Treatment method of organic silicon slag slurry

Abstract

The invention belongs to the technical field of organic silicon production, and particularly relates to a treatment method of organic silicon slag slurry, which comprises the following steps: putting the organic silicon slag slurry into a reaction kettle, and hydrolyzing and filtering by using silicon slurry hydrolysate; stirring and washing the silicon slag by using a hot silicon slurry treating agent solution and an alkaline washing solution in sequence to obtain neutral harmless silicon slag; and filtering, drying, neutralizing copper-rich filtrate, desalting, extracting copper and the like, and recycling. According to the treatment method of the organic silicon slag slurry, the organic silicon slag slurry is hydrolyzed by using the silicon slurry hydrolysate, and the silicon slag is washed and neutralized by using the hot silicon slurry treatment agent solution and the alkaline washing solution, so that high-quality silicon slag is obtained, the pH value of the silicon slag is 6-9, the surface of the silicon slag basically does not contain organic attachments, and the service life of the silicon slag is prolonged. The copper content is smaller than the leaching toxicity identification standard specified by the national standard, the treated silicon slag is a high-quality raw material of a high-temperature refractory material, meanwhile, copper ions are enriched in filtrate, copper can be recycled through copper extraction treatment, and harmless and resourceful treatment of the silicon slag is achieved.

Description

Technical Field

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

[0002] Organic silicon slurry is a byproduct of the reaction of silicon powder and methyl chloride in a fluidized bed catalyzed by copper powder during the synthesis of organic silicon monomers. It is a fluid solid-liquid mixture that accounts for about 3-5% of the monomer output. The slurry contains a large amount of high-boiling substances and a small amount of unreacted silicon powder and copper powder carried out of the fluidized bed. The high-boiling substances refer to the high-boiling polysilane mixture with a boiling range of 70.3-250°C and mainly composed of Si-Si bonds, Si-C-Si bonds and Si-O-Si bonds produced during the synthesis of organic silicon monomers. If this part of the material is exposed to the air, it will burn or form strong acid mist or liquid, which will cause serious pollution to the environment and must be harmlessly treated.

[0003] Patent CN112251608 discloses a method for resource utilization of organic silicon slurry residue hydrolysis residue and waste contact body, which obtains harmless silicon slag after multiple washings with hydrochloric acid and sodium hypochlorite, and the copper content of silicon slag meets the leaching toxicity identification standard. However, the silicon slag obtained by this method is acidic, contains some organic matter, and has a water content of up to 80%, which cannot be directly used, and the washing process is long, the processing efficiency is low, and the time cost is high. Summary of the invention

[0004] The present invention aims at the deficiencies of the existing slurry treatment technology and provides a method for treating organosilicon slurry, which can achieve harmless and resourceful treatment of methylchlorosilane monomer slurry.

[0005] A method for treating organosilicon slurry, characterized in that the method comprises the following steps: Step 1, adding organic silicon slurry to the reaction kettle, and then adding silicon slurry hydrolyzate, stirring, hydrolyzing to form silicon slag, filtering, the filter residue remains in the kettle, and the filtrate enters the filtrate buffer tank; Step 2: Add hot silicon slurry treatment agent solution to the reaction kettle, stir and wash, remove organic coatings on the surface of silicon slag, filter, leave the filter residue in the kettle, and let the filtrate enter the filtrate buffer tank; Step 3, adding hot alkaline washing liquid to the reaction kettle, stirring and washing to neutralize the silicon slag to neutrality, filtering, leaving the filter residue in the kettle, and the filtrate entering the filtrate buffer tank; Step 4: Discharge the filter residue and transport it to a dryer for drying, and recover copper from the copper-rich filtrate to complete the treatment.

[0006] Specifically, the organosilicon slurry is mainly composed of organosilicon high boiling point, silicon powder, elemental copper, cupric oxide, cuprous oxide, cupric chloride and cuprous chloride, with a solid content of 20-50%, of which the copper content is 3-8%.

[0007] Specifically, the reactor is heat-insulated, and the discharge port is equipped with a filter screen; Specifically, the temperature of the silicon slurry hydrolysis liquid is maintained at 70-75°C, the hydrolysis liquid is a solution formed by mixing one or more alcohols selected from methanol, ethanol, and propylene glycol with one or more alcoholamines selected from ethanolamine, diethanolamine, triethanolamine, and isopropanolamine and then mixing with water, the mass ratio of alcohol, alcoholamine to water is 0.3-0.5:0.5-0.8:1, the mass ratio of silicon slurry hydrolysis liquid to slag slurry is 2-5:1, and the hydrolysis time is 1-3h.

[0008] Specifically, the stirring speed of the stirring rod of the reactor is 50-300 r / min, preferably 80-200 r / min.

[0009] Specifically, the silicon slurry treating agent is a mixture of salt and copper extractant, the salt is a mixture of one or more of sodium sulfate, potassium sulfate, sodium chloride, potassium chloride, sodium thiolate, potassium thiolate and sodium benzoate, the copper extractant includes but is not limited to aldoximes, ketoximes and aldoxime-ketoxime mixtures, and the mass ratio of salt to copper extractant is 0.3-0.8:1.

[0010] The aldoximes are selected from 5-nonyl salicylaldehyde oxime, and the ketoximes are selected from 2-hydroxy-5-nonyl acetophenone oxime.

[0011] Specifically, the temperature of the hot silicon slurry treatment agent solution is maintained at 70-90° C., the mass ratio of the silicon slurry treatment agent to water is 0.08-0.15:1, the mass ratio of the silicon slurry treatment agent solution to silicon slag is 1.5-3:1, and the washing time is 30-60 minutes.

[0012] Specifically, the alkaline washing liquid is a mixed aqueous solution of one or more aqueous solutions of sodium hydroxide, potassium hydroxide, ammonia water and sodium carbonate.

[0013] Specifically, the temperature of the hot alkaline washing liquid is maintained at 70-90° C., the mass fraction of the alkaline washing liquid is 1-5wt%, the mass ratio of the alkaline washing liquid to the silicon slag is 1.5-3:1, and the washing time is 30-60min.

[0014] Specifically, the filtrate is mixed in a filtrate buffer tank, and then reused after being treated with neutralization, desalination and copper extraction.

[0015] Specifically, the copper content of the treated silicon slag is less than 100 mg / L as specified in the leaching toxicity identification standard (HJT 299-2007), the pH value is 6-9, and the moisture content of the silicon slag after drying is 10%-20%.

[0016] Beneficial effects: 1. The hydrolysis, filtration and washing processes of the organosilicon slurry in the present invention are all carried out in the same reactor, which has high processing efficiency and greatly saves time cost.

[0017] 2. In the present invention, the organosilicon slurry is hydrolyzed, washed and neutralized by a variety of hot solutions, wherein the silicon slurry hydrolyzate can not only reduce the severity of the reaction, but also quickly absorb the acidic gas and salt ions generated by the slurry hydrolysis, and reduce the degree of organic matter aggregation and the contact between the organic matter chain and the silicon powder by changing the potential and increasing the steric hindrance, and finally reduce the molecular weight of the organic hydrolyzate, thereby greatly avoiding the organic matter coating on the surface of the hydrolyzed silicon slag, which is beneficial to the extraction of copper ions in the silicon slag, greatly reducing the copper content in the silicon slag, and finally transforming it into harmless high-quality silicon slag containing a small amount of organic attachments, a water content of less than 20%, and a copper content of less than 100 mg / L, which is a high-quality raw material for high-temperature refractory materials. On the other hand, copper ions are enriched in the filtrate, and copper can be recovered after copper extraction treatment, thereby realizing the harmless and resourceful treatment of the organosilicon slurry, reducing environmental hazards and achieving economic benefits.

[0018] 3. The filtrate produced in the present invention can be reused after copper extraction, neutralization, precipitation and filtration, and then returned to the reactor after adding corresponding additives to continue hydrolysis, extraction and other operations. The wastewater reuse rate reaches more than 90%, which greatly saves water resources. DETAILED DESCRIPTION

[0019] The invention discloses a method for treating organosilicon slurry, comprising hydrolyzing the organosilicon slurry with a silicon slurry hydrolyzing solution, washing the organosilicon silicon slag with a hot silicon slurry treating agent solution and an alkaline washing solution, drying and recovering the silicon slag, and recovering copper in the filtrate.

[0020] Step 1, adding organic silicon slurry to the reaction kettle, and then adding silicon slurry hydrolyzate, stirring, hydrolyzing to form silicon slag, filtering, the filter residue remains in the kettle, and the filtrate enters the filtrate buffer tank; The organosilicon slurry is mainly composed of organosilicon high boiling point, silicon powder, elemental copper, cupric oxide, cuprous oxide, cupric chloride and cuprous chloride, with a solid content of 40-50%, of which the copper content is 3-8%.

[0021] Step 2: Add hot silicon slurry treatment agent solution to the reaction kettle, stir and wash, remove organic coatings on the surface of silicon slag, filter, leave the filter residue in the kettle, and let the filtrate enter the filtrate buffer tank; Step 3, adding hot alkaline washing liquid to the reaction kettle, stirring and washing to neutralize the silicon slag to neutrality, filtering, leaving the filter residue in the kettle, and the filtrate entering the filtrate buffer tank; Step 4: Discharge the filter residue and transport it to a dryer for drying, and recover copper from the copper-rich filtrate to complete the treatment.

[0022] Specific examples of the above process are given below.

[0023] In the embodiments and comparative examples, the mass ratio of alcohol, amine and water in the silicon slurry hydrolyzate used is 0.3:0.6:1, the mass ratio of salt and copper extractant in the silicon slurry treating agent solution used is 0.5:1, the mass ratio of silicon slurry treating agent and water is 0.12:1, and the mass fraction of alkaline washing liquid is 5wt%.

[0024] Example 1 Step 1: add 200 kg of organosilicon slurry to the reactor, then add 600 kg of a mixed aqueous solution of methanol and ethanolamine at a temperature of 70°C (the mass ratio of methanol, ethanolamine and water is 0.5:0.5:1), start stirring, the stirring rod stirring speed is 100 rpm, the hydrolysis time is 1 hour, silicon slag is formed, filtered, the filter residue remains in the reactor, and the filtrate enters the filtrate buffer tank; Step 2: add 300 kg of a silicon slurry treatment agent solution at a temperature of 75° C. into the reactor, wherein the salt is potassium sulfate and the copper extractant is 2-hydroxy-5-nonylacetophenone oxime, start stirring, the stirring rod stirring speed is 100 rpm, the washing time is 30 min, filter, leave the filter residue in the reactor, and the filtrate enters the filtrate buffer tank; Step 3: add 300 kg of 2 wt% potassium hydroxide solution at 70°C to the reactor, start stirring, stir the stirring rod at a speed of 100 rpm, wash for 30 min, filter, leave the filter residue in the reactor, and let the filtrate enter the filtrate buffer tank; Step 4: Discharge the filter residue and transport it to a dryer for drying, and recover copper from the copper-rich filtrate to complete the treatment.

[0025] After the toxicity leaching experiment, the copper content in the silicon slag leaching solution was 72.8 mg / L, and the pH value of the silicon slag finally treated was 8.2 and the water content was 13%.

[0026] Example 2 Step 1: add 200 kg of organosilicon slurry to the reactor, then add 800 kg of a mixed aqueous solution of methanol and ethanolamine at a temperature of 70°C (the mass ratio of methanol, ethanolamine and water is 0.5:0.5:1), start stirring, the stirring rod stirring speed is 150 rpm, the hydrolysis time is 2 hours, silicon slag is formed, filtered, the filter residue remains in the reactor, and the filtrate enters the filtrate buffer tank; Step 2: add 500 kg of a silicon slurry treatment agent solution at 80° C. into the reactor, wherein the salt is sodium chloride and the copper extractant is 2-hydroxy-5-nonylacetophenone oxime, start stirring, the stirring rod stirring speed is 150 rpm, the washing time is 450 min, filter, leave the filter residue in the reactor, and the filtrate enters the filtrate buffer tank; Step 3: add 500 kg of 2 wt% sodium hydroxide solution at 85°C to the reactor, start stirring, stir the stirring rod at a speed of 150 rpm, wash for 45 min, filter, leave the filter residue in the reactor, and let the filtrate enter the filtrate buffer tank; Step 4: Discharge the filter residue and transport it to a dryer for drying, and recover copper from the copper-rich filtrate to complete the treatment.

[0027] After the toxicity leaching experiment, the copper content in the leaching solution was 55.6 mg / L, and the pH value of the silicon slag obtained by the final treatment was 7.8 and the water content was 15%.

[0028] Example 3 Step 1: add 200 kg of organosilicon slurry to the reactor, then add 1000 kg of a mixed aqueous solution of methanol and ethanolamine at a temperature of 75°C (the mass ratio of methanol, ethanolamine and water is 0.5:0.5:1), start stirring, the stirring rod stirring speed is 200 rpm, the hydrolysis time is 3 hours, silicon slag is formed, filtered, the filter residue remains in the reactor, and the filtrate enters the filtrate buffer tank; Step 2: add 600 kg of a silicon slurry treatment agent solution at a temperature of 90° C. into the reactor, wherein the salt is sodium benzoate and the copper extractant is 2-hydroxy-5-nonylacetophenone oxime, start stirring, the stirring rod stirring speed is 200 rpm, the washing time is 60 min, filter, leave the filter residue in the reactor, and the filtrate enters the filtrate buffer tank; Step 3: add 600 kg of 2 wt% sodium hydroxide solution at 90°C to the reactor, start stirring, stir the stirring rod at a speed of 200 rpm, wash for 60 min, filter, leave the filter residue in the reactor, and let the filtrate enter the filtrate buffer tank; Step 4: Discharge the filter residue and transport it to a dryer for drying, and recover copper from the copper-rich filtrate to complete the treatment.

[0029] After the toxicity leaching experiment, the copper content in the leaching solution was 51.2 mg / L, and the pH value of the silicon slag obtained by the final treatment was 7.2 and the water content was 18%.

[0030] Comparative Example 1 Step 1: add 200 kg of organosilicon slurry to the reactor, then add 600 kg of cold water at 25°C, start stirring, stir the stirring rod at a stirring speed of 100 rpm, hydrolyze for 1 hour, form silicon slag, filter, leave the filter residue in the reactor, and let the filtrate enter the filtrate buffer tank; Step 2: Discharge the filter residue to complete the treatment.

[0031] After the toxicity leaching experiment, the copper content in the leaching solution was 3237 mg / L, and the pH value of the silicon slag obtained by the final treatment was 2.8 and the water content was 85%.

[0032] Comparative Example 2 Step 1: add 200 kg of organosilicon slurry to the reactor, then add 600 kg of cold water at 25°C, start stirring, stir the stirring rod at a stirring speed of 100 rpm, hydrolyze for 1 hour, form silicon slag, filter, leave the filter residue in the reactor, and let the filtrate enter the filtrate buffer tank; Step 2: add 300 kg of 2 wt% potassium hydroxide solution at 25°C to the reactor, start stirring, stir the stirring rod at a speed of 100 rpm, wash for 30 min, filter, leave the filter residue in the reactor, and let the filtrate enter the filtrate buffer tank; Step three, discharge the filter residue and transport it to a dryer for drying, and recover copper from the filtrate to complete the treatment.

[0033] After the toxicity leaching experiment, the copper content in the leaching solution was 1989 mg / L, and the pH value of the silicon slag obtained by the final treatment was 8.5 and the water content was 12%.

[0034] Comparative Example 3 Step 1: add 200 kg of organosilicon slurry to the reactor, then add 600 kg of a mixed aqueous solution of methanol and ethanolamine at 25°C (the mass ratio of methanol, ethanolamine and water is 0.5:0.5:1), start stirring, the stirring rod stirring speed is 100 rpm, the hydrolysis time is 1 hour, silicon slag is formed, filtered, the filter residue remains in the reactor, and the filtrate enters the filtrate buffer tank; Step 2: add 300 kg of potassium sulfate solution at 25°C into the reactor, start stirring, stir the stirring rod at a speed of 100 rpm, wash for 30 min, filter, leave the filter residue in the reactor, and let the filtrate enter the filtrate buffer tank; Step 3: add 300 kg of 2 wt% potassium hydroxide solution at 25°C to the reactor, start stirring, stir the stirring rod at a speed of 100 rpm, wash for 30 min, filter, leave the filter residue in the reactor, and let the filtrate enter the filtrate buffer tank; Step 4: Discharge the filter residue and transport it to a dryer for drying, and recover copper from the filtrate to complete the treatment.

[0035] After the toxicity leaching experiment, the copper content in the leaching solution was 1297 mg / L, and the pH value of the silicon slag obtained by the final treatment was 8.3 and the moisture content was 14%.

[0036] Comparative Example 4 Step 1: add 200 kg of organosilicon slurry to the reactor, then add 600 kg of a mixed aqueous solution of methanol and ethanolamine at 25°C (the mass ratio of methanol, ethanolamine and water is 0.5:0.5:1), start stirring, the stirring rod stirring speed is 100 rpm, the hydrolysis time is 1 hour, silicon slag is formed, filtered, the filter residue remains in the reactor, and the filtrate enters the filtrate buffer tank; Step 2: add 300 kg of 2-hydroxy-5-nonylacetophenone oxime solution at 25° C. into the reaction kettle, start stirring, stir the stirring rod at a speed of 100 rpm, wash for 30 min, filter, leave the filter residue in the kettle, and let the filtrate enter the filtrate buffer tank; Step 3: add 300 kg of 2 wt% potassium hydroxide solution at 25°C to the reactor, start stirring, stir the stirring rod at a speed of 100 rpm, wash for 30 min, filter, leave the filter residue in the reactor, and let the filtrate enter the filtrate buffer tank; Step 4: Discharge the filter residue and transport it to a dryer for drying, and recover copper from the filtrate to complete the treatment.

[0037] After the toxicity leaching experiment, the copper content in the leaching solution was 841 mg / L, and the pH value of the silicon slag obtained by the final treatment was 8.3 and the water content was 13%.

[0038] Comparative Example 5 Step 1: add 200 kg of organosilicon slurry to the reactor, then add 600 kg of a mixed aqueous solution of methanol and ethanolamine at 25°C (the mass ratio of methanol, ethanolamine and water is 0.5:0.5:1), start stirring, the stirring rod stirring speed is 100 rpm, the hydrolysis time is 1 hour, silicon slag is formed, filtered, the filter residue remains in the reactor, and the filtrate enters the filtrate buffer tank; Step 2: add 300 kg of silicon slurry treatment agent solution at a temperature of 25° C. into the reactor, wherein the salt is potassium sulfate and the copper extractant is 2-hydroxy-5-nonylacetophenone oxime, start stirring, the stirring rod stirring speed is 100 rpm, the washing time is 30 min, filter, leave the filter residue in the reactor, and the filtrate enters the filtrate buffer tank; Step 3: add 300 kg of 2 wt% potassium hydroxide solution at 25°C to the reactor, start stirring, stir the stirring rod at a speed of 100 rpm, wash for 30 min, filter, leave the filter residue in the reactor, and let the filtrate enter the filtrate buffer tank; Step 4: Discharge the filter residue and transport it to a dryer for drying. The filtrate is used to recover copper, and the treatment is completed.

[0039] After the toxicity leaching experiment, the copper content in the silicon slag leaching solution was 382 mg / L, and the pH value of the silicon slag finally treated was 8.3 and the water content was 14%.

Claims

1. A method for treating organosilicon slurry, characterized in that: The steps of this method are as follows: Step 1, adding organic silicon slurry to the reaction kettle, and then adding silicon slurry hydrolyzate, stirring, hydrolyzing to form silicon slag, filtering, the filter residue remains in the kettle, and the filtrate enters the filtrate buffer tank; Step 2: Add hot silicon slurry treatment agent solution to the reaction kettle, stir and wash, remove organic coatings on the surface of silicon slag, filter, leave the filter residue in the kettle, and let the filtrate enter the filtrate buffer tank; Step 3, adding hot alkaline washing liquid to the reaction kettle, stirring and washing to neutralize the silicon slag to neutrality, filtering, leaving the filter residue in the kettle, and the filtrate entering the filtrate buffer tank; Step 4: Discharge the filter residue and transport it to a dryer for drying, and recover copper from the copper-rich filtrate to complete the treatment.

2. The method for treating organosilicon slurry according to claim 1, characterized in that: The organosilicon slurry comprises organosilicon high boiling point, silicon powder, elemental copper, cupric oxide, cuprous oxide, cupric chloride and cuprous chloride, and has a solid content of 20-50%, wherein the copper content is 3-8%.

3. The method for treating organosilicon slurry according to claim 1, characterized in that: The temperature of the slurry hydrolysis liquid is maintained at 70-75°C; the hydrolysis liquid is a mixture of alcohol, alcohol amine and water; the mass ratio of the silicon slurry hydrolysis liquid to the slag slurry is 2-5:1, and the hydrolysis time is 1-3h.

4. The method for treating organosilicon slurry according to claim 1, characterized in that: The alcohol includes a mixture of one or more alcohols selected from methanol, ethanol and glycerol; The alcoholamine includes a mixture of one or more alcoholamines selected from ethanolamine, diethanolamine, triethanolamine and isopropanolamine; The mass ratio of alcohol, alcoholamine and water is 0.3-0.5:0.5-0.8:

1.

5. The method for treating organosilicon slurry according to claim 1, characterized in that: In step 1, the stirring speed is 50-300 r / min, preferably 80-200 r / min.

6. The method for treating organosilicon slurry according to claim 1, characterized in that: The silicon slurry treating agent is a mixture of salt and copper extractant, the salt is one or a mixture of sodium sulfate, potassium sulfate, sodium chloride, potassium chloride, sodium thiolate, potassium thiolate and sodium benzoate, the copper extractant includes but is not limited to aldoximes, ketoximes or aldoxime-ketoxime mixtures, and the mass ratio of salt to copper extractant is 0.3-0.8:

1.

7. The method for treating organosilicon slurry according to claim 1, characterized in that: The temperature of the hot silicon slurry treatment agent solution described in step 2 is maintained at 70-90°C, the mass ratio of silicon slurry treatment agent to water is 0.08-0.15:1, the mass ratio of silicon slurry treatment agent solution to silicon slag is 1.5-3:1, and the washing time is 30-60min.

8. The method for treating organosilicon slurry according to claim 1, characterized in that: The alkaline washing liquid is a mixed aqueous solution of one or more aqueous solutions of sodium hydroxide, potassium hydroxide, ammonia water and sodium carbonate.

9. The method for treating organosilicon slurry according to claim 1, characterized in that: The temperature of the hot alkaline washing liquid is maintained at 70-90° C., the mass fraction of the alkaline washing liquid is 1-5wt%, the mass ratio of the alkaline washing liquid to the silicon slag is 1.5-3:1, and the washing time is 30-60min.