Organic silicon slurry residue recovery treatment process

Abstract

The invention relates to the field of organic silicon, and provides an organic silicon slurry residue recovery treatment process which comprises the following steps: S11, gas pretreatment: pretreating a mixed gas of hydrogen chloride and chlorine to obtain a prepared mixed gas, and collecting the mixed gas of hydrogen chloride and chlorine from a process of preparing white carbon black from methyl trichlorosilane; s21, leaching reaction: carrying out hydrolysis treatment on the organic silicon slurry slag to obtain copper-containing silicon slag, blending the copper-containing silicon slag and water to obtain slurry, introducing the prepared mixed gas into the slurry to carry out leaching reaction, controlling the temperature of the leaching reaction to be 60-80 DEG C and the solid content of the slurry of the leaching reaction to be 15-30%, and separating to obtain copper-containing leachate; s31, grading treatment is conducted, specifically, copper ion concentration detection is conducted on the copper-containing leachate, and grading treatment is conducted at the same time; according to the process, cooperative treatment and resource utilization of the waste gas and the slurry residues are achieved, and a copper product with the higher additional value is obtained.

Description

Technical Field

[0001] This invention relates to the field of organosilicon technology, and more specifically, to a process for recycling and treating organosilicon slurry residue. Background Technology

[0002] Organosilicon materials are indispensable high-performance materials in modern industry. Their core monomer, methylchlorosilane, is mainly synthesized through a direct method. In this synthesis process, chloromethane and industrial silicon are used as the main raw materials. The industrial silicon is in the form of fine powder, chloromethane is in the form of gas, and the catalyst is solid copper powder. The reaction is carried out in a fluidized bed using a gas-solid phase reaction mode. The methylchlorosilane produced by the reaction is a liquid product, which contains unreacted silicon powder, catalyst copper powder, and other solid impurities.

[0003] Existing technologies for recovering these solid impurities mainly employ a two-stage separation process: First, most of the solid components are recovered at the top of the fluidized bed using a cyclone separator. Then, the liquid-phase methylchlorosilane product is washed with a methylchlorosilane solvent to further remove solid impurities. After these two stages of separation, the final solid-liquid mixture is the organosilicon slurry, which is a major byproduct of organosilicon production.

[0004] Furthermore, in this process chain, methyltrichlorosilane serves as a key intermediate. It is produced by gasifying the methyltrichlorosilane and then incinerating it with hydrogen and oxygen-containing air. This process generates a large amount of a mixed gas of hydrogen chloride and chlorine, which contains precipitated ...

[0005] Slurry residue, a major byproduct of this industry, is typically treated by hydrolysis with water, yielding a hydrochloric acid solution and silicon-containing solid residue. This residue contains a significant amount of copper, as well as some impurities such as iron and aluminum. Due to the substantial commercial value of copper, it requires further extraction and recovery through specialized processes. For example, patent CN114524408A discloses a green and comprehensive recycling method for organosilicon slurry residue. This method is based on hydrolysis and combines pretreatment methods such as sedimentation, vacuum distillation, and ball milling. Subsequently, hydrogen extraction, filtration, residue washing, and copper extraction are carried out to finally obtain water glass and copper sulfate products. Although this method achieves comprehensive utilization of slurry residue, its copper recovery product is copper sulfate, which has limited added value, and the process route is relatively complex.

[0006] For example, patent CN115475825A discloses a process for treating organosilicon slurry residue. This process involves separating the gas and solid phases through vacuum drying, recovering useful components from the gas phase, and leaching the solid phase using a sulfuric acid-hydrogen peroxide system after neutralization with lime slurry. Sponge copper is then obtained through iron powder replacement. While this process can recover copper resources, the product is sponge copper (copper content ≥80%), which has low purity. Furthermore, the introduction of iron powder introduces new impurities, and the ferrous sulfate solution generated after replacement requires further treatment.

[0007] It is evident that existing technologies have the following drawbacks: traditional slurry treatment processes often require the addition of chemicals such as sulfuric acid, hydrogen peroxide, and iron powder, which not only increases raw material costs but may also introduce new impurities; furthermore, the final products of copper recovery are mostly low-value-added products such as sponge copper, copper sulfate, or copper concentrate; in addition, the waste liquid generated during the treatment process often requires further treatment, posing a risk of secondary pollution. Summary of the Invention

[0008] In view of the above-mentioned shortcomings in the prior art, the core objective of the present invention is to solve the technical problem that when recovering copper from organosilicon slurry, only low-value-added products such as sponge copper or copper sulfate can be obtained, resulting in resource waste and secondary pollution.

[0009] This invention is achieved through the following technical solution: The first objective of this invention is to provide a process for recycling and treating organosilicon slurry residue, comprising the following steps: S11. Gas pretreatment: The mixed gas of hydrogen chloride and chlorine is pretreated to obtain a pre-mixed gas, wherein the mixed gas of hydrogen chloride and chlorine is collected from the process of preparing silica from methyltrichlorosilane. S21. Leaching reaction: The organosilicon slurry is hydrolyzed to obtain copper-containing silicon slag. The copper-containing silicon slag is then mixed with water to form a slurry. The pre-mixed gas is then introduced into the slurry to carry out a leaching reaction. The temperature of the leaching reaction is controlled at 60-80°C, and the solid content of the slurry is 15-30%. After separation, a copper-containing leachate is obtained. S31. Grading treatment: The copper ion concentration of the copper-containing leachate is detected, and grading treatment is performed simultaneously. When the copper ion concentration of the copper-containing leaching solution is ≥40 g / L, electrolytic copper is prepared by electrowinning. When the copper ion concentration of the copper-containing leaching solution is <40 g / L, selective crystallization is used to prepare electronic-grade cuprous chloride with a purity ≥99.5%. The mother liquor generated during the selective crystallization process is used to prepare polyaluminum ferric chloride coagulant.

[0010] Preferably, in step S11, the pretreatment includes: contacting the collected mixed gas of hydrogen chloride and chlorine with the washing liquid in a countercurrent manner, washing to remove silica dust, cooling the dust-removed gas to 10-40°C, and then performing gas-liquid separation on the cooled gas to remove entrained droplets to obtain purified mixed gas.

[0011] Preferably, in step S21, the hydrolysis treatment includes: mixing organosilicon slurry with water in a certain proportion, stirring and reacting, and then performing solid-liquid separation to obtain the copper-containing silicon slag.

[0012] Preferably, the mass ratio of the organosilicon slurry residue to the water is 1:(2-5).

[0013] Preferably, the conditions for the stirring reaction include: a reaction pressure of atmospheric pressure, a stirring temperature of 50–80°C, and a stirring time of 0.5–2 h.

[0014] Preferably, in step S21, the endpoint of the leaching reaction is: the redox potential of the reaction system stabilizes at 400-600 mV and is maintained for more than 5 minutes.

[0015] Preferably, the electrodeposition method employs a stainless steel cathode and a graphite anode, with a current density of 150–250 A / m. 2 During the electrolysis process, the concentration of copper ions in the copper-containing leachate is maintained at 35–45 g / L.

[0016] Preferably, the selective crystallization method includes the following steps: S12. Hot filtration treatment: The copper-containing leaching solution is hot filtered at 60-80℃ to remove solid impurities and obtain filtrate. S22. Crystallization separation treatment: The filtrate is cooled to 10-30°C at a rate of 1-5°C / min, and cuprous chloride seed crystals are added during the cooling process. After centrifugation, electronic-grade cuprous chloride product is obtained.

[0017] Preferably, the amount of cuprous chloride seed crystals added accounts for 0.5 to 2% of the total mass of the filtrate.

[0018] For mixed gases of HCl and Cl2 containing silica dust, this invention employs a combined purification process of countercurrent washing, cooling, and gas-liquid separation. Unlike the commonly used alkaline washing method that passively accepts pollutants, this invention actively removes silica dust that affects subsequent reactions through active dust removal and temperature control (10–40°C). It also avoids equipment corrosion caused by water vapor condensation in the gas through precise temperature management, providing a stable and pure raw material gas for subsequent leaching reactions. This pretreatment method fundamentally solves the problem of generating "acid-containing" waste.

[0019] More importantly, the inventors discovered that, through a waste-to-waste approach, a purified mixture of HCl and Cl2 gas can be passed into a copper-containing silicon slag slurry obtained from the hydrolysis of organosilicon slag. Cl2, acting as a strong oxidant, oxidizes elemental copper or low-valent copper to Cu. 2+ Meanwhile, HCl provides the necessary acidic environment and Cl... - The ligands form a stable copper chloride solution. Compared with the commonly used acid leaching process, this rational design abandons the conventional practice of adding sulfuric acid, hydrogen peroxide or air oxidants. It utilizes the "waste gas" of the upstream process to achieve efficient copper leaching in the downstream slurry. Furthermore, by controlling the leaching temperature, slurry solid content and using the redox potential as the indicator of the reaction endpoint, the copper leaching rate and reaction efficiency are fully optimized. Among these, the most important is the specific synergistic effect of the HCl-Cl2 mixed gas in copper leaching, which achieves efficient copper leaching. That is, the high oxidizing power of Cl2 and the acidity and coordination ability of HCl promote each other, forming a more efficient copper leaching environment than a single oxidant or acid leaching system. This synergistic effect allows for efficient copper leaching under relatively mild conditions (60-80℃).

[0020] Furthermore, based on the aforementioned waste-to-waste treatment approach, precise diversion is implemented according to the copper ion concentration in the leachate. For high-concentration leachates (Cu... 2+ Electrolytic copper (≥40 g / L) is directly prepared by electrowinning, with the current density controlled (150–250 A / m). 2 Maintaining a copper ion concentration (35–45 g / L) ensures electrodeposition efficiency and product purity; simultaneously, for low-concentration leachates (Cu... 2+ The invention further creatively provides a unique selective crystallization process for copper chloride with a purity of ≥99.5% by removing impurities through hot filtration, controlling the cooling rate (1-5℃ / min), and adding seed crystals (0.5-2%). This process breaks through the limitation of traditional technologies that can only produce industrial-grade copper products. Compared with the existing iron powder replacement method, the electrowinning-crystallization combined process of this invention not only avoids the product purity problem caused by the introduction of iron ions, but also upgrades the copper product grade from sponge copper (≥80%) to electrolytic copper and electronic-grade cuprous chloride (≥99.5%), achieving a leap in product value. Compared with the existing multi-step alkaline silicon extraction-acid leaching copper extraction method, the gas leaching route of this invention simplifies the process flow, reduces chemical consumption, and lowers operating costs.

[0021] Furthermore, the mother liquor produced after selective crystallization is no longer treated as wastewater. Instead, it is converted into polyaluminum ferric chloride coagulant with market value through pH adjustment (2.5–3.5) and thermal polymerization (60–90℃, 2–4 h), forming a complete resource recovery loop.

[0022] In summary, through a clever combination of processes, the mixed gas of HCl and Cl2, by-products from the methyltrichlorosilane to silica production process, is treated and then used to treat the hydrolysis slurry residue from the methylchlorosilane and industrial silicon synthesis process. Copper resources are extracted from the hydrolysis slurry residue, and the specific synergistic effect of the HCl-Cl2 mixed gas in copper leaching is utilized to achieve efficient copper leaching. This facilitates further graded preparation of high-value-added products. Compared to the existing common approach of uniformly treating slurry residue and coarsely utilizing it, the products obtained by this invention have higher added value, lower processing difficulty, and can achieve waste-to-waste treatment, thus realizing the effective utilization of resources.

[0023] Preferably, the preparation method of the polyaluminum ferric chloride coagulant includes the following steps: S13. Dilute the mother liquor generated during the selective crystallization process until the total iron and aluminum content in the mother liquor is 8-15%, and then adjust the pH to 2.5-3.5 to obtain a prepolymerization solution; S23. The prepolymer solution is stirred at 60-90°C and maintained for 2-4 hours to obtain liquid polyaluminum ferric chloride coagulant through polymerization reaction.

[0024] The mother liquor produced after selective crystallization of cuprous chloride is induced to undergo directional polymerization of residual aluminum and iron ions under precisely controlled physicochemical conditions, transforming it into a high-value-added inorganic polymeric flocculant. Specifically: First, the mother liquor is the residual solution after organosilicon slurry residue has been leached with HCl / Cl2 mixed gas and then selectively crystallized to remove most of the copper ions. It is a mixed system rich in aluminum ions, iron ions, chloride ions and residual hydrogen ions. It is diluted to a total iron and aluminum content of 8-15% to achieve the optimal reactant concentration. That is, if the concentration is too high, it will easily lead to local precipitation and damage the polymer structure; if the concentration is too low, the reaction driving force will be insufficient.

[0025] Subsequently, the pH was further precisely adjusted to a weakly acidic range of 2.5–3.5. This provided initial impetus for the hydrolysis of metal ions, promoting the hydrolysis of [Al(H2O)6]. 3+ and [Fe(H2O)6] 3+Preliminary hydrolysis occurs to generate mononuclear hydroxyl complexes. On the other hand, this pH window is precisely at the critical state of "hydrolysis initiated but not yet precipitated," effectively preventing the premature formation of amorphous hydroxides and preserving reactive centers for subsequent molecular polymerization. Furthermore, during the thermal polymerization stage, the directional construction of the polymer structure is achieved through the coordinated control of temperature and time. Specifically, under mild heating conditions of 60–90°C, the pre-formed mononuclear hydrolysis products undergo condensation polymerization via a "hydroxyl bridging" mechanism. The essence of this process is the interaction between metal ions via OH groups. - Bridge bonds connect them, gradually evolving from mononuclear bodies to form [Al] x Fe (OH) m Cl n ] - The general multi-core polymer chain; furthermore, continuous isothermal stirring not only accelerates this process but also promotes the maturation and stabilization of the polymer chain; more importantly, the introduction of iron ions produces a unique synergistic effect, namely, the aluminum center provides strong charge neutralization capacity, while the iron center endows the flocs with higher density and sedimentation performance. The flocculation effect of this aluminum-iron composite system is significantly better than that of single-component polyaluminum or polyiron. Compared with the existing technology that uses ordinary water treatment agents, through precise polymerization control, the residual mother liquor is transformed into a high-performance polymer coagulant, achieving a qualitative breakthrough from "low-value disposal" to "high-value conversion". This also makes the entire organosilicon slurry slag treatment process form a perfect material cycle, namely, the upstream waste gas is used for slurry leaching, the leaching liquid is graded to produce high-purity copper products, and finally even the residual mother liquor is transformed into water treatment chemicals with market value.

[0026] The second objective of this invention is to provide a product prepared by the above process, the product comprising one or more of the following: electrolytic copper, electronic-grade cuprous chloride with a purity ≥99.5%, and polyaluminum ferric chloride coagulant with an iron and aluminum content of 8-15%. Attached Figure Description

[0027] Figure 1 The process flow diagram provided for Example 1.

[0028] The technical solutions of the embodiments of the present invention have at least the following advantages and beneficial effects: (1) It realizes the synergistic treatment and resource utilization of waste gas and slurry residue.

[0029] (2) The synergistic leaching effect of HCl-Cl2 mixed gas significantly improves the leaching efficiency of copper while greatly reducing chemical consumption and processing costs.

[0030] (3) Through graded processing, traditional low-value-added copper products are upgraded to electrolytic copper and electronic-grade cuprous chloride, which greatly enhances the value of resources.

[0031] (4) A complete resource utilization closed loop has been established, which converts the mother liquor into polyaluminum ferric chloride coagulant, achieving zero discharge of waste liquid and full utilization of all components; the overall process is environmentally friendly and generates no secondary pollution. Detailed Implementation

[0032] Example 1 This embodiment provides a process for recycling and treating organosilicon slurry residue, including the following steps: (1) Gas pretreatment The mixture of hydrogen chloride and chlorine gas (containing approximately 150 mg / m³ of silica dust) generated during the process of preparing silica from methyltrichlorosilane was extracted. 3 The mixed gas is passed into a countercurrent scrubbing tower and comes into countercurrent contact with clean water to remove the entrained silica dust. The dust-removed gas is cooled to 25°C and the entrained liquid droplets are removed by a gas-liquid separator to obtain a purified HCl and Cl2 mixed gas for later use.

[0033] (2) Slurry residue hydrolysis treatment Take 1 kg of organosilicon slurry residue (moisture content of about 30% and copper content of 8.5%), mix it with water at a mass ratio of 1:3, stir and react at 70℃ for 1.5 h, and the reaction pressure is atmospheric pressure. After the reaction is completed, solid-liquid separation is performed to obtain copper-containing silicon slurry (moisture content of about 45%).

[0034] (3) Leaching reaction The copper-containing silicon slag was mixed with water at a solid content of 20% to form a slurry, and the purified mixed gas obtained in step 1 was introduced to carry out the leaching reaction. The reaction temperature was controlled at 70℃, the gas was continuously introduced and stirred, and the redox potential of the reaction system was monitored. When the potential stabilized at 480 mV and maintained for more than 5 minutes, the gas introduction was stopped. The total reaction time was 2.5 h. After the reaction, solid-liquid separation was performed to obtain a copper-containing leachate (copper ion concentration measured at 38 g / L).

[0035] (4) Graded processing The copper ion concentration in the leachate was found to be 38 g / L (<40 g / L). Selective crystallization was then used for treatment. Hot filtration treatment: The leachate is hot filtered at 70°C to remove solid impurities and obtain a clear filtrate; Crystallization separation process: The filtrate was cooled to 20°C at a cooling rate of 3°C / min. During the cooling process, 1% of cuprous chloride seed crystals by mass of the filtrate were added. After aging at this temperature for 30 min, centrifugation was performed to obtain electronic-grade cuprous chloride product. The purity was tested and found to be 99.6%, meeting the electronic-grade standard.

[0036] (5) Resource utilization of mother liquor The mother liquor was diluted to a total iron and aluminum content of 12%, and the pH was adjusted to 3.0 with dilute hydrochloric acid to obtain a prepolymerization solution. The prepolymerization solution was stirred and polymerized at 80°C for 3 h to obtain liquid polyaluminum chloride iron coagulant.

[0037] Example 2 This embodiment provides a process for recycling and treating organosilicon slurry residue, including the following steps: (1) Gas pretreatment The mixture of hydrogen chloride and chlorine gas (containing approximately 120 mg / m³ of silica dust) generated during the process of preparing silica from methyltrichlorosilane was taken from the silica production process. 3 The mixed gas is fed into a countercurrent scrubbing tower and comes into countercurrent contact with clean water to remove the entrained silica dust. The dust-removed gas is cooled to 10°C. The entrained liquid droplets are removed by a gas-liquid separator to obtain a purified HCl and Cl2 mixed gas for later use.

[0038] (2) Slurry residue hydrolysis treatment Take 1 kg of organosilicon slurry residue (moisture content of about 25% and copper content of 7.8%), mix it with water at a mass ratio of 1:2, stir and react at 50℃ for 2 h, and the reaction pressure is atmospheric pressure. After the reaction is completed, solid-liquid separation is performed to obtain copper-containing silicon slurry (moisture content of about 42%).

[0039] (3) Leaching reaction The copper-containing silicon slag was mixed with water at a solid content of 15% to form a slurry, and the purified mixed gas obtained in step 1 was introduced to carry out the leaching reaction. The reaction temperature was controlled at 60℃, the gas was continuously introduced and stirred, and the redox potential of the reaction system was monitored. When the potential stabilized at 400 mV and maintained for more than 5 minutes, the gas introduction was stopped. The total reaction time was 3 hours. After the reaction, solid-liquid separation was performed to obtain a copper-containing leachate (copper ion concentration measured to be 28 g / L).

[0040] (4) Graded processing The copper ion concentration in the leachate was found to be 28 g / L (<40 g / L). Selective crystallization was used for treatment: hot filtration: the leachate was hot-filtered at 60℃ to remove solid impurities, resulting in a clear filtrate; crystallization separation: the filtrate was cooled to 10℃ at a rate of 1℃ / min, and cuprous chloride seed crystals (0.5% of the total mass of the filtrate) were added during the cooling process. After aging at this temperature for 40 min, centrifugation was performed to obtain electronic-grade cuprous chloride product. The purity was tested to be 99.5%, meeting electronic-grade standards.

[0041] (5) Resource utilization of mother liquor The mother liquor was diluted to a total iron and aluminum content of 8%, and the pH was adjusted to 2.5 with dilute hydrochloric acid to obtain a prepolymerization solution. The prepolymerization solution was stirred and polymerized at 60°C for 4 h to obtain liquid polyaluminum chloride iron coagulant.

[0042] Example 3 This embodiment provides a process for recycling and treating organosilicon slurry residue, including the following steps: (1) Gas pretreatment (2) A mixture of hydrogen chloride and chlorine gas (containing approximately 180 mg / m³ of silica dust) generated during the process of preparing silica from methyltrichlorosilane. 3 The mixed gas is fed into a countercurrent scrubbing tower and comes into countercurrent contact with clean water to remove the entrained silica dust. The dust-removed gas is cooled to 40°C. The entrained liquid droplets are removed by a gas-liquid separator to obtain a purified HCl and Cl2 mixed gas for later use.

[0043] (2) Slurry residue hydrolysis treatment Take 1 kg of organosilicon slurry residue (moisture content of about 35% and copper content of 9.2%), mix it with water at a mass ratio of 1:5, stir and react at 80℃ for 0.5 h, and the reaction pressure is atmospheric pressure. After the reaction is completed, solid-liquid separation is performed to obtain copper-containing silicon slurry (moisture content of about 48%).

[0044] (3) Leaching reaction The copper-containing silicon slag was mixed with water at a solid content of 30% to form a slurry, and the purified mixed gas obtained in step 1 was introduced to carry out the leaching reaction. The reaction temperature was controlled at 80℃, the gas was continuously introduced and stirred, and the redox potential of the reaction system was monitored. When the potential stabilized at 600 mV and maintained for more than 5 minutes, the gas introduction was stopped. The total reaction time was 2 hours. After the reaction, solid-liquid separation was performed to obtain a copper-containing leachate (copper ion concentration measured to be 52 g / L).

[0045] (4) Graded processing The copper ion concentration in the leachate was found to be 52 g / L (≥40 g / L). Electrowinning was used for treatment: a stainless steel cathode and a graphite anode were employed, with the current density controlled at 250 A / m². 2 During the electrolysis process, the concentration of copper ions in the copper-containing leachate is maintained at 35-45 g / L to prepare electrolytic copper products that meet the standards.

[0046] (5) Resource utilization of mother liquor The residual liquid generated during the electrowinning process was diluted to a total iron and aluminum content of 15%, and the pH was adjusted to 3.5 with dilute hydrochloric acid to obtain a prepolymerization solution. The prepolymerization solution was stirred and polymerized at 90°C for 2 h to obtain liquid polyaluminum ferric chloride coagulant.

[0047] Comparative Example 1 The difference between this comparative example and the embodiment lies in the use of the traditional acid leaching-displacement method, which includes the following steps: (1) Gas pretreatment The mixed gas of hydrogen chloride and chlorine (containing approximately 150 mg / m³ of silica dust) generated during the process of preparing silica from methyltrichlorosilane was directly passed into an alkaline scrubbing tower and treated with sodium hydroxide solution to generate sodium hypochlorite waste liquid containing silica dust, which was disposed of as hazardous waste.

[0048] (2) Slurry residue hydrolysis treatment Take 1 kg of organosilicon slurry residue (moisture content of about 30% and copper content of 8.5%), mix it with water at a mass ratio of 1:3, stir and react at 70℃ for 1.5 h, and the reaction pressure is atmospheric pressure. After the reaction is completed, solid-liquid separation is performed to obtain copper-containing silicon slurry (moisture content of about 45%).

[0049] (3) Leaching reaction The copper-containing silicon slag was mixed with water at a solid content of 20% to form a slurry. Then, 98% sulfuric acid and 27.5% hydrogen peroxide (mass ratio 5:1:2) were added for acid leaching. The reaction temperature was controlled at 70℃, and the mixture was stirred for 2.5 h. After the reaction, solid-liquid separation was performed to obtain a copper-containing leachate (copper ion concentration measured at 35 g / L).

[0050] (4) Displacement treatment The leachate was transferred to a displacement reactor, and 200-mesh iron powder was added to carry out the displacement reaction. After the reaction was completed, the copper sponge containing water (copper content 82%) was separated by filtration. The displacement solution was a ferrous sulfate solution (concentration of about 6%), which was sent to a wastewater treatment plant for disposal.

[0051] Comparative Example 2 The difference between this comparative example and the embodiment lies in the use of a single Cl2 gas leaching process, including the following distinct steps: (1) Gas pretreatment Pure Cl2 gas (purity ≥ 99.5%) was used as the leaching gas, and no HCl gas was added.

[0052] (2) Slurry residue hydrolysis treatment Take 1 kg of organosilicon slurry residue (moisture content of about 30% and copper content of 8.5%), mix it with water at a mass ratio of 1:3, stir and react at 70℃ for 1.5 h, and the reaction pressure is atmospheric pressure. After the reaction is completed, solid-liquid separation is performed to obtain copper-containing silicon slurry (moisture content of about 45%).

[0053] (3) Leaching reaction The copper-containing silicon slag was mixed with water at a solid content of 20% to form a slurry, and pure Cl2 gas was introduced to carry out the leaching reaction. The reaction temperature was controlled at 70℃, and the gas was continuously introduced while stirring, and the redox potential of the reaction system was monitored. After 6 hours of reaction, the potential still could not stabilize at 480 mV, and the reaction was forced to terminate.

[0054] (4) Results Analysis After the reaction was completed, solid-liquid separation was performed, and the copper leaching rate was determined to be 72%. A large amount of unreacted metallic copper was observed in the reaction system, and the pH value of the slurry was high (pH>4), indicating that the oxidation of Cl2 was significantly inhibited in the absence of an acidic environment.

[0055] Comparative Example 3 The difference between this comparative example and the embodiment lies in the use of a single HCl gas leaching process, including the following distinct steps: (1) Gas pretreatment Pure HCl gas (purity ≥ 99.5%) was used as the leaching gas, and no Cl2 gas was added.

[0056] (2) Slurry residue hydrolysis treatment Take 1 kg of organosilicon slurry residue (moisture content of about 30% and copper content of 8.5%), mix it with water at a mass ratio of 1:3, stir and react at 70℃ for 1.5 h, and the reaction pressure is atmospheric pressure. After the reaction is completed, solid-liquid separation is performed to obtain copper-containing silicon slurry (moisture content of about 45%).

[0057] (3) Leaching reaction The copper-containing silicon slag was mixed with water at a solid content of 20% to form a slurry, and pure HCl gas was introduced to carry out the leaching reaction. The reaction temperature was controlled at 70℃, and the gas was continuously introduced while stirring. The redox potential of the reaction system was monitored. After 2.5 h of reaction, the potential stabilized at 450 mV.

[0058] (4) Results Analysis After the reaction was completed, solid-liquid separation was performed, and the copper leaching rate was found to be only 85%. The solid residue still contained a considerable amount of metallic copper and cuprous oxide, indicating that in the absence of a strong oxidant, a purely acidic environment alone cannot achieve complete copper leaching.

[0059] Analysis of Comparative Examples 1-3 shows that when Cl2 gas is used alone, the oxidation reaction rate is slow due to the lack of an acidic environment, and the leaching rate is only 72% after 6 hours. When HCl gas is used alone, although the reaction rate is acceptable, the leaching rate can only reach 85% due to the lack of a strong oxidant. Therefore, Comparative Examples 2 and 3 further verify from the opposite perspective that the mixed gas leaching system used in this invention produces a significant synergistic promoting effect.

[0060] Comparative Example 4 The difference between this comparative example and the embodiment lies in the absence of graded processing – a unified electrodeposition method, including the following distinguishing steps: (4) Electrowinning The leachate was directly electrowinning treated using a stainless steel cathode and a graphite anode, with the current density controlled at 150 A / m. 2Due to the low copper ion concentration, the current efficiency is only 65%, and cathode passivation occurs during the electrodeposition process, resulting in an electrolytic copper product with a purity of 98.2% and high energy consumption.

[0061] (5) Mother liquor treatment The residual liquid after electrowinning is directly discharged as wastewater without being utilized as a resource.

[0062] Comparative Example 5 The difference between this comparative example and the embodiment lies in the absence of gas pretreatment – ​​direct utilization, including the following distinguishing steps: (1) Direct utilization of gas The mixture of hydrogen chloride and chlorine gas (containing approximately 150 mg / m³ of silica dust) generated during the process of preparing silica from methyltrichlorosilane was extracted. 3 It was used directly in the leaching reaction without any pretreatment.

[0063] (3) Leaching reaction Copper-containing silicon slag was mixed with water at a solid content of 20% to form a slurry, which was then leached with untreated mixed gas. Due to the presence of silica dust, the reaction system exhibited severe foaming and agglomeration. After 2.5 hours of reaction, the redox potential remained unstable, and the copper leaching rate was only 68%.

[0064] (4) Graded processing The copper ion concentration in the leachate was only 26 g / L. Selective crystallization was used for treatment, but due to the high impurity content, the purity of the final product was only 97.8%, which did not meet the electronic grade standard.

[0065] (5) Mother liquor treatment Because the mother liquor contains a large amount of precipitated silica dust, it cannot be used to prepare polyaluminum ferric chloride coagulant and is directly disposed of as hazardous waste.

[0066] Analysis of Comparative Examples 1, 4, and 5 reveals that the traditional acid leaching-displacement process (Comparative Example 1) not only has high raw material costs and low product added value, but also generates ferrous sulfate wastewater, causing secondary pollution. The process without graded treatment (Comparative Example 4) directly electrowinning low-concentration copper liquid results in low current efficiency (65%), substandard product quality (purity 98.2%), and high energy consumption. The process without gas pretreatment (Comparative Example 5) suffers from interference from silica dust, leading to a disordered reaction system, a significant decrease in leaching rate (68%), and the inability to recover the mother liquor. This indicates that gas pretreatment, graded treatment, and mother liquor recovery constitute a synergistic treatment process, and the absence of any one of these processes will lead to a significant decline in the overall technical effectiveness.

Claims

1. A process for recycling and treating organosilicon slurry residue, characterized in that, Includes the following steps: S11. Gas pretreatment: The mixed gas of hydrogen chloride and chlorine is pretreated to obtain a pre-mixed gas, wherein the mixed gas of hydrogen chloride and chlorine is collected from the process of preparing silica from methyltrichlorosilane. S21. Leaching reaction: The organosilicon slurry is hydrolyzed to obtain copper-containing silicon slag. The copper-containing silicon slag is then mixed with water to form a slurry. The pre-mixed gas is then introduced into the slurry to carry out a leaching reaction. The temperature of the leaching reaction is controlled at 60-80°C, and the solid content of the slurry is 15-30%. After separation, a copper-containing leachate is obtained. S31. Grading treatment: The copper ion concentration of the copper-containing leachate is detected, and grading treatment is performed simultaneously. When the copper ion concentration of the copper-containing leaching solution is ≥40 g / L, electrolytic copper is prepared by electrowinning. When the copper ion concentration of the copper-containing leaching solution is <40 g / L, selective crystallization is used to prepare electronic-grade cuprous chloride with a purity ≥99.5%. The mother liquor generated during the selective crystallization process is used to prepare polyaluminum ferric chloride coagulant.

2. The organosilicon slurry residue recycling and treatment process according to claim 1, characterized in that, In step S11, the pretreatment includes: contacting the collected mixed gas of hydrogen chloride and chlorine with the washing liquid in a countercurrent manner, washing to remove silica dust, cooling the dust-removed gas to 10-40°C, and then performing gas-liquid separation on the cooled gas to remove entrained droplets to obtain purified mixed gas.

3. The organosilicon slurry residue recycling and treatment process according to claim 1, characterized in that, In step S21, the hydrolysis treatment includes: mixing organosilicon slurry with water in a certain proportion, stirring and reacting, and then performing solid-liquid separation to obtain the copper-containing silicon slag.

4. The organosilicon slurry residue recycling and treatment process according to claim 3, characterized in that, The mass ratio of the organosilicon slurry residue to the water is 1:(2-5); and / or, The conditions for the stirring reaction include: atmospheric pressure, stirring temperature of 50–80°C, and stirring time of 0.5–2 h.

5. The organosilicon slurry residue recycling process according to claim 1, characterized in that, In step S21, the endpoint of the leaching reaction is: the redox potential of the reaction system stabilizes at 400-600 mV and is maintained for more than 5 minutes.

6. The organosilicon slurry residue recycling process according to claim 1, characterized in that, The electrodeposition method employs a stainless steel cathode and a graphite anode, with a current density of 150–250 A / m. 2 During the electrolysis process, the concentration of copper ions in the copper-containing leachate is maintained at 35–45 g / L.

7. The organosilicon slurry residue recycling process according to claim 1, characterized in that, The selective crystallization method includes the following steps: S12. Hot filtration treatment: The copper-containing leaching solution is hot filtered at 60-80℃ to remove solid impurities and obtain filtrate. S22. Crystallization separation treatment: The filtrate is cooled to 10-30°C at a rate of 1-5°C / min, and cuprous chloride seed crystals are added during the cooling process. After centrifugation, electronic-grade cuprous chloride product is obtained.

8. The organosilicon slurry residue recycling process according to claim 7, characterized in that, The amount of cuprous chloride seed crystals added accounts for 0.5% to 2% of the total mass of the filtrate.

9. The organosilicon slurry residue recycling process according to claim 1, characterized in that, The preparation method of the polyaluminum ferric chloride coagulant includes the following steps: S13. Dilute the mother liquor generated during the selective crystallization process until the total iron and aluminum content in the mother liquor is 8-15%, and then adjust the pH to 2.5-3.5 to obtain a prepolymerization solution; S23. The prepolymer solution is stirred at 60-90°C and maintained for 2-4 hours to obtain liquid polyaluminum ferric chloride coagulant through polymerization reaction.

10. A product prepared by any one of the processes described in claims 1 to 9, characterized in that: The products include one or more of the following: electrolytic copper, electronic-grade cuprous chloride with a purity of ≥99.5%, and polyaluminum ferric chloride coagulant with an iron and aluminum content of 8-15%.

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