A method of treating silicone silicones

Abstract

The present invention discloses a method for treating organosilicon slurry, belonging to the field of materials chemistry. The method comprises the following steps: S1, filtering the organosilicon slurry to obtain filter cake I and high-boiling substances; S2, mixing filter cake I obtained in step S1 with a washing liquid, and filtering to obtain filter cake II and filtrate I; S3, mixing filter cake II obtained in step S2 with a washing liquid, and filtering to obtain filter cake III and filtrate II; S4, hydrolyzing filter cake III obtained in step S3 to obtain silicon slag and an oily phase. The method provided by the present invention effectively recovers high-boiling substances in the silicon slurry, and the particle size of the hydrolyzed silicon slag is less than 50 mesh. The oily phase after hydrolysis can be used to prepare high-boiling silicone oil.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of material chemical industry, and particularly relates to a treatment method of organic silicon silicon slurry. BACKGROUND

[0002] Organic silicon silicon slurry is a waste produced in the synthesis process of methyl chlorosilane monomer, which is mainly composed of a large amount of high-boiling substances (referred to as "high-boiling substances") and unreacted fine silicon powder. At present, the treatment method of silicon slurry is mainly direct hydrolysis, such as Chinese patent application No. 201410433395.4, Chinese patent No. 200310115386.2, and Chinese patent application No. 202111455208.9. However, this method not only causes a large amount of high-boiling substances to be wasted, but also results in uneven particle size of the obtained silicon slag, which is not conducive to subsequent chemical reaction process for extracting copper.

[0003] Physical crushing as a pretreatment method has been widely used in existing silicon slurry treatment technologies. For example, a treatment process of copper-containing silicon slag is described in Chinese patent CN114892004A, in which the first step is to crush the silicon slag. In addition, Yu Mengsong et al. (Comprehensive Utilization of Organic Silicon Slurry Residue Hydrolysis Waste [J]. Yu Mengsong; Li Zhao; Sun Yukun; Organic Silicon Materials. 2023, 2:40-46.) also mentioned that the preliminary treatment of organic silicon slurry residue hydrolysis waste also adopts crushing. However, this treatment method still has some problems, including low treatment efficiency and high energy consumption.

[0004] The traditional hydrolysis method often cannot effectively utilize the high-boiling substances in the silicon slurry, which not only leads to waste of resources, but also may cause environmental problems. Therefore, it is of great significance to seek a more effective treatment technology to improve resource utilization and reduce environmental pollution. SUMMARY

[0005] In view of the above problems, the present application provides a treatment method of organic silicon silicon slurry, which effectively recovers the high-boiling substances in the silicon slurry, and the particle size of the silicon slag after hydrolysis is less than 50 mesh, and the oil phase material after hydrolysis can be used to prepare high-boiling silicon oil.

[0006] The treatment method of organic silicon silicon slurry comprises the following steps:

[0007] S1, filtering the organic silicon silicon slurry to obtain filter cake I and high-boiling substances;

[0008] S2, mixing and stirring the filter cake I obtained in step S1 with a washing liquid, filtering to obtain filter cake II and filtrate I;

[0009] S3, mixing and stirring the filter cake II obtained in step S2 with the washing liquid, filtering to obtain filter cake III and filtrate II;

[0010] S4, hydrolyzing the filter cake III obtained in step S3 to obtain silicon residue and oil phase material.

[0011] There is high-boiling substance in the silicone silicon slurry, and direct hydrolysis will produce large solid particles, and meanwhile, the high-boiling substance is wasted. The silicone silicon slurry is filtered once to remove most of the high-boiling substance, and then the high-boiling substance is replaced out by using trimethylchlorosilane to wash and filter. In this way, there is a small amount of high-boiling substance and trimethylchlorosilane remaining in the silicone silicon slurry, and the trimethylchlorosilane can be used as an end-capping agent to prevent the high-boiling substance from crosslinking. Therefore, after hydrolysis of the silicone silicon slurry, small-particle silicon residue can be obtained, which is convenient for subsequent operation.

[0012] Preferably, the mass ratio of the filter cake I to the washing liquid in step S2 is 0.8-2:7.

[0013] Preferably, the washing liquid in step S2 is trimethylchlorosilane.

[0014] Preferably, the filtrate I in step S2 is subjected to rectification to obtain trimethylchlorosilane and high-boiling substance.

[0015] Further preferably, the rectification column still pot temperature of the rectification is 110-120 ℃, and the overhead temperature is 56-58 ℃. Under this rectification condition, the purity of the obtained trimethylchlorosilane is not less than 99%.

[0016] Further preferably, the trimethylchlorosilane obtained by the rectification is repeatedly applied to washing filter cake as the washing liquid.

[0017] Preferably, the high-boiling substance is subjected to cracking, and the cracking is carried out in a cracking kettle under the conditions of normal pressure and 130-140 ℃, with N,N-dimethylaniline as a catalyst and HCl gas.

[0018] Preferably, the mass ratio of the filter cake II to the washing liquid in step S3 is 0.8-2:7.5.

[0019] Preferably, the filtrate II in step S3 is used for washing filter cake in step S2.

[0020] Preferably, in step S4, the mass ratio of the filter cake to water is 0.5-1.5:3.

[0021] Preferably, the hydrolysis time in step S4 is 30-60 min.

[0022] Compared with the prior art, the application has the following beneficial effects:

[0023] 1. The present application makes rational use of the low boiling point and capping property of trimethylchlorosilane. Trimethylchlorosilane has a low boiling point and is easy to separate and recover by physical methods such as distillation. Its capping property helps to block the remaining high-boiling substances during the silicon slurry washing process, preventing them from excessive cross-linking with silicon powder to form large or uneven silicon residues. The silicon residue obtained by the treatment method of the organic silicon silicon slurry provided by the present application has a particle size of less than 50 mesh.

[0024] 2. The treatment method of the organic silicon silicon slurry provided by the present application, in the silicon slurry washing stage, trimethylchlorosilane helps to effectively recover the high-boiling substances dissolved in it, which not only improves the utilization rate of by-products, but also reduces material loss.

[0025] 3. The treatment method of the organic silicon silicon slurry provided by the present application improves production efficiency and product quality. In the hydrolysis step of the silicon slurry, the use of trimethylchlorosilane can avoid excessive cross-linking of the remaining high-boiling substances with silicon powder, thereby preventing the formation of large and uneven silicon residues, which is beneficial to maintaining the consistency and quality of the product. The oil phase material obtained after the hydrolysis process can be further used to produce high-boiling silicone oil, which has a wide range of applications in industry and commerce, thereby improving the economic value of by-products.

[0026] 4. The treatment method of the organic silicon silicon slurry provided by the present application significantly reduces the emission of harmful waste by reasonably recycling and reusing these by-products, which plays a positive role in environmental protection. Compared with traditional treatment methods, this technology can effectively reduce the consumption of raw materials and processing costs, while increasing the output of high-value products such as high-boiling silicone oil, thereby enhancing the market competitiveness of enterprises. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is a flowchart of a treatment method of an organic silicon silicon slurry of the present application. DETAILED DESCRIPTION

[0028] The technical solutions of the present application will be further described and explained by examples. The raw materials used in the examples can be purchased or prepared by conventional methods.

[0029] Example 1

[0030] A treatment method of an organic silicon silicon slurry, comprising the following steps:

[0031] S1, filter 100 g of organic silicon silicon slurry to obtain 20 g of filter cake I and 80 g of high-boiling substances;

[0032] S2, mix and stir 20 g of filter cake I obtained in step S1 with 70 g of trimethylchlorosilane, filter to obtain filter cake II and filtrate I;

[0033] The filtrate I is subjected to distillation, with the distillation tower bottom temperature at 115-119°C and the distillation tower top temperature at 57-58°C, and the obtained trimethylchlorosilane has a purity of about 99.1%. The obtained trimethylchlorosilane is repeatedly used as a washing liquid to wash the filter cake;

[0034] S3, the filter cake II obtained in the above process of step S2 and the trimethylchlorosilane obtained by distillation are mixed and stirred in a mass ratio of 2:7.5, and filtered to obtain filter cake III and filtrate II. The filtrate II can be directly used for washing the filter cake in step S2;

[0035] The high-boiling products obtained in step S1 and step S2 are cracked using nitrogen-nitrogen dimethylaniline as a catalyst in an amount of 1 wt % of the high-boiling products and HCl gas in a cracking reactor at normal pressure and a cracking temperature of 130-140° C., with an effective cracking rate of about 30%;

[0036] S4. The filter cake III obtained in step S3 is added into water at a mass ratio of filter cake to water of 1:3 for hydrolysis for 30 min, leaving a small amount of acidic oil phase material and silicon slag with smaller and more uniform particles.

[0037] Example 2

[0038] The process parameters of this embodiment are consistent with those of Example 1, and the only difference is that in step S2, the mass ratio of filter cake I to filtrate II obtained in Example 1 is 2:7.1.

[0039] Comparative Example 1

[0040] The process parameters of this embodiment are consistent with those of Example 1, and the only difference is that in step S2, the mass ratio of filter cake I to filtrate II obtained in Example 2 is 2:3.5.

[0041] Comparative Example 2

[0042] The process parameters of this embodiment are consistent with those of embodiment 1, and the only difference is that in step S3, the mass ratio of filter cake II to trimethylchlorosilane is 1:2.

[0043] Testing and Analysis

[0044] The acidic oil phases obtained in Examples 1-2 and Comparative Examples 1-2 were deacidified and dehydrated before use in the preparation of high-boiling silicone oil. The particle size of the silicon slag obtained and the results of the acidic oil phase trials are shown in Table 1.

[0045] Table 1: Particle size of silicon slag and acidic oil phase trial results

[0046]

[0047] From Table 1, it can be seen that the amount of filtrate II or trimethylchlorosilane is reduced, the size and uniformity of the silicon residue after hydrolysis are affected, and the obtained oil phase material is not suitable for preparing high-boiling silicon oil.

[0048] It should be understood that the above examples are only used to illustrate the content of the present application and not used to limit the protection scope of the present application. Furthermore, it should be understood that after reading the content of the present application, those skilled in the art can make various modifications or changes to the present application, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

Claims

1. A method for treating organosilicon slurry, characterized in that: The following steps are involved: S1. Filter the organosilicon slurry to obtain filter cake I and high boiling products; S2, mixing the filter cake I obtained in step S1 with the washing liquid trimethylchlorosilane, and filtering to obtain filter cake II and filtrate I; S3, mixing the filter cake II obtained in step S2 with the washing liquid trimethylchlorosilane, and filtering to obtain filter cake III and filtrate II; S4. Hydrolyze the filter cake III obtained in step S3 to obtain silicon slag with a particle size of less than 50 mesh and an oil phase material for preparing high-boiling silicone oil.

2. The method for treating organosilicon slurry according to claim 1, characterized in that: The mass ratio of the filter cake I to the washing liquid in step S2 is 0.8-2:

7.

3. The method for treating organosilicon slurry according to claim 1, characterized in that: The filtrate I in step S2 is distilled to obtain trimethylchlorosilane and high boiling products.

4. The method for treating organosilicon slurry according to claim 3, characterized in that: The distillation tower has a bottom temperature of 110-120°C and a top temperature of 56-58°C.

5. The method for treating organosilicon slurry according to claim 3, characterized in that: The trimethylchlorosilane obtained by the rectification is repeatedly used as a washing liquid to wash the filter cake.

6. The method for treating organosilicon slurry according to claim 1, characterized in that: The high boiling point product is cracked with HCl gas in a cracking kettle at normal pressure and 130-140°C using dimethylaniline as a catalyst.

7. The method for treating organosilicon slurry according to claim 1, characterized in that: The mass ratio of the filter cake II to the washing liquid in step S3 is 0.8-2:7.

5.

8. The method for treating organosilicon slurry according to claim 1, characterized in that: The filtrate II in step S3 is used to wash the filter cake in step S2.

9. The method for treating organosilicon slurry according to claim 1, characterized in that: In step S4, the mass ratio of filter cake to water is 0.5-1.5:3, and the hydrolysis time is 30-60 min.

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