirconium tetrachloride is introduced into the hydrolysis tank 3 and then hydrolyzed to form zirconium oxychloride so as to obtain a hydrolyzate mixture. In this example, the hydrolysis tank 3 is made of graphite.

An evaporator 4 is connected to the hydrolysis reservoir 3, and the hydrolyzate mixture is introduced into the evaporator 4 for evaporation. In this example, the evaporator 4 is made of graphite.

A crystallizer 5 is connected to the evaporator 4, and the hydrolyzate mixture after evaporation is introduced into the crystallizer 5 for crystallization. In this example, the crystallizer 5 is made of glass facing material.

A first solid-liquid separator 6 is connected to the crystallizer 5, and the hydrolyzate mixture after crystallization is introduced into the first solid-liquid separator 6 to separate the solid and liquid phases so as to obtain solid zirconium oxychloride; more specifically, the solid-liquid separator 6 in this example is a belt filter, and preferably the belt filter is a vacuum belt filter.

A second reactor 7 is connected to the first solid-liquid separator 6, and solid zirconium oxychloride is introduced into the second reactor 7 and heated to produce zirconium oxide. In this example, the second reactor 7 may have a heating temperature from 800ºC to 1000ºC.

A washing column 8 is connected to the first cooling separator 2, and the first gas-phase mixture from which rough solid zirconium tetrachloride has been removed is introduced into the washing column 8, then it is washed using silicon tetrachloride as a washing solution to recover liquid silicon tetrachloride so that obtain a second gas-phase mixture containing carbon monoxide and hydrogen gas. In this example, the washing column 8 is a sieve tray column, and the washing column 8 is preferably designed to use silicon tetrachloride as the washing solution. The top of the washing column 8 is equipped with a second temperature detection device and a second washing solution flow control device, and the second temperature detection device and a second washing solution flow control device are connected in a cascade circuit to control the washing column 8 to maintain a proper cooling temperature. In this example, the washing column 8 preferably has a heating temperature of -15ºC to 5ºC.

In addition, the methylchlorosilane production apparatus in this example mainly includes: a third reactor 9, a fourth reactor 10 and a fifth reactor 11.

The third reactor 9 is connected to the washing column 8, and the second gas-phase mixture is introduced into the third reactor 9 and is compressed and heated to react the second gas-phase mixture to form methanol, so as to obtain the third gas-phase mixture. In this example, the third reactor 9 must have heating and pressurizing functions, and the third reactor 9 may have a heating temperature of 220ºC to 250ºC and a pressure of 5.0 MPa to 6.0 MPa.

Connected to the third reactor 9 is a fourth reactor 10. A third gas-phase mixture is introduced into the fourth reactor 10, and hydrogen chloride is introduced into the fourth reactor 10, both of which are heated to react methanol with hydrogen chloride to form chloromethane, so as to obtain a fourth gas-phase mixture. In this example, the fourth reactor 10 may have a heating temperature of from 130ºC to 150ºC.

Connected to the fourth reactor 10 is a fifth reactor 11. A fourth gas-phase mixture is introduced into the fifth reactor 11, and silicon powder is introduced into the fifth reactor, both of which are heated to react chloromethane with the silicon powder to form methylchlorosilane, so as to obtain a fifth gas-phase mixture. More specifically, the fifth reactor 11 is a fluidized bed reactor and may have a heating temperature of 280°C to 320°C.

More specifically, the methylchlorosilane producing apparatus in this example further includes:

a third cooler 12, which is connected to the fifth reactor 11, and this third cooler 12 is used for cooling the fifth gas-phase mixture exiting the fifth reactor 11 to form a liquid;

a third storage tank 13, which is connected to the third cooler 12, and this third storage tank 13 is used to store the resulting liquid after cooling by the third cooler 12, which liquid is methyl chlorosilane.

It should be noted that the device for producing methylchlorosilane in this example further includes:

a hydrogen line 14 which is connected to the inlet of the third reactor 9 and is used for introducing hydrogen gas into the third reactor 9, and this hydrogen line 14 is provided with a first valve 16;

a hydrogen chloride line 38, which is connected to the inlet 39 of the first reactor and is used for introducing hydrogen chloride into the first reactor 1, and the hydrogen chloride line 38 is provided with a second valve 40;

a hydrocarbon detector 15, preferably located between the washing column 8 and the third reactor 9, which is used to detect the molar ratio of carbon to hydrogen in the gases introduced into the third reactor 9 and transmit the detected value of the molar ratio of carbon to hydrogen;

a controller that is electrically connected to the hydrocarbon detector and is used to receive a value of the molar ratio of carbon to hydrogen in gases that are introduced into the third reactor 9 detected by the hydrocarbon detector 15, and the controller is also electrically connected to the above first valve and the above second valve; a carbon to hydrogen molar ratio value is preset in the controller, and the carbon to hydrogen molar ratio detected by the hydrocarbon detector is compared by the controller with the preset value; when the molar ratio of carbon to hydrogen detected by the hydrocarbon detector becomes greater than the preset molar ratio of carbon to hydrogen, the controller opens the first valve 16 to introduce hydrogen gas into the third reactor 9 until the molar ratio of carbon to hydrogen becomes equal to the predetermined molar ratio the ratio of carbon to hydrogen, and then the controller closes the first valve 16; when the molar ratio of carbon to hydrogen detected by the hydrocarbon detector becomes less than the predetermined molar ratio of carbon to hydrogen, the controller closes the second valve 40 to reduce the amount of hydrogen chloride introduced into the first reactor 1 until the detected molar ratio of carbon to hydrogen becomes equal to the preset a given molar ratio of carbon to hydrogen, and then the controller opens the second valve 40.

Preferably, the combined plant for producing zirconium oxide and methylchlorosilane in this example further includes:

a stripping column 17, wherein the gas outlet of the stripping column 17 is connected to the inlet of the fourth reactor 10,

the inlet of the stripping column 17 is connected to the evaporator 4, and the gas-phase products evaporated by the evaporator 4 are introduced into the stripping column 17 to strip off hydrogen chloride, and the stripped hydrogen chloride is introduced into the fourth reactor 10 as a source of hydrogen chloride; and/or

the inlet of the stripping column 17 is connected to the crystallizer 5, and the gas-phase products crystallized in the crystallizer 5 are introduced into the stripping column 17 to strip off hydrogen chloride, and the stripped hydrogen chloride is introduced into the fourth reactor 10 as a source of hydrogen chloride.

It should be noted that the combined installation for producing zirconium oxide and methylchlorosilane in this example additionally includes:

a stripping column 17, wherein the gas outlet of the stripping column 17 is connected to the inlet of the fourth reactor 10,

the inlet of the stripping column 17 is connected to the evaporator 4, and the gas-phase products evaporated by the evaporator 4 are introduced into the stripping column 17 to strip off hydrogen chloride, and the stripped hydrogen chloride is introduced into the fourth reactor 10 as a source of hydrogen chloride; and/or

the inlet of the stripping column 17 is connected to the crystallizer 5, and the gas-phase products crystallized in the crystallizer 5 are introduced into the stripping column 17 to strip off hydrogen chloride, and the stripped hydrogen chloride is introduced into the fourth reactor 10 as a source of hydrogen chloride; And

The liquid outlet of the stripping column 17 is connected to the inlet of the hydrolysis tank 3, and the effluent liquid from the stripping column 17 is further sent to the hydrolysis tank 3 as hydrolysis water, thereby reducing the amount of water consumed for hydrolysis in the hydrolysis tank 3.

It should be noted that the device for producing methylchlorosilane in this example further includes:

heat exchanger 18, which is connected to the stripping column 17 and also connected to the evaporator 4, and the gas-phase products obtained by evaporating the hydrolyzate mixture in the evaporator 4 are introduced into the heat exchanger 18 as a heat source, and the hydrolyzate mixture is introduced into the heat exchanger 18 to increase the temperature due to heat exchange , and then the hydrolyzate mixture, after increasing the temperature due to heat exchange, is introduced into the evaporator 4 for evaporation, and then the gas-phase products obtained by evaporating the hydrolyzate mixture in the evaporator 4 are introduced into the heat exchanger 18 to reduce the temperature due to heat exchange, after which the gas-phase products are introduced into the stripping column 17 for steaming.

More specifically, heat exchanger 18 is used to recover heat from the gas phase produced in the evaporator and to preheat the hydrolyzate mixture exiting the hydrolysis tank. The heat exchanger 18 includes a cold source inlet, a cold source outlet, a heat source inlet, and a heat source outlet, wherein: the cold source inlet is connected to the outlet of the hydrolysis tank, and the cold source outlet is connected to the evaporator inlet, while the source inlet The heat source is connected to the gas outlet of the evaporator, and the heat source outlet is connected to the inlet of the stripping column. The gas-phase products obtained by evaporation in the evaporator 4 are introduced into the heat exchanger as a heat source through the heat source inlet, and the hydrolyzate mixture obtained from the hydrolysis tank 3 is introduced into the heat exchanger 18 through the cold source inlet to increase the temperature by heat exchange with the above source heat (that is, gas-phase products obtained by evaporation in the evaporator 4), and then the hydrolyzate mixture, after increasing the temperature due to heat exchange through the heat exchanger 18, is introduced into the evaporator 4 for evaporation, the gas-phase products obtained by evaporation in the evaporator 4 are introduced into the heat exchanger 18 to reduce the temperature due to heat exchange with the above hydrolyzate mixture introduced into the heat exchanger from the hydrolysis reservoir 3, after which it becomes a gas-liquid mixture. The gas-liquid mixture is then introduced into the stripping column 17 through a heat source inlet. In this example, the heat exchanger 18 is a shell-and-tube heat exchanger 18, and the heat exchanger 18 is made of graphite.

More specifically, the methylchlorosilane producing apparatus in this example further includes:

a stripping column evaporation boiler 19 is connected to the stripping column 17, and this stripping column evaporating boiler 19 is used to heat the bottom portion of the stripping column 17. More specifically, the inlet of the stripping column evaporation boiler 19 is connected to the stripping column boiler outlet, and the gas outlet of the flashing column 19 of the stripper is connected to the inlet of the stripper so as to return the gasification products to the stripper for re-stripping. The liquid outlet of the stripper boiler 19 and/or the stripper is connected to the hydrolysis tank 3 and is used to allow the effluent in the stripper boiler 19 and/or the stripper to further flow into the hydrolysis tank 3 so as to be used as water for hydrolysis, thereby the amount of water consumed for hydrolysis in the hydrolysis tank 3 can be reduced.

It should be noted that the zirconium oxide production device in this example further includes:

a second solid-liquid separator 20, wherein the inlet of the second solid-liquid separator 20 is connected to the outlet of the hydrolysis tank 3, the outlet of the second solid-liquid separator 20 is connected to the inlet of the evaporator 4, and the hydrolyzate mixture is introduced through the hydrolysis tank 3 into the second separator 20 solid-liquid phase to perform solid-liquid separation to remove solid impurities, and then flows into the evaporator 4. More specifically, the second solid-liquid separator 20 in this example is a filter press, and this filter press is made of FRPP (i.e. glass fiber reinforced polypropylene pipes).

More specifically, the zirconium oxide producing apparatus in this example further includes:

a first cooler 21, which is placed between the washing column 8 and the third reactor 9, and the inlet of the first cooler 21 is connected to the gas outlet of the washing column 8, the gas outlet of the first cooler 21 is connected to the inlet of the third reactor 9, and the first cooler 21 is used to cool the second gas-phase mixture exiting the wash column 8 to separate (or in other words, precipitate) liquid silicon tetrachloride so as to obtain purified second gas phase products. In this example, the first cooler 21 is a tubular heat exchanger.

In this example, the liquid outlet of the first cooler 21 is connected to the inlet of the first cooling separator 2, and liquid silicon tetrachloride separated from the second gas-phase mixture is introduced into the first cooling separator 2 as a cold source for cooling the first gas-phase mixture so as to separate rough solid tetrachloride zirconium; and/or

the liquid outlet of the first cooler 21 is connected to the inlet of the washing column 8, and liquid silicon tetrachloride separated by cooling the second gas-phase mixture is introduced into the washing column 8 for washing to remove or extract metal chloride impurities such as silicon tetrachloride in the second gas-phase mixture.

More specifically, the combined plant for producing zirconium oxide and methylchlorosilane in this example further includes:

a first storage tank 22, the inlet of the first storage tank 22 is connected to the outlet of the first cooler 21, the first storage tank 22 is used to store liquid silicon tetrachloride separated by the first cooler 21, a portion of the liquid silicon tetrachloride in the first storage tank 22 flows into the first transfer pump 23, which can then be used as a cold source for the first cooler 21 and/or used as a wash solution in the wash column 8, and the other part flows out for a subsequent process, for example, a polysilicon production process, that is, the first reservoir -storage 22 can also be connected to a device for producing polycrystalline silicon, such as a hydrochlorination reactor;

a first transfer pump 23, wherein an inlet of the first transfer pump 23 is connected to an outlet of the first storage tank 22, an outlet of the first transfer pump 23 is connected to an outlet of the washing column 8, and the first transfer pump 23 is used for pumping liquid silicon tetrachloride in the first storage tank 22 into washing column 8 as a washing solution, and/or the outlet of the first transfer pump 23 is connected to the first cooling separator 2, and the first transfer pump 23 is used to pump liquid silicon tetrachloride in the first storage tank 22 to the first cooling separator 2 of the washing column as a source cooling. In this example, the first transfer pump 23 is a sealed electric pump.

More specifically, the methylchlorosilane producing apparatus in this example further includes:

a compressor 24, wherein the inlet of the compressor 24 is connected to the gas outlet of the first cooler 21, the outlet of the compressor 24 is connected to the third reactor 9, and the compressor 24 is used to compress the purified products of the second gas phase.

It should be noted that the device for producing methylchlorosilane in this example additionally includes a second cooler 25 and a distillation column 26.

The second cooler 25 is connected to the third reactor 9 and is used to cool the third gas-phase mixture exiting the third reactor 9 so as to separate and produce raw methanol.

The distillation column 26 is located between the second cooler 25 and the fourth reactor 10 and is used for rectification and purification of raw methanol to obtain purified products of the third gas phase. More specifically, the inlet and gas outlet of the distillation column 26 are connected to the second cooler 25 and the fourth reactor 10, respectively, and the raw methanol is rectified and purified in the distillation column 29 to obtain purified third gas phase products. In this example, the process of rectification of raw methanol in a distillation column can be carried out in a standard way, which will not be repeated here.

In this example, the gas outlet of the second cooler 25 is connected to the inlet of the compressor 24. After the uncooled gases in the second cooler 25 are compressed by the compressor, they continue to flow into the third reactor 9 for reaction.

More specifically, the methylchlorosilane production apparatus in this example further includes a second storage tank 27 and a second transfer pump 28.

The second storage tank 27 is located between the second cooler 25 and the distillation column 26. More specifically, the inlet of the second storage tank 27 is connected to the liquid outlet of the second cooler 25, and the outlet of the second storage tank 27 is connected to the inlet of the distillation column 26. The second storage tank 27 is used for storing raw methanol;

The second transfer pump 28 is located between the second storage tank 27 and the distillation column. More specifically, the inlet of the second transfer pump 28 is connected to the second storage tank 27, and the outlet of the second transfer pump 28 is connected to the distillation column 26. The second transfer pump 28 is used to pump raw methanol to the distillation column 26.

It should be noted that the device for producing methylchlorosilane in this example further includes:

a washing and cooling column 29 connected to a fourth reactor 10, wherein the fourth gas-phase mixture enters the washing and cooling column 29, and water is used as the washing solution for washing and cooling to remove methanol and hydrogen chloride, in this example water (i.e. the washing solution) for the washing and cooling column 29 is demineralized water;

a drying column 30 placed between the washing and cooling column 29 and the fifth reactor 11, the drying column 30 being used for drying and removing dimethyl ether, a by-product during the reaction of water, methanol and hydrogen chloride to form methylchlorosilane, so as to obtain the purified products of the fourth gas phase. More specifically, the inlet of the drying column is connected to the gas outlet of the washing and cooling column, the outlet (gas outlet) of the drying column 30 is connected to the fifth reactor 11, and the drying column 30 is provided with a desiccant. In this example, the desiccant is preferably concentrated sulfuric acid.

More specifically, the methylchlorosilane producing apparatus in this example further includes:

a heater 31, wherein the inlet of the heater 31 is connected to the gas outlet of the drying column 30, the outlet of the heater 31 is connected to the inlet of the fifth reactor 11, and the heater 31 is used for heating the purified products of the fourth gas phase.

More specifically, the zirconium oxide producing apparatus in this example further includes:

a mill 32, the inlet of the mill 32 being connected to a solid outlet of the first solid-liquid separator 6, and the mill 32 being used to grind the solid separated by the first solid-liquid separator 6 so as to further release liquid from the solid;

a centrifugal separator 33, wherein the inlet of the centrifugal separator 33 is connected to the outlet of the mill 32, the outlet of the centrifugal separator 33 is connected to the inlet of the second reactor 7, and the centrifugal separator 33 is used for separating solid matter (ie ZrOCl ₂ 8H ₂ O).

It should be noted that in this example, the liquid outlet of the first solid-liquid separator 6 is connected to the inlet of the hydrolysis tank 3, which is used to allow the liquid separated in the first solid-liquid separator 6 to flow into the hydrolysis tank 3 so as to supplement water for hydrolysis, which can reduce the amount of water consumed for hydrolysis in the hydrolysis tank 3.

It should be noted that the device for producing methylchlorosilane in this example further includes:

a cooling separator 34 at the top of the stripping column, which is connected to the top of the stripping column 17. A cooling separator 34 at the top of the stripping column is used to cool and separate water, and the cooled and separated water flows back to the stripping column 17, and the gas outlet of the upper reboiler of the stripping column 17 connected to the quadruple reactor 10. More specifically, the stripper top cooling separator inlet is connected to the stripper gas outlet, the stripper top liquid separator liquid outlet is connected to the stripper top inlet, and the stripper top cooling separator gas inlet is connected to the fourth reactor; a cooling separator at the top of the stripper is used to cool the separated water, the cooled and separated water flows back into the stripper, and then the hydrogen chloride from which the water has been removed flows into the fourth reactor.

As shown in FIG. 3, an example of the present invention presents a combination method for producing zirconium oxide and methylchlorosilane using the above combination production plant, and this combination method includes the following steps:

(1) obtaining a first gas-phase mixture as an intermediate product: mixing and heating zircon sand, carbon reducing agent, chlorine gas, silicon heat replenishing agent and hydrogen chloride, wherein zircon sand, carbon reducing agent and chlorine gas react to form zirconium tetrachloride, silicon tetrachloride and carbon monoxide ; and the heat replenishing agent silicon, chlorine gas and hydrogen chloride react to form silicon tetrachloride and hydrogen gas so as to obtain a first gas-phase mixture;

wherein the heating temperature is from 1050ºC to 1200ºC, in this example the heating temperature is preferably 1050ºC; The molar ratio of zircon sand to the heat-replenishing agent silicon is 1:(1.2-1.6). In this example, the molar ratio is preferably 1:1.6, and silicon powder is preferably used as the silicon heat replenishing agent; the amount of carbon reducing agent must be maintained in excess, preferably chlorine gas and hydrogen chloride may also be in slight excess, and the specific amount can be selected according to the actual situation, which is not further specified in this example.

More specifically, in the first reactor 1, zircon sand, carbon reducing agent, chlorine gas, heat replenishing agent silicon and hydrogen chloride are mixed and the mixture is heated at a heating temperature of 1050ºC, wherein zircon sand, carbon reducing agent and chlorine gas react to form zirconium tetrachloride, silicon tetrachloride and monoxide carbon by carbochlorination reaction; and the heat replenishing agent silicon, chlorine gas and hydrogen chloride react at high temperature to form silicon tetrachloride and hydrogen gas so as to obtain a first gas-phase mixture; The molar ratio of zircon sand to silicon powder is 1:1.6.

In this example, the combination method further includes removing hydrogen chloride and chlorine gas from the first gas phase mixture. In this example, dechlorinator 35 is used to remove hydrogen chloride and chlorine gas.

More specifically, hydrogen chloride and chlorine gas are removed by passing the first gas-phase mixture through silicon powder in a dechlorinator 35.

(2) Preparation of zirconium oxide: cooling the first gas-phase mixture from which hydrogen chloride and chlorine gas have been removed to isolate crude solid zirconium tetrachloride; hydrolyzing the rough solid zirconium tetrachloride to form zirconium oxychloride to obtain a hydrolyzate mixture; then subjecting the hydrolyzate mixture to evaporation, crystallization and separation of solid and liquid phases to obtain solid zirconium oxychloride (the main component is ZrOCl ₂ 8H ₂ O); and then heating and calcining the solid zirconium oxychloride to obtain zirconium oxide by decomposition;

wherein the water for hydrolysis of solid zirconium oxychloride includes added fresh water, wherein the added fresh water is preferably demineralized water, and the weight ratio of zirconium tetrachloride to hydrolysis water is 1:(3-4). In this example, the mass ratio is preferably 1:3; and the treatment temperature for evaporating zirconium tetrachloride and water is from 85ºC to 100ºC, preferably 85ºC; the crystallization treatment temperature is from 30ºC to 45ºC, preferably 30ºC; the temperature at which solid zirconium oxychloride is heated and calcined is 800ºC to 1000ºC, and the preferred calcination temperature is 1000ºC; A belt filter, such as a vacuum belt filter, is used to separate the solid and liquid phases.

Optionally, the hydrolysis water in this example also includes waste water obtained from other stages of the combined production process in this example, such as low concentration acidic waste water obtained from the hydrochloric acid stripping process in the stripper 17, and liquid phase products obtained from time of evaporation, crystallization and separation of solid and liquid phases of the hydrolyzate mixture.

In this example, optionally before subjecting the hydrolyzate mixture to evaporation, crystallization, and solid-liquid separation to produce solid zirconium oxychloride, the combination method further includes the following steps: subjecting the hydrolyzate mixture to a solid-liquid separation treatment to remove solid impurities. In this example, subjecting the hydrolyzate mixture to a solid-liquid separation treatment means filtering the hydrolyzate mixture in a filter press, and the solids removed by filtration include unreacted zircon sand and a reducing agent.

Optionally, before heating and calcining the solid zirconium oxychloride, the combination method further includes the following steps: grinding the solid zirconium oxychloride to release liquid trapped in the solid zirconium oxychloride.

More specifically, the first gas-phase mixture from which hydrogen chloride and chlorine gas have been removed is cooled and separated in the first cooling separator 2 to separate rough solid zirconium tetrachloride, and the rough solid zirconium tetrachloride is introduced into the hydrolysis tank 3. Fresh water is added to the hydrolysis tank 3, and the fresh water added is demineralized water, and the water in the hydrolysis tank 3 includes: the low concentration acidic waste water obtained from the hydrochloric acid stripping process in the stripping column 17, and the filtrate obtained by filtration of the zirconium oxychloride crystal suspension. The mass ratio of crude zirconium tetrachloride to water is 1:3. The rough zirconium tetrachloride is hydrolyzed in the hydrolysis tank 3 to form zirconium oxychloride so as to obtain a hydrolyzate mixture, and then the hydrolyzate mixture is filtered in a filter press (ie, the second solid-liquid separator 20) to remove solid impurities, wherein the solid impurities include unreacted zircon sand and reducing agent;

Then the hydrolyzate mixture, from which impurities have been removed, is evaporated at 85ºC in evaporator 4 to obtain a concentrated solution with a ZrOCl ₂ (zirconium oxychloride) concentration of over 20 wt.%, and the concentrated solution is subjected to crystallization in crystallizer 5 at 30ºC to obtain a ZrOCl suspension ₂ 8H ₂ O (zirconium oxychloride octahydrate), the suspension after crystallization is filtered on a vacuum belt filter (i.e., the first solid-liquid separator 6) to obtain a solid phase, which is the filter cake ZrOCl ₂ 8H ₂ O. The resulting in filtration, the liquid is returned and introduced into the hydrolysis tank 3, and the solid filter cake obtained by separating the first solid and liquid phase separator 6 is introduced into the grinding mill 32, and the filter cake is ground to release the liquid trapped in the solid during crystallization, so as to obtain sludge, and then this sludge is introduced into the centrifugal separator 33 for separation by centrifugation to obtain ZrOCl ₂ 8H ₂ O as a product, and the solid zirconium oxychloride is calcined in the second reactor 7 at a high temperature, and the second reactor 7 has a calcination temperature 1000ºС. ZrOCl ₂ ·8H ₂ O decomposes into zirconium oxide, hydrogen chloride gas and water vapor.

(3) Obtaining a second gas-phase mixture as an intermediate product: washing the first gas-phase mixture from which the crude solid zirconium tetrachloride has been removed, cooling to separate and recover silicon tetrachloride therefrom, so as to obtain a second gas-phase mixture containing carbon monoxide and hydrogen gas . In this example, silicon tetrachloride (liquid) is used as the wash solution for washing.

It should be noted that step (3) also includes further purification of the second gas-phase mixture, and its specific steps are as follows: introducing the second gas-phase mixture into the first cooler 21 to cool and separate liquid silicon tetrachloride to obtain purified second gas-phase products, separated liquid tetrachloride the silicon is then sent to the first storage tank 22 for temporary storage.

In this example, part of the liquid silicon tetrachloride in the first storage tank 22 can be used as a cold source (such as a cold source in the first cooler 2) and/or a washing solution (such as a washing solution in a washing column 8), and the other part can be used for downstream processes such as polycrystalline silicon processes.

More specifically, the first gas-phase mixture separated from the rough solid zirconium tetrachloride in the first cooling separator 2 is washed using silicon tetrachloride as a washing solution to extract silicon tetrachloride therefrom, so as to obtain a second gas-phase mixture containing carbon monoxide and hydrogen gas ;

introducing a second gas-phase mixture into the first cooler 21 to cool and separate the liquid silicon tetrachloride so as to obtain purified products of the second gas phase, and the separated liquid silicon tetrachloride flows into the first storage tank 22, and pumping a portion of the liquid silicon tetrachloride from the first storage tank 22 into the wash column 8 by means of the first transfer pump 23 for use as a wash solution and pumping another part of it into the first cooler 2 by means of the first transfer pump 23 to use as a cold source for cooling the first gas-phase product, and the rest flows out for subsequent processes.

(4) Obtaining the intermediate product of methanol: the second gas-phase mixture is compressed and heated to react and produce methanol so as to obtain the third gas-phase mixture, where the compression pressure is from 5.0 MPa to 6.0 MPa, and the heating temperature is from 220ºС to 250ºС. In this example, the compression pressure is preferably 5.0 MPa, and the heating temperature is preferably 220°C.

In addition, the molar ratio of carbon to hydrogen in the purified products of the second gas phase is 1:(4-5), preferably the molar ratio of carbon to hydrogen is 1:4. Therefore, before subjecting the above purified second gas phase products to compression and heating to react to form methanol, the carbon to hydrogen molar ratio is detected and adjusted to achieve a desired carbon to hydrogen molar ratio range.

More specifically, the purified second gas-phase mixture is compressed by the compressor 24 and then introduced into the third reactor 9, and a hydrocarbon detector 15 is used to detect the molar ratio of carbon to hydrogen in the gases introduced into the third reactor 9; the preset molar ratio of carbon to hydrogen is 1:4; when the detected molar ratio of carbon to hydrogen becomes larger than the predetermined molar ratio of carbon to hydrogen, the controller opens the first valve 16 on the hydrogen pipeline 14 to introduce hydrogen gas into the third reactor 9 until the molar ratio of carbon to hydrogen becomes equal to a predetermined molar ratio of carbon to hydrogen, then the first valve 16 is closed by the controller; when the detected molar ratio of carbon to hydrogen becomes less than the preset molar ratio of carbon to hydrogen, the controller closes the second valve 40 to reduce the amount of hydrogen chloride introduced into the first reactor 1 until the molar ratio of carbon to hydrogen becomes equal to the predetermined molar ratio carbon to hydrogen, and the second valve 40 is opened by the controller.

The third reactor 9 has a compression pressure of 5.0 MPa and a heating temperature of 220ºC. A reaction is carried out to produce methanol so as to obtain a third gas-phase mixture.

In this example, it also includes purification of the third gas-phase mixture, which in particular includes the following steps:

introducing a third gas-phase mixture obtained from the reaction in the third reactor 9 into a second cooler 25 for cooling and separation so as to obtain raw methanol (i.e., a liquid-phase product obtained by cooling) and gas-phase products that are not cooled to liquid-phase products . The uncooled liquid products may be returned for mixing with the above purified second gas phase products, and then enter the third reactor 9 to react to form methanol. The raw methanol flows into the second storage tank 27, and then is pumped into the distillation column 26 by means of a second transfer pump 28, and the raw methanol is distilled and purified in the distillation column 26. The effluent is removed from the distillation column 26 to obtain purified third gas phase products, and the main component of the third gas phase products is methanol.

It should be noted that in this example, the technological conditions for purifying raw methanol in a distillation column may be existing traditional technological conditions, which will not be repeated here.

(5) Preparation of the chloromethane intermediate: mixing and heating the third gas-phase mixture with hydrogen chloride to react to form chloromethane and dimethyl ether so as to obtain a fourth gas-phase mixture;

wherein the heating temperature of the third gas-phase mixture and hydrogen chloride is from 130 to 150ºC, preferably 130ºC.

In this example, the combination method further includes the step of adding a catalyst, and the catalyst is preferably zinc chloride.

More specifically, the third gas-phase mixture is introduced into the fourth reactor 10, and hydrogen chloride is introduced into the fourth reactor 10, and they are heated in the fourth reactor 10, and the heating temperature is 130ºC, and the catalyst used for the reaction is zinc chloride, and a hydrochlorination reaction is carried out to form chloromethane and dimethyl ether to obtain a fourth gas phase mixture.

In this example, the hydrogen chloride introduced into the fourth reactor 10 in step (4) may be additionally introduced hydrogen chloride or hydrogen chloride separated from gas-phase products separated during the production of zirconium oxide, namely, one or more gas-phase products obtained by evaporating the hydrolyzate mixture in evaporator 4 and crystallization of the hydrolyzate mixture in the crystallizer 5, is introduced into the stripping column 17 to strip off hydrogen chloride, and the stripped hydrogen chloride is purified and then passed into the fourth reactor 10 as a source of the necessary hydrogen chloride.

In this example, the stripping column 17 has a stripping temperature from 40ºC to 60ºC and a pressure from 0.1 MPa to 0.3 MPa. In this example, the stripping column 17 preferably has a stripping temperature of 40ºC and a pressure of 0.3 MPa.

In some optional embodiments, stripping column 17 has a top temperature of 40°C to 60°C and a bottom temperature of 100°C to 120°C and a pressure of 20 kPa to 40 kPa.

More specifically, gas-phase products obtained by evaporating the hydrolyzate mixture in the evaporator 4 and crystallizing the hydrolyzate mixture in the crystallizer 5 are introduced into the stripping column 17 for stripping hydrogen chloride, and the stripping column 17 has a stripping temperature of 40ºC and a pressure of 0.3 MPa; introducing hydrogen chloride withdrawn from the gas-phase outlet of the stripping column 17 into a cooling separator 34 at the top of the stripping column to cool and separate water therefrom so as to obtain hydrogen chloride gas with a purity of more than 99.9 wt.% and a moisture content of less than 1000 ^ppm ; allow the water after cooling and separation to flow back into the stripping column 17, and discharge the waste liquid obtained after stripping (mainly low concentration waste acid) into the hydrolysis tank 3 as hydrolysis water; then hydrogen chloride from which water has been removed is introduced into the fourth reactor 10 as a source of hydrogen chloride;

The combined production method according to this example makes it possible to effectively use the acidic waste gas and waste liquid generated during the production of zirconium oxide with great benefit, avoid environmental pollution, reduce the cost of treating waste acid and gas, while at the same time reducing the cost of producing methyl chlorosilane.

It should be noted that in this example, gas-phase products obtained by evaporating the hydrolyzate mixture in the evaporator 4 are introduced into the heat exchanger 18 as a heat source; the hydrolyzate mixture from the hydrolysis tank 3 is introduced into the heat exchanger 18 to increase the temperature due to heat exchange, and then the hydrolyzate mixture, after increasing the temperature due to heat exchange, is introduced into the evaporator 4 for evaporation, and then the gas-phase products obtained by evaporating the hydrolyzate mixture in the evaporator 4 are introduced into the heat exchanger 18 to reduce the temperature due to heat exchange, after which the gas-phase products are introduced into the stripping column 17 for stripping; the bottom part of the stripping column 17 is heated by the evaporation boiler 19 of the stripping column and the waste liquid from the stripping column 17 is forced to further flow into the hydrolysis tank 3.

(6) Production of methylchlorosilane: heating the fourth gas-phase mixture and adding silicon powder, reacting chloromethane in the fourth gas-phase mixture with silicon powder to form methylchlorosilane so as to obtain a fifth gas-phase mixture, wherein the heating temperature of the fourth gas-phase mixture (i.e., the reaction temperature in the fifth reactor) is from 280ºC to 320ºC, preferably 280ºC. In this example, a catalyst is added during the reaction of chloromethane and silicon powder, and this catalyst may be copper or a copper salt, preferably copper.

It should be noted that in this example, before subjecting the fourth gas-phase mixture to reaction with silicon powder to form methylchlorosilane, the fourth gas-phase mixture is purified, washed and dried to obtain purified fourth gas-phase products. More specifically, the combined method includes the following steps:

introducing the fourth gas-phase mixture into the washing and cooling column 29, washing and cooling the fourth gas-phase mixture using water as a washing solution to remove methanol and hydrogen chloride from the fourth gas-phase mixture, and then introducing into the drying column 30 for drying to remove water and dimethyl ether , in order to obtain purified products of the fourth gas phase. In this example, the purity of methylchlorosilane in the purified products of the fourth gas phase is more than 99 wt.%.

More specifically, the above purified fourth gas phase mixture (ie, purified products of the fourth gas phase) is heated by the heater 31, and then the fourth gas phase mixture is introduced into the fifth reactor 11 at a heating temperature of 280°C; introducing silicon powder into the fifth reactor 11, heating to react chloromethane with silicon powder using copper or a copper salt as a catalyst to form methylchlorosilane, so as to obtain a fifth gas-phase mixture; the reaction process is exothermic, and the heat generated by the reaction process in the fifth reactor 11 is removed by cooling water to ensure that the fifth reactor 11 has a temperature of 280ºC; introducing the fifth gas-phase mixture into the third cooler 12 to cool and obtain a liquid, then introducing the resulting liquid into a third storage tank 13 for storing the cooled liquid, said liquid being methyl chlorosilane. When rectifying and purifying methylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane, trimethylchlorosilane and methyldichlorosilane are obtained.

In some optional embodiments, the zircon sand in this example is ZrSiO ₄ and the molar ratio of raw materials used is ZrSiO ₄ :C:Cl ₂ :Si:HCl=1:(4-5):4:(3-4): (12-16), the mass ratio is ZrSiO ₄ :C:Cl ₂ :Si:HCl=183:(48-60):283:(84-112):(439-583); After the zircon sand is subjected to the carbochlorination reaction, it is passed through silicon powder in a dechlorinator 35 to remove hydrogen chloride and chlorine gas, and the resulting product (i.e. the first gas phase mixture) has the composition: ZrCl = (186-233) kg, CO = (89-112) kg, SiCl ₄ = (815-849) kg, H ₂ = (12-16) kg; SiCl ₄ (zirconium tetrachloride) is hydrolyzed and calcined to form the zirconium oxide product (98-123) kg; after purification and cooling of the first gas-phase mixture, a second gas-phase mixture is obtained; after subjecting the second gas-phase mixture to cooling, methanolization reaction, cooling and rectification, 81-128 kg of methanol (ie purified products of the third gas phase) are obtained; the purified products of the third gas phase are subjected to a hydrochlorination reaction, stripping and drying to obtain 109-201 kg of methylchlorosilane (ie, purified products of the fourth gas phase); the purified products of the third gas phase are subjected to a hydrochlorination reaction, stripping and drying to obtain 109-201 kg of methylchlorosilane (ie, purified products of the fourth gas phase); after subjecting methylchlorosilane and silicon powder to liquefaction reaction treatment, cooling and separation, the product methylchlorosilane is obtained; after subjecting the methylchlorosilane product to rectification and purification, 98-361 kg of dimethyldichlorosilane can be obtained.

The combined method for producing zirconium oxide and methylchlorosilane and the combined installation in these examples make it possible to recycle the elements of chlorine, carbon and hydrogen, reduce the cost of producing chloromethane by 50-65% and reduce the cost of producing methylchlorosilane (mainly related to dimethyldichlorosilane) by 20-35 %; at the same time, they reduce the cost of treating waste water and waste gas during zirconium oxide production, in turn further reducing the total cost of zirconium oxide production by 10% to 15%, and finally avoiding greenhouse gas emissions . More specifically, this can be reflected in the following aspects:

Table 1 - Cost analysis of methanol production from natural gas (RMB/ton)

Raw gaseous materials 1050 Electricity 32 Auxiliary materials 72.5 Labor costs 4 Depreciation and management fees 212.6

In step (4), carbon monoxide and hydrogen gas in the exhaust gases during the production of zirconium oxide in steps (1) to (3) are converted into valuable materials, which not only makes it unnecessary to process the exhaust gases during the production of zirconium oxide, but also makes waste gases such as carbon monoxide and hydrogen gas are directly used as feedstock to produce methanol. During methanol production, carbon monoxide and hydrogen gas feedstocks account for up to 80% of the costs (as shown in Table 1), so methanol production costs can be reduced quite significantly, thereby reducing downstream production costs of methylchlorosilane (5) and (6).

In addition, in step (2), the hydrogen chloride-containing waste water and waste gas are directly used as raw materials for producing methyl chlorosilane in the subsequent step (5) by stripping in the stripping column 17, so that the hydrogen chloride-containing waste water and waste gas are converted into valuable materials, which not only eliminates the cost of treating waste water and waste gas, but also reduces the cost of producing methyl chlorosilane, thereby reducing the production costs of producing methyl chlorosilane in the downstream stage (6).

In the example of the present invention, carbon monoxide and hydrogen chloride generated during the production of zirconium oxide are used as raw materials for the production of methylchlorosilane, so that both the off-gases and silicon tetrachloride can be effectively reused with great benefit, which reduces the waste treatment costs. gases and silicon tetrachloride, eliminates environmental pollution, reduces the cost of production of methylchlorosilane and polycrystalline silicon and increases the technological level, as well as overall economic benefits.

Example 3

As shown in FIG. 2, the example of the present invention is a combined plant for producing zirconium oxide and methylchlorosilane, and the difference from the combined plant of Example 2 is as follows: the dechlorinator 35 is placed between the first reactor 1 and the first cooling separator 2, the inlet of the dechlorinator 35 is connected to the outlet of the first reactor 1 , and the outlet of the dechlorinator 35 is connected to the first cooling separator 2.

The example of the present invention also presents a combined method for producing zirconium oxide and methylchlorosilane using the above combination plant, and the difference from the combination method of Example 2 is as follows:

at stage (1), the first reactor 1 has a heating temperature of 1200ºC, and the molar ratio of zircon sand to silicon powder is 1:1.3;

at stage (2), the mass ratio of crude zirconium tetrachloride to water is 1:4, the evaporator 5 has a temperature of 100ºC, the crystallizer has a temperature of 40ºC, and the second reactor 7 has a high-temperature calcination temperature of 800ºC;

at stage (4), the preset molar ratio of carbon to hydrogen is 1:5, the third reactor 9 has a compression pressure of 6.0 MPa and a heating temperature of 250ºC;

at stage (5) the fourth reactor 10 has a heating temperature of 140ºC; stripping column 17 has a stripping temperature of 50ºC and a pressure of 0.1 MPa;

at stage (6), the fifth reactor 11 has a heating temperature of 320ºC.

Example 4

The example of the present invention is a combined process for producing zirconium oxide and methylchlorosilane using the combination plant of Example 2, and the difference from the method of Example 2 is as follows:

at stage (1), the first reactor 1 has a heating temperature of 1100ºC, and the molar ratio of zircon sand to silicon powder is 1:1.4;

at stage (2), the mass ratio of crude zirconium tetrachloride to water is 1:3.5, the evaporator 5 has a temperature of 95ºC, the crystallizer has a temperature of 45ºC, and the second reactor 7 has a high-temperature calcination temperature of 900ºC;

at stage (4), the preset molar ratio of carbon to hydrogen is 1:4.5, the third reactor 9 has a compression pressure of 5.5 MPa and a heating temperature of 235ºC;

at stage (5) the fourth reactor 10 has a heating temperature of 150ºC; stripping column 17 has a stripping temperature of 60ºC and a pressure of 0.2 MPa;

at stage (6), the fifth reactor 11 has a heating temperature of 300ºC.

Example 5

An example of the present invention is a combined plant for producing zirconium oxide, methyl chlorosilane and polycrystalline silicon, the plant including a combined plant for producing zirconium oxide and methyl chlorosilane according to Example 1 and further including:

a polycrystalline silicon producing device which is connected to the zirconium oxide producing device and is used to produce polycrystalline silicon using silicon tetrachloride recovered by the zirconium oxide producing device as a raw material.

The example of the present invention also provides a combined method for producing zirconium oxide, methyl chlorosilane and polycrystalline silicon using the above combined plant for producing zirconium oxide, methyl chlorosilane and polycrystalline silicon, comprising:

using liquid-phase products separated during the combined process for producing zirconium oxide and methylchlorosilane according to Example 1, said liquid-phase products including silicon tetrachloride, and said silicon tetrachloride being used as a raw material for producing polycrystalline silicon. More specifically, the stages are as follows:

using the liquid-phase silicon tetrachloride products separated during the combined process as a raw material for producing polycrystalline silicon, which includes first performing hydrochlorination of silicon tetrachloride to form trichlorosilane, and then carrying out a reduction reaction of trichlorosilane with hydrogen to obtain polycrystalline silicon.

In the example of the present invention, not only the carbon monoxide and hydrogen chloride generated during the production of zirconium oxide are used as raw materials for the production of methylchlorosilane, but also silicon tetrachloride, a by-product formed during the production of zirconium oxide, is used as a raw material for the production of polycrystalline silicon , and thus both waste gases and silicon tetrachloride can be effectively reused with great benefit, which reduces the cost of processing waste gases and silicon tetrachloride by-product, eliminates environmental pollution, reduces the cost of producing methylchlorosilane and polycrystalline silicon and increases technological efficiency level, as well as cumulative economic benefits.

Example 6

An example of the present invention is a combination plant for producing zirconium oxide, methylchlorosilane and polycrystalline silicon used in a combined method for producing zirconium oxide, methylchlorosilane and polycrystalline silicon, the plant including a combined plant for producing zirconium oxide and methylchlorosilane according to Example 2 or Example 3, and the zirconium oxide producing apparatus of this example is also used for separating silicon tetrachloride during the production of zirconium oxide.

As shown in FIG. 1 or FIG. 2, the combined installation for producing zirconium oxide, methylchlorosilane and polycrystalline silicon in this example further includes:

a polycrystalline silicon producing device (not shown in the figure), which is connected to the zirconium oxide producing device and is used to produce polycrystalline silicon using silicon tetrachloride separated by the zirconium oxide producing device as a raw material.

In addition, the device for producing polycrystalline silicon includes a hydrochlorination reactor, a rectification and purification unit, and a CVD reduction furnace (CVD, i.e. chemical vapor deposition).

A hydrochlorination reactor, preferably a fluidized bed reactor, is connected to the zirconium oxide producing device, for example, connected to the first storage tank 20, and is used to carry out a hydrochlorination reaction of the silicon tetrachloride by-product produced by the zirconium oxide producing device with silicon powder, hydrogen gas, hydrogen chloride to form trichlorosilane.

The rectification and purification unit includes a tray distillation column and a packed distillation column, wherein the tray distillation column is connected to the hydrochlorination reactor and is used to remove silicon tetrachloride from the mixed solution of trichlorosilane and silicon tetrachloride formed in the hydrochlorination reactor and high-boiling metal impurities, the high-boiling impurities metals include aluminum chloride, ferric chloride, calcium chloride, etc.; Connected to the tray distillation column is a packed distillation column, which is used to purify liquid trichlorosilane, from which silicon tetrachloride and high-boiling metal impurities have been removed in the tray distillation column, so as to further remove dichlorodihydrosilane and metal impurities such as phosphorus chloride and boron chloride, in liquid trichlorosilane to obtain purified trichlorosilane.

The CVD reduction furnace is coupled to a packed distillation column and is used to conduct a chemical vapor deposition reaction of purified trichlorosilane with hydrogen gas under heating conditions to reduce trichlorosilane to polycrystalline silicon. The CVD oven may have a heating temperature of from 1000°C to 1100°C, and in this example, the CVD oven preferably has a heating temperature of 1080°C.

It should be noted that in this example, the polycrystalline silicon production apparatus may also use a conventional process method such as the Siemens process or a modified Siemens process, and the similarities will not be repeated separately.

The example of the present invention also presents a combined method for producing zirconium oxide, methyl chlorosilane and polycrystalline silicon using the above combined plant for producing zirconium oxide, methyl chlorosilane and polycrystalline silicon, and, in addition to having steps (1) to (6) according to Example 3, the method further includes step (7):

(7) producing polycrystalline silicon: using liquid products of silicon tetrachloride separated during the production of zirconium oxide as raw materials for producing polycrystalline silicon, which involves first hydrochlorinating said silicon tetrachloride to form trichlorosilane, and then carrying out a reduction reaction of trichlorosilane with hydrogen to form polycrystalline silicon.

More specifically, silicon tetrachloride separated in step (3) is used as a raw material and introduced into a polycrystalline silicon producing apparatus to produce polycrystalline silicon, that is, silicon tetrachloride is first introduced into a hydrochlorination reactor as a raw material, and then silicon powder is added , hydrogen gas, hydrogen chloride and other raw materials, causing the above raw materials to undergo a hydrochlorination reaction to form trichlorosilane; then introducing silicon trichloride sequentially into the plate distillation column and the packed distillation column for purification to obtain purified trichlorosilane; thereafter, the purified trichlorosilane is introduced into the CVD reduction furnace and hydrogen gas is supplied, so that the trichlorosilane and hydrogen undergo a reduction reaction to obtain polycrystalline silicon.

It should be noted that in this example, the method for producing polycrystalline silicon is preferably carried out using the Siemens process or a modified Siemens process, and the specific process parameters and the same steps will not be repeated here.

In the example of the present invention, not only the carbon monoxide and hydrogen chloride generated during the production of zirconium oxide are used as raw materials for the production of methylchlorosilane, but also silicon tetrachloride, a by-product formed during the production of zirconium oxide, is used as a raw material for the production of polycrystalline silicon , so that both the waste gases and the by-product silicon tetrachloride can be effectively reused with great benefit, which reduces the processing costs of waste gases and silicon tetrachloride, eliminates environmental pollution, reduces the production costs of methyl chlorosilane and polycrystalline silicon, and improves the technological level, and overall economic benefits.

Example 7

An example of the present invention is a combined plant for the production of zirconium oxide and polycrystalline silicon, the plant including:

a zirconium oxide producing device which is used to produce zirconium oxide using zircon sand, carbon reducing agent, chlorine gas, silicon heat replenishing agent and hydrogen chloride as raw materials, and a zirconium oxide producing device is also used to separate the gas-phase products of carbon monoxide, hydrogen gas and hydrogen chloride , formed during the production of zirconium oxide;

a polycrystalline silicon producing device which is connected to said zirconium oxide producing device and is used to produce polycrystalline silicon using silicon tetrachloride separated by said zirconium oxide producing device as a raw material.

It should be noted that in this example, the zirconium oxide producing device is the same as the zirconium oxide producing device in Example 6, and the details are not repeated here. Off-gases such as carbon monoxide and hydrogen chloride separated from the zirconium oxide production device can be used for downstream processes such as the production of methylchlorosilane.

It should be noted that the device for producing polycrystalline silicon in this example is the same as the device for producing polycrystalline silicon in Example 6, and the details are not repeated here.

The example of the present invention also provides a combined method for producing zirconium oxide and polycrystalline silicon using the above combined plant for producing zirconium oxide and polycrystalline silicon, the method comprising:

producing zirconium oxide using zircon sand, carbon reducing agent, chlorine gas, silicon heat replenishing agent and hydrogen chloride as raw materials, wherein the liquid phase products separated during the production of zirconium oxide include silicon tetrachloride; And

producing polycrystalline silicon using liquid-phase products separated during the production of zirconium oxide as raw materials.

It should be noted that the methods for producing zirconium oxide and polycrystalline silicon in this example are the same as those in Example 6, which will not be repeated here.

In the example of the present invention, silicon tetrachloride, a by-product generated during the production of zirconium oxide, is used as a raw material for the production of polycrystalline silicon, so that the by-product silicon tetrachloride can be effectively reused with great benefit, which reduces the cost of processing the by-product and further reduces the cost of producing polycrystalline silicon, and increases the technological level, as well as overall economic benefits.

It may be understood that the above-described embodiments are purely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited to them. Various variations and modifications may be made by those skilled in the art without departing from the spirit and spirit of the present invention, and these variations and modifications are also within the scope of the present invention.

Claims (87)

1. A combined method for producing zirconium oxide and methylchlorosilane, including: producing zirconium oxide using zirconium sand, carbon as a reducing agent, chlorine gas, silicon as a heat replenishing agent and hydrogen chloride as raw materials, wherein the products separated during the production of zirconium oxide include gas-phase products and liquid-phase products, and said gas-phase products include monoxide carbon, hydrogen gas and hydrogen chloride; And producing methylchlorosilane using gas-phase products separated during the production of zirconium oxide as raw materials, wherein the combined method includes the following stages: mixing and heating zircon sand, carbon reducing agent, chlorine gas, silicon heat replenishing agent and hydrogen chloride in the first reactor, wherein the zircon sand, carbon reducing agent and chlorine gas react to form zirconium tetrachloride, silicon tetrachloride and carbon monoxide; the heat replenishing agent silicon, chlorine gas and hydrogen chloride react to form silicon tetrachloride and hydrogen gas so as to obtain a first gas-phase mixture; removing hydrogen chloride and chlorine gas from the first gas-phase mixture by passing the first gas-phase mixture through silicon powder in a dechlorinator; cooling the first gas-phase mixture from which hydrogen chloride and chlorine gas have been removed to separate the rough solid zirconium tetrachloride; hydrolyzing the rough solid zirconium tetrachloride to form zirconium oxychloride to obtain a hydrolyzate mixture; then subjecting the hydrolyzate mixture to evaporation, crystallization and solid-liquid separation to obtain solid zirconium oxychloride; and heating the solid zirconium oxychloride in a second reactor to produce zirconium oxide; washing the first gas-phase mixture from which the rough solid zirconium tetrachloride has been removed using silicon tetrachloride as a washing solution to recover silicon tetrachloride thereto, so as to obtain a second gas-phase mixture containing carbon monoxide and hydrogen gas; introducing a second gas-phase mixture into a third reactor; compression and heating to react and form methanol so as to obtain a third gas-phase mixture; introducing a third gas-phase mixture into a fourth reactor and introducing hydrogen chloride into the fourth reactor, heating to react methanol with hydrogen chloride to form chloromethane so as to obtain a fourth gas-phase mixture; introducing a fourth gas-phase mixture into a fifth reactor; and introducing silicon powder into the fifth reactor, heating to react chloromethane with the silicon powder to form methylchlorosilane so as to obtain a fifth gas-phase mixture. 2. A combined method for producing zirconium oxide and methylchlorosilane according to claim 1, wherein the combined method additionally includes the following steps: detecting the molar ratio of carbon to hydrogen in gases introduced into the third reactor using a hydrocarbon detector, when the detected molar ratio of carbon to hydrogen is greater than a predetermined molar ratio of carbon to hydrogen, hydrogen gas is introduced into the third reactor until the molar ratio of carbon to hydrogen in the gases introduced into the third reactor will not be equal to the predetermined molar ratio of carbon to hydrogen; when the detected molar ratio of carbon to hydrogen is less than the predetermined molar ratio of carbon to hydrogen, reduce the amount of hydrogen chloride introduced into the first reactor until the molar ratio of carbon to hydrogen in the gases introduced into the third reactor is equal to the predetermined molar ratio of carbon to hydrogen. 3. A combined method for producing zirconium oxide and methylchlorosilane according to claim 2, wherein the predetermined molar ratio of carbon to hydrogen is from 1:4 to 1:5. 4. A combined method for producing zirconium oxide and methylchlorosilane according to any one of claims 1-3, wherein the third reactor has a pressure from 5.0 to 6.0 MPa and a heating temperature from 220 to 250°C. 5. A combined method for producing zirconium oxide and methylchlorosilane according to any one of claims 1-3, wherein the combined method additionally includes the following steps: introducing one or more of the gas-phase products obtained by evaporating the hydrolyzate mixture and crystallizing the hydrolyzate mixture into a stripper column for stripping hydrogen chloride, and then the stripped hydrogen chloride is used as a source of hydrogen chloride for introduction into the fourth reactor. 6. A combined method for producing zirconium oxide and methylchlorosilane according to claim 5, wherein said stripping column has a stripping temperature from 40 to 60°C and a pressure from 0.1 to 0.3 MPa. 7. A combined method for producing zirconium oxide and methylchlorosilane according to claim 5, wherein the combined method additionally includes the following steps: introducing gas-phase products obtained by evaporating the hydrolyzate mixture into the heat exchanger as a heat source; introducing the hydrolyzate mixture into the heat exchanger to increase the temperature by heat exchange, then evaporating the hydrolyzate mixture after increasing the temperature by heat exchange; introducing the gas-phase products obtained by evaporating the hydrolyzate mixture into a heat exchanger to reduce the temperature due to heat exchange, followed by introducing the gas-phase products into a stripping column for stripping. 8. A combined method for producing zirconium oxide and methylchlorosilane according to claim 5, wherein the combined method additionally includes the following steps: cooling the hydrogen chloride removed from the gas-phase outlet of the stripping column to separate water therefrom; and introducing the hydrogen chloride from which the water has been removed into the fourth reactor. 9. A combined method for producing zirconium oxide and methylchlorosilane according to any one of claims 1-3, 6, 7 and 8, and, before subjecting the hydrolyzate mixture to evaporation, crystallization and separation of solid and liquid phases to obtain solid zirconium oxychloride, the combined method additionally includes the following stages: subjecting the hydrolyzate mixture to solid-liquid separation to remove solid impurities from it. 10. A combined method for producing zirconium oxide and methylchlorosilane according to any of claims 1-3, 6, 7 and 8, and, before introducing the second gas-phase mixture into the third reactor, the combined method additionally includes the following stages: cooling the second gas phase mixture to separate the liquid silicon tetrachloride so as to obtain purified products of the second gas phase. 11. A combined method for producing zirconium oxide and methylchlorosilane according to claim 10, wherein the combined method additionally includes the following steps: using liquid silicon tetrachloride, separated by cooling the second gas-phase mixture, as a cold source for the cooling step to separate rough solid zirconium tetrachloride from the first gas-phase mixture; and/or using liquid silicon tetrachloride recovered by cooling the second gas-phase mixture as a washing solution for the step of washing the first gas-phase mixture from which silicon tetrachloride was separated to remove silicon tetrachloride therefrom. 12. A combined method for producing zirconium oxide and methylchlorosilane according to any of claims 1-3, 6, 7, 8 and 11, and, before introducing the third gas-phase mixture into the fourth reactor, the combined method additionally includes the following stages: cooling the third gas-phase mixture to obtain raw methanol and purifying the raw methanol by rectification to obtain purified products of the third gas phase. 13. A combined method for producing zirconium oxide and methylchlorosilane according to any of claims 1-3, 6, 7, 8 and 11, and, before introducing the fourth gas-phase mixture into the fifth reactor, the combined method additionally includes the following stages: washing and cooling the fourth gas phase mixture using water as a wash solution to remove methanol and hydrogen chloride, and then drying to remove water so as to obtain purified fourth gas phase products. 14. A combined method for producing zirconium oxide and methylchlorosilane according to any one of claims 1-3, 6, 7, 8 and 11, wherein the first reactor has a heating temperature from 1050 to 1200°C and/or the second reactor has a heating temperature from 800 to 1000° WITH. 15. A combined method for producing zirconium oxide and methylchlorosilane according to any one of claims 1-3, 6, 7, 8 and 11, wherein the fourth reactor has a heating temperature from 130 to 150°C. 16. A combined method for producing zirconium oxide and methylchlorosilane according to any one of claims 1-3, 6, 7, 8 and 11, wherein the fifth reactor has a heating temperature from 280 to 320°C. 17. A combined method for producing zirconium oxide and methylchlorosilane according to any one of claims 1-3, 6, 7, 8 and 11, wherein the combined method additionally includes the following stages: returning the liquid obtained by evaporation, crystallization and solid-liquid separation of the hydrolyzate mixture into the hydrolyzate mixture, which is obtained by hydrolyzing the crude solid zirconium tetrachloride to form zirconium oxychloride, and then subjecting the hydrolyzate mixture to evaporation, crystallization and solid-liquid separation. 18. A combined method for producing zirconium oxide, methyl chlorosilane and polycrystalline silicon, wherein said liquid-phase products separated during the combined method for producing zirconium oxide and methyl chlorosilane according to claim 1 include silicon tetrachloride, and said silicon tetrachloride is used as a raw material for producing polycrystalline silicon. 19. A combined method for producing zirconium oxide, methylchlorosilane and polycrystalline silicon according to claim 18, wherein the combined method for producing zirconium oxide and methylchlorosilane according to any of claims 1-3, 6, 7, 8 and 11 additionally includes the following stages: using said liquid-phase silicon tetrachloride products separated during the production of zirconium oxide as a raw material for producing polycrystalline silicon, which involves first hydrochlorinating said silicon tetrachloride to produce trichlorosilane, and then conducting a reduction reaction of trichlorosilane with hydrogen to produce polycrystalline silicon. 20. An installation used for a combined method for producing zirconium oxide and methylchlorosilane according to any one of claims 1-17, including: zirconium oxide production device, which is used to produce zirconium oxide using zircon sand, carbon reducing agent, chlorine gas, silicon heat replenishing agent and hydrogen chloride as raw materials, and is also used to separate the gas-phase products of carbon monoxide, hydrogen gas and hydrogen chloride generated during obtaining zirconium oxide; a methylchlorosilane producing device which is connected to said zirconium oxide producing device and which is used to produce methyl chlorosilane using gas-phase products of carbon monoxide, hydrogen gas and hydrogen chloride separated from said zirconium oxide producing device as raw materials, and the zirconium oxide production device includes a first reactor, a dechlorinator, a first cooling separator, a hydrolysis tank, an evaporator, a crystallizer, a first solid-liquid separator, a second reactor and a washing column, the methylchlorosilane producing apparatus includes a third reactor, a fourth reactor and a fifth reactor; said first reactor is used for mixing and heating zircon sand, carbon reducing agent, chlorine gas, silicon heat-replenishing agent and hydrogen chloride, reacting zircon sand, carbon reducing agent and chlorine gas to form zirconium tetrachloride, silicon tetrachloride and carbon monoxide and reacting silicon heat-replenishing agent, chlorine gas, hydrogen chloride to form silicon tetrachloride, hydrogen gas to obtain a first gas-phase mixture; said dechlorinator is placed between said first reactor and said first cooling separator and said dechlorinator is connected to said first reactor and said first cooling separator, respectively; alternatively, said dechlorinator is disposed in said first reactor and separates a first reaction chamber provided in the first reactor from the outlet of the first reactor, and the dechlorinator is used to remove chlorine gas, hydrogen chloride from the first gas phase mixture using silicon powder therein; said first cooling separator is connected to said first reactor and is used to cool the introduced first gas-phase mixture from which hydrogen chloride and chlorine have been removed so as to separate rough solid zirconium tetrachloride and obtain a first gas-phase mixture without rough solid zirconium tetrachloride; said hydrolysis tank is connected to said first cooling separator and said rough solid zirconium tetrachloride is introduced into the hydrolysis tank and then hydrolyzed to form zirconium oxychloride so as to obtain a hydrolyzate mixture; said evaporator is connected to said hydrolysis tank and said hydrolyzate mixture is introduced into the evaporator for evaporation; said crystallizer is connected to said evaporator, and the hydrolyzate mixture after evaporation is introduced into the crystallizer for crystallization; said first solid-liquid separator is connected to said crystallizer, and the hydrolyzate mixture after crystallization is introduced into the first solid-liquid separator to separate the solid and liquid phases so as to obtain solid zirconium oxychloride; said second reactor is connected to said first solid-liquid separator, and solid zirconium oxychloride is introduced into the second reactor and heated to produce zirconium oxide; said washing column is connected to said first cooling separator, and the first gas-phase mixture from which the rough solid zirconium tetrachloride has been removed is washed using silicon tetrachloride as a washing solution to recover liquid silicon tetrachloride so as to obtain a second gas-phase mixture containing carbon monoxide and hydrogen gas; said third reactor is connected to said washing column, and said second gas-phase mixture is introduced into the third reactor, compressed and heated to react and produce methanol so as to obtain a third gas-phase mixture; said fourth reactor is connected to said third reactor, said third gas-phase mixture is introduced into the fourth reactor, hydrogen chloride is introduced into the fourth reactor, and both of them are heated to react methanol with hydrogen chloride and form chloromethane so as to obtain a fourth gas-phase mixture; said fifth reactor is connected to said fourth reactor, said fourth gas-phase mixture is introduced into the fifth reactor, silicon powder is introduced into the fifth reactor, and both of them are heated to react chloromethane with the silicon powder and form methylchlorosilane so as to obtain a fifth gas-phase mixture. 21. An installation used for a combined method for producing zirconium oxide and methylchlorosilane according to claim 20, wherein said device for producing methylchlorosilane further includes: a hydrogen pipeline connected to an inlet of said third reactor, said hydrogen pipeline being used for introducing hydrogen gas into the third reactor, and said hydrogen pipeline being equipped with a first valve; a hydrogen chloride line connected to the inlet of said first reactor, said hydrogen chloride line being used for introducing hydrogen chloride into the first reactor, and said hydrogen chloride line being provided with a second valve; a hydrocarbon detector for detecting the molar ratio of carbon to hydrogen in gases introduced into said third reactor; a controller for receiving a value of a molar ratio of carbon to hydrogen in the gases in said third reactor detected by said hydrocarbon detector; when the molar ratio of carbon to hydrogen detected by the hydrocarbon detector becomes greater than a predetermined molar ratio of carbon to hydrogen, the controller opens the first valve to introduce hydrogen gas into the third reactor until the detected molar ratio of carbon to hydrogen becomes equal to the predetermined molar ratio of carbon to hydrogen, and then the controller closes the first valve; when the molar ratio of carbon to hydrogen detected by the hydrocarbon detector becomes less than the preset molar ratio of carbon to hydrogen, the controller closes the second valve to reduce the amount of hydrogen chloride introduced into the first reactor until the molar ratio of carbon to hydrogen becomes equal to the predetermined molar ratio carbon to hydrogen, and then the controller opens the second valve. 22. An installation used for a combined method for producing zirconium oxide and methylchlorosilane according to claim 20 or 21, wherein said device for producing methylchlorosilane further includes: a stripping column, wherein a gas outlet of said stripping column is connected to an inlet of said fourth reactor, the inlet of said stripping column is connected to said evaporator, and the gas-phase products evaporated by the evaporator are introduced into the stripping column to strip off hydrogen chloride, and the stripped hydrogen chloride is introduced into said fourth reactor as a source of hydrogen chloride; and/or the inlet of said stripping column is connected to said crystallizer, and the gas-phase products crystallized by the crystallizer are introduced into the stripping column to strip off hydrogen chloride, and the stripped hydrogen chloride is introduced into said fourth reactor as a source of hydrogen chloride. 23. An installation used for a combined method for producing zirconium oxide and methylchlorosilane according to claim 22, wherein said device for producing methylchlorosilane further includes: a heat exchanger which is connected to said stripping column and also connected to said evaporator, and gas-phase products obtained by evaporating the hydrolyzate mixture by means of the evaporator are introduced into the heat exchanger as a heat source, and the hydrolyzate mixture is introduced into the heat exchanger to raise the temperature by heat exchange, and then gas-phase The products obtained by evaporation of the hydrolyzate mixture are introduced into the heat exchanger to reduce the temperature by heat exchange, after which the gas-phase products are introduced into the stripper column for stripping. 24. An installation used for a combined method for producing zirconium oxide and methylchlorosilane according to claim 22, wherein said device for producing methylchlorosilane further includes: a cooling separator at the top of the stripping column, wherein an inlet of the cooling separator at the top of the stripping column is connected to a gas outlet of the stripping column, a liquid outlet of the cooling separator at the top of the stripping column is connected to the inlet at the top of the stripping column, and a gas outlet of the cooling separator at the top of the stripping column is connected to said fourth reactor, and a cooling separator at the top of the stripper is used to cool and separate the water, and the cooled and separated water flows back into the stripper, and the hydrogen chloride from which the water has been removed flows into the fourth reactor. 25. An installation used for a combined method for producing zirconium oxide and methyl chlorosilane according to any one of claims 20, 21, 23 and 24, wherein said device for producing zirconium oxide further includes: a second solid-liquid separator, wherein an inlet of said second solid-liquid separator is connected to an outlet of said hydrolysis tank, an outlet of the second solid-liquid separator is connected to an inlet of said evaporator, and the hydrolyzate mixture is introduced through the hydrolysis tank into the second solid-liquid separator to perform solid-liquid separation, removing solid impurities, and then flows into the evaporator. 26. An installation used for a combined method for producing zirconium oxide and methylchlorosilane according to any one of claims 20, 21, 23 and 24, wherein said device for producing zirconium oxide further includes: a first cooler that is disposed between said wash column and said third reactor, wherein an inlet of said first cooler is connected to a gas outlet of the wash column, a gas outlet of the first cooler is connected to an inlet of the third reactor, and the first cooler is used to cool the second gas-phase mixture to separate liquid silicon tetrachloride , in order to obtain purified products of the second gas phase. 27. An apparatus used for the combined process for producing zirconium oxide and methyl chlorosilane according to claim 26, wherein a liquid outlet of said first cooler is connected to an inlet of said first cooling separator, and liquid silicon tetrachloride separated from the second gas-phase mixture is introduced into the first cooling separator at as a cold source for cooling the first gas-phase mixture so as to separate the rough solid zirconium tetrachloride; and/or a liquid outlet of said first cooler is connected to an inlet of the washing column, and liquid silicon tetrachloride separated by cooling the second gas-phase mixture is introduced into the washing column for washing to recover silicon tetrachloride. 28. An installation used for a combined method for producing zirconium oxide and methylchlorosilane, according to any one of claims 20, 21, 23, 24 and 27, wherein said device for producing methylchlorosilane further includes: a second cooler connected to said third reactor, the third gas-phase mixture entering said second cooler for cooling to produce raw methanol; a distillation column placed between said second cooler and said fourth reactor, wherein the distillation column is connected to the second cooler and the fourth reactor, respectively, and the raw methanol is introduced into the distillation column for purification to obtain purified third gas phase products. 29. An installation used for a combined method for producing zirconium oxide and methylchlorosilane, according to any one of claims 20, 21, 23, 24 and 27, wherein said device for producing methylchlorosilane further includes: a washing and cooling column connected to said fourth reactor, the fourth gas-phase mixture being sent to said washing and cooling column and using water as a washing and cooling solution to remove methanol and hydrogen chloride; a drying column placed between said washing and cooling column and said fifth reactor, the drying column being used for drying and removing dimethyl ether, a by-product during the reaction of water, methanol and hydrogen chloride to form methyl chlorosilane, so as to obtain purified products of the fourth gas phase . 30. An apparatus used for a combined process for producing zirconium oxide and methyl chlorosilane according to any one of claims 20, 21, 23, 24 and 27, wherein the liquid outlet of said first solid-liquid separator is connected to the inlet of said hydrolysis reservoir, and the liquid in the first solid-liquid separator flows into the hydrolysis tank. 31. An installation used for a combined method for producing zirconium oxide, methylchlorosilane and polycrystalline silicon according to claim 18 or 19, and, in addition to the installation used for a combined method for producing zirconium oxide and methylchlorosilane, according to any of paragraphs 20, 21, 23, 24 , 27, it additionally includes: a polycrystalline silicon producing device which is connected to said zirconium oxide producing device and is used to produce polycrystalline silicon using silicon tetrachloride separated by said zirconium oxide producing device as a raw material.