Environment-friendly silicone waste catalyst and method for resource utilization of slurry and residue

Abstract

The application relates to the field of resource utilization of silicone production hazardous waste. In view of the problems of low resource recovery rate of silicone waste catalyst and slurry residue, secondary pollution and the like in the prior art, the application provides an environmentally-friendly method for resource utilization of silicone waste catalyst and slurry residue. First, the slurry residue is hydrolyzed by concentrated hydrochloric acid to separate filter residue and hydrochloric acid filtrate; the waste catalyst is mixed with the filter residue after slurry inactivation and acid immersion to extract silicon powder; sponge copper is recovered by iron powder replacement, and iron hydroxide is obtained by alkali precipitation, so that efficient recovery of silicon, copper and iron is realized; the silicon powder and the iron hydroxide are used to prepare a magnetic silicon-based catalyst, a Fenton system is constructed by combining the catalyst with hydrogen peroxide to reduce wastewater pollution, zirconium elements are innovatively introduced to enhance the bonding strength of iron and silicon, ZrO2 formed by oxygen-free calcination and ferroferric oxide form a heterojunction, which can accelerate electron transfer, promote hydrogen peroxide decomposition, the catalyst can be recycled multiple times, and the problems of resource waste and secondary pollution are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of resource utilization of organic silicon production hazardous waste, in particular to an environmentally friendly organic silicon waste catalyst and a method for resource utilization of slurry and residue. BACKGROUND

[0002] As a new synthetic material with inorganic (Si-O) and organic (Si-C) hybrid structure, organic silicon material has designable molecular structure and functional groups, and exhibits excellent comprehensive performance. In terms of temperature resistance, weather resistance, electrical performance, radiation resistance, surface performance, repairability, and safety and environmental protection (including low flammability, low toxicity, no odor, physiological inertia, and human-friendly characteristics), it performs well. These properties and effects make it an indispensable high-performance material in many fields and modern technologies. Organic silicon materials have been widely used in aerospace, electronic information, electric power, new energy, modern transportation, consumer electronics, building engineering, textile and clothing, petroleum and chemical industry, medical and health care, agriculture and water conservancy, environmental protection, machinery, food, interior decoration, daily chemical and personal care products, and many other fields and high-tech industries.

[0003] The organic silicon waste catalyst is a mixture of fine dust discharged from a cyclone separator and waste residue discharged from the bottom of a fluidized bed after chloromethane and silicon powder are synthesized into methyl chlorosilane monomers with copper as a catalyst, containing a large amount of silicon powder, copper and a small amount of zinc. After the dust-containing high-boiling substance discharged in the monomer synthesis is recovered by a flash tank, the remaining high-boiling substance, copper catalyst and silicon powder form a slurry residue. The slurry residue contains a large amount of methyl chlorosilane monomer, part of copper and silicon powder, and a small amount of zinc. Due to its flammable and volatile characteristics, it can easily cause strong acid mist and combustion if exposed to air, so it must be harmlessly treated. At present, many organic silicon production enterprises discharge the slurry into a water tank for hydrolysis, and the discharged hydrogen chloride seriously pollutes the environment, and the cuprous ions in the slurry are easily ignited and exploded due to their strong reducing property, causing serious safety hazards.

[0004] For the treatment and resource utilization of organic silicon waste catalyst and slurry residue, domestic and foreign research has been conducted for many years. The existing technology for treating waste catalyst usually only recovers copper to generate ferrous chloride byproduct, which can easily cause resource waste, low economic benefit, and secondary pollution. SUMMARY

[0005] To address the problems of low resource recovery rate and secondary pollution associated with existing organosilicon waste catalysts and slurry residues, this invention proposes an environmentally friendly method for the resource utilization of organosilicon waste catalysts and slurry residues. First, the slurry residue is hydrolyzed with concentrated hydrochloric acid to separate filter residue and hydrochloric acid filtrate. The waste catalyst is then deactivated through pulping and mixed with the filter residue for acid leaching to extract silicon powder. Sponge copper is recovered by iron powder replacement, and ferric hydroxide is obtained through alkaline precipitation, achieving efficient recovery of silicon, copper, and iron. A magnetic silicon-based catalyst is prepared using silicon powder and ferric hydroxide, and a Fenton system is constructed using hydrogen peroxide to reduce wastewater pollution. The innovative introduction of zirconium enhances the bonding strength between iron and silicon, while the heterojunction formed by ZrO2 (iron tetroxide) after calcination accelerates electron transfer and promotes hydrogen peroxide decomposition. The catalyst can be recovered multiple times, solving the problems of resource waste and secondary pollution, and demonstrating significant economic and environmental benefits.

[0006] To achieve the above objectives, this application adopts the following technical solution:

[0007] This application provides an environmentally friendly method for the resource utilization of waste organosilicon catalysts and slurry residue, including the following steps:

[0008] S1. Mix the slurry residue to be used with concentrated hydrochloric acid to form hydrolysate. After the hydrolysis reaction, filter residue, hydrochloric acid filtrate and gaseous HCl are obtained.

[0009] S2. The organosilicon waste catalyst to be utilized is pulped and deactivated to obtain deactivated waste catalyst. The filter residue is added to the deactivated waste catalyst to obtain a mixture. Hydrochloric acid and sodium chlorate are added to obtain silicon powder and copper-containing solution.

[0010] S4. Add iron powder to the copper-containing solution to carry out a displacement reaction, and obtain sponge copper and iron-containing solution;

[0011] S5. Add sodium hydroxide to the iron-containing solution to obtain ferric hydroxide and salt solution;

[0012] S6. A magnetic silicon-based catalyst is prepared using the silicon powder, hydrochloric acid, ferric compound, ferrous salt and zirconium oxychloride.

[0013] S7. Add the magnetic silicon-based catalyst and hydrogen peroxide to the salt solution. After the catalytic oxidation reaction, recover the magnetic silicon-based catalyst and discharge the wastewater.

[0014] Beneficial technical effects:

[0015] This invention utilizes concentrated hydrochloric acid to hydrolyze slurry residue, deactivating organosilicon waste catalysts through pulping. The deactivated waste catalysts and hydrolyzed slurry residue are treated under acidic conditions to obtain silicon powder and a copper-containing solution. Iron powder is then used to replace the copper powder to obtain sponge copper, followed by iron removal through sodium hydroxide precipitation, achieving resource utilization. Simultaneously, using the produced ferric hydroxide, finished hydrochloric acid, and silicon powder, a magnetic silicon-based catalyst containing iron oxides is prepared. This catalyst forms a Fenton system with hydrogen peroxide, degrading organic pollutants in wastewater and adsorbing zinc ions, reducing secondary pollution from wastewater discharge. By introducing ferrous salts to retain the magnetic magnetite (Fe3O4) in the iron oxide, and innovatively adding zirconium oxychloride as a bridging element between silicon and iron, the bonding strength between iron and silicon is enhanced, forming a stable bonding network. Furthermore, the ZrO2 formed after calcination, while protecting the Fe-O bonds from breakage, forms a heterojunction with the magnetite, accelerating electron transfer and the efficiency of hydrogen peroxide decomposition to release active groups, thus speeding up wastewater treatment. The silicon powder, ferric hydroxide, and sponge copper produced by the method of this invention can all be sold as commodities, which have excellent economic value. While realizing the efficient resource utilization of organosilicon slurry residue and waste catalyst, no secondary pollutants are generated. Attached Figure Description

[0016] Figure 1 This is a schematic flowchart of the method for resource utilization of organosilicon waste catalysts and slurry residue according to the present invention. Detailed Implementation

[0017] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the application will be further described in detail below with reference to embodiments. However, this should not be construed as limiting the scope of this application to the following examples. All other embodiments obtained by those skilled in the art without creative effort without departing from the above-described methodological spirit of this application are within the scope of protection of this application.

[0018] In this application, the terminology used is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.

[0019] The singular forms “for,” “or,” “a,” “any,” and “” used in this application are intended to include the plural forms unless the context clearly indicates otherwise.

[0020] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0021] This invention provides an environmentally friendly method for the resource utilization of waste organosilicon catalysts and slurry residue, comprising the following steps:

[0022] S1. Mix the slurry residue to be used with concentrated hydrochloric acid to form hydrolysate. After the hydrolysis reaction, filter residue, hydrochloric acid filtrate and gaseous HCl are obtained.

[0023] S2. The organosilicon waste catalyst to be utilized is pulped and deactivated to obtain deactivated waste catalyst. The filter residue is added to the deactivated waste catalyst to obtain a mixture. Hydrochloric acid and sodium chlorate are added to obtain silicon powder and copper-containing solution.

[0024] S4. Add iron powder to the copper-containing solution to carry out a displacement reaction, and obtain sponge copper and iron-containing solution;

[0025] S5. Add sodium hydroxide to the iron-containing solution to obtain ferric hydroxide and salt solution;

[0026] S6. A magnetic silicon-based catalyst is prepared using the silicon powder, hydrochloric acid, ferric compound, ferrous salt and zirconium oxychloride.

[0027] S7. Add the magnetic silicon-based catalyst and hydrogen peroxide to the salt solution. After the catalytic oxidation reaction, recover the magnetic silicon-based catalyst and discharge the wastewater.

[0028] In one feasible implementation scenario, the concentration of concentrated hydrochloric acid is 20% to 25%, and the dosage is as follows: add until the pH of the mixture of slurry and concentrated hydrochloric acid is less than 2, then stop adding. The hydrolysis reaction time is 1-2 hours, and the temperature of the mixture is kept below 50°C.

[0029] The slurry residue to be utilized is pressurized with nitrogen and fed into a slurry residue buffer tank, and then pressurized with nitrogen or fed by gravity into a slurry residue hydrolysis tank. Due to its flammable and volatile properties, the entire process is kept sealed and free from contact with air. Simultaneously with the slurry residue entering the hydrolysis tank, stirring is started and maintained, and 20%–25% concentrated hydrochloric acid is added. Addition is stopped when the pH is less than 2. During the reaction, the reaction temperature is controlled below 50°C. The heat generated during hydrolysis is carried away by circulating cooling water, which can be used for the pulping deactivation of the organosilicon waste catalyst. After the reaction, the material is pumped to the first filter press. The hydrochloric acid filtrate is returned to the hydrolysis tank, and concentrated hydrochloric acid is added for the next batch of hydrolysis. The filter residue is fed into a secondary acid leaching copper extraction unit. The HCl gas volatilized during hydrolysis enters the HCl absorption tower. The main reaction equations are as follows:

[0030] 2(CH3)3SiCl+H2O=(CH3)3SiOSi(CH3)3+2HCl;

[0031] (CH3)3SiCl+C6H5(CH3)2SiCl+H2O=(CH3)3SiOSi(CH3)2C6H5+2HCl;

[0032] 2(CH3)3SiCl+nCH2=CHEtSiCl2+(n+1)H2O=(CH3)3SiO(SiCH=CH2EtO) n Si(CH3)3+(2n+2)HCl.

[0033] In one feasible implementation scenario, pulping deactivation includes: mixing the waste organosilicon catalyst to be utilized with water at a solid-liquid ratio of 1:(2.7-3.2), keeping it sealed and not in contact with air; the pulping deactivation time is 1-2 hours.

[0034] The solid-liquid ratio for the deactivation of the waste organosilicon catalyst is controlled at 1:(2.7-3.2). First, circulating cooling water is added to the deactivation device of the waste organosilicon catalyst according to the ratio, and stirring is started. Then, the waste organosilicon catalyst is transported to the deactivation device through a negative pressure pipeline, keeping the entire process sealed and preventing contact with air. Stirring is maintained and the internal circulation device is turned on for 1-2 hours. After the deactivation is completed, it is pumped to the secondary acid leaching copper extraction device.

[0035] In one feasible implementation scenario, the hydrochloric acid filtrate is returned to the unused slurry residue; the gaseous HCl is absorbed to obtain the finished hydrochloric acid; the hydrochloric acid dosage is: the addition is stopped when the pH of the mixture is less than 2; the hydrochloric acid is a mixture of finished hydrochloric acid and hydrochloric acid filtrate; the acid leaching time is 2-4 hours.

[0036] The recycling of materials generated during resource utilization not only saves resources but also creates economic benefits. HCl gas is absorbed by an HCl absorption tower to obtain hydrochloric acid. Incompletely absorbed gas is discharged into the atmosphere after passing through an alkaline scrubbing tower and a liquid seal tank. The finished hydrochloric acid can be sold commercially and can also be desorbed to produce HCl gas for use in chloromethane production, thus possessing high economic value.

[0037] In one feasible implementation, the amount of sodium chlorate added is 5% to 8% of the mass of the mixture.

[0038] The deactivated organosilicon waste catalyst and the filter residue from the hydrolysis of the pulp residue are fed into a secondary acid leaching copper extraction unit. Stirring is started, and finished hydrochloric acid is added simultaneously. The process is stopped when the pH is less than 2. Sodium chlorate (5%–8% by weight of the mixture) is added to improve acid leaching efficiency. Utilizing the property that metals and metal oxides can react with acids, copper oxide reacts with hydrochloric acid to produce copper chloride, and cuprous oxide reacts with hydrochloric acid to produce copper chloride and elemental copper. Elemental copper is then soaked and stirred in a hydrochloric acid solution with the strong oxidant sodium chlorate, reacting to produce copper chloride and sodium chloride, ultimately yielding a CuCl2 solution. The reaction time is 2–4 hours. After the reaction, the solution is pumped to a second filter press. After solid-liquid separation, the copper-containing solution enters a reduction unit, and the filtrate is silicon powder. Silicon powder can be used in the smelting of stainless steel and aluminum alloys, as well as as silicon concentrate for industrial silicon smelting, and as a raw material for the production of methylchlorosilane. The main reaction equations are as follows:

[0039] CuO + 2HCl = CuCl2 + H2O (Main reaction in primary acid leaching);

[0040] Cu₂O + 2HCl = Cu + CuCl₂ + H₂O (Main reaction in the first acid leaching);

[0041] NaClO3 + 6HCl + 3Cu = 3CuCl2 + NaCl + 3H2O (Main reaction of secondary acid leaching).

[0042] In one feasible implementation scenario, the particle size of the iron powder is 150nm-200nm, the molar concentration ratio of the iron powder to the copper content of the copper-containing solution is (1.4-1.6):1, and the displacement reaction time is 2-3h.

[0043] The copper-containing solution is pumped to the reduction device, and the molar concentration of copper ions in each batch of copper-containing solution is measured. Stirring is started, and iron powder with a particle size of 150nm-200nm is added. The molar concentration ratio of iron powder to copper in the copper-containing solution is (1.4-1.6):1. Utilizing the higher reducing power of iron than copper, the reduced iron powder is added to the copper-containing solution under aeration to undergo a displacement reaction with copper ions, producing ferrous chloride and elemental copper. The reaction time is 2-3 hours. After the reaction, the solution is pumped to a third filter press. After solid-liquid separation, the filtrate is an iron-containing solution, which enters a precipitation device. The filtrate is sponge copper, meeting the product standard of YS / T1366-2020, "Nonferrous Metals Industry Standard for Sponge Copper". The main reaction equations are as follows:

[0044] Fe + CuCl2 = FeCl2 + Cu.

[0045] In one feasible implementation scenario, the treatment of the iron-containing solution also includes: adding sodium hydroxide at a rate that stops when the pH of the iron-containing solution reaches 7-8, with a precipitation time of 1.5-2 hours.

[0046] The iron-containing solution enters a precipitation device, where sodium hydroxide is added. The amount added is determined based on the reaction pH, and addition is stopped when the pH reaches 7-8. Utilizing the thermodynamic instability of ferrous ions, ferrous chloride is oxidized to produce ferric chloride and ferric hydroxide precipitates. Taking advantage of the alkali insolubility of ferric hydroxide, sodium hydroxide reacts chemically with ferric chloride to produce ferric hydroxide precipitate and sodium chloride. Solid-liquid separation is performed using a fourth filter press to obtain ferric hydroxide and a salt solution. The salt solution enters a catalytic oxidation unit. The ferric hydroxide can be sold as a raw material for iron smelting; the salt solution enters the catalytic oxidation unit. The main reaction equations are as follows:

[0047] 12FeCl2+3O2+6H2O=8FeCl3+4Fe(OH)3↓

[0048] FeCl3 + 3NaOH = Fe(OH)3↓ + 3NaCl

[0049] In one feasible implementation, the preparation of the acid-etched silicon powder specifically involves: the trivalent iron compound including ferric hydroxide precipitated in S5; and the ferrous salt being one of ferrous sulfate heptahydrate and ferrous chloride.

[0050] In one feasible implementation scenario, the preparation method of the magnetic silicon-based catalyst is as follows: Silicon powder is mixed with 10%–12% sodium hydroxide at a mass ratio of 1:(4.8–5.3) and dissolved to obtain activated silica gel; a ferric compound is mixed with a ferrous salt, hydrochloric acid is added to pH=2–3, and zirconium oxychloride is added to obtain a mixed solution; the molar ratio of the ferric compound, ferrous salt, and zirconium oxychloride is 2:(1.0–1.2):(0.7–0.9); the activated silica gel is mixed with the mixed solution at a mass ratio of 1:(8–10), ammonia is added dropwise to pH=9–10, and the mixture is aged for 10–12 h to obtain a catalyst precursor; the catalyst precursor is calcined at 700–800 °C for 2–3 h under a nitrogen atmosphere to obtain the magnetic silicon-based catalyst.

[0051] A catalyst was prepared by adding ferrous salt and zirconium oxychloride to silicon powder obtained from waste silicone catalysts and slurries, finished hydrochloric acid, and ferric hydroxide. Silicon powder hydrolyzes to sodium silicate under alkaline conditions, and sodium silicate hydrolyzes to silicic acid under acidic conditions, forming an activated gel rich in silanol groups, providing active sites for iron and zirconium; ammonia water... 3+ Fe 2+ and Zr 4+ It co-precipitates with silicate to form Fe-Zr-Si gel, Fe 3+ Fe 2+ Under alkaline conditions provided by ammonia, hydroxides are formed, and upon calcination, magnetic iron(III) oxide (Zr) is produced. 4+ As a "crosslinking agent," it simultaneously connects Fe and Si through oxygen bridges (-O-) at high temperatures, forming Si-O-Zr-O-Fe bonds, which enhances the bonding strength and ensures that iron is firmly bonded to the silicon surface, making it difficult for it to fall off. Simultaneously, the ZrO2 generated after high-temperature treatment exhibits high chemical inertness and strong acid resistance, effectively reducing H₂O content. +The introduction of ZrO2 inhibits the erosion of Fe-O bonds; it also suppresses the sintering of the silicon matrix at high temperatures, forming a porous structure, increasing the specific surface area, and enhancing the adsorption capacity for zinc ions. Furthermore, the heterojunction formed by ZrO2 and iron(III) oxide accelerates electron transfer and improves the efficiency of hydrogen peroxide decomposition into active groups. In this application, zirconium oxychloride is first mixed with an iron solution to form a stable iron-zirconium bond. Then, activated silica gel is added to connect silicon to the iron-zirconium bond structure, forming an iron-zirconium-silicon structure. Compared to directly mixing the iron, silicon, and zirconium sources simultaneously, this method avoids the direct formation of unstable bonds between iron and silicon, thereby improving catalyst stability and solving the problems of catalyst instability and poor recyclability.

[0052] In one feasible implementation scenario, the dosage of the magnetic silicon-based catalyst is 0.5-1.0 g / L; the dosage of hydrogen peroxide is 50-100 mg / L; and the reaction time for catalytic oxidation is 0.5-1.5 h.

[0053] A magnetic silicon-based catalyst, when combined with hydrogen peroxide (H2O2), forms an advanced oxidation technology—Fenton oxidation. The catalyst activates the hydrogen peroxide to decompose and generate active groups. These active groups can gradually break down organic pollutants in the solution from large molecules into smaller molecules, until they are degraded into carbon dioxide and water. Simultaneously, the catalyst has adsorption properties, which can adsorb and fix residual zinc ions in the system, achieving a removal effect. Then, the magnetic silicon-based catalyst is recycled and reused through magnetic separation. Without causing secondary pollution, the COD value of the discharged wastewater is reduced to meet the discharge standards, eliminating the need for further wastewater treatment.

[0054] The following will describe in detail, with reference to different embodiments, a method for the resource utilization of waste organosilicon catalysts and slurry provided in this application.

[0055] Example 1

[0056] like Figure 1 As shown, an environmentally friendly method for the resource utilization of waste organosilicon catalysts and slurry residue includes the following steps:

[0057] 1. Pressurize the slurry residue with nitrogen and introduce it into the slurry residue buffer tank. Then, pressurize it with nitrogen or allow it to flow by gravity into the slurry residue hydrolysis tank. Start stirring and add 20% concentrated hydrochloric acid until the pH of the system in the slurry residue hydrolysis tank is less than 2. Stop adding the hydrochloric acid and stir for 2 hours. Use circulating cooling water to control the system temperature below 50°C. Pump the material from the slurry residue hydrolysis tank into the first filter press. The filter residue enters the secondary acid leaching copper extraction unit. The hydrochloric acid filtrate is returned to the slurry residue hydrolysis tank, and the gaseous HCl enters the HCl absorption tower.

[0058] 2. Gaseous HCl is passed through the HCl absorption tower to obtain the finished hydrochloric acid; unabsorbed gas enters the alkaline washing tower and liquid seal tank, and is discharged into the atmosphere after neutralization;

[0059] 3. Control the solid-liquid ratio of the organosilicon waste catalyst during pulping and deactivation to 1:2.7. First, add circulating cooling water to the organosilicon waste catalyst deactivation device according to the ratio, start stirring, and then transport the waste catalyst to the deactivation device through a negative pressure pipeline, keeping it sealed and preventing contact with air throughout the process. Keep stirring and start the internal circulation device. After 1 hour, pump it to the secondary acid leaching copper extraction device, start stirring, and add finished hydrochloric acid at the same time. Stop when the pH is less than 2. Add 5% sodium chlorate of the total mass of the deactivated organosilicon waste catalyst and the filter residue from the first filter press after hydrolysis of the pulp residue, react for 4 hours, and pass through the second filter press to obtain silicon powder and copper-containing solution. The copper-containing solution is sent to the reduction device.

[0060] 4. The copper-containing solution is pumped to the reduction device, and the molar concentration of copper ions in each batch of copper-containing solution is measured. Stirring is started, and iron powder with a particle size of 150 nm is added. The molar concentration ratio of iron powder to copper in the copper-containing solution is 1.4:1. The reaction is stirred for 3 hours. After the reaction is completed, the solution is fed into the third filter press to obtain sponge copper and iron-containing solution. The iron-containing solution is then fed into the precipitation device.

[0061] 5. Add sodium hydroxide to the precipitation device. Stop adding sodium hydroxide when the pH reaches 7. Stir the reaction for 2 hours. Then, transfer the solution to the fourth filter press to obtain ferric hydroxide and a salt solution. The salt solution is then transferred to the catalytic oxidation device.

[0062] 6. Silica powder and 10% sodium hydroxide were mixed at a mass ratio of 1:4.8 and dissolved to obtain activated silica gel; ferric hydroxide and ferrous chloride were mixed, and hydrochloric acid was added to pH=2, followed by the addition of zirconium oxychloride to obtain a mixed solution, which was then allowed to stand for 1 hour; the molar ratio of ferric hydroxide, ferrous chloride, and zirconium oxychloride was 2:1.0:0.9; the activated silica gel was mixed with the mixed solution at a mass ratio of 1:8, and ammonia was added dropwise to pH=9, followed by aging for 10 hours to obtain a catalyst precursor; the catalyst precursor was calcined at 700℃ for 3 hours under a nitrogen atmosphere to obtain the magnetic silicon-based catalyst.

[0063] 7. Add the magnetic silicon-based catalyst and hydrogen peroxide to the catalytic oxidation device. The dosage of the magnetic silicon-based catalyst is 0.5 g / L and the dosage of hydrogen peroxide is 50 mg / L. After reacting for 1.5 h, the mixture enters the magnetic separation device. The magnetic silicon-based catalyst is recovered by the magnetic field and returned to the catalytic oxidation device. The aqueous phase is discharged to the outside as wastewater.

[0064] Example 2

[0065] like Figure 1 As shown, an environmentally friendly method for the resource utilization of waste organosilicon catalysts and slurry residue includes the following steps:

[0066] 1. The slurry residue is pressurized with nitrogen and fed into the slurry residue buffer tank. Then, it is pressurized with nitrogen or fed into the slurry residue hydrolysis tank by gravity. Stirring is started, and 25% concentrated hydrochloric acid is added until the pH of the system in the slurry residue hydrolysis tank is less than 2. The addition is stopped, and the mixture is stirred for 1.5 hours. The system temperature is controlled to be below 50°C using circulating cooling water. The material in the slurry residue hydrolysis tank is pumped into the first filter press. The filter residue is fed into the secondary acid leaching copper extraction unit. The hydrochloric acid filtrate is returned to the slurry residue hydrolysis tank, and the gaseous HCl is fed into the HCl absorption tower.

[0067] 2. Gaseous HCl is passed through the HCl absorption tower to obtain the finished hydrochloric acid; unabsorbed gas enters the alkaline washing tower and liquid seal tank, and is discharged into the atmosphere after neutralization;

[0068] 3. Control the solid-liquid ratio of the organosilicon waste catalyst during pulping and deactivation to 1:3. First, add circulating cooling water to the organosilicon waste catalyst deactivation device according to the ratio, start stirring, and then transport the waste catalyst to the deactivation device through a negative pressure pipeline, keeping it sealed and preventing contact with air throughout the process. Keep stirring and start the internal circulation device. After 1.5 hours, pump it to the secondary acid leaching copper extraction device, start stirring, and add finished hydrochloric acid at the same time. Stop when the pH is less than 2. Add 6% sodium chlorate of the total mass of the deactivated organosilicon waste catalyst and the filter residue from the first filter press after hydrolysis of the pulp residue, react for 3 hours, and pass through the second filter press to obtain silicon powder and copper-containing solution. The copper-containing solution is then fed into the reduction device.

[0069] 4. The copper-containing solution is pumped to the reduction device, and the molar concentration of copper ions in each batch of copper-containing solution is measured. Stirring is started, and iron powder with a particle size of 200 nm is added. The molar concentration ratio of iron powder to copper in the copper-containing solution is 1.5:1. The reaction is stirred for 2.5 hours. After the reaction is completed, the solution is fed into the third filter press to obtain sponge copper and iron-containing solution. The iron-containing solution is then fed into the precipitation device.

[0070] 5. Add sodium hydroxide to the precipitation device. Stop adding sodium hydroxide when the pH reaches 8. Stir the reaction for 1.5 hours. Then, transfer the solution to the fourth filter press to obtain ferric hydroxide and a salt solution. The salt solution is then transferred to the catalytic oxidation device.

[0071] 6. Silica powder and 11% sodium hydroxide were mixed at a mass ratio of 1:5 and dissolved to obtain activated silica gel; ferric hydroxide and ferrous sulfate heptahydrate were mixed, and finished hydrochloric acid was added to pH=3, followed by the addition of zirconium oxychloride to obtain a mixed solution, which was allowed to stand for 1 hour; the molar ratio of ferric hydroxide, ferrous sulfate heptahydrate, and zirconium oxychloride was 2:1.1:0.8; the activated silica gel was mixed with the mixed solution at a mass ratio of 1:9, and ammonia was added dropwise to pH=9, and the mixture was aged for 11 hours to obtain a catalyst precursor; the catalyst precursor was calcined at 800℃ for 2.5 hours under a nitrogen atmosphere to obtain the magnetic silicon-based catalyst.

[0072] 7. Add the magnetic silicon-based catalyst and hydrogen peroxide to the catalytic oxidation device. The dosage of the magnetic silicon-based catalyst is 0.8 g / L and the dosage of hydrogen peroxide is 80 mg / L. After reacting for 1 hour, the mixture enters the magnetic separation device. The magnetic silicon-based catalyst is recovered by the magnetic field and returned to the catalytic oxidation device. The aqueous phase is discharged to the outside as wastewater.

[0073] Example 3

[0074] like Figure 1 As shown, an environmentally friendly method for the resource utilization of waste organosilicon catalysts and slurry residue includes the following steps:

[0075] 1. Pressurize the slurry residue with nitrogen and introduce it into the slurry residue buffer tank. Then, pressurize it with nitrogen or allow it to flow by gravity into the slurry residue hydrolysis tank. Start stirring and add 25% concentrated hydrochloric acid until the pH of the system in the slurry residue hydrolysis tank is less than 2. Stop adding the hydrochloric acid and stir for 1 hour. Use circulating cooling water to control the system temperature below 50°C. Pump the material from the slurry residue hydrolysis tank into the first filter press. The filter residue enters the secondary acid leaching copper extraction unit. The hydrochloric acid filtrate is returned to the slurry residue hydrolysis tank, and the gaseous HCl enters the HCl absorption tower.

[0076] 2. Gaseous HCl is passed through the HCl absorption tower to obtain the finished hydrochloric acid; unabsorbed gas enters the alkaline washing tower and liquid seal tank, and is discharged into the atmosphere after neutralization;

[0077] 3. Control the solid-liquid ratio of the organosilicon waste catalyst during pulping and deactivation to 1:3.2. First, add circulating cooling water to the organosilicon waste catalyst deactivation device according to the ratio, start stirring, and then transport the waste catalyst to the deactivation device through a negative pressure pipeline, keeping it sealed and preventing contact with air throughout the process. Keep stirring and start the internal circulation device. After 2 hours, pump it to the secondary acid leaching copper extraction device, start stirring, and add finished hydrochloric acid at the same time. Stop when the pH is less than 2. Add 8% sodium chlorate of the total mass of the deactivated organosilicon waste catalyst and the filter residue from the first filter press after hydrolysis of the pulp residue. React for 2 hours, and pass through the second filter press to obtain silicon powder and copper-containing solution. The copper-containing solution is sent to the reduction device.

[0078] 4. The copper-containing solution is pumped to the reduction device, and the molar concentration of copper ions in each batch of copper-containing solution is measured. Stirring is started, and iron powder with a particle size of 2000 nm is added. The molar concentration ratio of iron powder to copper in the copper-containing solution is 1.6:1. The reaction is stirred for 2 hours. After the reaction is completed, the solution is fed into the third filter press to obtain sponge copper and iron-containing solution. The iron-containing solution is then fed into the precipitation device.

[0079] 5. Add sodium hydroxide to the precipitation device. Stop adding sodium hydroxide when the pH reaches 8. Stir the reaction for 1.5 hours. Then, transfer the solution to the fourth filter press to obtain ferric hydroxide and a salt solution. The salt solution is then transferred to the catalytic oxidation device.

[0080] 6. Silica powder and 12% sodium hydroxide were mixed at a mass ratio of 1:5.3 and dissolved to obtain activated silica gel; ferric hydroxide and ferrous chloride were mixed, and hydrochloric acid was added to pH=3, followed by the addition of zirconium oxychloride to obtain a mixed solution, which was then allowed to stand for 1 hour; the molar ratio of ferric hydroxide, ferrous chloride, and zirconium oxychloride was 2:1.2:0.7; the activated silica gel was mixed with the mixed solution at a mass ratio of 1:10, and ammonia was added dropwise to pH=10, followed by aging for 12 hours to obtain a catalyst precursor; the catalyst precursor was calcined at 800℃ for 3 hours under a nitrogen atmosphere to obtain the magnetic silicon-based catalyst.

[0081] 7. Add the magnetic silicon-based catalyst and hydrogen peroxide to the catalytic oxidation device. The dosage of the magnetic silicon-based catalyst is 1.0 g / L and the dosage of hydrogen peroxide is 100 mg / L. After reacting for 0.5 h, the mixture enters the magnetic separation device. The magnetic silicon-based catalyst is recovered by the magnetic field and returned to the catalytic oxidation device. The aqueous phase is discharged to the outside as wastewater.

[0082] Comparative Example 1

[0083] An environmentally friendly method for the resource utilization of organosilicon waste catalyst and slurry residue is provided. The steps and parameters are the same as in Example 2, except that no magnetic silicon-based catalyst is added and the salt solution does not enter the catalytic oxidation device but is directly discharged as wastewater.

[0084] Comparative Example 2

[0085] An environmentally friendly method for the resource utilization of waste organosilicon catalysts and slurry residues is provided. The steps and parameters are the same as in Example 2, except that zirconium oxychloride is not added during the preparation of the magnetic silicon-based catalyst.

[0086] Comparative Example 3

[0087] An environmentally friendly method for the resource utilization of waste organosilicon catalysts and slurry residues is provided. The steps and parameters are the same as in Example 2. The difference is that when preparing the magnetic silicon-based catalyst, ferric hydroxide, ferrous sulfate heptahydrate, zirconium oxychloride, and activated silica gel are directly mixed together.

[0088] Resource utilization effect test:

[0089] The silicon, copper, and iron contents in the organosilicon waste catalyst and slurry in Examples 1-3 and Comparative Examples 1-3 were tested. The masses of the obtained silicon powder, sponge copper, and iron hydroxide were recorded, and the recovery rates of silicon, copper, and iron were calculated. The COD content and zinc ion concentration of the wastewater in Examples 1-3 and Comparative Examples 1-3 were measured. The test results are shown in Table 1.

[0090] Table 1. Test results of resource utilization effectiveness of Examples 1-3 and Comparative Examples 1-3

[0091]

[0092] As shown in Table 1, the silicon recovery rates obtained in Examples 1-3 were 94.64%–95.72%; the copper recovery rates were 96.38%–94.27%; the iron recovery rates were 94.27%–96.38%; and the COD content of the wastewater was 7.3–11.6 mg / m³. 3 The zinc ion concentration was 0.5-0.8 mg / L, and the COD content of Comparative Example 1 was 138.9 mg / m³. 3 The zinc ion concentration was 15.6 mg / L, which is much higher than that in the example, indicating that the method provided by the present invention can achieve efficient resource recycling of organosilicon waste catalysts and slurry residues without secondary pollution.

[0093] In Comparative Example 1, no magnetic silicon-based catalyst was added to the salt solution, and the salt solution was used as wastewater. The COD content was 138.9 mg / m³. 3 The zinc ion concentration was 15.6 mg / L, far exceeding that of the previous example. The magnetic silicon-based catalyst contains iron oxide, which forms a Fenton system with hydrogen peroxide to degrade organic pollutants while simultaneously adsorbing zinc ions. Without the catalyst, residual organic pollutants in the wastewater cannot be effectively degraded, and zinc ions will also enter the environment with the wastewater, causing secondary pollution.

[0094] Cyclic testing:

[0095] The magnetic silicon-based catalysts recovered from the magnetic separation devices in Examples 1-3 and Comparative Examples 2-3 were returned to the catalytic oxidation device and circulated 5 times. The COD content and zinc ion concentration of the salt solution and wastewater in the 5th cycle were measured, and the COD removal rate and zinc removal rate were calculated. The results are shown in Table 2.

[0096] Table 2. Results of cyclic testing for Examples 1-3 and Comparative Examples 2-3

[0097]

[0098] Table 2 shows that the COD removal rate of the first wastewater cycle was 90.9%–95.5%, and the zinc removal rate was 95.4%–97.7%; the COD removal rate of the fifth wastewater cycle was 88.7%–92.6%, and the zinc removal rate was 93.7%–94.8%, showing no significant decrease. In Comparative Examples 2 and 3, the COD and zinc removal rates in the fifth cycle were much lower than those in the first cycle. This indicates that the magnetic silicon-based catalyst prepared in the embodiments of this invention has excellent performance, stable structure, can be reused multiple times, has a long service life, does not require frequent preparation, and is low in cost.

[0099] In Comparative Example 2, without the addition of zirconium oxychloride, the COD removal rate in the fifth cycle was only 20.8%. Zirconium oxychloride acts as a bridging element in the catalyst, enhancing the bonding strength between iron and silicon by forming Si-O-Zr-O-Fe bonds. Without zirconium, the bond between iron and silicon is loose, leading to an unstable catalyst structure, a continuous reduction in active sites, and weakened magnetism, making it prone to loss during magnetic separation and recovery. The absence of zirconium also prevents the formation of heterojunctions between ZrO2 and Fe3O4 after calcination, reducing electron transfer rates, weakening the promoting effect on hydrogen peroxide decomposition, decreasing free radical generation efficiency, and significantly reducing the degradation and adsorption capacity of organic pollutants (COD) and zinc ions in wastewater. Simultaneously, the active component iron is more easily corroded in an acidic environment, resulting in a sharp decline in catalytic performance after multiple cycles.

[0100] In Comparative Example 3, a mixed solution of ferric compound and ferrous salt was first mixed with activated silica gel, and then zirconium oxychloride was added. In the fifth cycle, the COD removal rate decreased to 40.7%, and the zinc removal rate was only 61.3%. In the Example, zirconium oxychloride was first mixed with an iron solution to ensure Zr... 4+ Preferred to Fe 3+ / Fe 2+ Combined with silica gel, iron salts and zirconium salts are mixed simultaneously with silica gel, and iron and silicon will directly form Fe-O-Si bonds. 4+ The inability to effectively insert ZrO2 results in the absence of the Si-O-Zr-O-Fe network. After calcination, ZrO2 mainly exists as isolated particles rather than forming a tight heterostructure with Fe3O4, leading to discontinuous electron transfer pathways and reduced catalytic activity. Furthermore, the absence of ZrO2 reduces the catalyst's specific surface area, decreasing the number of adsorption sites for zinc ions and deteriorating wastewater treatment efficiency. Simultaneously, the loose structure exacerbates mechanical wear on the catalyst, resulting in faster performance degradation during recycling.

[0101] The above results demonstrate and describe the basic principles and main features of this application, as well as its advantages.

[0102] Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this application. Various changes and modifications can be made to this application without departing from the spirit and scope thereof, and all such changes and modifications fall within the scope of this application as claimed. The scope of protection of this application is defined by the equivalents of the appended claims.

Claims

1. A method for the resource utilization of environmentally friendly organosilicon waste catalysts and slurry residue, characterized in that, Includes the following steps: S1. Mix the slurry residue to be used with concentrated hydrochloric acid to form a mixture. After hydrolysis, filter residue, hydrochloric acid filtrate and gaseous HCl are obtained. S2. The waste organosilicon catalyst to be utilized is pulped and deactivated to obtain deactivated waste catalyst. The filter residue is added to the deactivated waste catalyst to obtain a mixture. Hydrochloric acid and sodium chlorate are added, and after acid leaching, silicon powder and copper-containing solution are obtained. S4. Add iron powder to the copper-containing solution to carry out a displacement reaction, and obtain sponge copper and iron-containing solution; S5. Add sodium hydroxide to the iron-containing solution to precipitate iron hydroxide and a salt solution; S6. A magnetic silicon-based catalyst is prepared using the silicon powder, hydrochloric acid, ferric compound, ferrous salt and zirconium oxychloride. S7. Add the magnetic silicon-based catalyst and hydrogen peroxide to the salt solution. After the catalytic oxidation reaction, recover the magnetic silicon-based catalyst and discharge the wastewater.

2. The method for the resource utilization of environmentally friendly organosilicon waste catalyst and slurry as described in claim 1, characterized in that, The concentration of the concentrated hydrochloric acid is 20% to 25%, and the dosage is as follows: when the pH of the mixture of the slurry to be used and the concentrated hydrochloric acid is less than 2, the addition is stopped. The hydrolysis reaction time is 1-2 hours, and the temperature of the mixture is kept below 50°C.

3. The method for the resource utilization of environmentally friendly organosilicon waste catalyst and slurry residue as described in claim 1, characterized in that, The pulping deactivation includes: mixing the waste organosilicon catalyst to be utilized with water at a solid-liquid ratio of 1:(2.7-3.2), keeping it sealed and not in contact with air; the pulping deactivation time is 1-2 hours.

4. The method for the resource utilization of environmentally friendly organosilicon waste catalyst and slurry as described in claim 1, characterized in that, The hydrochloric acid filtrate is returned to the unused slurry residue; the gaseous HCl is absorbed to obtain the finished hydrochloric acid; The amount of hydrochloric acid added is: added until the pH of the mixture is less than 2, then the addition is stopped; the hydrochloric acid is a mixture of the finished hydrochloric acid and the hydrochloric acid filtrate; the acid leaching time is 2-4 hours.

5. The method for the resource utilization of environmentally friendly organosilicon waste catalyst and slurry residue as described in claim 1, characterized in that, The amount of sodium chlorate added is 5% to 8% of the mass of the mixture.

6. The method for the resource utilization of environmentally friendly organosilicon waste catalyst and slurry as described in claim 1, characterized in that, The iron powder has a particle size of 150nm-200nm, and the molar concentration ratio of the iron powder to the copper content in the copper-containing solution is (1.4-1.6):1; the displacement reaction time is 2-3h.

7. The method for the resource utilization of environmentally friendly organosilicon waste catalyst and slurry as described in claim 1, characterized in that, The amount of sodium hydroxide added is such that the addition is stopped when the pH of the iron-containing solution reaches 7-8, and the precipitation time is 1.5-2 hours.

8. The method for the resource utilization of environmentally friendly organosilicon waste catalyst and slurry residue as described in claim 1, characterized in that, The ferric compound includes the ferric hydroxide precipitated in S5; the ferrous salt is one of ferrous sulfate heptahydrate and ferrous chloride.

9. The method for the resource utilization of environmentally friendly organosilicon waste catalyst and slurry as described in claim 1, characterized in that, The preparation method of the magnetic silicon-based catalyst is as follows: the silicon powder is mixed with 10% to 12% sodium hydroxide at a mass ratio of 1:(4.8-5.3) and dissolved to obtain activated silica gel; the ferric compound is mixed with the ferrous salt, hydrochloric acid is added to pH=2-3, and zirconium oxychloride is added to obtain a mixed solution; the molar ratio of the ferric compound, ferrous salt and zirconium oxychloride is 2:(1.0-1.2):(0.7-0.9); the activated silica gel is mixed with the mixed solution at a mass ratio of 1:(8-10), ammonia is added dropwise to pH=9-10, and the mixture is aged for 10-12 hours to obtain a catalyst precursor; the catalyst precursor is calcined at 700-800℃ for 2-3 hours under a nitrogen atmosphere to obtain the magnetic silicon-based catalyst.

10. The method for the resource utilization of environmentally friendly organosilicon waste catalyst and slurry as described in claim 1, characterized in that, The dosage of the magnetic silicon-based catalyst is 0.5-1.0 g / L; the dosage of hydrogen peroxide is 50-100 mg / L; and the reaction time of the catalytic oxidation is 0.5-1.5 h.

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