A method for preparing refined cuprous chloride from waste sludge of liquid-phase DMC catalyst

Abstract

The present invention discloses a method for preparing refined cuprous chloride from the catalyst waste sludge filtered out by a liquid-phase DMC device, which includes: slowly adding the catalyst waste sludge to an ammonium chloride solution and adding a masking agent to adjust the pH value, followed by solid-liquid separation; adding ammonia water to the liquid to adjust the pH value and then performing solid-liquid separation again; adding hydrochloric acid and hydroxylamine hydrochloride to the obtained solid part, heating under nitrogen protection, introducing chlorine gas into it, continuously reacting for 2-5 hours, drying in an airtight manner, and obtaining a cuprous chloride product. This method turns waste into treasure, has low production costs, high product purity, a short process flow, and is safe, environmentally friendly.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical engineering, and particularly relates to a method for preparing refined cuprous chloride from waste sludge of a liquid-phase DMC catalyst. Background Art

[0002] In the preparation of DMC (dimethyl carbonate) by the liquid-phase oxidative carbonylation of methanol, methanol, carbon monoxide and oxygen are used as raw materials, and the products are DMC and water. The main component of the catalyst is a copper-based complex. The reaction equation is as follows. This technology can currently

[0003]

[0004] be a homogeneous liquid-phase circulation reaction or a single-pot batch reaction. During the reaction process, due to the occurrence of by-products, the complexing agent decomposes, causing the copper ions to lose protection. At the same time, the presence of water in the system will cause the hydrolysis of copper ions, generating basic copper chloride, copper hydroxide, and copper salt precipitates formed by the decomposition of the complexing agent and copper. In addition, there will be a small amount of precipitates of iron, calcium, silicon, sulfur and other ions mixed in due to equipment corrosion. These precipitates or insoluble substances can be filtered out through the filtration system in the production device or obtained by intermittent cleaning of the reactor, resulting in the loss of the effective components of the catalyst in the system, the decline of catalytic activity, and the reduction of production capacity. At the same time, in order to restore the catalytic activity of the system, adding new catalyst will increase the economic cost of the enterprise. A liquid-phase DMC device with an annual output of 100,000 tons will produce about 100-300 tons of catalyst waste sludge every year. If directly discarded, it is neither economical nor environmentally friendly.

[0005] Generally, the copper source of the copper-based complex catalyst used in the synthesis of liquid-phase DMC is cuprous chloride. Cuprous chloride is a white tetrahedral crystal, showing iron-gray when melted. During the storage process of cuprous chloride crystals, it is extremely easy to oxidize in air and water to form basic copper chloride (CuCl2·xCuO·4H2O). Even after being sealed, it is also extremely easy to be oxidized over time, resulting in a decrease in the purity of cuprous chloride. At the same time, due to the complexity of the copper source, low-purity copper sources in the preparation process will introduce more impurity ions, and low-purity cuprous chloride will lead to a decrease in the catalytic activity of the prepared copper-based complex catalyst, and even the catalytic activity is completely lost due to catalyst poisoning. Therefore, the copper-based complex catalyst must use refined cuprous chloride that meets the national standard as the copper source. Summary of the Invention

[0006] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method for preparing refined cuprous chloride from the catalyst waste sludge filtered out by a liquid-phase DMC device. This method turns waste into treasure, has low production costs, high product purity, a short process flow, and is safe and environmentally friendly.

[0007] The present invention is achieved through the following technical solutions:

[0008] A method for preparing refined cuprous chloride from the waste sludge of a liquid-phase DMC catalyst, comprising the following steps:

[0009] Step 1: Slowly add the catalyst waste sludge to the ammonium chloride solution under stirring to obtain a first mixture, and adjust the pH value of the first mixture to 1.5 - 2; continue stirring for 30 - 60 min, and then perform solid-liquid separation to obtain the solid part as the first solid and the liquid part as the first liquid which enters Step 2;

[0010] The catalyst waste sludge is the catalyst waste sludge generated during the preparation of DMC by the methanol liquid-phase oxidative carbonylation method;

[0011] The mass ratio of the catalyst waste sludge to the ammonium chloride solution is 1:(1 - 2);

[0012] Step 2: Add a masking agent to the first liquid obtained in Step 1 to adjust the pH value to 7.1 - 7.5, stir for 1 - 2 h to obtain a second mixture, and perform solid-liquid separation on the second mixture to obtain the solid part as the second solid and the liquid part as the second liquid which enters Step 3; the main function of the masking agent is to remove impurity ions such as iron ions in copper;

[0013] The masking agent is a mixture prepared from triethanolamine and an imidazole-based agent in a molar ratio of 1:1;

[0014] Step 3: Add ammonia water to the second liquid obtained in Step 2 to adjust the pH value to 13 - 14, stir for 1 - 2 h to obtain a third mixture, and perform solid-liquid separation on the third mixture to obtain the solid part as the third solid and the liquid part as the third liquid;

[0015] Step 4: Add hydrochloric acid to the third solid obtained in Step 3 and stir for 1 - 2 h to obtain a fourth mixture;

[0016] The addition amount of hydrochloric acid is 2 - 4 times the mass of the third solid;

[0017] Step 5: Add hydroxylamine hydrochloride to the fourth mixture, and under nitrogen protection, heat it up to 80 - 100 °C and continuously stir for 2 - 5 h to obtain a fifth mixture;

[0018] The addition amount of hydroxylamine hydrochloride is 1 - 1.5 times the mass of the third solid;

[0019] Step 6: Heat the fifth mixture to 150 - 300 °C, introduce chlorine gas into it, and continuously react for 2 - 5 h to obtain a sixth mixture after the reaction;

[0020] The partial pressure of chlorine gas in the reaction system is 0.3 - 1 MPa,

[0021] Step 7: Dry the sixth mixture under air isolation to obtain cuprous chloride product.

[0022] In the above technical solution, in Step 1, the ammonium chloride solution is a saturated ammonium chloride solution.

[0023] In the above technical solution, in Step 1, the mass ratio of the catalyst waste sludge to the ammonium chloride solution is 1:2.

[0024] In the above technical solution, in Step 1, the method for adjusting the pH of the first mixture is to add one or more of dilute hydrochloric acid, dilute acetic acid, or dilute citric acid to the first mixture, preferably dilute hydrochloric acid; further, the acid concentration is 0.1 - 1 mol / L.

[0025] In the above technical solution, in Step 2, the masking agent is a solution of a mixture prepared by mixing triethanolamine and an imidazole-based agent in a molar ratio of 1:1, and its concentration is 0.1 - 1 mol / L.

[0026] In the above technical solution, in Step 2, the imidazole-based agent is one or more of benzimidazole, N-methylimidazole, and 4-methylimidazole.

[0027] In the above technical solution, in Step 3, the concentration of the ammonia water is 20 - 30 wt%.

[0028] In the above technical solution, in Step 3, the obtained third liquid is recycled for the preparation of ammonium chloride solution.

[0029] In the above technical solution, the solid-liquid separation process is carried out by filtration.

[0030] In the above technical solution, in Step 4, the concentration of the hydrochloric acid is 1 - 6 mol / L.

[0031] In the above technical solution, in Step 5, under the state of nitrogen protection, the oxygen content is lower than 0.01 vol%.

[0032] In the above technical solution, in Step 6, the reaction tail gas is absorbed by the absorption liquid, the absorption liquid is deionized water, the absorption liquid after adsorption is recycled for the preparation of hydrochloric acid solution, and after the reaction is completed, the reaction atmosphere is replaced with nitrogen, and the gas displaced after the reaction is also absorbed by the absorption liquid.

[0033] In the above technical solution, in Step 6, the chlorine gas introduced is high-purity chlorine gas with a purity of 99.99 vol%.

[0034] In the above technical solution, in Step 7, the sixth mixture is dried under air isolation by spray drying to obtain dried cuprous chloride powder, and granulation, screening are carried out under air isolation and stored away from light.

[0035] In the above technical solution, steps 1 to 6 are all carried out in an enamel reactor.

[0036] The advantages and beneficial effects of the present invention are as follows:

[0037] 1. This process recovers the catalyst waste sludge filtered out from the liquid-phase DMC device and prepares refined cuprous chloride. This process turns waste into treasure, and the utilization rate of the catalyst waste sludge is higher than 95%; 2. Compared with the expensive price of high-purity reagents in the existing process, the catalyst waste sludge itself is a waste, and the raw material cost is low; 3. Compared with the existing process, the types of metal ions in the raw materials of this process are complex. By adding a masking agent for separation, the product purity is high, and the cuprous chloride content is higher than 99%, meeting the requirements of the national standard HG / T 2960-2010; 4. The process flow of this process is more reasonable, and the tail gas and tail liquid can be reused, which is safe and environmentally friendly. Brief Description of the Drawings

[0038] Figure 1 It is a comparison chart of the FTIR spectrum of the refined cuprous chloride finally obtained in Example 1 and the standard spectrum library;

[0039] Figure 2 It is the SEM electron micrograph of the refined cuprous chloride finally obtained in Example 1;

[0040] Figure 3 It is the sample element analysis result of the refined cuprous chloride finally obtained in Example 1;

[0041] Figure 4 It is the comparison chart of the XRD spectrum of the refined cuprous chloride finally obtained in Example 1 and the standard card;

[0042] Figure 5 It is the particle size analysis chart of the refined cuprous chloride finally obtained in Example 1;

[0043] Figure 6 It is the weight loss curve of the refined cuprous chloride finally obtained in Example 1 under air and nitrogen atmospheres;

[0044] Figure 7 It is the specific surface area curve of the refined cuprous chloride finally obtained in Example 1;

[0045] Figure 8 It is the physical adsorption curve of the refined cuprous chloride finally obtained in Example 1.

[0046] For those of ordinary skill in the art, without creative efforts, other related drawings can be obtained based on the above drawings. Detailed Embodiments

[0047] To enable those skilled in the art to better understand the solution of the present invention, the technical solution of the present invention will be further described below in conjunction with specific embodiments.

[0048] Example 1:

[0049] Step 1: Add 200 g of saturated ammonium chloride solution to an enamel reactor, start stirring, slowly add 100 g of catalyst waste sludge into the reactor, then slowly add 0.1 mol / L dilute hydrochloric acid into the reactor to adjust the pH of the reactor liquid to 1.5, continue stirring for 30 min, and then filter the reactor liquid to obtain filtrate 1 and filter residue 1. The filter residue is dried and weighed, and the mass is 2.562 g.

[0050] Step 2: Return filtrate 1 to the reactor, start stirring, add a mixed solution of 0.1 mol / L triethanolamine and benzimidazole (where the molar ratio of triethanolamine to benzimidazole is 1:1) into the reactor, use it to adjust the pH of the reactor liquid to 7.1, stir for 1 h, filter the reactor liquid to obtain filtrate 2 and filter residue 2. The filter residue is dried and weighed, and the mass is 0.039 g.

[0051] Step 3: Return filtrate 2 to the reactor, add 20% concentration ammonia water into the reactor to adjust the pH to 13, stir for 1.5 h, filter the reactor liquid to obtain a filter cake and filtrate 3. The filter cake is dried and weighed, and the mass is 97.254 g. Filtrate 3 is used to prepare the saturated ammonium chloride solution in Step 1.

[0052] Step 4: Put 97.254 g of the filter cake into an enamel reactor, add 194.508 g of 1 mol / L hydrochloric acid into the reactor, and stir for 2 h;

[0053] Step 5: Add 100 g of hydroxylamine hydrochloride into the reactor, then displace the system with nitrogen to make the oxygen content in the reactor lower than 0.01%, heat the reactor to 80 °C, and keep stirring for 2 h;

[0054] Step 6: Continue to heat the reactor to 150 °C, and introduce high-purity chlorine gas to make its partial pressure 1 MPa, and continue to react for 2 h. The tail gas at the outlet of the reactor during this process is absorbed by deionized water;

[0055] Step 7: After the reaction, the gas in the reactor is displaced with nitrogen, and this process is still absorbed by the solvent in Step 6; the absorption liquid after the reaction can be reused for the preparation of the hydrochloric acid solution in Step 3.

[0056] Step 8: Drain the reactor liquid in the reactor into a spray dryer for drying (isolating air). The dried cuprous chloride powder is granulated and sieved in a granulator that isolates air. The sieved cuprous chloride is directly sealed in a packaging bag with a black inner lining bag to avoid light. The purity of the sieved cuprous chloride is 99.23%.

[0057] Example 2:

[0058] Step 1: Add 500 g of saturated ammonium chloride solution into an enamel reactor, start stirring, slowly add 250 g of catalyst waste sludge into the reactor, then slowly add 0.5 mol / L dilute hydrochloric acid into the reactor to adjust the pH of the reactor liquid to 1.7, continue stirring for 45 min, then filter the reactor liquid to obtain filtrate 1 and filter residue 1. After drying the filter residue, weigh it, and the mass is 7.253 g.

[0059] Step 2: Return filtrate 1 to the reactor, start stirring, add a mixed solution of 0.5 mol / L triethanolamine and N-methylimidazole (the molar ratio of triethanolamine to N-methylimidazole is 1:1) into the reactor, use it to adjust the pH of the reactor liquid to 7.3, stir for 1.5 h, filter the reactor liquid to obtain filtrate 2 and filter residue 2. After drying the filter residue, weigh it, and the mass is 1.257 g.

[0060] Step 3: Return filtrate 2 to the reactor, add 25% ammonia water into the reactor to adjust the pH to 13.5, stir for 1.5 h, filter the reactor liquid to obtain a filter cake. After drying and weighing the filter cake, the mass is 241.374 g, and filtrate 3. Filtrate 3 is used to prepare the saturated ammonium chloride solution in Step 1.

[0061] Step 4: Put 241.374 g of the filter cake into an enamel reactor, add 724.122 g of 3 mol / L hydrochloric acid into the reactor, and stir for 3.5 h;

[0062] Step 5: Add 301 g of hydroxylamine hydrochloride into the reactor, then displace the system with nitrogen to make the oxygen content in the reactor less than 0.01%, heat the reactor to 90 °C, and keep stirring for 3.5 h;

[0063] Step 6: Continue to heat the reactor to 225 °C, and introduce high-purity chlorine gas to make its partial pressure 0.5 MPa, continue the reaction for 3.5 h. During this process, the tail gas at the outlet of the reactor is absorbed with deionized water;

[0064] Step 7: After the reaction, displace the gas in the reactor with nitrogen. This process is still absorbed with the solvent in Step 6; the absorbed liquid after the reaction can be reused for the preparation of the hydrochloric acid solution in Step 3.

[0065] Step 8: Drain the reactor liquid in the reactor into a spray dryer for drying (isolating air). The dried cuprous chloride powder is granulated and sieved in a granulator that isolates air. The sieved cuprous chloride is directly sealed in a packaging bag with a black inner lining bag to avoid light. The purity of the sieved cuprous chloride is 99.38%.

[0066] Example 3:

[0067] Step 1: Add 2000 g of saturated ammonium chloride solution to an enamel reactor. Start stirring and slowly add 1000 g of catalyst waste mud into the reactor. Then slowly add 1 mol / L dilute hydrochloric acid into the reactor to adjust the pH of the reactor liquid to 2.0. Continue stirring for 60 min, and then filter the reactor liquid to obtain filtrate 1 and filter residue 1. The filter residue is dried and weighed, and the mass is 20.325 g.

[0068] Step 2: Return filtrate 1 to the reactor. After starting stirring, add a mixed solution of 1 mol / L triethanolamine and 4-methylimidazole (the molar ratio of triethanolamine to 4-methylimidazole is 1:1) into the reactor, and use it to adjust the pH of the reactor liquid to 7.5. Stir for 2 h, and then filter the reactor liquid to obtain filtrate 2 and filter residue 2. The filter residue is dried and weighed, and the mass is 3.258 g.

[0069] Step 3: Return filtrate 2 to the reactor. Add 30% ammonia water into the reactor to adjust the pH to 14.0. Stir for 2 h, and then filter the reactor liquid to obtain a filter cake. The filter cake is dried and weighed, and the mass is 975.351 g, and filtrate 3. Filtrate 3 is used to prepare the saturated ammonium chloride solution in Step 1.

[0070] Step 4: Put 975.351 g of the filter cake into an enamel reactor, and add 3901.404 g of 6 mol / L hydrochloric acid into the reactor. Stir for 5 h;

[0071] Step 5: Add 1462 g of hydroxylamine hydrochloride into the reactor, and then displace the system with nitrogen to make the oxygen content in the reactor less than 0.01%. Heat the reactor to 100 °C and keep stirring for 5 h;

[0072] Step 6: Continue to heat the reactor to 300 °C, and introduce high-purity chlorine gas to make its partial pressure 0.3 MPa. Continue the reaction for 5 h. The tail gas at the outlet of the reactor during this process is absorbed with deionized water;

[0073] Step 7: After the reaction is completed, displace the gas in the reactor with nitrogen. This process is still absorbed with the solvent in Step 3; the absorption liquid after the reaction can be repeatedly used for the preparation of the hydrochloric acid solution in Step 3.

[0074] Step 8: Drain the reactor liquid in the reactor into a spray dryer for drying (isolating air). The dried cuprous chloride powder is granulated and sieved in a granulator that isolates air. The sieved cuprous chloride is directly sealed in a packaging bag with a black inner lining bag in the dark. The purity of the sieved cuprous chloride is 99.51%.

[0075] To verify the purity of CuCl in the refined cuprous chloride after being refined by the refining process for deteriorated cuprous chloride, the refined cuprous chloride finally obtained in Example 1 was characterized and analyzed:

[0076] The CuCl content complies with the provisions of the national standard HG / T 2960-2010 and is greater than or equal to 99%, while the CuCl2 content is less than or equal to 0.6%.

[0077] Analytical instruments used:

[0078] EDS energy spectrometer; XRD X-ray diffractometer; ICP-OES inductively coupled plasma emission spectrometer; FTIR Fourier transform infrared spectrometer; GC-2014C gas chromatograph; Mastersizer 3000E laser particle size analyzer; ASAP2460 dual-station specific surface area and pore size analyzer from Micromeritics, USA; Karl Fischer moisture analyzer; ultraviolet spectrophotometer; national standard analysis method HG / T-2960-2010

[0079] The FTIR analysis results are shown in Figure 1 , and it can be seen from the infrared spectrum analysis that the sample is mainly CuCl, which is basically consistent with the standard picture of CuCl.

[0080] The SEM image is shown in Figure 2 , and the sample element analysis results are shown in Figure 3 ; it can be seen from the SEM picture and the element analysis results that the sample has a high purity and the main components are two elements, Cu and Cl.

[0081] The XRD analysis results are shown in Figure 4 , and the sample full width at half maximum data are shown in Table 1 below; the sample shows typical diffraction peaks of cuprous chloride crystals, and the average crystal grain size is about 61.5 nm;

[0082] Table 1. Full width at half maximum data of the sample

[0083]

[0084] Remarks: hlk represents the crystal plane, FWHM represents the full width at half maximum, represents that the unit of crystal grain size is angstrom, and 1 angstrom = 0.1 nm

[0085] The ICP-OES analysis results of the sample are shown in Table 2 below. It can be seen from the ICP-OES analysis results that the sample has a high purity, and the contents of elements such as Al, Fe, K, Mg, Na, and Si are all less than 100 ppm.

[0086] Table 2. ICP-OES analysis results

[0087]

[0088]

[0089] The particle size analysis of the sample is shown in Figure 5 , and it can be seen from the particle size analysis results that 95% of the particle size of this sample is less than 66.5 μm.

[0090] The thermogravimetric analysis of the sample is shown in Figure 6 , and the weight loss curves of the sample in air and nitrogen atmospheres can be obtained. The sample has less weight loss before 426 °C, and the weight loss increases after 426 °C. Since the melting point of CuCl is 426 °C, the molten sample is carried away by the protective gas, indicating that the purity of the cuprous chloride product is relatively high.

[0091] The specific surface area analysis of the sample is shown in Figure 7 , and the physical adsorption analysis of the sample is shown in Figure 8 ; the specific surface area of the sample is 89.5332 ± 0.3675 m 2 / g.

[0092] The Karl Fischer moisture meter is used to analyze the moisture content of the sample, and its water content is 0.193 wt%.

[0093] According to the national standard analysis method of HG / T - 2960 - 2010 for the sample, the experimental results show that the contents of SO4 2- , NO3 - are both less than 10 ppm.

[0094] Ultraviolet spectrophotometry is used to analyze Cu 2+ . The sample of Cu 2+ is analyzed according to the method of preparing standard series of Cu ions with different concentrations. The experimental results show that the content of Cu 2+ is 0.477%.

[0095] The test results are summarized as follows:

[0096]

[0097]

[0098] Relative terms such as "first" and "second" are only used to distinguish one component with the same name from another, and do not necessarily require or imply any such actual relationship or order between these components.

[0099] The above provides an exemplary description of the present invention. It should be noted that without departing from the core of the present invention, any simple deformation, modification, or equivalent replacement that can be made by those skilled in the art without creative efforts falls within the protection scope of the present invention.

Claims

1. A method for preparing refined cuprous chloride from waste sludge of liquid-phase DMC catalyst, characterized in that, It includes the following steps: Step 1: Slowly add catalyst waste sludge to the ammonium chloride solution under stirring to obtain a first mixture, and adjust the pH value of the first mixture to 1.5 - 2; continue stirring for 30 - 60 min, then perform solid-liquid separation to obtain a solid part as the first solid, and the liquid part obtained is the first liquid which enters Step 2; The catalyst waste sludge is the catalyst waste sludge generated during the preparation of DMC by the methanol liquid-phase oxidative carbonylation method; The mass ratio of the catalyst waste sludge to the ammonium chloride solution is 1:(1 - 2); Step 2: Add a masking agent to the first liquid obtained in Step 1 to adjust the pH value to 7.1 - 7.5, stir for 1 - 2 h to obtain a second mixture, perform solid-liquid separation on the second mixture to obtain a solid part as the second solid, and the liquid part obtained is the second liquid which enters Step 3; The masking agent is a mixture prepared by mixing triethanolamine and an imidazole-based agent in a molar ratio of 1:1; Step 3: Add ammonia water to the second liquid obtained in Step 2 to adjust the pH value to 13 - 14, stir for 1 - 2 h to obtain a third mixture, perform solid-liquid separation on the third mixture to obtain a solid part as the third solid, and the liquid part obtained is the third liquid; Step 4: Add hydrochloric acid to the third solid obtained in Step 3 and stir for 1 - 2 h to obtain a fourth mixture; The addition amount of hydrochloric acid is 2 - 4 times the mass of the third solid; Step 5: Add hydroxylamine hydrochloride to the fourth mixture, and under nitrogen protection, heat it up to 80 - 100 °C, continuously stir for 2 - 5 h to obtain a fifth mixture; The addition amount of hydroxylamine hydrochloride is 1 - 1.5 times the mass of the third solid; Step 6: Heat the fifth mixture to 150 - 300 °C, introduce chlorine gas into it, and continuously react for 2 - 5 h to obtain a sixth mixture after the reaction ends; The partial pressure of chlorine gas in the reaction system is 0.3 - 1 MPa, Step 7: Dry the sixth mixture in an airtight manner to obtain cuprous chloride products.

2. The method for preparing refined cuprous chloride from the waste sludge of the liquid-phase DMC catalyst according to claim 1, wherein In Step 1, the ammonium chloride solution is a saturated ammonium chloride solution; the mass ratio of the catalyst waste sludge to the ammonium chloride solution is 1:

2.

3. The method for preparing refined cuprous chloride from the waste sludge of the liquid-phase DMC catalyst according to claim 1, wherein In Step 1, the method for adjusting the pH of the first mixture is to add one or more of dilute hydrochloric acid, dilute acetic acid, or dilute citric acid to the first mixture.

4. The method for preparing refined cuprous chloride from waste sludge of liquid-phase DMC catalyst according to claim 1, characterized in that, In Step 1, the method for adjusting the pH of the first mixture is to add dilute hydrochloric acid to the first mixture; the acid concentration is 0.1 - 1 mol / L.

5. The method for preparing refined cuprous chloride from the waste sludge of the liquid-phase DMC catalyst according to claim 1, characterized in that, In Step 2, the masking agent is a solution of a mixture prepared by mixing triethanolamine and an imidazole-based agent in a molar ratio of 1:1, and its concentration is 0.1 - 1 mol / L.

6. The method for preparing refined cuprous chloride from the waste sludge of a liquid-phase DMC catalyst according to claim 1, characterized in that, In Step 2, the imidazole-based agent is one or more of benzimidazole, N-methylimidazole, and 4-methylimidazole.

7. The method for preparing refined cuprous chloride from the waste sludge of the liquid-phase DMC catalyst according to claim 1, characterized in that, In Step 3, the concentration of the ammonia water is 20 - 30 wt%; the third liquid obtained is recycled for the preparation of ammonium chloride solution.

8. The method for preparing refined cuprous chloride from the waste sludge of the liquid-phase DMC catalyst according to claim 1, characterized in that, The solid-liquid separation process is carried out by filtration.

9. The method for preparing refined cuprous chloride from the waste sludge of a liquid-phase DMC catalyst according to claim 1, characterized in that, In Step 4, the concentration of the hydrochloric acid is 1 - 6 mol / L; In Step 5, under nitrogen protection, the oxygen content is less than 0.01 vol%.

10. The method for preparing refined cuprous chloride from liquid-phase DMC catalyst waste sludge according to claim 1, characterized in that, In step 6, the reaction tail gas is absorbed by an absorption liquid, which is deionized water. After adsorption, the absorption liquid is recovered for the preparation of hydrochloric acid solution. After the reaction is completed, the post-reaction atmosphere is replaced with nitrogen, and the gas displaced after the reaction is also absorbed by the absorption liquid. The introduced chlorine gas is high-purity chlorine gas with a purity of 99.99 vol%.

11. The method for preparing refined cuprous chloride from liquid-phase DMC catalyst waste sludge according to claim 1, characterized in that, In step 7, the sixth mixture is obtained as dried cuprous chloride powder by spray drying in an air-insulated state, and granulated, screened and stored in the dark in an air-insulated manner.

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