A method for preparing ternary copper catalyst by gas phase reduction of waste organosilicon contact

Abstract

The present invention belongs to the field of metal recovery and smelting, and in particular, relates to a method for preparing a ternary copper catalyst by gas phase reduction of waste organosilicon contacts. The method comprises: loading waste organosilicon contacts treated with oxidation roasting and a reducing medium into a shell-and-tube reactor, introducing a mixed reaction gas of fluorine gas and a diluent gas into the shell-and-tube reactor, controlling the reaction temperature through the shell-and-tube reactor, recovering the product of the shell-and-tube reactor after the reaction, and directly obtaining a ternary copper catalyst through heavy liquid separation. The present invention realizes the preparation of a ternary copper catalyst from waste organosilicon contacts by a one-step method, can ensure the quality of the product during the preparation process, and can achieve effective and thorough separation of silicon and copper components, with extremely high overall preparation efficiency, and is suitable for industrial production and application.

Description

Technical Field

[0001] The invention belongs to the field of metal recovery and smelting, and in particular relates to a method for preparing a ternary copper catalyst by utilizing gas phase reduction of waste organosilicon contacts. Background Art

[0002] In the production process of organosilicon, silicon and methyl chloride are used as the main raw materials, ternary copper and zinc are used as catalysts and additives respectively, among which ternary copper is the main catalyst component, which is often used to catalyze the synthesis of organosilicon monomers such as dimethyldichloromethane. In this process, when the silicon powder conversion rate and the selectivity of methylchlorosilane monomer reach a certain level, the remaining silicon powder and catalyst need to be discharged from the reactor to form industrial waste residue, i.e., waste organosilicon contact body.

[0003] Waste silicone contacts also contain a large amount of silicon and copper. The silicon content in some waste silicone contacts can reach 70-85wt%, while the copper content can reach 15-25wt%. As a metal material with high value, copper has a high recycling value. However, due to the small particles of waste silicone contacts, the silicon and copper are tightly combined, and most of the copper exists in the form of oxides, which makes it difficult to recycle.

[0004] In order to recover copper and / or copper compounds from waste silicone contacts, technicians in this field have conducted various attempts. In previous studies, our company has made significant improvements. For example, CN110791650B, a method for recovering metallic copper using waste silicone contacts, uses carbon-deficient reduction to recover metallic copper in waste silicone contacts. However, the metallic copper recovered by this method needs to be prepared into a ternary copper catalyst again, which requires specific process treatment. Therefore, how to prepare a ternary copper catalyst by direct reduction of waste silicone contacts has always been a key research direction. The ability to directly obtain a ternary copper catalyst from waste silicone contacts is of great significance to the overall silicone industry and the ternary copper catalyst industry. Summary of the invention

[0005] In order to solve the problem that the current method cannot effectively obtain a ternary copper catalyst directly from waste organosilicon contacts, but needs to first obtain metallic copper and then convert it into a ternary copper catalyst, the present invention provides a method for preparing a ternary copper catalyst by gas phase reduction of waste organosilicon contacts.

[0006] The main purpose of the present invention is:

[0007] 1. It can directly and effectively realize the preparation of ternary copper catalyst;

[0008] Second, the prepared ternary copper catalyst has good use effect.

[0009] To achieve the above objectives, the present invention adopts the following technical solutions.

[0010] A method for preparing a ternary copper catalyst by gas phase reduction of waste organosilicon contacts,

[0011] The method comprises:

[0012] The tubular reactor is loaded with waste organosilicon contacts treated with oxidation and roasting and a reducing medium, a mixed reaction gas of fluorine gas and diluent gas is introduced into the tubular reactor, the reaction temperature is controlled by the tubular reactor, and the tubular reactor product is recovered after the reaction and a ternary copper catalyst is directly obtained by heavy liquid separation.

[0013] In the technical solution of the present invention, a one-step gas phase method can be used to directly prepare a ternary copper catalyst. And by matching specific components, the formed ternary copper catalyst and silicon component are directly separated to improve the preparation efficiency. Specifically, in order to separate the silicon-copper component and ensure the effective preparation of the ternary copper catalyst, the reducing medium used in the present invention must be a carbon reducing medium. In the shell-and-tube reactor, the following main reactions will first occur, including but not limited to:

[0014] 2CuO+C=Cu+CO2

[0015] 4CuO+C=2Cu2O+CO2

[0016] CuO+C=Cu+CO

[0017] 2CuO+C=Cu2O+CO

[0018] CuO+CO=Cu+CO2

[0019] 2CuO+CO=Cu2O-CO2

[0020] The cuprous oxide and elemental copper required for the ternary copper catalyst can be formed by the above reaction, so the reduction medium is controlled to perform a carbon-deficient reaction, that is, the preparation of the ternary copper catalyst can be achieved. The introduction of fluorine gas is to separate the copper and silicon components. Directly introducing fluorine gas will react with copper compounds or metallic copper to oxidize them, resulting in the inability to effectively obtain a ternary copper catalyst or introduce fluorine impurities into the ternary copper catalyst. The use of the carbon-based reducing medium selected by the present invention is also embodied here. The carbon monoxide produced by the carbon-based reducing medium will react with fluorine gas to form fluorophosgene (COF2). The formation and use of fluorophosgene is the core of the technical solution of the present invention. It can specifically produce corrosion to silicon dioxide while avoiding oxidation corrosion of metallic copper and / or copper compounds, while limiting the reduction effect, and performing a carbon-deficient reaction. The corrosion can directly and effectively achieve the separation of silicon-based components and copper-based components, thereby simultaneously achieving the separation and preparation of the ternary copper catalyst.

[0021] If the above reaction process is carried out in a conventional furnace reactor or a stirred reactor, the above reaction effect cannot be produced. The tubular reactor is a relatively special reactor that can effectively control the temperature and can fully and effectively carry out solid-solid reactions, gas-solid reactions and gas-gas reactions. It is currently the only reaction equipment and container suitable for the technical solution of the present invention after testing.

[0022] As a preference,

[0023] The volume proportion of the dilution gas in the mixed reaction gas is 75-90% VOL;

[0024] The mixed reaction gas flow rate is 1-3 BV / min.

[0025] Specifically, the diluent gas should be an inert gas such as argon. Controlling the diluent gas and the proportion and the amount of the mixed reaction gas is the key to ensuring the preparation effect of the ternary copper catalyst of the present invention. If too little fluorine gas is introduced, the yield of the ternary copper catalyst will be limited, and if the amount of fluorine gas introduced is too large, the purity of the ternary copper catalyst will be reduced. Among them, the gas flow rate is BV as a unit, and 1BV is the tube volume of a tube reactor. For a tube reactor with a volume of 3 cubic meters, 3 to 9 cubic meters of mixed reaction gas are introduced per minute.

[0026] As a preference,

[0027] The mixed reaction gas is heated to ≥120° C. before entering the tubular reactor.

[0028] The mixed reaction gas temperature is increased to avoid excessive temperature drop of the tubular reactor after the reaction gas is introduced. At the same time, the reaction efficiency of fluorine and carbon monoxide is low under low temperature conditions, and it is easy to react with metallic copper or copper compounds, resulting in a decrease in the purity of the final product. Therefore, slightly increasing the mixed reaction gas temperature and controlling it at 120-150°C can produce a relatively optimal preparation effect.

[0029] As a preference,

[0030] The reducing medium is carbon black and / or coke and / or activated carbon and / or graphite.

[0031] The above reducing media are all common and commonly used carbon-based reducing media, which have good use effects in the present invention.

[0032] Preferably, the waste organosilicon contact body treated by oxidation and roasting and the reducing medium are mixed and uniformly loaded in a tubular reactor in a mass ratio of 1:(0.15-0.30).

[0033] The present invention requires the use of a relatively large amount of carbon source, mainly to ensure that sufficient carbon monoxide can be produced to cooperate with fluorine gas to achieve silicon-copper separation, while avoiding reaction between fluorine gas and the target product, that is, producing an isolation effect. The effect of fluorine gas on carbon monoxide can cause it to produce a "carbon deficiency" phenomenon, so that copper oxide cannot be completely reduced.

[0034] As a preference,

[0035] The reaction temperature in the tubular reactor is controlled to be 450-600°C.

[0036] Reduction needs to provide at least 400°C to ensure that copper oxide and carbon can react more efficiently, ensure the reaction process and reaction rate, and carbon reduction of copper is a positively promoted reaction. Once the reaction starts at 400°C, it will continuously promote the reaction and increase the reaction rate. Under the above temperature conditions, carbon can be efficiently reduced to form cuprous oxide and metallic copper, and the reaction rate is fast, which can make metallic copper and metallic copper-cuprous oxide powders quickly peel off to form more delicate copper component powders, and the copper component in the original large granular or even blocky organic silicon waste contact body is pulverized and falls down driven by airflow and separated from the silicon component.

[0037] As a preference,

[0038] A screen is provided at the lower end of the tube port of the tubular reactor, and the mesh number of the screen is ≥20 meshes.

[0039] It has been verified through experiments that the mesh size of the ternary copper catalyst prepared by the gas phase reduction method of the present invention can basically reach more than 20 meshes, and after the initial screening through the above-mentioned sieve, the preliminary separation of impurities can basically be achieved.

[0040] The beneficial effects of the present invention are:

[0041] The present invention realizes the preparation of a ternary copper catalyst from waste organic silicon contacts by a one-step method, can ensure the quality of the product during the preparation process, realize effective and thorough separation of silicon and copper components, has an extremely high overall preparation efficiency, and is suitable for industrial production and application. DETAILED DESCRIPTION

[0042] The present invention is further described in detail below in conjunction with specific embodiments. Those of ordinary skill in the art will be able to implement the present invention based on these descriptions. In addition, the embodiments of the present invention involved in the following description are generally only embodiments of a part of the present invention, rather than all embodiments. Therefore, based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work should fall within the scope of protection of the present invention.

[0043] Unless otherwise specified, the raw materials used in the examples of the present invention are all commercially available or available to those skilled in the art; unless otherwise specified, the methods used in the examples of the present invention are all methods known to those skilled in the art.

[0044] Example 1

[0045] A method for preparing a ternary copper catalyst by gas phase reduction of waste organosilicon contacts, the method comprising:

[0046] The waste organosilicon contact body treated by oxidation and roasting and the reducing medium are loaded into the tubular reactor, the mixed reaction gas of fluorine gas and diluent gas is introduced into the tubular reactor, the reaction temperature is controlled by the tubular reactor, and the product of the tubular reactor is recovered after the reaction and the ternary copper catalyst is directly obtained by heavy liquid separation;

[0047] Specifically, the waste organosilicon contact was placed in a calcining furnace and subjected to oxidation roasting at 600°C for 2.5 hours in an air atmosphere to remove organic impurities to obtain a solid product, which was weighed and the density of the solid product was calculated by a liquid drainage method, and the density of the solid product was recorded, and the copper content in the obtained solid product was characterized by spectral analysis;

[0048] A carbon source is added by stirring ball milling, and the calcined solid product is mixed with carbon black powder in a mass ratio of 1:0.25, and loaded into a shell-and-tube reactor. A 20-mesh sieve plate is provided at the lower end of the shell-and-tube reactor, and a recovery container is provided below the sieve plate. The recovery container is filled with Krelich liquid as a heavy liquid for screening silicon components and ternary copper components. After the shell-and-tube reactor is heated to 500° C., a mixed reaction gas (fluorine gas and argon gas volume ratio of 1.5:8.5) heated to 135° C. is continuously introduced into the shell-and-tube reactor. The flow rate of the mixed reaction gas is controlled to 2BV / min, and the reaction is terminated after the separated reaction tail gas is flammable. The recovery container is allowed to stand for separation to remove upper suspended particle impurities, and then the target product is obtained by filtering and separating to remove the heavy liquid. The target product is washed with deionized water and dried to obtain a ternary copper catalyst.

[0049] The obtained ternary copper catalyst was characterized by XRD. The characterization results showed that obvious target peaks appeared in the spectrum, among which 2θ=35.5° and 2θ=38.7° were the characteristic peaks of CuO, 2θ=36.6° was the characteristic peak of Cu2O, and 2θ=43.4° was the characteristic peak of Cu. The content of copper element in the obtained ternary copper catalyst was characterized by spectral analysis, and the copper recovery rate was calculated with the characterization content in the original waste organic silicon contact body. After characterization and calculation, the copper recovery rate of the waste organic silicon contact body in this embodiment was 91.2%, that is, the product yield was 91.2% of the theoretical maximum yield. The impurities in the product were characterized. The characterization results showed that the main impurity was ZnO, and its component content was less than 0.1 wt%, and the total impurity content was about 0.11 wt%. It can be seen that the ternary copper catalyst prepared by the present invention has a high purity and the product composition is Cu-Cu2O-CuO, which is a ternary copper catalyst.

[0050] The catalytic performance of the ternary copper catalyst was characterized. The test process was as follows: 20 g of silicon powder, 0.8 g of the ternary copper catalyst prepared in this example, and 0.1 g of zinc powder were mixed and ground to form a contact body; before the reaction, the reaction system was first purged with nitrogen gas, and then switched to MeCl gas. After preheating, MeCl reacted with the contact body, and the product after the reaction flowed out from the lower end of the reactor. After condensation by a condenser, it was collected with toluene solution to obtain a test liquid, and the tail gas was post-treated with alkaline solution; the test liquid was fixed to volume and quantitatively analyzed by gas chromatography. The characterization results are shown below.

[0051]

[0052] Note: The reaction conditions for the catalytic performance test are preheating temperature of 350°C, reaction temperature of 325°C, reaction pressure of normal pressure, MeCl flow rate of 25 mL / min, and reaction time of 24 h. In the table: M1 is MeSiCl (monomethyltrichlorosilane), M2 is MeSiCl (dimethyldichlorosilane), M3 is MeSiCl (trimethylmonochlorosilane), M1H is MeHSiCl (monomethylhydrogen-containing silane), M2H is MeHSiCl (dimethylhydrogen-containing silane), LF is a low-boiling substance, and HF is a high-boiling substance. The product selectivity is the ratio of the mass of the target product to the sum of the masses of all reaction products. The silicon powder conversion rate is the ratio of the mass difference before and after the reaction to the total mass before the reaction, that is, (m 反应前 -m 反应后 ) / m 反应前 ×100%, where m is the mass of the contact body.

[0053] It can be seen from the above results that the ternary copper catalyst prepared in the present invention has good product selectivity and can be directly used in the production of organosilicon.

[0054] Example 2

[0055] A method for preparing a ternary copper catalyst by gas phase reduction of waste organosilicon contacts, the method comprising:

[0056] The waste organosilicon contact body treated by oxidation and roasting and the reducing medium are loaded into the tubular reactor, the mixed reaction gas of fluorine gas and diluent gas is introduced into the tubular reactor, the reaction temperature is controlled by the tubular reactor, and the product of the tubular reactor is recovered after the reaction and the ternary copper catalyst is directly obtained by heavy liquid separation;

[0057] Specifically, the waste organosilicon contact was placed in a calcining furnace and subjected to oxidation roasting at 600°C for 2.5 hours in an air atmosphere to remove organic impurities to obtain a solid product, which was weighed and the density of the solid product was calculated by a liquid drainage method, and the density of the solid product was recorded, and the copper content in the obtained solid product was characterized by spectral analysis;

[0058] A carbon source is added by stirring ball milling, and the calcined solid product is mixed with carbon black powder in a mass ratio of 1:0.15, and loaded into a tubular reactor. A 20-mesh sieve plate is provided at the lower end of the tubular reactor, and a recovery container is provided below the sieve plate. The recovery container is filled with Krelich liquid as a heavy liquid for screening silicon components and ternary copper components. After the tubular reactor is heated to 450°C, a mixed reaction gas (fluorine gas and argon gas volume ratio of 1:9) heated to 135°C is continuously introduced into the tubular reactor. The flow rate of the mixed reaction gas is controlled to be 1 BV / min, and the reaction is terminated after the separated reaction tail gas is flammable. The recovery container is allowed to stand for separation to remove upper suspended particle impurities, and then the target product is obtained by filtering and separating the heavy liquid, and the target product is washed with deionized water and dried to obtain a ternary copper catalyst.

[0059] The obtained ternary copper catalyst was characterized by XRD. The characterization results showed that obvious target peaks appeared in the spectrum, among which 2θ=35.5° and 2θ=38.7° were the characteristic peaks of CuO, 2θ=36.6° was the characteristic peak of Cu2O, and 2θ=43.4° was the characteristic peak of Cu. The content of copper element in the obtained ternary copper catalyst was characterized by spectral analysis, and the copper recovery rate was calculated with the characterization content in the original waste organic silicon contact body. After characterization and calculation, the copper recovery rate of the waste organic silicon contact body in this embodiment was 90.5%, that is, the product yield was 90.5% of the theoretical maximum yield. The impurities in the product were characterized. The characterization results showed that the main impurity was ZnO, and its component content was about 0.1 wt%, and the total impurity content was about 0.13 wt%. It can be seen that the ternary copper catalyst prepared by the present invention has a high purity and the product composition is Cu-Cu2O-CuO, which is a ternary copper catalyst.

[0060] The catalytic performance of the ternary copper catalyst was characterized. The test process was as follows: 20 g of silicon powder, 0.8 g of the ternary copper catalyst prepared in this example, and 0.1 g of zinc powder were mixed and ground to form a contact body; before the reaction, the reaction system was first purged with nitrogen gas, and then switched to MeCl gas. After preheating, MeCl reacted with the contact body, and the product after the reaction flowed out from the lower end of the reactor. After condensation by a condenser, it was collected with toluene solution to obtain a test liquid, and the tail gas was post-treated with alkaline solution; the test liquid was fixed to volume and quantitatively analyzed by gas chromatography. The characterization results are shown below.

[0061]

[0062] Note: The reaction conditions for the catalytic performance test are preheating temperature of 350°C, reaction temperature of 325°C, reaction pressure of normal pressure, MeCl flow rate of 25 mL / min, and reaction time of 24 h. In the table: M1 is MeSiCl (monomethyltrichlorosilane), M2 is MeSiCl (dimethyldichlorosilane), M3 is MeSiCl (trimethylmonochlorosilane), M1H is MeHSiCl (monomethylhydrogen-containing silane), M2H is MeHSiCl (dimethylhydrogen-containing silane), LF is a low-boiling substance, and HF is a high-boiling substance. The product selectivity is the ratio of the mass of the target product to the sum of the masses of all reaction products. The silicon powder conversion rate is the ratio of the mass difference before and after the reaction to the total mass before the reaction, that is, (m 反应前 -m 反应后 ) / m 反应前 ×100%, where m is the mass of the contact body.

[0063] It can be seen from the above results that the ternary copper catalyst prepared in the present invention has good product selectivity and can be directly used in the production of organosilicon.

[0064] Example 3

[0065] A method for preparing a ternary copper catalyst by gas phase reduction of waste organosilicon contacts, the method comprising:

[0066] The waste organosilicon contact body treated by oxidation and roasting and the reducing medium are loaded into the tubular reactor, the mixed reaction gas of fluorine gas and diluent gas is introduced into the tubular reactor, the reaction temperature is controlled by the tubular reactor, and the product of the tubular reactor is recovered after the reaction and the ternary copper catalyst is directly obtained by heavy liquid separation;

[0067] Specifically, the waste organosilicon contact was placed in a calcining furnace and subjected to oxidation roasting at 600°C for 2.5 hours in an air atmosphere to remove organic impurities to obtain a solid product, which was weighed and the density of the solid product was calculated by a liquid drainage method, and the density of the solid product was recorded, and the copper content in the obtained solid product was characterized by spectral analysis;

[0068] A carbon source is added by stirring ball milling, and the calcined solid product is mixed with carbon black powder in a mass ratio of 1:0.3, and loaded into a tubular reactor. A 20-mesh sieve plate is provided at the lower end of the tubular reactor, and a recovery container is provided below the sieve plate. The recovery container is filled with Krelich liquid as a heavy liquid for screening silicon components and ternary copper components. After the tubular reactor is heated to 600°C, a mixed reaction gas (fluorine gas and argon gas volume ratio of 2.5:7.5) heated to 135°C is continuously introduced into the tubular reactor. The flow rate of the mixed reaction gas is controlled to 3 BV / min, and the reaction is terminated after the separated reaction tail gas is flammable. The recovery container is allowed to stand for separation to remove upper suspended particle impurities, and then the target product is obtained by filtering and separating the heavy liquid, and the target product is washed with deionized water and dried to obtain a ternary copper catalyst.

[0069] The obtained ternary copper catalyst was characterized by XRD. The characterization results showed that obvious target peaks appeared in the spectrum, among which 2θ=35.5° and 2θ=38.7° were the characteristic peaks of CuO, 2θ=36.6° was the characteristic peak of Cu2O, and 2θ=43.4° was the characteristic peak of Cu. The content of copper element in the obtained ternary copper catalyst was characterized by spectral analysis, and the copper recovery rate was calculated with the characterization content in the original waste organic silicon contact body. After characterization and calculation, the copper recovery rate of the waste organic silicon contact body in this embodiment was 92.0%, that is, the product yield was 92.0% of the theoretical maximum yield. The impurities in the product were characterized. The characterization results showed that the main impurity was ZnO, and its component content was less than 0.1 wt%, and the total impurity content was about 0.09 wt%. It can be seen that the ternary copper catalyst prepared by the present invention has a high purity and the product composition is Cu-Cu2O-CuO, which is a ternary copper catalyst.

[0070] The catalytic performance of the ternary copper catalyst was characterized. The test process was as follows: 20 g of silicon powder, 0.8 g of the ternary copper catalyst prepared in this example, and 0.1 g of zinc powder were mixed and ground to form a contact body; before the reaction, the reaction system was first purged with nitrogen gas, and then switched to MeCl gas. After preheating, MeCl reacted with the contact body, and the product after the reaction flowed out from the lower end of the reactor. After condensation by a condenser, it was collected with toluene solution to obtain a test liquid, and the tail gas was post-treated with alkaline solution; the test liquid was fixed to volume and quantitatively analyzed by gas chromatography. The characterization results are shown below.

[0071]

[0072] Note: The reaction conditions for the catalytic performance test are preheating temperature of 350°C, reaction temperature of 325°C, reaction pressure of normal pressure, MeCl flow rate of 25 mL / min, and reaction time of 24 h. In the table: M1 is MeSiCl (monomethyltrichlorosilane), M2 is MeSiCl (dimethyldichlorosilane), M3 is MeSiCl (trimethylmonochlorosilane), M1H is MeHSiCl (monomethylhydrogen-containing silane), M2H is MeHSiCl (dimethylhydrogen-containing silane), LF is a low-boiling substance, and HF is a high-boiling substance. The product selectivity is the ratio of the mass of the target product to the sum of the masses of all reaction products. The silicon powder conversion rate is the ratio of the mass difference before and after the reaction to the total mass before the reaction, that is, (m 反应前 -m 反应后 ) / m 反应前 ×100%, where: m is the mass of the contact body.

[0073] It can be seen from the above results that the ternary copper catalyst prepared in the present invention has good product selectivity and can be directly used in the production of organosilicon.

[0074] It can be clearly seen from the above Examples 1 to 3 that the technical solution of the present invention can effectively and directly convert waste silicone contacts into ternary copper catalysts with practical and economic value, can achieve efficient waste recycling and regeneration, has great potential value for environmental protection, and has obvious industrial value.

[0075] Comparative Example 1

[0076] A method for preparing a ternary copper catalyst by gas phase reduction of waste organosilicon contacts, the method comprising:

[0077] The waste organosilicon contact body treated by oxidation and roasting and the reducing medium are loaded into the tubular reactor, the mixed reaction gas of fluorine gas and diluent gas is introduced into the tubular reactor, the reaction temperature is controlled by the tubular reactor, and the product of the tubular reactor is recovered after the reaction and the ternary copper catalyst is directly obtained by heavy liquid separation;

[0078] Specifically, the waste organosilicon contact was placed in a calcining furnace and subjected to oxidation roasting at 600°C for 2.5 hours in an air atmosphere to remove organic impurities to obtain a solid product, which was weighed and the density of the solid product was calculated by a liquid drainage method, and the density of the solid product was recorded, and the copper content in the obtained solid product was characterized by spectral analysis;

[0079] A carbon source is added by stirring ball milling, and the calcined solid product is mixed with carbon black powder in a mass ratio of 1:0.25, and loaded into a shell-and-tube reactor. A 20-mesh sieve plate is provided at the lower end of the shell-and-tube reactor, and a recovery container is provided below the sieve plate. The recovery container is filled with Krelich liquid as a heavy liquid for screening silicon components and ternary copper components. After the shell-and-tube reactor is heated to 500° C., a mixed reaction gas (fluorine gas and argon gas volume ratio of 0.5:9.5) heated to 135° C. is continuously introduced into the shell-and-tube reactor. The flow rate of the mixed reaction gas is controlled to 1BV / min, and the reaction is terminated after the separated reaction tail gas is flammable. The recovery container is allowed to stand for separation to remove upper suspended particle impurities, and then the target product is obtained by filtering and separating to remove the heavy liquid. The target product is washed with deionized water and dried to obtain a ternary copper catalyst.

[0080] The obtained ternary copper catalyst was characterized by XRD. The characterization results showed that obvious target peaks appeared in the spectrum, among which 2θ=35.5° and 2θ=38.7° were the characteristic peaks of CuO, 2θ=36.6° was the characteristic peak of Cu2O, and 2θ=43.4° was the characteristic peak of Cu. The copper content in the obtained ternary copper catalyst was characterized by spectral analysis, and the copper recovery rate was calculated with the characterization content in the original waste organic silicon contact body. After characterization and calculation, the copper recovery rate of the waste organic silicon contact body in this embodiment was 77.2%, that is, the product yield was 77.2% of the theoretical maximum yield. The impurities in the product were characterized. The characterization results showed that the main impurity was ZnO, and its component content was less than 0.1wt%, and the total impurity content was about 0.12wt%. It can be seen that the ternary copper catalyst prepared by the present invention has a high purity and the product composition is Cu-Cu2O-CuO, which is a ternary copper catalyst.

[0081] The catalytic performance of the ternary copper catalyst was characterized. The test process was as follows: 20 g of silicon powder, 0.8 g of the ternary copper catalyst prepared in this example, and 0.1 g of zinc powder were mixed and ground to form a contact body; before the reaction, the reaction system was first purged with nitrogen gas, and then switched to MeCl gas. After preheating, MeCl reacted with the contact body, and the product after the reaction flowed out from the lower end of the reactor. After condensation by a condenser, it was collected with toluene solution to obtain a test liquid, and the tail gas was post-treated with alkaline solution; the test liquid was fixed to volume and quantitatively analyzed by gas chromatography. The characterization results are shown below.

[0082]

[0083] Note: The reaction conditions for the catalytic performance test are preheating temperature of 350°C, reaction temperature of 325°C, reaction pressure of normal pressure, MeCl flow rate of 25 mL / min, and reaction time of 24 h. In the table: M1 is MeSiCl (monomethyltrichlorosilane), M2 is MeSiCl (dimethyldichlorosilane), M3 is MeSiCl (trimethylmonochlorosilane), M1H is MeHSiCl (monomethylhydrogen-containing silane), M2H is MeHSiCl (dimethylhydrogen-containing silane), LF is a low-boiling substance, and HF is a high-boiling substance. The product selectivity is the ratio of the mass of the target product to the sum of the masses of all reaction products. The silicon powder conversion rate is the ratio of the mass difference before and after the reaction to the total mass before the reaction, that is, (m 反应前 -m 反应后 ) / m 反应前 ×100%, where m is the mass of the contact body.

[0084] From the above results, it can be seen that the ternary copper catalyst prepared by the present invention has good product selectivity and can be directly used in the production of organic silicon. However, it can be clearly seen from the comparison between this example and Example 1 that the purity and performance of the prepared ternary copper catalyst are relatively close, but the product yield is much lower than that of Example 1, which shows that the gas flow rate of fluorine gas has a significant impact on the actual preparation effect.

[0085] On this basis, based on the scheme of this example, the composition and flow rate of the mixed reaction gas are changed as follows: the volume ratio of fluorine gas and argon gas is 3.5:6.5, and the flow rate of the mixed reaction gas is controlled to 3.5 BV / min.

[0086] The obtained ternary copper catalyst was characterized by XRD. The characterization results showed that obvious target peaks appeared in the spectrum, among which 2θ=35.5° and 2θ=38.7° were the characteristic peaks of CuO, 2θ=36.6° was the characteristic peak of Cu2O, and 2θ=43.4° was the characteristic peak of Cu. However, at the same time, a significant fluoride characteristic peak appeared, indicating the presence of fluoride impurities. The copper content in the obtained ternary copper catalyst was characterized by spectral analysis, and the copper recovery rate was calculated with the characterization content in the original waste organosilicon contact body. After characterization and calculation, the copper recovery rate of the waste organosilicon contact body in this embodiment was 91.9%, that is, the product yield was 91.9% of the theoretical maximum yield. The impurities in the product were characterized, and the characterization results showed that the main impurity was fluoride, and the total impurity content was about 8.13 wt%. It can be seen that the purity of the ternary copper catalyst prepared in this example is relatively low. The same catalytic performance characterization was further performed, and the characterization results are as follows.

[0087]

[0088]

[0089] The catalytic performance characterization results also show that the increase in the impurity content of the present invention leads to a significant decrease in the product selectivity and conversion rate of the overall ternary copper catalyst.

[0090] Comparative Example 2

[0091] A method for preparing a ternary copper catalyst by gas phase reduction of waste organosilicon contacts, the method comprising:

[0092] The waste organosilicon contacts and reducing medium which have been oxidatively calcined are evenly laid in a high-temperature atmosphere furnace, a mixed reaction gas of fluorine gas and diluent gas is introduced into the high-temperature atmosphere furnace, the reaction temperature of the high-temperature atmosphere furnace is controlled, and after the reaction, the product of the high-temperature atmosphere furnace is recovered and a ternary copper catalyst is directly obtained through heavy liquid separation;

[0093] Specifically, the waste organosilicon contact was placed in a calcining furnace and subjected to oxidation roasting at 600°C for 2.5 hours in an air atmosphere to remove organic impurities to obtain a solid product, which was weighed and the density of the solid product was calculated by a liquid drainage method, and the density of the solid product was recorded, and the copper content in the obtained solid product was characterized by spectral analysis;

[0094] The carbon source is added by stirring ball milling, and the calcined solid product and carbon black powder are mixed in a mass ratio of 1:0.25, and laid in a high-temperature atmosphere furnace. After the high-temperature atmosphere furnace is heated to 500°C, a mixed reaction gas (fluorine gas and argon gas volume ratio of 1.5:8.5) heated to 135°C is continuously introduced into the high-temperature atmosphere furnace, and the flow rate of the mixed reaction gas is controlled to be 0.35BV / min (relative to the gas volume flow rate of the calcined solid product and the carbon black powder, which is basically the same as that in Example 1), and the reaction tail gas discharged is terminated after it is flammable. The final product is separated by a recovery container, and the recovery container is filled with Krelich liquid as a heavy liquid for screening silicon components and ternary copper components. The upper suspended particle impurities are removed by standing separation, and then the target product is obtained by filtering and separating to remove the heavy liquid. The target product is washed with deionized water and dried to obtain a ternary copper catalyst.

[0095] The obtained ternary copper catalyst was characterized by XRD. The characterization results showed that obvious target peaks appeared in the spectrum, among which 2θ=35.5° and 2θ=38.7° were the characteristic peaks of CuO, 2θ=36.6° was the characteristic peak of Cu2O, and 2θ=43.4° was the characteristic peak of Cu. The copper content in the obtained ternary copper catalyst was characterized by spectral analysis, and the copper recovery rate was calculated by comparing with the characterization content in the original waste organosilicon contact body. After characterization and calculation, the copper recovery rate of the waste organosilicon contact body in this embodiment was 76.5%, that is, the product yield was 76.5% of the theoretical maximum yield. The impurities in the product were characterized. The characterization results showed that the main impurities were silicon dioxide and zinc oxide, and the total impurity content was about 1.27 wt%.

[0096] The catalytic performance of the ternary copper catalyst was characterized. The test process was as follows: 20 g of silicon powder, 0.8 g of the ternary copper catalyst prepared in this example, and 0.1 g of zinc powder were mixed and ground to form a contact body; before the reaction, the reaction system was first purged with nitrogen gas, and then switched to MeCl gas. After preheating, MeCl reacted with the contact body, and the product after the reaction flowed out from the lower end of the reactor. After condensation by a condenser, it was collected with toluene solution to obtain a test liquid, and the tail gas was post-treated with alkaline solution; the test liquid was fixed to volume and quantitatively analyzed by gas chromatography. The characterization results are shown below.

[0097]

[0098] Note: The reaction conditions for the catalytic performance test are preheating temperature of 350°C, reaction temperature of 325°C, reaction pressure of normal pressure, MeCl flow rate of 25 mL / min, and reaction time of 24 h. In the table: M1 is MeSiCl (monomethyltrichlorosilane), M2 is MeSiCl (dimethyldichlorosilane), M3 is MeSiCl (trimethylmonochlorosilane), M1H is MeHSiCl (monomethylhydrogen-containing silane), M2H is MeHSiCl (dimethylhydrogen-containing silane), LF is a low-boiling substance, and HF is a high-boiling substance. The product selectivity is the ratio of the mass of the target product to the sum of the masses of all reaction products. The silicon powder conversion rate is the ratio of the mass difference before and after the reaction to the total mass before the reaction, that is, (m 反应前 -m 反应后 ) / m 反应前 ×100%, where: m is the mass of the contact body.

[0099] It can be seen from the above results that the selectivity and conversion rate of the ternary copper catalyst prepared in this example are significantly lower than those in Example 1. It can be seen that for the process of the present invention, the choice of reactor will have a very significant impact on the results.

Claims

1. A method for preparing a Cu-Cu2O-CuO ternary copper catalyst by gas phase reduction of waste organosilicon contacts, characterized in that: The method comprises: The waste organosilicon contact body treated by oxidation and roasting and a reducing medium are loaded into a tubular reactor, a mixed reaction gas of fluorine gas and a diluent gas is introduced into the tubular reactor, the reaction temperature is controlled by the tubular reactor, and the product of the tubular reactor is recovered after the reaction and a Cu-Cu2O-CuO ternary copper catalyst is directly obtained by heavy liquid separation; The volume proportion of the dilution gas in the mixed reaction gas is 75-90%VOL; The mixed reaction gas flow rate is 1 to 3 BV / min; The waste organosilicon contact body treated by oxidation and roasting and the reducing medium are mixed and uniformly loaded in a tubular reactor at a mass ratio of 1: (0.15-0.30); The reaction temperature in the tubular reactor is controlled to be 450-600°C; The reducing medium is carbon black and / or coke and / or activated carbon and / or graphite.

2. The method for preparing a Cu-Cu2O-CuO ternary copper catalyst by gas phase reduction of waste organosilicon contacts according to claim 1, characterized in that: The mixed reaction gas is heated to ≥120°C before entering the tubular reactor.

3. The method for preparing a Cu-Cu2O-CuO ternary copper catalyst by gas phase reduction of waste organosilicon contacts according to claim 1, characterized in that: A screen is provided at the lower end of the tube port of the tubular reactor, and the mesh number of the screen is ≥20 meshes.

Images