A method for treating organosilicon slag slurry

Abstract

This invention belongs to the field of organosilicon production technology, specifically relating to a method for treating organosilicon slag slurry. The organosilicon slag slurry is fed into a reaction vessel and hydrolyzed and filtered using a silicone slurry hydrolysate. The slag is then sequentially washed with a hot silicone slurry treatment agent solution and an alkaline washing solution, resulting in neutralized and harmless silicone slag. After filtration and drying, the copper-rich filtrate is neutralized, desalinated, and subjected to copper extraction before reuse. This method for treating organosilicon slag slurry involves hydrolyzing the slag with a silicone slurry hydrolysate, washing and neutralizing the slag with a hot silicone slurry treatment agent solution and an alkaline washing solution, yielding high-quality silicone slag with a pH value of 6-9, virtually no organic deposits on its surface, and a copper content lower than the national standard for leaching toxicity identification. The treated silicone slag is a high-quality raw material for high-temperature refractory materials. Simultaneously, copper ions are enriched in the filtrate, allowing for copper recovery through copper extraction, thus achieving the harmless and resource-based treatment of the silicone slag.

Description

Technical Field

[0001] This invention belongs to the field of chemical engineering, and specifically relates to a method for treating organosilicon slag slurry. Background Technology

[0002] Organosilicon slurry is a byproduct generated during the synthesis of organosilicon monomers from the reaction of silicon powder and chloromethane in a fluidized bed catalyzed by copper powder. It is a fluid solid-liquid mixture, accounting for approximately 3-5% of the monomer yield. The slurry contains a large amount of high-boiling-point substances and a small amount of unreacted silicon powder and copper powder carried out by the fluidized bed. The high-boiling-point substances refer to a mixture of high-boiling-point polysilanes with boiling ranges of 70.3-250℃, mainly composed of Si-Si, Si-C-Si, and Si-O-Si bonds, produced during the synthesis of organosilicon monomers. If this material is exposed to air, it may burn or form strong acid mist or liquid, causing serious environmental pollution, and must be treated to render it harmless.

[0003] Patent CN112251608 discloses a method for the resource utilization of organosilicon slurry residue and waste catalyst. The method involves multiple washings with hydrochloric acid and sodium hypochlorite to obtain harmless silicon slag, with the copper content meeting the leaching toxicity identification standards. However, the silicon slag obtained by this method is acidic, contains some organic matter, and has a water content as high as 80%, making it unusable directly. Furthermore, the washing process is lengthy, inefficient, and time-consuming. Summary of the Invention

[0004] This invention addresses the shortcomings of existing slurry treatment technologies by providing a method for treating organosilicon slurry, which can achieve the harmless and resource-based treatment of methylchlorosilane monomer slurry.

[0005] A method for treating organosilicon slag slurry, characterized by the following steps: Step 1: Add organosilicon slag slurry to the reactor, then add silicone slag hydrolysate, stir, hydrolyze to form silicone slag, filter, the filter residue remains in the reactor, and the filtrate enters the filtrate buffer tank; Step 2: Add hot silicon slurry treatment agent solution to the reactor, stir and wash to remove the organic coating on the surface of the silicon slag, filter, leave the filter residue in the reactor, and let the filtrate enter the filtrate buffer tank. Step 3: Add hot alkaline washing solution to the reactor, stir and wash to neutralize the silicon slag to neutral, filter, leave the filter residue in the reactor, and let the filtrate enter the filtrate buffer tank. Step four: Discharge the filter residue and transport it to a dryer for drying. The copper-rich filtrate is then used for copper recovery, thus completing the treatment.

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

[0007] Specifically, the reactor is insulated and has a built-in filter at the discharge port; Specifically, the temperature of the silicon slurry hydrolysate is maintained at 70-75℃. The hydrolysate is a solution formed by mixing one or more alcohols selected from methanol, ethanol, and glycerol with one or more alcoholic amines selected from ethanolamine, diethanolamine, triethanolamine, and isopropanolamine, and then mixing with water. The mass ratio of alcohol, alcoholic amine, and water is 0.3-0.5:0.5-0.8:1. The mass ratio of silicon slurry hydrolysate to slurry is 2-5:1. The hydrolysis time is 1-3 hours.

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

[0009] Specifically, the silicon slurry treatment agent is a mixture of salt and copper extractant. The salt is one or a mixture of several 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. The mass ratio of salt to copper extractant is 0.3-0.8:1.

[0010] The aldoloximes are selected from 5-nonylsalicylic acid oxime, and the ketoximes are selected from 2-hydroxy-5-nonylacetophenone oxime.

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

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

[0013] Specifically, the temperature of the hot alkaline washing solution is maintained at 70-90℃, the mass fraction of the alkaline washing solution is 1-5wt%, the mass ratio of the alkaline washing solution 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 treated with neutralization, desalination, and copper extraction before being reused.

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

[0016] Beneficial effects: 1. In this invention, the hydrolysis, filtration, and washing processes of organosilicon slurry are all carried out in the same reactor, resulting in high processing efficiency and significant time savings.

[0017] 2. In this invention, organosilicon slag slurry is hydrolyzed, washed, and neutralized using various hot solutions. The hydrolysate can reduce the intensity of the reaction and rapidly absorb the acidic gases and salt ions generated during slag hydrolysis. By changing the potential and increasing steric hindrance, the degree of organic matter aggregation is reduced, and the contact between organic matter chains and silicon powder is decreased, ultimately reducing the molecular weight of the organic hydrolysate. This greatly avoids organic matter coating the surface of the hydrolyzed silicon slag, which is beneficial for extracting copper ions from the silicon slag. This significantly reduces the copper content in the silicon slag, ultimately transforming it into a harmless, high-quality silicon slag with a small amount of organic matter, a water content of less than 20%, and a copper content of less than 100 mg / L. This 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 through copper extraction treatment. This achieves the harmless and resource-based treatment of organosilicon slag slurry, reducing environmental hazards and realizing economic benefits.

[0018] 3. The filtrate produced in this invention can be reused after copper extraction, neutralization, precipitation and filtration. After adding appropriate additives, it can be returned to the reactor for further hydrolysis, extraction and other operations. The wastewater reuse rate reaches more than 90%, which greatly saves water resources. Detailed Implementation

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

[0020] Step 1: Add organosilicon slag slurry to the reactor, then add silicone slag hydrolysate, stir, hydrolyze to form silicone slag, filter, the filter residue remains in the reactor, and the filtrate enters the filtrate buffer tank; The organosilicon slurry mainly consists of organosilicon high-boiling-point substances, silicon powder, elemental copper, copper oxide, cuprous oxide, cuprous 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 reactor, stir and wash to remove the organic coating on the surface of the silicon slag, filter, leave the filter residue in the reactor, and let the filtrate enter the filtrate buffer tank. Step 3: Add hot alkaline washing solution to the reactor, stir and wash to neutralize the silicon slag to neutral, filter, leave the filter residue in the reactor, and let the filtrate enter the filtrate buffer tank. Step four: Discharge the filter residue and transport it to a dryer for drying. The copper-rich filtrate is then used for copper recovery, thus completing the treatment.

[0022] The following are specific embodiments of the above process.

[0023] In the examples and comparative examples, the mass ratio of alcohol, alkanolamine and water in the silicone slurry hydrolysate was 0.3:0.6:1, the mass ratio of salt and copper extractant in the silicone slurry treatment agent solution was 0.5:1, the mass ratio of silicone slurry treatment agent and water was 0.12:1, and the mass fraction of alkaline washing solution was 5 wt%.

[0024] Example 1 Step 1: Add 200 kg of organosilicon slag slurry to the reactor, then add 600 kg of a mixed aqueous solution of methanol and ethanolamine at 70℃ (methanol, ethanolamine and water mass ratio of 0.5:0.5:1), start stirring, stir the rod at 100 rpm, hydrolyze for 1 hour to form silica slag, filter, leave the filter residue in the reactor, and let the filtrate enter the filtrate buffer tank; Step 2: Add 300 kg of a silicon slurry treatment agent solution at 75°C to the reactor, wherein the salt is potassium sulfate and the copper extractant is 2-hydroxy-5-nonylacetophenone oxime. Start stirring, with the stirring rod speed at 100 rpm, and wash for 30 min. Filter, leaving 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, set the stirring rod speed to 100 rpm, wash for 30 min, filter, leave the filter residue in the reactor, and let the filtrate enter the filtrate buffer tank. Step four: Discharge the filter residue and transport it to a dryer for drying. The copper-rich filtrate is then used for copper recovery, thus completing the treatment.

[0025] After toxicity leaching experiments, the copper content in the silica slag leachate was 72.8 mg / L, and the final treated silica slag had a pH of 8.2 and a water content of 13%.

[0026] Example 2 Step 1: Add 200 kg of organosilicon slag slurry to the reactor, then add 800 kg of a mixed aqueous solution of methanol and ethanolamine at 70℃ (the mass ratio of methanol, ethanolamine and water is 0.5:0.5:1). Start stirring, with the stirring rod speed at 150 rpm, and hydrolyze for 2 hours to form silica slag. Filter the solution, leaving the filter residue in the reactor, and let the filtrate enter the filtrate buffer tank. Step 2: Add 500 kg of a silicone slurry treatment agent solution at 80°C to the reactor, wherein the salt is sodium chloride and the copper extractant is 2-hydroxy-5-nonylacetophenone oxime. Start stirring, with the stirring rod speed at 150 rpm and the washing time at 450 min. Filter, leaving 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, set the stirring rod speed to 150 rpm, wash for 45 min, filter, leave the filter residue in the reactor, and let the filtrate enter the filtrate buffer tank. Step four: Discharge the filter residue and transport it to a dryer for drying. The copper-rich filtrate is then used for copper recovery, thus completing the treatment.

[0027] After toxicity leaching tests, the copper content in the leachate was 55.6 mg / L, and the final treated silica slag had a pH of 7.8 and a moisture content of 15%.

[0028] Example 3 Step 1: Add 200 kg of organosilicon slag slurry to the reactor, then add 1000 kg of a mixed aqueous solution of methanol and ethanolamine at 75℃ (mass ratio of methanol, ethanolamine and water is 0.5:0.5:1), start stirring, stir the rod at 200 rpm, and hydrolyze for 3 hours to form silica slag. Filter the solution, leaving the filter residue in the reactor, and let the filtrate enter the filtrate buffer tank. Step 2: Add 600 kg of a silica slurry treatment agent solution at 90°C to the reactor, wherein the salt is sodium benzoate and the copper extractant is 2-hydroxy-5-nonylacetophenone oxime. Start stirring, with the stirring rod speed at 200 rpm, and wash for 60 min. Filter, leaving 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, set the stirring rod speed to 200 rpm, wash for 60 min, filter, leave the filter residue in the reactor, and let the filtrate enter the filtrate buffer tank. Step four: Discharge the filter residue and transport it to a dryer for drying. The copper-rich filtrate is then used for copper recovery, thus completing the treatment.

[0029] After toxicity leaching tests, the copper content in the leachate was 51.2 mg / L, and the final treated silica slag had a pH of 7.2 and a moisture content of 18%.

[0030] Compare with Example 1 Step 1: Add 200 kg of organosilicon slag slurry to the reactor, then add 600 kg of cold water at 25°C, start stirring, stir at 100 rpm, hydrolysis time 1 hour, form silica slag, filter, filter residue remains in the reactor, and filtrate enters the filtrate buffer tank. Step two: Discharge the filter residue to complete the process.

[0031] After toxicity leaching tests, the copper content in the leachate was 3237 mg / L, and the final treated silica slag had a pH of 2.8 and a moisture content of 85%.

[0032] Compare with Example 2 Step 1: Add 200 kg of organosilicon slag slurry to the reactor, then add 600 kg of cold water at 25°C, start stirring, stir at 100 rpm, hydrolysis time 1 hour, form silica slag, filter, filter residue remains in the reactor, and filtrate enters the filtrate buffer tank. Step 2: Add 300 kg of 2 wt% potassium hydroxide solution at 25°C to the reactor, start stirring, set the stirring rod speed to 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: Discharge the filter residue and transport it to a dryer for drying. The filtrate is then used for copper recovery, thus completing the treatment.

[0033] After toxicity leaching tests, the copper content in the leachate was 1989 mg / L, and the final treated silica slag had a pH of 8.5 and a moisture content of 12%.

[0034] Compare with Example 3 Step 1: Add 200 kg of organosilicon slag 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, with the stirring rod speed at 100 rpm, and hydrolyze for 1 hour to form silica slag. Filter the solution, leaving the filter residue in the reactor, and let the filtrate enter the filtrate buffer tank. Step 2: Add 300 kg of potassium sulfate solution at 25°C to the reactor, start stirring, stir at 100 rpm, wash for 30 minutes, 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, set the stirring rod speed to 100 rpm, wash for 30 min, filter, leave the filter residue in the reactor, and let the filtrate enter the filtrate buffer tank. Step four: Discharge the filter residue and transport it to a dryer for drying. The filtrate is then used for copper recovery, thus completing the treatment.

[0035] After toxicity leaching tests, the copper content in the leachate was 1297 mg / L, and the final treated silica slag had a pH of 8.3 and a moisture content of 14%.

[0036] Compare with Example 4 Step 1: Add 200 kg of organosilicon slag 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, with the stirring rod speed at 100 rpm, and hydrolyze for 1 hour to form silica slag. Filter the solution, leaving the filter residue in the reactor, and let the filtrate enter the filtrate buffer tank. Step 2: Add 300 kg of 2-hydroxy-5-nonylacetophenone oxime solution at 25°C to the reactor, start stirring, stir at 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, set the stirring rod speed to 100 rpm, wash for 30 min, filter, leave the filter residue in the reactor, and let the filtrate enter the filtrate buffer tank. Step four: Discharge the filter residue and transport it to a dryer for drying. The filtrate is then used for copper recovery, thus completing the treatment.

[0037] After toxicity leaching tests, the copper content in the leachate was 841 mg / L, and the final treated silica slag had a pH of 8.3 and a moisture content of 13%.

[0038] Compare with Example 5 Step 1: Add 200 kg of organosilicon slag 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, with the stirring rod speed at 100 rpm, and hydrolyze for 1 hour to form silica slag. Filter the solution, leaving the filter residue in the reactor, and let the filtrate enter the filtrate buffer tank. Step 2: Add 300 kg of silicon slurry treatment agent solution at 25°C to the reactor, wherein the salt is potassium sulfate and the copper extractant is 2-hydroxy-5-nonylacetophenone oxime. Start stirring, with the stirring rod speed at 100 rpm, and wash for 30 min. Filter, leaving 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, set the stirring rod speed to 100 rpm, wash for 30 min, filter, leave the filter residue in the reactor, and let the filtrate enter the filtrate buffer tank. Step four: Discharge the filter residue and transport it to a dryer for drying. The filtrate is then used for copper recovery, thus completing the treatment.

[0039] After toxicity leaching experiments, the copper content in the silica slag leachate was 382 mg / L, and the final treated silica slag had a pH of 8.3 and a water content of 14%.

Claims

1. A method for treating organosilicon slurry, characterized in that, The steps of this method are as follows: Step 1: Add organosilicon slag slurry to the reactor, then add silicone slag hydrolysate, stir, and hydrolyze to form silicone slag. Filter the mixture, leaving the filter residue in the reactor, and let the filtrate enter the filtrate buffer tank. The hydrolysate is a mixture of alcohol, alkanolamine, and water. The alcohol includes one or more of methanol, ethanol, and glycerol. The alkanolamines mentioned include one or more alkanolamines selected from ethanolamine, diethanolamine, triethanolamine, and isopropanolamine; Step 2: Add a hot silica slurry treatment agent solution to the reactor, stir and wash to remove the organic coating on the surface of the silica slag, filter, leave the filter residue in the reactor, and let the filtrate enter the filtrate buffer tank; the silica slurry treatment agent is a mixture of salt and copper extractant, the salt is one or a mixture of several of sodium sulfate, potassium sulfate, sodium chloride, potassium chloride, sodium thiolate, potassium thiolate and sodium benzoate, and the copper extractant includes aldoximes, ketoximes or a mixture of aldoxime-ketoximes; Step 3: Add hot alkaline washing solution to the reaction vessel, stir and wash to neutralize the silicon slag to neutral, filter, leave the filter residue in the vessel, and let the filtrate enter the filtrate buffer tank; the alkaline washing solution is a mixed aqueous solution of one or more of sodium hydroxide, potassium hydroxide, ammonia and sodium carbonate. Step four: Discharge the filter residue and transport it to a dryer for drying. The copper-rich filtrate is then used for copper recovery, thus completing the treatment.

2. The method for treating organosilicon slurry as described in claim 1, characterized in that: The organosilicon slurry comprises organosilicon high-boiling-point substances, silicon powder, elemental copper, copper oxide, cuprous oxide, cuprous chloride, and cuprous chloride, with a solid content of 20-50%, of which the copper content is 3-8%.

3. The method for treating organosilicon slurry as described in claim 1, characterized in that: The temperature of the silica slurry hydrolysate is maintained at 70-75℃; the mass ratio of silica slurry hydrolysate to slurry is 2-5:1, and the hydrolysis time is 1-3 hours.

4. The method for treating organosilicon slurry as described in claim 1, characterized in that: The mass ratio of alcohol, alkanolamine to water is 0.3-0.5:0.5-0.8:

1.

5. The method for treating organosilicon slurry as described in claim 1, characterized in that: The stirring speed in step one is 50-300 r / min.

6. The method for treating organosilicon slurry as described in claim 5, characterized in that: The stirring speed in step one is 80-200 r / min.

7. The method for treating organosilicon slurry as described in claim 1, characterized in that: The mass ratio of salt to copper extractant is 0.3-0.8:

1.

8. The method for treating organosilicon slurry as described in claim 1, characterized in that: In step two, the temperature of the hot silicone slurry treatment agent solution is maintained at 70-90℃, the mass ratio of silicone slurry treatment agent to water is 0.08-0.15:1, the mass ratio of silicone slurry treatment agent solution to silicone slag is 1.5-3:1, and the washing time is 30-60 minutes.

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