CN102795653B - A method for reclaiming copper oxide and zinc oxide from organosilicon waste contacts - Google Patents

Abstract

The invention relates to the field of recycling organosilicon waste contacts, in particular, the invention relates to a method for recycling copper oxide and zinc oxide from organosilicon waste contacts. The method comprises the following steps: 1) at 20-100°C, use an ammonia-ammonium salt mixed solution containing an oxidant to leach the waste contacts for 1-8 hours, and obtain copper ammonia and zinc ammonia after separation. Complexing solution and solid, washing and drying the solid to obtain silicon powder; 2) distilling the complex solution of copper ammonia and zinc ammonia at 40-100°C for 1-10 hours to precipitate the compound of copper, and separate the precipitate and the compound containing Zinc mother liquor, the precipitate is washed, dried, and roasted to obtain copper oxide powder, 3) Add ammonium salt to the zinc-containing mother liquor obtained in step 2), adjust the temperature to 20-80°C, and pH value to 4-8 to obtain alkali Formula zinc carbonate precipitation, after separation, washing, drying and roasting, zinc oxide powder is obtained. The yield and purity of the copper oxide obtained by using the ammonia method to treat the waste contacts are both higher than 95%.

Description

A method for reclaiming copper oxide and zinc oxide from organosilicon waste contacts

technical field

The invention relates to the field of recycling organosilicon waste contacts, in particular, the invention relates to a method for recycling copper oxide and zinc oxide from organosilicon waste contacts.

Background technique

In the production process of organosilicon, silicon and methyl chloride are used as raw materials for production, and ternary copper catalyst (main catalyst) and zinc (auxiliary agent) are often used to promote the synthesis of organosilicon monomers such as dimethyldichloromethane. When the conversion rate of silicon powder and the selectivity of methyl chlorosilane monomer reach a certain level, it is necessary to discharge the remaining silicon powder and spent catalyst out of the reactor to form industrial waste, which is called organosilicon waste contact body. The main components of the waste contact body are silicon, copper, carbon, zinc, etc., and their weight contents in the waste contact body are 65% to 80%, 3% to 20%, 1% to 10%, and 0.05% to 2.0%. Due to the small particles and high activity of copper powder, the waste contact body is prone to oxidation reaction when it encounters air, causing the organic matter and carbon in it to burn and emit pungent white smoke, which is not easy to store, seriously pollutes the environment, and has serious " "Three Wastes" issue. As early as the 1950s, research on the recycling of organic silicon waste contacts has been carried out in foreign countries (US5306328, US4758352). Immerse the waste contact with an oxidizing acid or an acid solution containing oxidants such as hydrogen peroxide and sodium hypochlorite, convert the copper catalyst in the waste contact into soluble divalent copper ions into the acid solution, and then add a reducing agent such as reduced iron powder or Zinc powder replaces copper to obtain metallic copper powder. However, the oxidizing acid liquid in the above-mentioned process corrodes the treatment equipment seriously, and the acid wastewater formed in the treatment process is difficult to discharge, which is likely to cause secondary pollution to the environment, and the reductant iron powder or zinc powder needs to be recycled. More complicated and costly. At present, domestic organic silicon companies generally dispose of waste contacts by burying them or selling them to small enterprises at low prices, without recycling waste contacts. Domestic scientific research institutions mainly adopt foreign treatment processes to recover copper (CN1083418A, CN1844422A) in the research on waste contact body treatment and recovery of copper, and there are no other more environmentally friendly and economical related process researches. With the expansion of the production capacity of methylchlorosilane in my country in recent years, the output of this monomer has exceeded 1.5 million tons in 2010, and it is expected that the production capacity will reach 2.5 million tons in 2012, and the waste contacts produced will reach 90,000 tons, causing serious Environmental protection and safety issues have become bottlenecks restricting the development of silicone companies. Therefore, to solve the "three wastes" problem of waste contacts, and to carry out research on recycling copper through environmentally friendly and economical waste contacts harmless treatment process is a technical problem that must be solved in the field of organic silicon. It is of great significance to promote the healthy development of my country's organic silicon industry.

Contents of the invention

The purpose of the present invention is to provide a copper oxide recovery method for organosilicon waste contacts in order to overcome the problems of complex process flow, easy to cause secondary pollution to the environment and high processing cost in the current organic silicon waste contact body treatment and recovery copper process. and zinc oxide methods.

According to the method for recovering copper oxide and zinc oxide from organic silicon waste contacts of the present invention, the method comprises the following steps:

1) At 20-100°C, use an ammonia-ammonium salt mixed solution containing an oxidant to leach the waste contacts for 1-8 hours, and obtain a complex solution and solid of copper ammonia and zinc ammonia after separation. The solid is washed and dried to obtain silicon powder;

2) Distill the complex solution of copper ammonia and zinc ammonia obtained in step 1) at 40-100° C. for 1-10 hours to precipitate copper compounds, separate the precipitates and zinc-containing mother liquor, wash the precipitates, dry them, After roasting, copper oxide powder is obtained, and the steamed ammonia is absorbed with ammonia liquid, and returned to step 1) for recycling;

3) Add ammonium salt to the zinc-containing mother liquor obtained in step 2), adjust the temperature to 20-80° C., and the pH value to 4-8 to obtain basic zinc carbonate precipitation, and obtain zinc oxide after separation, washing, drying and roasting powder, while the mother liquor obtained after centrifugal separation containing ammonium salt is returned to 1) for recycling.

According to the method for recovering copper oxide and zinc oxide from organic silicon waste contacts of the present invention, the oxidant is air, oxygen or hydrogen peroxide.

According to the method for recovering copper oxide and zinc oxide from organosilicon waste contacts of the present invention, the ammonia in the ammonia-ammonium salt mixed liquid is commercial ammonia water, and the ammonium salt is one of ammonium chloride, ammonium carbonate or ammonium bicarbonate. kind.

According to the method for recovering copper oxide and zinc oxide from organosilicon waste contacts of the present invention, the molar ratio of ammonia to ammonium salt in the ammonia-ammonium salt mixture is 1:1.5-5, and the ammonia-ammonium salt mixture and waste contact The mass ratio of body is 1:1~2.

According to the method for recovering copper oxide and zinc oxide from organosilicon waste contacts of the present invention, the calcination temperature is 200-800°C.

The main reaction that each step of the present invention takes place is as follows:

1)Cu+1/2O ₂ +(NH ₄ ) ₂ CO ₃ +2NH ₃ →[Cu(NH ₃ ) ₄ ] ²⁺ +CO ₃ ^2- +H ₂ O

CuO+(NH ₄ ) ₂ CO ₃ +2NH ₃ →[Cu(NH ₃ ) ₄ ] ²⁺ +CO ₃ ^2- +H ₂ O

Cu ₂ O+1/2O ₂ +2(NH ₄ ) ₂ CO ₃ +4NH ₃ →2[Cu(NH ₃ ) ₄ ] ²⁺ +2CO ₃ ^2- +2H ₂ O

Zn+1/2O ₂ +(NH ₄ ) ₂ CO ₃ +2NH ₃ →[Zn(NH ₃ ) ₄ ] ²⁺ +CO ₃ ^2- +H ₂ O

2)[Cu(NH ₃ ) ₄ ] ²⁺ →Cu ²⁺ +4NH ₃

2Cu ²⁺ +CO ₃ ^2- +2OH ^- →Cu ₂ (OH) ₂ CO ₃ (s)↓

Cu ₂ (OH) ₂ CO ₃ (s)→2CuO+CO ₂ ↑+H ₂ O

3) 3Zn(NH ₃ ) ₄ CO ₃ +2H ₂ O→ZnCO ₃ ·2Zn(OH) ₂ (s)↓+12NH ₃ +2CO ₂ ↑

ZnCO ₃ 2Zn(OH) ₂ →3ZnO+CO ₂ ↑+2H ₂ O

In the present invention, the waste contact body is treated by the ammonia method and the ratio between the metal ion and the complex ion is controlled to oxidize the copper and zinc in the waste contact body and form a complex to enter the solution, and then according to the copper ammonium complex Different from the stability of the zinc ammonia complex, the temperature is controlled to decompose the copper ammonia complex, precipitate out, realize the separation of copper ions and zinc ions, and finally calcinate to obtain zinc oxide and copper oxide. In this method, ammonia The recycling of gas and ammonium-containing mother liquor has a short process, high efficiency, and is conducive to large-scale treatment. At the same time, the materials in the entire treatment process can be recycled, without the discharge of three wastes, and avoid secondary pollution to the environment, thereby realizing the green treatment of waste contacts.

Compared with existing methods, the waste contact body treatment method proposed by the present invention has the following advantages:

1. Compared with the currently widely used acid process, the present invention adopts the ammonia method to treat waste contacts. The process is short, the efficiency is high, and it is conducive to large-scale treatment. At the same time, the materials in the entire treatment process can be recycled, and there is no discharge of three wastes, which avoids environmental pollution. Secondary pollution, so as to realize the green treatment of waste contacts.

2. Compared with the acid process, the present invention adopts the ammonia method to treat the waste contacts, which is less corrosive to the operating equipment, and the materials can be recycled, which greatly reduces the treatment cost and has higher economic benefits.

3. In the present invention, the yield and purity of copper oxide obtained by using the ammonia method to treat waste contacts are both higher than 95%.

Description of drawings

Fig. 1 is the flow chart of ammonia leaching method of the present invention processing organosilicon waste contact body method;

Fig. 2 is the XRD spectrogram of organosilicon waste contact body of the present invention;

Fig. 3 is the XRD spectrogram of the present invention's ammonia leaching method to process organic silicon waste contacts and reclaim silicon powder;

Fig. 4 is the XRD spectrogram of copper oxide reclaimed by ammonia leaching method of the present invention to process organosilicon waste contacts;

Fig. 5 is the XRD spectrum of zinc oxide, a by-product recovered from organosilicon waste contact bodies treated by ammonia immersion method in the present invention.

Detailed ways

The following examples further illustrate the invention, but the invention is not limited to the following examples.

Example 1.

72.0kg of ammonia (25.0wt%) and 34.0kg of ammonium carbonate are added to 250.0kg of water to form a mixed solution (the mol ratio of ammonia to ammonium carbonate is 3.0), and then 100.0kg of waste contacts (containing copper 15.0wt%, zinc 1.5wt%, the mass ratio of ammonia-ammonium salt to waste contact body is 1.06), and stirred in air at 20°C for 8h. After filtering or centrifuging, the solid slag was washed and dried to obtain 80.0kg of silicon powder. Raise the temperature of the mother liquor after centrifugation to 40°C and keep it warm for 10 hours. A large amount of blue-green precipitates will be produced in the solution. At the same time, the released ammonia gas can be absorbed by 10wt% ammonia water and can be recycled as a raw material for impregnating waste contacts. After filtration or centrifugal separation, the precipitate was washed, dried, and calcined at 450° C. for 5 hours to obtain 18.0 kg of finished copper oxide with a purity of 97% and a total recovery of 96%. Add 2.5kg of ammonium carbonate to the separated mother liquor, the reaction temperature is 20°C, the pH value is 4.0, a white precipitate is precipitated in the solution, after filtration or centrifugation, the precipitate is washed, dried, and roasted at 600°C for 4 hours to obtain 1.80kg of ammonium carbonate Zinc, the total recovery rate is 96%, and the purity is 97%. The separated mother liquor is recycled as raw material for impregnating waste contacts.

The above-mentioned copper oxide and zinc oxide extracted from waste contacts were tested by XRD on the X'Pert PRO MPD multifunctional X-ray diffractometer produced by Panalytical Company (Panalytical) in the Netherlands.

Figure 2 is the XRD spectrum of the organic silicon waste contact, in which the diffraction peaks at 2θ of 28.4°, 36.4° and 43.3° correspond to the characteristic diffraction peaks of silicon, copper and zinc respectively, indicating that the waste contact mainly contains silicon, copper and zinc.

Fig. 3 is the XRD spectrogram of reclaiming silicon powder after ammonia leaching process waste contact body in embodiment 1, wherein 2θ is the diffraction peak of 28.4 ° is the characteristic diffraction peak of silicon, does not have the diffraction peak of other copper catalysts and zinc, shows The separation of copper, zinc and silicon was achieved by impregnating waste contacts with ammonia.

Fig. 4 is the XRD spectrogram of the copper oxide powder obtained after treating the waste contacts in Example 1, wherein the diffraction peaks with 2θ of 35.5° and 38.9° are the characteristic diffraction peaks of copper oxide, and there are no other substances Diffraction peaks indicate that pure copper oxide can be obtained by adopting the ammonia immersion method in the present invention to treat waste contacts.

Fig. 5 is the XRD spectrogram of the by-product zinc oxide obtained after the treatment of the waste contact body in Example 1, wherein the diffraction peaks with 2θ of 31.9°, 34.6° and 36.4° are the characteristic diffraction peaks of zinc oxide, There are diffraction peaks of other substances, indicating that the by-product obtained by using the ammonia immersion method to treat the waste contact body is pure zinc oxide.

Example 2.

80.0kg of ammonia water (25.0wt%) and 45.0kg of ammonium carbonate are added to 200kg of water to form a mixed solution (the mol ratio of ammonia to ammonium carbonate is 2.5), and then 100.0kg of waste contacts (containing copper 15.0wt%, zinc 1.5 wt%, the mass ratio of ammonia-ammonium salt to waste contact body is 1.25), stirred at 70°C with air for 6h, filtered or centrifuged, washed and dried the solid slag to obtain 78.0kg of silicon powder. Raise the temperature of the separated mother liquor to 80° C. and keep it warm for 5 hours. A large amount of blue-green precipitates will be produced in the solution. At the same time, the released ammonia gas can be absorbed by 10wt% ammonia water and can be recycled as a raw material for impregnating waste contacts. After filtration or centrifugation, the precipitate was washed, dried, and calcined at 500°C for 4 hours to obtain 18.5kg of finished copper oxide with a purity of 96% and a total recovery of 98%. Add 3.5kg of ammonium carbonate to the separated mother liquor, the reaction temperature is 60°C, the pH value is 7.0, a white precipitate is precipitated in the solution, after filtration or centrifugation, the precipitate is washed, dried, and roasted at 500°C for 5 hours to obtain 1.83kg of oxidized Zinc, the total recovery rate is 98%, and the purity is 96%. The separated mother liquor is recycled as raw material for impregnating waste contacts.

Example 3.

Add 91.0kg of ammonia water (25.0wt%) and 40.0kg of ammonium carbonate into 200kg of water to form a mixed solution (the mol ratio of ammonia to ammonium carbonate is 3.2), then add 100.0kg of waste contacts (containing copper 15.0wt%, zinc 1.5 % by weight, the mass ratio of ammonia-ammonium salt to waste contact body is 1.31), stirred at 100° C. with air for 1 h, filtered or centrifuged, washed and dried the solid slag to obtain 79.5 kg of silicon powder. Raise the temperature of the mother liquor after centrifugation to 100°C and keep it warm for 1 hour. A large amount of blue-green precipitates will be produced in the solution. At the same time, the released ammonia gas can be absorbed by 10wt% ammonia water and can be recycled as a raw material for impregnating waste contacts. After filtration or centrifugation, the precipitate was washed, dried, and calcined at 500°C for 6 hours to obtain 18.2kg of finished copper oxide with a purity of 96% and a total recovery of 97%. Add 4.0kg of ammonium carbonate to the separated mother liquor, the reaction temperature is 80°C, the pH value is 8.0, and precipitates are precipitated in the solution. After filtration or centrifugation, the precipitates are washed and dried, and roasted at 500°C for 5 hours to obtain 1.80kg of zinc oxide , the total recovery was 96%, and the purity was 95%. The separated mother liquor is recycled as raw material for impregnating waste contacts.

Example 4.

107.0kg of ammonia water (25.0wt%) and 50.0kg of ammonium bicarbonate are added to 200kg of water to form a mixed solution (the mol ratio of ammonia to ammonium bicarbonate is 2.5), and then 100.0kg of waste contacts (containing copper 15.0wt%, Zinc 1.5wt%, the mass ratio of ammonia-ammonium salt to waste contact body is 1.57), stirred at 80°C for 5 hours, filtered or centrifuged, washed and dried the solid slag to obtain 79.0kg of silicon powder. Raise the temperature of the separated mother liquor to 80° C. and keep it warm for 5 hours. A large amount of blue-green precipitates will be produced in the solution. At the same time, the released ammonia gas can be absorbed by 10wt% ammonia water and can be recycled as a raw material for impregnating waste contacts. After filtration or centrifugation, the precipitate was washed, dried, and calcined at 500° C. for 5 hours to obtain 17.8 kg of finished copper oxide with a purity of 96% and a total recovery of 95%. Add 3.5kg of ammonium carbonate to the separated mother liquor, the reaction temperature is 60°C, the pH value is 7.0, and precipitates are precipitated in the solution. After filtration or centrifugation, the precipitates are washed, dried, and roasted at 500°C for 5 hours to obtain 1.79kg of zinc oxide , the total recovery rate was 96%, and the purity was 98%. The separated mother liquor is recycled as raw material for impregnating waste contacts.

Example 5.

117.0kg of ammonia water (25.0wt%) and 45.5kg of ammonium bicarbonate were added to 230kg of water to form a mixed solution (the mol ratio of ammonia to ammonium bicarbonate was 3.0), and then 100.0kg of waste contacts (containing copper 15.0wt%, Zinc 1.5wt%, the mass ratio of ammonia-ammonium salt to waste contact body is 1.62), stirred at 70°C with air for 6h, filtered or centrifuged, washed and dried the solid slag to obtain 78.8kg of silicon powder. Raise the temperature of the separated mother liquor to 80°C and keep it warm for 6 hours. A large amount of blue-green precipitates will be produced in the solution. At the same time, the released ammonia gas can be absorbed with 10wt% ammonia water and can be recycled as raw materials for impregnating waste contacts. After filtration or centrifugation, the precipitate was washed, dried, and calcined at 500° C. for 5 hours to obtain 18.2 kg of finished copper oxide with a purity of 95% and a total recovery of 96%. Add 3.0kg of ammonium carbonate to the separated mother liquor, the reaction temperature is 70°C, the pH value is 6.5, and precipitates are precipitated in the solution. After filtration or centrifugation, the precipitates are washed and dried, and roasted at 500°C for 5 hours to obtain 1.8kg of zinc oxide , the total recovery rate was 96%, and the purity was 96%. The separated mother liquor is recycled as raw material for impregnating waste contacts.

Example 6.

71.0kg of ammonia (25.0wt%) and 50.0kg of ammonium carbonate are added to 200kg of water to form a mixed solution (the mol ratio of ammonia to ammonium carbonate is 2), and then 100.0kg of waste contacts (containing copper 15.0wt%, zinc 1.5 % by weight, the mass ratio of ammonia-ammonium salt to waste contact body is 1.21), stirred at 80° C. with air for 6 hours, filtered or centrifuged, washed and dried the solid slag to obtain 80.5 kg of silicon powder. Raise the temperature of the separated mother liquor to 80° C. and keep it warm for 5 hours. A large amount of blue-green precipitates will be produced in the solution. At the same time, the released ammonia gas can be absorbed by 10wt% ammonia water and can be recycled as a raw material for impregnating waste contacts. After filtration or centrifugation, the precipitate was washed, dried, and calcined at 500°C for 6 hours to obtain 18.5kg of finished copper oxide with a purity of 96% and a total recovery of 99%. Add 4.0kg of ammonium carbonate to the separated mother liquor, the reaction temperature is 60°C, the pH value is 7.5, and precipitates are precipitated in the solution. After filtration or centrifugation, the precipitates are washed, dried, and roasted at 500°C for 5 hours to obtain 1.82kg of zinc oxide , the total recovery rate was 97%, and the purity was 97%. The separated mother liquor is recycled as raw material for impregnating waste contacts.

Claims (4)

1. a method for reclaiming copper oxide and zinc oxide from organic silicon waste contact body, is characterized in that, described method comprises the following steps: 1) At 20-100°C, the waste contacts are leached with an oxidant-containing ammonia-ammonium salt mixed solution for 1-8 hours. After separation, the complex solution and solid of copper ammonia and zinc ammonia are obtained. The solid is washed and dried to obtain silicon powder; 2) Distill the complex solution of copper ammonia and zinc ammonia obtained in step 1) at 40-100° C. for 1-10 hours to precipitate copper compounds, separate the precipitates and zinc-containing mother liquor, wash the precipitates, dry them, After roasting, copper oxide powder is obtained, and the steamed ammonia is absorbed with ammonia liquid, and returned to step 1) for recycling; 3) Add ammonium salt to the zinc-containing mother liquor obtained in step 2), adjust the pH value to 4-8, and the temperature to 20-80° C. to obtain basic zinc carbonate precipitation, and obtain zinc oxide after centrifugal separation, washing, drying and roasting powder, while the mother liquor obtained after centrifugation and containing ammonium salt is returned to 1) for recycling; In the step 1), the molar ratio of ammonia to ammonium salt in the ammonia-ammonium salt mixture is 1:1.5-5, and the mass ratio of ammonia-ammonium salt mixture to waste contact is 1:1-2.0; The ammonium salt in the step 1) is ammonium carbonate or ammonium bicarbonate. 2. The method for reclaiming copper oxide and zinc oxide from organic silicon waste contacts according to claim 1, characterized in that the oxidant in the step 1) is air, oxygen or hydrogen peroxide. 3. The method for reclaiming copper oxide and zinc oxide from organic silicon waste contacts according to claim 1, characterized in that the ammonia in the ammonia-ammonium salt mixture in the step 1) is ammonia water. 4. The method for recovering copper oxide and zinc oxide from organic silicon waste contacts according to claim 1, characterized in that the calcination temperature in steps 2) and 3) is 200-800°C.