Device and method for synthesizing trichlorosilane from organic silicon waste contact

Abstract

The invention discloses a device and a method for synthesizing trichlorosilane from a waste contact body. A waste contact body is arranged in a transparent glass tube reaction tube, and a fixed sieve plate is arranged at the middle lower part of the reaction tube. The reaction tube is fixed in a reaction resistance furnace and is filled with organic silicon waste contact bodies, reaction gas enters from the lower end of the reaction tube after being decompressed and preheated by a steel cylinder and is subjected to a synthetic reaction with the waste contact bodies, obtained reaction products and other gas enter a cooler after being filtered by quartz wool, and condensation products are collected into a liquid collection bottle; and the non-condensable acid gas enters a tail gas absorption device. The invention provides a small-scale test device and method for synthesizing trichlorosilane from organic silicon waste contact bodies, the operation is simple, and test data has important guiding significance for engineering device construction.

Description

Technical Field

[0001] The invention belongs to the technical field of comprehensive utilization of three wastes, and specifically relates to a device and a method for synthesizing trichlorosilane by utilizing waste organic silicon contacts. Background Art

[0002] Waste silicone contacts are residual reactants in the production process of methylchlorosilane. They contain elements such as Si, C, Cu, and Fe. They are black solid powders with high activity and are very easy to spontaneously combust. Due to their certain harmfulness and environmental impact, it is very important to treat them reasonably and recycle them. Some research and practice are dedicated to exploring the resource recycling technology of waste silicone contacts. Through specific methods, waste silicone contacts are treated to recover copper.

[0003] CN110791650A "A method for recovering metallic copper using waste organosilicon contacts" relates to a method for recovering metallic copper using waste organosilicon contacts, which includes oxidizing and roasting the waste organosilicon contacts to remove organic impurities, and then obtaining metallic copper through steps such as carbon-deficient reduction and heavy liquid separation. The method has the advantages of low pollution, high metallic copper yield, and high material utilization.

[0004] CN202210488587.X "A method for recovering copper from waste silicone contacts" introduces a method for recovering copper from waste silicone contacts. The waste silicone contacts, water, and additives are stirred to obtain water leaching residue and water leaching leachate; the water leaching residue is acid-leached, and an oxidant is added to react to obtain decopperized slag and copper-containing leachate; the copper-containing leachate is deoiled and purified, and the acidity is adjusted to obtain copper electrolytic solution; the copper electrolytic solution is subjected to two-stage cyclone electrolysis to obtain Grade A copper (Cu>99.99%) and No. 2 standard copper (Cu>99.90%) that meet GB / T 467-2010 standards.

[0005] CN116212871A "A method for preparing a ternary copper catalyst by gas phase reduction of waste organosilicon contacts" discloses a method for preparing a ternary copper catalyst by gas phase reduction of waste organosilicon contacts. The method comprises loading waste organosilicon contacts that have been oxidatively roasted and a reducing medium into a tubular reactor, introducing a mixed reaction gas of fluorine gas and a diluent gas into the tubular reactor, controlling the reaction temperature through the tubular reactor, recovering the tubular reactor product after the reaction, and directly obtaining the ternary copper catalyst through heavy liquid separation.

[0006] In addition, there are also studies on the use of waste contacts to synthesize organosilicon monomers. For example, the waste contacts discharged from the fluidized bed and recovered from the external cyclone separator can be treated with N2 at 1100°C for 3 minutes, and then placed in a stirred bed and reacted with MeCl at 300°C to produce methylchlorosilane monomers. High-temperature N2 treatment is very effective in improving the activity (yield) of the contacts and the selectivity of Me2SiCl2. For another example, heating the waste contacts with halogenated benzene under the action of a copper catalyst can produce phenylchlorosilane monomers.

[0007] Patent CN101391775 has disclosed a method for synthesizing trichlorosilane from waste contacts in the production of organochlorosilanes, using waste contacts as raw materials and dry HCl diluted with a diluent gas to prepare trichlorosilane by gas-solid phase direct synthesis. The prepared trichlorosilane can be used to synthesize single crystal silicon, polycrystalline silicon, high-purity silicon and special organosilanes.

[0008] At present, there are no engineering cases of synthesizing trichlorosilane using waste organosilicon contacts at home and abroad, and there are few reports on its reaction research. This is because there is a certain degree of difficulty in producing trichlorosilane using waste organosilicon contacts. Waste contacts usually contain a large amount of copper and a small amount of zinc and other impurities, making it difficult to prepare high-purity trichlorosilane. In addition, the content of each component in the waste contact fluctuates greatly with the synthesis of organosilicon, and it is highly active, the reaction process is highly exothermic, and the reaction rate is difficult to control. Summary of the invention

[0009] The present invention aims to disclose a device and method for synthesizing trichlorosilane from waste organosilicon contacts, study the reaction conditions and reaction characteristics of the waste contacts to synthesize trichlorosilane, provide reliable basic data for the engineering of direct synthesis of trichlorosilane from waste contacts, and develop higher utilization value for waste contacts to achieve effective utilization of resources and protection of the environment.

[0010] A device for synthesizing trichlorosilane from waste contactors, wherein a hydrogen chloride cylinder, a hydrogen cylinder, and a nitrogen storage tank are respectively connected to a main pipeline through pipelines, and the main pipeline is connected to a preheater; The preheater is connected to the reaction tube, the outlet of the reaction tube is connected to the condenser, and the condenser is connected to the liquid collecting bottle.

[0011] The hydrogen chloride cylinder is connected to the main pipeline via the hydrogen chloride gas pressure reducing valve, the hydrogen chloride gas flow meter and the needle valve in sequence; The hydrogen cylinder is connected to the main pipe through a hydrogen gas pressure reducing valve, a hydrogen gas flow meter, and a needle valve; the nitrogen storage tank is connected to the main pipe through a nitrogen pressure reducing valve, a nitrogen flow meter, and a needle valve; A pressure gauge is installed between the main pipeline and the preheater.

[0012] Hydrogen chloride pipelines, nitrogen pipelines, valves and flow meters on the pipelines are preferably made of stainless steel. Hydrogen chloride preheaters, reactors, condensers, liquid collectors, tail gas absorbers and the connecting pipelines between them are made of pressure-resistant glass.

[0013] There is a preheating resistance furnace outside the preheater, and there is a reaction resistance furnace outside the reaction tube.

[0014] A fixed sieve plate is provided in the middle and lower part of the reaction tube, and after the waste contact body is filled in the middle and upper part, quartz wool is plugged in the upper part.

[0015] A method for synthesizing trichlorosilane from waste contacts comprises the following steps: Weigh an appropriate amount of waste contact body and place it in a reaction tube, set a fixed sieve plate at the bottom of the reaction tube and quartz wool at the top; A preheater is connected to the lower part of the reaction tube, and nitrogen is used to purge the preheater and the reaction tube to replace the air; Set the temperature control program of the preheating resistance furnace and the reaction resistance furnace, and start them; Passing HCl gas or a mixed gas of HCl and H2; Open the condenser to circulate condensed water, and the condensed water temperature is -10-10℃. The reaction product is condensed into the liquid collection bottle, and the non-condensable acidic gas is absorbed by the alkali solution. After the reaction is completed, close the reaction gas valve, open the nitrogen valve for replacement, stop heating, and conduct chemical analysis on the material in the liquid collection bottle. After the system cools to room temperature, remove the reaction tube and conduct data analysis on the internal residue.

[0016] The particle size of the waste contact body is less than 20 μm, and the components of the waste contact body are Si: 60%-85%; Cu: 5%-15%; Fe: 2%-5%; Aluminum: 0.5%-3%; Carbon: 1-5%; the aperture of the fixed sieve plate is less than 10 μm; and the specification of quartz wool is 1-3 μm.

[0017] The upper and lower ends of the reaction tube are wrapped with high temperature resistant glass fiber tape, and the outlet of the reaction tube and the connection with the glass instrument are wrapped with raw tape and then connected.

[0018] The inlet flow rate of hydrogen chloride gas is 10-25 mL / min; the inlet flow rate of hydrogen gas is 3-8 mL / min. The amount of nitrogen used in the nitrogen replacement system is not less than 6 times the volume of the reaction tube.

[0019] More preferably, the inlet flow rate of hydrogen chloride gas is 15-25 mL / min; the inlet flow rate of hydrogen gas is 5-8 mL / min.

[0020] The reaction pressure in the reactor is 0.1-0.5MPa, and the reaction time is 20-30h.

[0021] The method for synthesizing trichlorosilane from waste contacts adopts the device for preparation.

[0022] The present invention has the following characteristics: 1. The system is simple and can be built in the laboratory with low investment.

[0023] 2. The reaction gas enters from the bottom of the reaction tube. The reaction gas enters from the top of the reaction tube and continuously compacts the waste contact body, causing the pressure in the reaction tube to change and causing fluctuations in the reaction process.

[0024] 3. After the program is preset, the reaction process does not require human intervention.

[0025] 4. The experimental data obtained have good regularity and have strong guiding significance for plant production: it can explore the influence of reaction temperature on reaction selectivity, analyze the change of particle size of waste contact bodies under different reaction degrees, and explore the maximum conversion rate of waste contact bodies.

[0026] 5. The PTFE tape at the connection of the instrument can prevent the hydrolysis and cross-linking of trichlorosilane after leakage occurs at the connection, making the device unable to be disassembled, and at the same time it can also improve the air tightness of the device.

[0027] 6. The reaction gas enters from the bottom, which may cause local channels to appear in the waste contact layer and uneven distribution of the reaction gas, resulting in reduced conversion rate and selectivity of the waste contact. Therefore, a sieve plate with small and dense pores is selected to distribute the reaction gas.

[0028] 7. The addition of additional gas sources can explore how to improve the selectivity of trichlorosilane. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the device of the present invention, wherein: 1. Hydrogen chloride cylinder; 2. Hydrogen cylinder; 3. Hydrogen chloride gas pressure reducing valve; 4. Hydrogen chloride gas flow meter; 5. Needle valve; 6. Hydrogen gas pressure reducing valve; 7. Hydrogen gas flow meter; 8. Needle valve; 9. Nitrogen; 10. Nitrogen pressure reducing valve; 11. Nitrogen flow meter; 12. Needle valve; 13. Pressure gauge; 14. Preheating resistance furnace; 15. Reaction resistance furnace; 16. Preheater; 17. Reaction tube sieve plate; 18. Quartz wool; 19. Condenser; 20. Liquid collecting bottle; 21. Tail gas absorption; 22. Reaction tube. DETAILED DESCRIPTION

[0030] The technical solution of the present invention is further described below through embodiments.

[0031] Example 1 This patent invents a device for synthesizing trichlorosilane from waste contacts. A hydrogen chloride cylinder 1 is connected to a main pipe after passing through a hydrogen chloride gas pressure reducing valve 3, a hydrogen chloride gas flow meter 4, and a needle valve 5. A hydrogen cylinder 2 is connected to a main pipe after passing through a hydrogen gas pressure reducing valve 6, a hydrogen gas flow meter 7, and a needle valve 8. A nitrogen source 9 is connected to the main pipe after passing through a nitrogen pressure reducing valve 10, a nitrogen flow meter 11, and a needle valve 12. A pressure gauge 13 is installed between the main pipe and a preheater 16. The preheater 16 is connected to a reaction tube 22, and then connected in sequence to a glass bent pipe, a condenser 19, a liquid collecting bottle 20, and a tail gas absorber 21. A preheating resistance furnace 14 is provided outside the preheater, and a reaction resistance furnace 15 is provided outside the reaction tube. A fixed sieve plate 17 is provided in the middle and lower part of the reaction tube 22, and quartz wool 18 is plugged in the middle and upper part after the waste contacts are filled.

[0032] The above device is used to carry out the following process: Weigh 10g of waste silicone contacts, the particle size of the waste contacts is 5-19μm, and the specification of quartz wool is 1-3μm. Figure 1 The device was built, the length of the reaction tube used was about 55cm, the inner diameter of the reaction tube was about 1.5-1.7cm, the aperture of the sieve plate was 5-10μm, the nitrogen replacement flow rate was set to 25mL / min, and the replacement time was 30min; the preheating resistance furnace operation program was set: the initial temperature was 25℃, the temperature was raised to 200℃ in 60min, and the heating was stopped after stabilizing for 1440min, and the reaction resistance furnace program was set: the initial temperature, the temperature was raised to 250℃ in 60min, and the heating was stopped after stabilizing for 1440min; the condensed water temperature was set to -10℃, and the circulation was started; after the system replacement was completed, 10mL / min HCl gas and 0mL / min H2 gas were introduced, the total pipe pressure was 0.2Mpa, the flow rate was 10mL / min, and the resistance furnace operation program was started; the experiment ended after 25h, sampling and analysis were performed, the HCl gas was stopped, and the system was replaced with 25mL / min nitrogen. The conversion rate of the waste contact body was 36.94%, and the product HSiCl3 content was 80.56%.

[0033] Example 2 The experimental conditions were the same as those in Example 1, except that the reaction temperature was changed to 280° C., and other conditions remained unchanged. The conversion rate of the waste contact body was 37.44%, and the content of HSiCl 3 in the product was 73.64%.

[0034] Example 3 The experimental conditions were the same as those in Example 1, except that the reaction temperature was changed to 220° C., and other conditions remained unchanged. The conversion rate of the waste contact body was 32.31%, and the content of HSiCl 3 in the product was 83.11%.

[0035] Example 4 The experimental conditions were the same as those in Example 1, except that the HCl gas flow rate was changed to 25 mL / min, and other conditions remained unchanged. The conversion rate of the waste contactor was 58.56%, and the content of HSiCl3 in the product was 71.64%.

[0036] Example 5 The experimental conditions were the same as those in Example 2, except that the HCl gas flow rate was changed to 25 mL / min, and other conditions remained unchanged. The conversion rate of the waste contactor was 58.77%, and the content of HSiCl3 in the product was 60.16%.

[0037] Example 6 The experimental conditions were the same as those in Example 3, except that the HCl gas flow rate was changed to 25 mL / min. Other conditions remained unchanged. The conversion rate of the waste contactor was 54.59%, and the content of HSiCl3 in the product was 75.43%.

[0038] Example 7 The experimental conditions were the same as those in Example 4, except that the aperture of the sieve plate of the reaction tube was changed to 50-120 μm, and other conditions remained unchanged. The conversion rate of the waste contact body was 42.36%, and the content of HSiCl3 in the product was 69.32%.

[0039] Example 8 The experimental conditions were the same as those in Example 4, except that the nitrogen replacement time was reduced to 20 min, and other conditions remained unchanged. The conversion rate of the waste contact was 58.32%, and the content of HSiCl3 in the product was 70.96%. During the cleaning process of the reaction tube, it was found that there was a small amount of white substance on the surface of the residue in the reaction tube (no white substance was produced under normal experimental conditions, and it only appeared when the replacement requirements were not met. If the oxygen content is measured, an oxygen meter must be added, which is more troublesome, and the waste contact contains a small amount of acidic substances, which may damage the oxygen meter).

[0040] Example 9 The experimental conditions were the same as those in Example 4, except that the quartz wool specification was changed to 5-10 μm, and other conditions remained unchanged. The waste contact conversion rate was 58.01%, and the product HSiCl3 content was 70.98%. However, during the kneading process, the quartz wool of this specification was brittle and easily damaged, producing white powder.

[0041] Example 10 The experimental conditions were the same as those in Example 6, except that the HCl gas flow rate was changed to 20 mL / min, the hydrogen gas flow rate was changed to 5 mL / min, and other conditions remained unchanged. The conversion rate of the waste contact body was 50.32%, and the content of HSiCl3 in the product was 76.32%.

[0042] It should be understood that the above embodiments are only used to illustrate the present invention and are not used to limit the scope of protection of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

Claims

1. A device for synthesizing trichlorosilane from waste contacts, characterized in that: The hydrogen chloride cylinder (1), the hydrogen cylinder (2), and the nitrogen storage tank (9) are respectively connected to a main pipeline via pipelines, and the main pipeline is connected to a preheater (16); The preheater (16) is connected to the reaction tube (22), the outlet of the reaction tube (22) is connected to the condenser (19), and the condenser (19) is connected to the liquid collecting bottle (20).

2. The device for synthesizing trichlorosilane from waste contacts according to claim 1, characterized in that: The hydrogen chloride cylinder (1) is connected to the main pipeline via the hydrogen chloride gas pressure reducing valve (3), the hydrogen chloride gas flow meter (4) and the needle valve (5) in sequence; The hydrogen cylinder (2) is connected to the main pipe via a hydrogen gas pressure reducing valve (6), a hydrogen gas flow meter (7), and a needle valve (8); the nitrogen storage tank (9) is connected to the main pipe via a nitrogen pressure reducing valve (10), a nitrogen flow meter (11), and a needle valve (12); A pressure gauge (13) is installed between the main pipeline and the preheater (16).

3. The device for synthesizing trichlorosilane from waste contacts according to claim 1, characterized in that: A preheating resistance furnace (14) is disposed outside the preheater (16), and a reaction resistance furnace (15) is disposed outside the reaction tube.

4. The device for synthesizing trichlorosilane from waste contacts according to claim 1, characterized in that: A fixed sieve plate (17) is provided in the middle and lower part of the reaction tube (22), and after the waste contact body is filled in the middle and upper part, the upper part is plugged with quartz wool (18).

5. A method for synthesizing trichlorosilane from waste contacts, characterized in that: The steps include: Weigh an appropriate amount of waste contact body and place it in a reaction tube, set a fixed sieve plate at the bottom of the reaction tube and quartz wool at the top; A preheater is connected to the lower part of the reaction tube, and nitrogen is used to purge the preheater and the reaction tube to replace the air; Set the temperature control program of the preheating resistance furnace and the reaction resistance furnace, and start them; Passing HCl gas or a mixed gas of HCl and H2; The condenser is turned on to circulate condensed water, and the condensed water temperature is -10-10℃. The reaction products are condensed into a liquid collecting bottle, and the non-condensable acidic gas is absorbed by the alkali solution. After the reaction is completed, the reaction gas valve is closed, and the nitrogen valve is opened for replacement. The heating is stopped, and trichlorosilane material is obtained in the liquid collecting bottle for chemical analysis. After the system is cooled to room temperature, the reaction tube is removed and data analysis is performed on the internal residue.

6. The method for synthesizing trichlorosilane from waste contacts according to claim 5, characterized in that: The particle size of the waste contact body is less than 20 μm; the aperture of the fixed sieve plate is less than 10 μm; and the specification of the quartz wool is 1 to 3 μm.

7. The method for synthesizing trichlorosilane from waste contacts according to claim 5, characterized in that: The upper and lower ends of the reaction tube are wrapped with high temperature resistant glass fiber tape, and the outlet of the reaction tube and the connection with the glass instrument are wrapped with raw tape and then connected.

8. The method for synthesizing trichlorosilane from waste contacts according to claim 5, characterized in that: The inlet flow rate of hydrogen chloride gas is 10-25 mL / min; the inlet flow rate of hydrogen gas is 3-8 mL / min.

9. The method for synthesizing trichlorosilane from waste contacts according to claim 5, characterized in that: The reaction pressure in the reactor is 0.1-0.5MPa, and the reaction time is 20-30h.

10. The method for synthesizing trichlorosilane from waste contacts according to any one of claims 5 to 9, characterized in that: The preparation is carried out using the device described in any one of claims 1 to 4.

Images