Treatment method of organic silicon slurry

Abstract

The invention discloses a treatment method of organic silicon slurry, and belongs to the field of material chemical industry. The method comprises the following steps: S1, filtering organic silicon slurry to obtain a filter cake I and a high-boiling residue; s2, mixing and stirring the filter cake I obtained in the step S1 with a washing solution, and filtering to obtain a filter cake II and a filtrate I; s3, mixing and stirring the filter cake II obtained in the step S2 with a washing solution, and filtering to obtain a filter cake III and a filtrate II; and S4, hydrolyzing the filter cake III obtained in the step S3 to obtain silicon slag and an oil-phase substance. According to the method provided by the invention, the high-boiling-point substance in the silicon slurry is effectively recovered, the particle size of the hydrolyzed silicon slag is less than 50 meshes, and the hydrolyzed oil-phase substance can be used for preparing the high-boiling-point silicone oil.

Description

Technical Field

[0001] The invention belongs to the field of material chemical industry, and in particular belongs to a method for treating organic silicon slurry. Background Art

[0002] Silicone slurry is a waste generated during the synthesis of methylchlorosilane monomers. It is mainly composed of a large amount of high-boiling substances (referred to as "high-boiling substances") mixed with unreacted fine silicon powder. At present, the treatment method of silicon slurry mostly adopts the direct hydrolysis method, such as the Chinese patent application with application number 201410433395.4, the Chinese patent with application number 200310115386.2, and the Chinese patent application with application number 202111455208.9. However, this method not only causes a large amount of high-boiling substances to be wasted, but also the particle size of the resulting silicon slag is uneven, which is not conducive to the subsequent chemical reaction process for extracting metallic copper.

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

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

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

[0006] The method for treating the organosilicon slurry comprises the following steps: S1, filtering 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, and filtering to obtain filter cake II and filtrate I; S3, mixing the filter cake II obtained in step S2 with the washing liquid, and filtering to obtain filter cake III and filtrate II; S4, hydrolyzing the filter cake III obtained in step S3 to obtain silicon slag and oil phase material.

[0007] There are high-boiling substances in the silicone slurry. Direct hydrolysis will produce large solid particles and waste high-boiling substances. First, filter the silicone slurry once to remove most of the high-boiling substances, then wash and filter it with trimethylchlorosilane to replace the high-boiling substances. In this way, a small amount of high-boiling substances and trimethylchlorosilane will remain in the silicone slurry. Trimethylchlorosilane can be used as a capping agent to prevent high-boiling substances from cross-linking. Therefore, small particles of silicon slag can be obtained after the silicone slurry is hydrolyzed, which is convenient for subsequent operations.

[0008] Preferably, the mass ratio of the filter cake I to the washing liquid in step S2 is 0.8-2:7.

[0009] Preferably, the washing liquid in step S2 is trimethylchlorosilane.

[0010] Preferably, the filtrate I in step S2 is distilled to obtain trimethylchlorosilane and high boiling products.

[0011] More preferably, the bottom temperature of the distillation tower is 110-120° C., and the top temperature is 56-58° C. The purity of trimethylchlorosilane obtained under this distillation condition is not less than 99%.

[0012] More preferably, the trimethylchlorosilane obtained by the distillation is repeatedly used as a washing liquid to wash the filter cake.

[0013] Preferably, the high boiling point is cracked by using nitrogen-nitrogen dimethylaniline as a catalyst and cracking it with HCl gas in a cracking kettle at normal pressure and 130-140°C.

[0014] Preferably, the mass ratio of the filter cake II to the washing liquid in step S3 is 0.8-2:7.5.

[0015] Preferably, the filtrate II in step S3 is used to wash the filter cake in step S2.

[0016] Preferably, in step S4, the mass ratio of filter cake to water is 0.5-1.5:3.

[0017] Preferably, the hydrolysis time in step S4 is 30 to 60 min.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention makes reasonable use of the low boiling point and end-capping property of trimethylchlorosilane. Trimethylchlorosilane has a low boiling point and is easy to separate and recover by physical methods such as distillation. Its end-capping property helps to block the remaining high-boiling substances during the silicon slurry washing process, preventing them from excessively cross-linking and curing with silicon powder to form large or uneven silicon slag. The silicon slag particle size obtained by the method for treating the organosilicon silicon slurry provided by the present invention is less than 50 mesh.

[0019] 2. In the method for treating organosilicon slurry provided by the present invention, in the slurry washing stage, trimethylchlorosilane helps to effectively recover the high-boiling substances dissolved therein, which not only improves the utilization rate of by-products but also reduces material losses.

[0020] 3. The method for treating the organosilicon slurry provided by the present invention improves production efficiency and product quality. In the hydrolysis step of the slurry, the use of trimethylchlorosilane can avoid excessive cross-linking of the remaining high-boiling substances with the silicon powder, thereby preventing the formation of large and uneven silicon slag particles, which is conducive 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 increasing the economic value of the by-product.

[0021] 4. The method for treating organosilicon slurry provided by the present invention significantly reduces the emission of harmful wastes by reasonably recovering and reusing these by-products, thus playing a positive role in environmental protection. Compared with traditional treatment methods, this technology can effectively reduce the consumption of raw materials and treatment 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 THE DRAWINGS

[0022] Figure 1 It is a schematic flow chart of a method for treating an organosilicon slurry of the present invention. DETAILED DESCRIPTION

[0023] The technical scheme of the present invention is further described below by way of examples. The raw materials used in the examples can be purchased from the market or prepared by conventional methods.

[0024] Example 1 A method for treating organosilicon slurry comprises the following steps: S1. Filter 100 g of organosilicon slurry to obtain 20 g of filter cake I and 80 g of high boiling products; S2, mixing 20 g of filter cake I obtained in step S1 with 70 g of trimethylchlorosilane, and filtering to obtain filter cake II and filtrate I; The filtrate I is distilled, the temperature of the distillation tower bottom is 115-119°C, the temperature of the distillation tower top is 57-58°C, and the purity of the obtained trimethylchlorosilane is about 99.1%. The obtained trimethylchlorosilane is repeatedly used as a washing liquid to wash the filter cake; S3, mixing the filter cake II obtained in the above process in step S2 with trimethylchlorosilane obtained by distillation in a mass ratio of 2:7.5, filtering to obtain filter cake III and filtrate II, wherein the filtrate II can be directly used for washing the filter cake in step S2; The high boiling products obtained in step S1 and step S2 are cracked, using nitrogen-nitrogen dimethylaniline as a catalyst, with an amount of 1wt% of the high boiling products, and HCl gas in a cracking kettle for cracking, at normal pressure, a cracking temperature of 130-140°C, and an effective cracking rate of about 30%; 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, and a small amount of acidic oil phase material and silicon slag with smaller and more uniform particles are removed.

[0025] Example 2 The process parameters of this embodiment are consistent with those of embodiment 1, and the only difference is that in step S2, the mass ratio of filter cake I to filtrate II obtained in embodiment 1 is 2:7.1.

[0026] Comparative Example 1 The process parameters of this embodiment are consistent with those of embodiment 1, and the only difference is that in step S2, the mass ratio of filter cake I to filtrate II obtained in embodiment 2 is 2:3.5.

[0027] Comparative Example 2 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.

[0028] Testing and analysis The acidic oil phases obtained in Examples 1-2 and Comparative Examples 1-2 were used for trial preparation of high-boiling silicone oil after deacidification and dehydration. The particle size of the obtained silicon slag and the trial use of the acidic oil phase are shown in Table 1.

[0029] Table 1: Particle size of silicon slag and trial results of acidic oil phase

[0030] It can be seen from Table 1 that reducing the amount of filtrate II or trimethylchlorosilane will affect the size and uniformity of the silicon slag after hydrolysis, and will also make the obtained oil phase material unsuitable for preparing high-boiling silicone oil.

[0031] 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 method for treating organosilicon slurry, characterized in that: The following steps are involved: S1, filtering 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, and filtering to obtain filter cake II and filtrate I; S3, mixing the filter cake II obtained in step S2 with the washing liquid, and filtering to obtain filter cake III and filtrate II; S4, hydrolyzing the filter cake III obtained in step S3 to obtain silicon slag and oil phase material.

2. The method for treating organic silicon 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 organic silicon slurry according to claim 1, characterized in that: The washing liquid is trimethylchlorosilane.

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

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

6. The method for treating organic silicon slurry according to claim 4, characterized in that: The trimethylchlorosilane obtained by the distillation is repeatedly used as a washing liquid to wash the filter cake.

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

8. 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.

9. 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.

10. The method for treating organic silicon 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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