Method for comprehensive recovery of copper components by combining flameless combustion and pyrolysis of copper-containing sludge

Abstract

The present invention belongs to the field of sludge treatment and provides a method for comprehensively recovering copper components from copper-containing sludge by combining flameless combustion and pyrolysis. Aniline monomer and silicon carbide nanowires are dispersed in an acidic solution, oxidatively polymerized to form a polyaniline / silicon carbide composite material, which is then loaded with ammonium molybdate and subjected to high-temperature carbonization and sulfurization to obtain a functional material with molybdenum carbide as an active component. A phosphazene-based composite material with pollutant adsorption capacity is prepared by reacting hexachlorocyclotriphosphazene with hexagonal boron nitride, supplemented with cerium oxide and ferrous sulfide. The Mo2C@SiC-C material and the phosphazene complex serve as a catalyst and an adsorbent, respectively, and are synergistically used in a multi-stage heat treatment process. In the preheating stage, the porous structure of the material preliminarily adsorbs volatile pollutant gases. In the pyrolysis stage, the Mo2C catalyzes the decomposition of organic matter to reduce the generation of harmful gases. In the reduction stage, the Mo2C reduces the activation energy of the copper oxide reduction reaction to improve the recovery efficiency of metallic copper.

Description

Technical Field

[0001] The invention belongs to the field of sludge treatment and relates to a method for comprehensively recovering copper components by combining flameless combustion and pyrolysis of copper-containing sludge. Background Art

[0002] Copper-containing sludge, a typical hazardous waste from industrial sectors such as electroplating, metal processing, and electronics manufacturing, has long been a challenge in the interdisciplinary research of environmental engineering and metallurgy. This sludge is complex, containing both recyclable copper resources and high concentrations of organic matter, halogen compounds, and various heavy metals. If improperly handled, it can easily enter the environment through leaching, dust, or incineration, causing soil pollution, water toxicity accumulation, and ecosystem degradation. Traditional treatment methods such as landfilling, incineration, and hydrometallurgy have been effective at certain times, but their inherent technical shortcomings are becoming increasingly apparent. Landfilling, while simple, occupies land resources for a long time, and if anti-seepage measures fail, heavy metals and acidic substances will slowly be released, posing a potential threat to groundwater. Incineration, while capable of volume reduction and heat recovery, consumes significant energy due to the high-temperature combustion process and generates secondary pollutants such as hydrogen chloride, hydrogen fluoride, and dioxins, resulting in high tail gas treatment costs. Hydrometallurgy, which extracts copper through acid leaching, faces challenges such as organic interference and difficult wastewater treatment. With the tightening of environmental protection regulations and the deepening of the concept of resource recycling, the development of efficient and clean copper-containing sludge treatment technology has become an urgent need in the industry.

[0003] Pyrolysis technology is considered a key approach to breaking through the bottlenecks of traditional processes. Under oxygen-deficient or oxygen-limited conditions, pyrolysis decomposes organic matter through moderate heating to produce combustible gases and char, while simultaneously enriching metal components in the residue. Compared to incineration, pyrolysis effectively inhibits dioxin formation, reduces acidic gas emissions, and achieves higher copper concentrations in the residue. However, conventional pyrolysis processes still face multiple challenges in practical application. First, the reduction efficiency of copper oxides is limited by slow reaction kinetics, making copper recovery difficult in the absence of efficient catalysts. Second, the decomposition of chlorine- and fluorine-containing organic matter during pyrolysis releases large amounts of hydrogen chloride and hydrogen fluoride. Traditional adsorbents such as calcium oxide and activated carbon are prone to sintering or deactivation at high temperatures, resulting in inefficient acid gas removal. These intertwined challenges make single pyrolysis technology difficult to meet the needs of industrial applications. The introduction of flameless combustion technology offers new possibilities for optimizing the pyrolysis process. Flameless combustion preheats the combustion-supporting gas and dilutes the oxygen concentration in the reaction zone, achieving low-temperature, uniform oxidation of the fuel, avoiding the localized high temperatures and drastic temperature fluctuations associated with traditional combustion. This characteristic enables coupling with the pyrolysis process to form an energy-sustaining system: combustible gases (such as carbon monoxide and hydrogen) produced by pyrolysis are oxidized at low temperature in a flameless combustion chamber, and the released heat is fed back to the pyrolysis reaction zone, reducing reliance on external energy. Furthermore, the weakly oxidizing environment of flameless combustion helps regulate the copper reduction pathway and promotes the conversion of copper oxide to metallic copper. Therefore, this invention focuses on the synergistic treatment of copper-containing sludge with flameless combustion and pyrolysis to achieve efficient copper recovery. Summary of the Invention

[0004] To address the shortcomings of the existing technology, the present invention aims to provide a method for comprehensive copper recovery from copper-containing sludge by combining flameless combustion and pyrolysis. First, a Mo2C@SiC-C composite material with molybdenum carbide as the active component and silicon carbide as the structural framework is prepared through chemical polymerization and high-temperature carbonization and sulfurization techniques. This composite material effectively catalyzes the reduction of copper oxides at high temperatures. Second, a phosphazene-based composite with adsorption and degradation properties is prepared by composite modification of hexachlorocyclotriphosphazene with hexagonal boron nitride, supplemented by functional enhancements such as cerium oxide and ferrous sulfide. This composite material is used to capture and stabilize volatile pollutants released during heat treatment. A staged heat treatment process is employed, comprising preheating, pyrolysis, reduction, and slag stabilization. In each stage, the Mo2C@SiC-C and phosphazene composite materials perform catalytic, adsorbent, and stabilizing functions, synergistically improving the reduction efficiency of copper oxides, reducing pollutant emissions, and stabilizing solid waste residues, thereby meeting practical production needs.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides a method for comprehensive recovery of copper components from copper-containing sludge by combining flameless combustion and pyrolysis, the method comprising:

[0007] S1, dispersing aniline monomer and silicon carbide nanowires in a hydrochloric acid solution, adding ammonium persulfate to react, obtaining a precursor powder, immersing the precursor powder in an ammonium molybdate solution to react, obtaining a molybdenum-loaded precursor, placing the molybdenum-loaded precursor in a tube furnace, introducing a mixed gas, and heating and maintaining the temperature to obtain Mo2C@SiC-C;

[0008] S2, dispersing hexachlorocyclotriphosphazene and hexagonal boron nitride in dimethylformamide, stirring, solidifying, and crushing, and then immersing the crushed powder in a cerium oxide / ferrous sulfide suspension to obtain a composite powder, and mixing the sulfur-modified zeolite with the composite powder to obtain a phosphazene complex;

[0009] In S3, the dried copper-containing sludge, Mo2C@SiC-C and phosphazene complex are crushed and mixed, and the preheating stage, pyrolysis stage, reduction stage and slag phase stabilization stage reaction process are carried out in sequence. After the reaction, it is cooled to room temperature under nitrogen protection. After crushing, the copper-rich phase is separated and immersed in acid solution, and electrolytic purification is carried out to achieve copper recovery.

[0010] A method for comprehensive recovery of copper components from copper-containing sludge by combining flameless combustion and pyrolysis, the method specifically comprising:

[0011] A1, placing dry artificial zeolite in a tubular furnace, introducing nitrogen, raising the temperature to 400-420°C, switching to a mixed gas and continuing calcination to obtain sulfur-modified zeolite;

[0012] S1, dispersing aniline monomer and silicon carbide nanowires in a hydrochloric acid solution, adding ammonium persulfate after ultrasonic treatment, adjusting the temperature to a first temperature and stirring, vacuum drying after the reaction to obtain a precursor powder, immersing the precursor powder in an ammonium molybdate solution, adjusting the temperature to a first temperature and stirring to react, filtering, drying and grinding to obtain a molybdenum-loaded precursor, placing the molybdenum-loaded precursor in a tube furnace, introducing a mixed gas, and heating to 900-920°C and maintaining the temperature to obtain Mo2C@SiC-C;

[0013] S2, dispersing hexachlorocyclotriphosphazene and hexagonal boron nitride in dimethylformamide, adjusting the temperature to a first temperature with stirring, curing at 180-190° C. and then crushing, immersing the crushed powder in a cerium oxide / ferrous sulfide suspension, ultrasonically treating, and vacuum drying to obtain a composite powder, mixing the sulfur-modified zeolite with the composite powder, and pressing into flaky particles to obtain a phosphazene complex;

[0014] In S3, the dried copper-containing sludge, Mo2C@SiC-C and phosphazene complex are crushed and mixed, and then transferred to a reactor. The preheating stage, pyrolysis stage, reduction stage and slag phase stabilization stage reaction process are carried out in sequence. After the reaction, the mixture is cooled to room temperature under nitrogen protection. After crushing, the copper-rich phase is separated and immersed in acid solution, and electrolytic purification is performed to achieve copper recovery.

[0015] In S1, aniline monomers are dispersed in dilute hydrochloric acid. The introduction of hydrochloric acid not only provides an acidic environment but also protonates the aniline molecules, forming an aniline salt. This improves the aniline's solubility and chemical reactivity, creating favorable conditions for subsequent polymerization reactions. Because the amino groups in the aniline salt are protonated, forming positively charged amino ions, the intermolecular electrostatic repulsion is reduced and the amino groups' oxidizing properties are enhanced. Ammonium persulfate, acting as an oxidant, decomposes under acidic conditions to produce sulfate radicals, which oxidize the aniline molecules to form aniline radicals. These radicals couple to form aniline dimers or trimers, which then undergo further free radical addition reactions to form long-chain polyaniline molecules. Silicon carbide, a ceramic material with excellent thermal stability and mechanical strength, is uniformly embedded in the polymer matrix through hydrogen bonds between its surface hydroxyl groups and the amino groups in the polyaniline chains, forming a three-dimensional network structure. The high thermal conductivity and mechanical strength of silicon carbide nanowires play a key role in this stage. Their thermal conductivity ensures uniform heat distribution during polymerization, preventing local overheating and structural defects. Their rigid skeleton inhibits polymer shrinkage during the subsequent carbonization process, maintaining the stability of the porous structure. Ammonium molybdate loading is achieved via a sol-gel method. Ammonium molybdate dissociates into molybdate ions in an ethanol-water mixture. These negatively charged ions are electrostatically adsorbed onto the positively charged polyaniline surface. Upon heating, amino groups on the polyaniline chains coordinate with the molybdate ions, forming a stable complex. This coordination process not only secures the position of the molybdenum species but also prevents their migration and aggregation during subsequent high-temperature treatment. In the subsequent high-temperature carbonization and sulfurization stages, the polyaniline is pyrolyzed in a mixed atmosphere of nitrogen and hydrogen sulfide to form a porous carbon matrix. Simultaneously, the molybdate ions are reduced and carbonized by the hydrogen sulfide, forming nanoscale molybdenum carbide particles. The surface of the silicon carbide nanowires is partially sulfurized to form a transition layer, and finally a core-shell structure with silicon carbide as the core and molybdenum carbide as the shell is formed. This structure prevents the high-temperature sintering of molybdenum carbide particles through a physical isolation effect. At the same time, the sulfurized transition layer preferentially adsorbs chloride ions in the reaction, protecting the core catalytic active sites from poisoning and improving the durability of the catalyst.

[0016] In the preheating stage, a mixture of copper-containing sludge and catalyst enters the reactor and gradually heats under a nitrogen atmosphere. Low-boiling-point organic matter in the sludge begins to volatilize, while the molybdenum carbide on the catalyst surface is initially activated. As the temperature rises to the pyrolysis stage, the introduction of limited oxygen triggers partial oxidation of the organic matter, generating carbon monoxide and hydrogen. These reducing gases, catalyzed by the molybdenum carbide, react with the copper oxide in the sludge, gradually reducing it to cuprous oxide. The catalyst's core-shell structure plays a key role in this stage: the silicon carbide core maintains structural stability, preventing sintering of the active components at high temperatures; the molybdenum carbide shell provides abundant active sites, lowering the activation energy of the reduction reaction and increasing the reaction rate. Entering the reduction stage, the carbon monoxide content increases, and the strongly reducing atmosphere further promotes the conversion of cuprous oxide to metallic copper. Simultaneously, the silicon and aluminum oxides in the sludge begin to soften at high temperatures, reacting with the silicon carbide in the catalyst to form a silicon-oxygen network. This network not only inhibits the binding of copper to aluminosilicates but also provides physical support for the subsequent aggregation of copper particles.

[0017] Zeolites, a typical microporous aluminosilicate material, have a framework composed of silicon-oxygen tetrahedra and aluminum-oxygen tetrahedra connected by oxygen bridges to form a three-dimensional network. During high-temperature calcination under nitrogen, residual organic templates or adsorbed water on the zeolite surface are removed, exposing more active hydroxyl sites. These hydroxyl groups become key reaction sites during the subsequent hydrogen sulfide treatment: hydrogen sulfide molecules diffuse into the zeolite pores and undergo substitution reactions with surface hydroxyl groups, forming a stable thiol-modified layer. This not only alters the zeolite's surface chemistry but also, by introducing sulfur active sites, imparts the zeolite with the ability to specifically adsorb gaseous heavy metals. The strong interaction of thiol groups with heavy metals such as mercury and lead stems from the coordination of the sulfur atom's lone electron pairs with the heavy metal's vacant orbitals. The zeolite's microporous structure preferentially captures small pollutants through a size-selective effect, preventing pore clogging by larger molecules. During the high-temperature pyrolysis stage, the thiol groups on the sulfur-modified zeolite remain stable in a reducing atmosphere, continuously capturing volatile heavy metal vapors. At the same time, the framework resists high-temperature sintering, maintaining its porosity and adsorption capacity.

[0018] Hexachlorocyclotriphosphazene undergoes ring-opening polymerization under solvothermal conditions to form a cross-linked polyphosphazene network. The incorporation of hexagonal boron nitride nanosheets enhances the thermal stability and mechanical strength of the polymer through physical intercalation and chemical interactions. The phosphorus-nitrogen backbone of the polyphosphazene chain not only provides abundant Lewis acid sites but also, through subsequent loading with cerium oxide and ferrous sulfide, achieves multifunctionality. Cerium oxide nanoparticles are anchored to the polyphosphazene chains through coordination. Their surface oxygen vacancies catalyze the oxidative conversion of sulfur dioxide during the pyrolysis phase, solidifying gaseous sulfur oxides into stable sulfates. Ferrous sulfide particles are dispersed within the pores of the composite and, at high temperatures, release active sulfur species that react with heavy metals to form non-volatile sulfides. The mesoporous structure of the phosphazene complex provides mass transfer pathways for these reactions, while the conductive network formed after carbonization facilitates electron transfer, accelerating the kinetics of the sulfurization reaction.

[0019] During the initial stages of pyrolysis, the polyphosphazene chains within the phosphazene complex are not yet fully carbonized. Their flexible structure captures acidic gases such as hydrogen chloride through physical adsorption, while cerium oxide begins to catalyze the oxidation of sulfur dioxide. At this stage, due to the relatively low temperature, the sulfur-modified zeolite primarily relies on physical adsorption within its microporous structure to intercept some heavy metal vapors. As the temperature rises to the mid-to-late stages of pyrolysis, the phosphazene complex gradually carbonizes, exposing numerous active sites within its rigid porous framework. Chemical adsorption dominates: phosphorus atoms within the polyphosphazene chains react with hydrogen chloride to form stable phosphorus-chlorine bonds, securing the acidic gases to the carbon skeleton. Sulfur radicals generated by the decomposition of ferrous sulfide bind to heavy metals such as mercury and lead to form sulfide particles. Simultaneously, the thiol groups within the sulfur-modified zeolite become fully activated at high temperatures, capturing residual mercury vapor through chemical bonding, while its microporous structure inhibits adsorbate desorption through confinement. The synergistic effect of these two factors is further accentuated during the high temperatures of the reduction stage. The conductive network formed by the carbonization of the phosphazene complex and hexagonal boron nitride jointly promote electron migration, enhance the reactivity of ferrous sulfide, and enable the release of sulfur species and the heavy metal sulfidation process to proceed efficiently. Sulfur-modified zeolite prevents large molecular sulfides from entering the pores through microporous screening, ensuring that the thiol sites are preferentially used for the adsorption of gaseous heavy metals. At this time, the captured hydrogen chloride is locked in the carbon skeleton in the form of chemical bonds, while products such as mercury sulfide are embedded in the mesopores of the complex or wrapped by the molten glass phase to achieve morphological stabilization. This hierarchical adsorption-catalysis mechanism not only covers pollutants of different molecular sizes, but also converts gaseous harmful substances into solid stable phases through chemical conversion, completely blocking their environmental release path. The silicon-sulfur bond of the sulfur-modified zeolite gives the thiol group excellent high-temperature stability, allowing it to maintain adsorption activity during the thermal decomposition-reduction process; the strong coordination between cerium oxide and polyphosphazene in the phosphazene complex prevents the agglomeration and inactivation of the nanoparticles, while the layered structure of hexagonal boron nitride inhibits the shrinkage and collapse of the carbon skeleton, ensuring the durability of the material under extreme conditions and enabling it to adapt to the complex chemical environment in the treatment of copper-containing sludge.

[0020] In the flameless combustion-pyrolysis combined treatment process for copper-containing sludge, synergistic material design is achieved through the complementary functionalities of multiple components, encompassing the goals of pollutant adsorption and metal recovery. Sulfur-modified zeolites, modified with surface thiol groups, achieve specific capture of gaseous heavy metals. Their microporous structure preferentially intercepts small-molecule pollutants, while the strong covalent bonding ability of thiol groups ensures stable heavy metal retention. Compared to traditional materials, the silicon-sulfur bonds of sulfur-modified zeolites offer greater thermal stability, maintaining adsorption activity at high temperatures and preventing secondary contamination. Phosphazene complexes, based on polyphosphazene chains, chemically adsorb acidic gases, catalyze the conversion of sulfur oxides, and release active sulfur species to drive heavy metal sulfidation. The phosphorus atoms in the polyphosphazene chains form strong coordination bonds with hydrogen chloride, chemically fixing the acidic gases within the carbonized framework. Ferrous sulfide decomposes at high temperatures to release sulfur species, which react with gaseous heavy metals to form non-volatile sulfides. Core-shell catalysts enhance the reduction efficiency of copper oxides through the synergistic effect of a silicon carbide core and a molybdenum carbide shell. The high melting point and thermal conductivity of silicon carbide inhibit sintering of active components, while the active sites enriched on the surface of molybdenum carbide accelerate the reduction reaction kinetics. The micropores of sulfur-modified zeolites dominate the adsorption of small-molecule pollutants, while the mesopores of the phosphazene complex accommodate large-molecule sulfides and provide gas diffusion channels. The open pores of the core-shell catalyst reduce gas diffusion resistance. The conductive network formed after carbonization of the phosphazene complex and hexagonal boron nitride jointly accelerate electron transfer and promote the sulfurization reaction. At the same time, the heterojunction interface of the core-shell catalyst enhances the charge transfer efficiency. The silicon-sulfur bond of the zeolite and the phosphorus-cerium coordination bond of the complex enhance stability through chemical bonding. The pre-sulfurized intermediate layer of the core-shell catalyst preferentially adsorbs chloride ions to protect the active sites, and hexagonal boron nitride inhibits the shrinkage of the carbon skeleton to maintain structural stability.

[0021] As a preferred technical solution of the present invention, in A1, the mixed gas is an H2S / N2 mixed gas, the volume fraction of H2S is 10%, and the total flow rate is 100 mL / min.

[0022] In some optional embodiments, the calcination time is 2-3h, for example, it can be 2h, 2.1h, 2.2h, 2.3h, 2.4h, 2.5h, 2.6h, 2.7h, 2.8h, 2.9h or 3h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0023] As a preferred technical solution of the present invention, in S1, the mass ratio of the aniline monomer, the silicon carbide nanowires and the ammonium persulfate is (50-55): (2.5-3.5): (10-13), for example, it can be (50.0, 50.5, 51.0, 51.5, 52.0, 52.5, 53.0, 53.5, 54.0, 54.5 or 55.0): (2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4 or 3.5): (10.0, 10.3, 10.6, 10.9, 11.2, 11.5, 11.8, 12.1, 12.4, 12.7 or 13.0), but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0024] In some optional examples, the concentration of the hydrochloric acid solution is 0.1M.

[0025] In some optional embodiments, the ultrasonic treatment time is 1-2h, for example, it can be 1h, 1.1h, 1.2h, 1.3h, 1.4h, 1.5h, 1.6h, 1.7h, 1.8h, 1.9h or 2h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0026] In some optional embodiments, the first temperature is 60-70°C, for example, it can be 60°C, 61°C, 62°C, 63°C, 64°C, 65°C, 66°C, 67°C, 68°C, 69°C or 70°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0027] In some optional embodiments, the vacuum drying temperature is 80-90°C, for example, it can be 80°C, 81°C, 82°C, 83°C, 84°C, 85°C, 86°C, 87°C, 88°C, 89°C or 90°C, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0028] In some optional embodiments, the vacuum drying time is 10-12h, for example, it can be 10h, 10.2h, 10.4h, 10.6h, 10.8h, 11h, 11.2h, 11.4h, 11.6h, 11.8h or 12h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0029] In some optional examples, the mass volume ratio of the precursor powder to the ammonium molybdate solution is 1 g:10 mL.

[0030] In some optional examples, the concentration of the ammonium molybdate solution is 0.5M.

[0031] In some optional embodiments, the first temperature stirring reaction time is 6-7h, for example, it can be 6h, 6.1h, 6.2h, 6.3h, 6.4h, 6.5h, 6.6h, 6.7h, 6.8h, 6.9h or 7h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0032] In some optional examples, the mixed gas is nitrogen and hydrogen sulfide, with a volume ratio of 98:2 and a total flow rate of 200 mL / min.

[0033] In some optional examples, the heating rate is 5°C / min.

[0034] In some optional embodiments, the 900°C insulation time is 2-3h, for example, it can be 2h, 2.1h, 2.2h, 2.3h, 2.4h, 2.5h, 2.6h, 2.7h, 2.8h, 2.9h or 3h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0035] As a preferred technical solution of the present invention, in S2, the mass volume ratio of the hexachlorocyclotriphosphazene, hexagonal boron nitride and cerium oxide / ferrous sulfide suspension is (45-50) g: (5-8) g: 100 mL, for example, it can be (45.0, 45.5, 46.0, 46.5, 47.0, 47.5, 48.0, 48.5, 49.0, 49.5 or 50.0) g: (5.0, 5.3, 5.6, 5.9, 6.2, 6.5, 6.8, 7.1, 7.4, 7.7 or 8.0) g: 100 mL, but is not limited to the listed values, and other values ​​not listed within this numerical range are also applicable.

[0036] In some optional embodiments, the stirring time at the first temperature is 4-5h, for example, 4h, 4.1h, 4.2h, 4.3h, 4.4h, 4.5h, 4.6h, 4.7h, 4.8h, 4.9h or 5h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0037] In some optional embodiments, the 180°C curing time is 2-3h, for example, it can be 2h, 2.1h, 2.2h, 2.3h, 2.4h, 2.5h, 2.6h, 2.7h, 2.8h, 2.9h or 3h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0038] In some optional examples, the solvent of the cerium oxide / ferrous sulfide suspension is ethanol, the mass ratio of cerium oxide to ferrous sulfide is 5:3, and the mass volume ratio of cerium oxide to ethanol is 2.5 g:100 mL.

[0039] In some optional examples, the mass ratio of the sulfur-modified zeolite to the composite powder is 15:85.

[0040] As a preferred technical solution of the present invention, in S3, the mass ratio of the dried copper-containing sludge, Mo2C@SiC-C and the phosphazene complex is 82:10:8.

[0041] In some optional examples, the temperature of the preheating section is 350-400° C., nitrogen is introduced at a flow rate of 1 L / min, the mixed material is continuously fed at a rate of 500 g / min, and the residence time in the preheating section is 20-30 min.

[0042] In some optional examples, the temperature of the pyrolysis section is 550-600°C, a N2 / O2 mixed gas is introduced, the O2 volume ratio is 3%, the total flow rate is 1 L / min, and the residence time of the pyrolysis section is 50-60 min.

[0043] In some optional examples, the temperature of the reduction section is 800-850°C, a N2 / CO mixed gas is introduced, CO accounts for 10% by volume, the total flow rate is 1 L / min, and the residence time of the reduction section is 40-50 min.

[0044] In some optional examples, the temperature of the slag phase stabilization section is 800° C., nitrogen is introduced at a flow rate of 1 L / min, and the residence time of the slag phase stabilization section is 30-40 min.

[0045] Compared with the prior art, the present invention has the following beneficial effects: (1) Mo2C@SiC-C effectively inhibits the high-temperature sintering of molybdenum carbide particles through the physical isolation of the silicon carbide core, maintaining a high-density active site; the excellent catalytic activity of the molybdenum carbide shell reduces the activation energy of copper oxide reduction and increases the reaction rate, and the intermediate layer formed by pre-sulfurization of its surface preferentially adsorbs chloride ions, ensuring long-term stable operation in a chlorine-containing environment; (2) The phosphazene complex integrates the functions of acid gas adsorption, sulfur oxide catalytic conversion and heavy metal sulfurization. The polyphosphazene chain fixes hydrogen chloride through chemical bonds, cerium oxide catalyzes sulfur dioxide to generate stable sulfate, and ferrous sulfide releases active sulfur substances to solidify heavy metals; (3) The coordinated design of Mo2C@SiC-C and the phosphazene complex covers the entire process of metal reduction and pollution control. While the core-shell catalyst accelerates copper reduction, the phosphazene complex blocks the poisoning of the catalyst by acid gases, and the graded adsorption mechanism of the sulfur-modified zeolite and the phosphazene complex realizes pollutant removal. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 Flowchart of the method for comprehensive recovery of copper components by combining flameless combustion and pyrolysis of copper-containing sludge provided in Examples 1-4 of the present invention. DETAILED DESCRIPTION

[0047] The technical solutions of the present invention are described in detail below in conjunction with specific embodiments and their accompanying drawings. The embodiments described herein are specific embodiments of the present invention and are used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary and should not be understood as limiting the embodiments of the present invention and the scope of protection of the present invention. In addition to the embodiments described herein, those skilled in the art can also adopt other obvious technical solutions based on the contents disclosed in the claims of this application and its specification, including technical solutions that adopt any obvious replacements and modifications to the embodiments described herein.

[0048] The chemical reagents used in the examples and comparative examples of the present invention are all commercially available products and have not been subjected to any further purification treatment.

[0049] Example 1

[0050] This embodiment provides a method for comprehensive recovery of copper components from copper-containing sludge by combining flameless combustion and pyrolysis, the method specifically comprising the following steps:

[0051] A1, placing dried artificial zeolite in a tube furnace, introducing nitrogen, raising the temperature to 400°C, switching to a mixed gas, wherein the mixed gas is an H2S / N2 mixed gas with a volume fraction of H2S of 10% and a total flow rate of 100 mL / min, and continuing calcination for 2.5 h to obtain sulfur-modified zeolite;

[0052] S1, 52g of aniline monomer and 2.5g of silicon carbide nanowires were dispersed in 500mL of 0.1M hydrochloric acid solution, ultrasonically treated for 1.5h, and then 10g of ammonium persulfate was added. The temperature was adjusted to 66°C and stirred. After the reaction, the mixture was vacuum dried at 88°C for 11.2h to obtain a precursor powder. 20g of the precursor powder was immersed in 200mL of 0.5M ammonium molybdate solution, the temperature was adjusted to 62°C and stirred for 6.3h, filtered, dried and ground to obtain a molybdenum-loaded precursor. The molybdenum-loaded precursor was placed in a tube furnace and introduced with a mixed gas of nitrogen and hydrogen sulfide in a volume ratio of 98:2 at a total flow rate of 200mL / min. The temperature was raised to 900°C at 5°C / min and kept at this temperature for 2.0h to obtain Mo2C@SiC-C;

[0053] S2, dispersing 45 g of hexachlorocyclotriphosphazene and 5 g of hexagonal boron nitride in 200 mL of dimethylformamide, adjusting the temperature to 63°C and stirring for 4.2 h, curing at 180°C for 2.5 h, and then crushing. The crushed product was immersed in 100 mL of cerium oxide / ferrous sulfide suspension, ultrasonically treated, and vacuum dried to obtain a composite powder. 15 g of sulfur-modified zeolite was mixed with 85 g of the composite powder and pressed into flaky particles to obtain a phosphazene complex;

[0054] S3, 82g of dry copper-containing sludge, 10g of Mo2C@SiC-C and 8g of phosphazene complex were crushed and mixed, transferred to the reactor, and the reaction process of preheating section, pyrolysis section, reduction section and slag phase stabilization section was carried out in sequence. The temperature of the preheating section was 350°C, nitrogen was introduced at a flow rate of 1L / min, and the mixture was continuously fed at a rate of 500g / min. The residence time of the preheating section was 22min. The temperature of the pyrolysis section was 580°C, N2 / O2 mixed gas was introduced, and O2 accounted for 3% by volume. The flow rate is 1L / min, the residence time in the pyrolysis section is 50min, the temperature of the reduction section is 810°C, an N2 / CO mixed gas is introduced, CO accounts for 10% by volume, the total flow rate is 1L / min, the residence time in the reduction section is 44min, the temperature of the slag phase stabilization section is 800°C, nitrogen is introduced, the flow rate is 1L / min, the residence time in the slag phase stabilization section is 33min, after the reaction is completed, it is cooled to room temperature under nitrogen protection, the copper-rich phase is separated after crushing and immersed in acid solution, and electrolytic purification is performed to achieve copper recovery.

[0055] Example 2

[0056] This embodiment provides a method for comprehensive recovery of copper components from copper-containing sludge by combining flameless combustion and pyrolysis, the method specifically comprising the following steps:

[0057] A1, placing dried artificial zeolite in a tube furnace, introducing nitrogen, raising the temperature to 420°C, switching to a mixed gas, wherein the mixed gas is an H2S / N2 mixed gas with a volume fraction of H2S of 10% and a total flow rate of 100 mL / min, and continuing calcination for 2.0 h to obtain sulfur-modified zeolite;

[0058] S1, 50g of aniline monomer and 2.8g of silicon carbide nanowires were dispersed in 500mL of 0.1M hydrochloric acid solution, ultrasonically treated for 1.3h, and then 11g of ammonium persulfate was added. The temperature was adjusted to 70℃ and stirred. After the reaction, it was vacuum dried at 80℃ for 10.5h to obtain a precursor powder. 20g of the precursor powder was immersed in 200mL of 0.5M ammonium molybdate solution, the temperature was adjusted to 60℃ and stirred for 6.0h, filtered, dried and ground to obtain a molybdenum-loaded precursor. The molybdenum-loaded precursor was placed in a tube furnace and introduced with a mixed gas of nitrogen and hydrogen sulfide in a volume ratio of 98:2 at a total flow rate of 200mL / min. The temperature was raised to 920℃ at 5°C / min and kept for 2.6h to obtain Mo2C@SiC-C;

[0059] S2, dispersing 47 g of hexachlorocyclotriphosphazene and 8 g of hexagonal boron nitride in 200 mL of dimethylformamide, adjusting the temperature to 60°C and stirring for 4.0 h, curing at 190°C for 2.0 h, and then crushing. The crushed product was immersed in 100 mL of cerium oxide / ferrous sulfide suspension, ultrasonically treated, and vacuum dried to obtain a composite powder. 15 g of sulfur-modified zeolite was mixed with 85 g of the composite powder and pressed into flaky particles to obtain a phosphazene complex;

[0060] S3, 82g of dry copper-containing sludge, 10g of Mo2C@SiC-C and 8g of phosphazene complex were crushed and mixed, transferred to the reactor, and the preheating section, pyrolysis section, reduction section and slag phase stabilization section reaction process were carried out in sequence. The temperature of the preheating section was 400℃, nitrogen was introduced at a flow rate of 1L / min, and the mixture was continuously fed at a rate of 500g / min. The residence time of the preheating section was 20min. The temperature of the pyrolysis section was 550℃, N2 / O2 mixed gas was introduced, and O2 accounted for 3% by volume. The flow rate is 1L / min, the residence time in the pyrolysis section is 54min, the temperature of the reduction section is 800℃, N2 / CO mixed gas is introduced, CO volume accounts for 10%, the total flow rate is 1L / min, the residence time in the reduction section is 40min, the temperature of the slag phase stabilization section is 800℃, nitrogen is introduced, the flow rate is 1L / min, the residence time in the slag phase stabilization section is 37min, after the reaction is completed, it is cooled to room temperature under nitrogen protection, the copper-rich phase is separated after crushing and immersed in acid solution, and electrolytic purification is carried out to achieve copper recovery.

[0061] Example 3

[0062] This embodiment provides a method for comprehensive recovery of copper components from copper-containing sludge by combining flameless combustion and pyrolysis, the method specifically comprising the following steps:

[0063] A1, placing dried artificial zeolite in a tube furnace, introducing nitrogen, raising the temperature to 410°C, switching to a mixed gas, wherein the mixed gas is an H2S / N2 mixed gas with a volume fraction of H2S of 10% and a total flow rate of 100 mL / min, and continuing calcination for 2.7 h to obtain sulfur-modified zeolite;

[0064] S1, 55g of aniline monomer and 3.5g of silicon carbide nanowires were dispersed in 500mL of 0.1M hydrochloric acid solution, ultrasonically treated for 1.0h, and then 13g of ammonium persulfate was added. The temperature was adjusted to 60°C and stirred. After the reaction, it was vacuum dried at 90°C for 10.0h to obtain a precursor powder. 20g of the precursor powder was immersed in 200mL of 0.5M ammonium molybdate solution, the temperature was adjusted to 70°C and stirred for 6.7h, filtered, dried and ground to obtain a molybdenum-loaded precursor. The molybdenum-loaded precursor was placed in a tube furnace and introduced with a mixed gas of nitrogen and hydrogen sulfide in a volume ratio of 98:2 at a total flow rate of 200mL / min. The temperature was raised to 910°C at 5°C / min and kept for 3.0h to obtain Mo2C@SiC-C;

[0065] S2, dispersing 50 g of hexachlorocyclotriphosphazene and 7 g of hexagonal boron nitride in 200 mL of dimethylformamide, adjusting the temperature to 70°C and stirring for 4.8 h, curing at 184°C for 3.0 h, and then crushing. The crushed product was immersed in 100 mL of cerium oxide / ferrous sulfide suspension, ultrasonically treated, and vacuum dried to obtain a composite powder. 15 g of sulfur-modified zeolite was mixed with 85 g of the composite powder and pressed into flaky particles to obtain a phosphazene complex;

[0066] S3, 82g of dry copper-containing sludge, 10g of Mo2C@SiC-C and 8g of phosphazene complex were crushed and mixed, transferred to the reactor, and the reaction process of preheating section, pyrolysis section, reduction section and slag phase stabilization section was carried out in sequence. The temperature of the preheating section was 380°C, nitrogen was introduced at a flow rate of 1L / min, and the mixture was continuously fed at a rate of 500g / min. The residence time of the preheating section was 30min. The temperature of the pyrolysis section was 600°C, N2 / O2 mixed gas was introduced, and O2 accounted for 3% by volume. The total The flow rate is 1L / min, the residence time in the pyrolysis section is 60min, the temperature of the reduction section is 850°C, an N2 / CO mixed gas is introduced, CO accounts for 10% by volume, the total flow rate is 1L / min, the residence time in the reduction section is 50min, the temperature of the slag phase stabilization section is 800°C, nitrogen is introduced, the flow rate is 1L / min, the residence time in the slag phase stabilization section is 40min, after the reaction is completed, it is cooled to room temperature under nitrogen protection, the copper-rich phase is separated after crushing and immersed in acid solution, and electrolytic purification is performed to achieve copper recovery.

[0067] Example 4

[0068] This embodiment provides a method for comprehensive recovery of copper components from copper-containing sludge by combining flameless combustion and pyrolysis, the method specifically comprising the following steps:

[0069] A1, placing dried artificial zeolite in a tube furnace, introducing nitrogen, raising the temperature to 415°C, switching to a mixed gas, wherein the mixed gas is an H2S / N2 mixed gas with a volume fraction of H2S of 10% and a total flow rate of 100 mL / min, and continuing calcination for 3.0 h to obtain sulfur-modified zeolite;

[0070] S1, 53g of aniline monomer and 3.1g of silicon carbide nanowires were dispersed in 500mL of 0.1M hydrochloric acid solution, ultrasonically treated for 2.0h, and then 12g of ammonium persulfate was added. The temperature was adjusted to 62°C and stirred. After the reaction, the mixture was vacuum dried at 84°C for 12.0h to obtain a precursor powder. 20g of the precursor powder was immersed in 200mL of 0.5M ammonium molybdate solution, the temperature was adjusted to 66°C and stirred for 7.0h, filtered, dried and ground to obtain a molybdenum-loaded precursor. The molybdenum-loaded precursor was placed in a tube furnace and introduced with a mixed gas of nitrogen and hydrogen sulfide in a volume ratio of 98:2 at a total flow rate of 200mL / min. The temperature was raised to 905°C at 5°C / min and kept at this temperature for 2.7h to obtain Mo2C@SiC-C;

[0071] S2, dispersing 49 g of hexachlorocyclotriphosphazene and 6 g of hexagonal boron nitride in 200 mL of dimethylformamide, adjusting the temperature to 67°C and stirring for 5.0 h, curing at 188°C for 2.7 h, and then crushing. The crushed product was immersed in 100 mL of cerium oxide / ferrous sulfide suspension, ultrasonically treated, and vacuum dried to obtain a composite powder. 15 g of sulfur-modified zeolite was mixed with 85 g of the composite powder and pressed into flaky particles to obtain a phosphazene complex;

[0072] S3, 82g of dry copper-containing sludge, 10g of Mo2C@SiC-C and 8g of phosphazene complex were crushed and mixed, transferred to the reactor, and the reaction process of preheating section, pyrolysis section, reduction section and slag phase stabilization section was carried out in sequence. The temperature of the preheating section was 360℃, nitrogen was introduced with a flow rate of 1L / min, and the mixture was continuously fed at a rate of 500g / min. The residence time of the preheating section was 27min. The temperature of the pyrolysis section was 560℃, and N2 / O2 mixed gas was introduced, with O2 accounting for 3% by volume and a total flow rate of 1L / m in, the residence time of the pyrolysis section is 57 min, the temperature of the reduction section is 830 ° C, N2 / CO mixed gas is introduced, CO volume accounts for 10%, the total flow rate is 1 L / min, the residence time of the reduction section is 47 min, the temperature of the slag phase stabilization section is 800 ° C, nitrogen is introduced with a flow rate of 1 L / min, and the residence time of the slag phase stabilization section is 30 min. After the reaction is completed, it is cooled to room temperature under nitrogen protection, the copper-rich phase is separated after crushing and immersed in acid to obtain a copper-containing leachate, and the copper-containing leachate is electrolyzed and purified to achieve copper recovery.

[0073] Comparative Example 1

[0074] This comparative example provides a method for comprehensive recovery of copper components by combining flameless combustion and pyrolysis of copper-containing sludge. The difference between this method and Example 1 is that the mass of Mo2C@SiC-C in S3 is 20 g, which is 10 g more than that in Example 1. The other process parameters and operating conditions are exactly the same as those in Example 1.

[0075] Comparative Example 2

[0076] This comparative example provides a method for comprehensive recovery of copper components by combining flameless combustion and pyrolysis of copper-containing sludge. The difference between this method and Example 1 is that the mass of Mo2C@SiC-C in S3 is 1 g, which is 9 g less than that in Example 1. The other process parameters and operating conditions are exactly the same as those in Example 1.

[0077] Comparative Example 3

[0078] This comparative example provides a method for comprehensive recovery of copper components by combining flameless combustion and pyrolysis of copper-containing sludge. The difference between this method and Example 1 is that the mass of the phosphazene complex in S3 is 15 g, which is 7 g more than that in Example 1. The other process parameters and operating conditions are exactly the same as those in Example 1.

[0079] Comparative Example 4

[0080] This comparative example provides a method for comprehensive recovery of copper components by combining flameless combustion and pyrolysis of copper-containing sludge. The difference between this method and Example 1 is that the mass of the phosphazene complex in S3 is 1 g, which is 7 g less than that in Example 1. The other process parameters and operating conditions are exactly the same as those in Example 1.

[0081] Draw a standard curve: Pipette 0.00ml, 1.00ml, 2.00ml, 3.00ml, 4.00ml, and 5.00ml of a 200μg / ml copper standard solution, use an atomic absorption spectrophotometer to measure their absorbance in turn, and draw a standard curve.

[0082] Determine the copper content of sludge: After drying, sieve the sludge through a mesh and weigh 1.000g. Place the sludge in a polytetrafluoroethylene crucible. Place the sludge in a hot plate and add 80wt.% nitric acid. Heat until nearly dry, then stop heating. Add 40wt.% HF and 70wt.% perchloric acid. Heat until nearly dry. Remove the sludge and add 10wt.% nitric acid. Constant volume will yield the sample to be tested. Measure the absorbance of the sample and substitute it into the standard curve equation. The copper content of the sludge is 11.4wt.%.

[0083] Leaching rate determination: The supernatant of the leachate was taken and diluted to 50 mL. The concentration was determined by atomic absorption spectroscopy and converted to a mass fraction in the copper-containing leachate. The leaching rate was then compared with the copper content in the sludge. The hydrogen chloride concentration in exhaust emissions was tested according to the HJ549-2016 standard, and the test section was the exhaust gas from the reduction stage. The test results are shown in Table 1.

[0084] Table 1 Test results of copper-containing sludge of Examples 1-4 and Comparative Examples 1-4

[0085] Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Leaching rate (%) 96.2 95.1 94.7 95.4 82.4 63.6 78.7 95.8 <![CDATA[Hydrogen chloride concentration (mg / cm 3 )]]> 9 10 10 10 10 11 8 13

[0086] As shown in Table 1, compared to Example 1, the leaching rate of Comparative Example 1 decreased, while the hydrogen chloride concentration increased; while the leaching rate of Comparative Example 2 decreased, while the hydrogen chloride concentration increased. This is because the Mo2C@SiC-C in Comparative Example 1 is excessive. Under the condition of a certain amount of copper oxide, the active sites of Mo2C may become "supersaturated." That is, the excess Mo2C cannot further increase the reaction rate. Too much may cause localized accumulation in the mixture, hindering the contact between copper oxide and the reducing gas, and reducing the leaching rate. In Comparative Example 2, the Mo2C@SiC-C is insufficient, and the reaction rate of copper oxide with CO in a reducing atmosphere is significantly reduced, reducing the leaching rate. Compared to Example 1, the leaching rate of Comparative Example 3 decreased, while the hydrogen chloride concentration decreased; while the leaching rate of Comparative Example 4 decreased, while the hydrogen chloride concentration increased. This is because the phosphazene complex in Comparative Example 3 is excessive, which can fully absorb the hydrogen chloride gas. At the same time, the excessive phosphazene complex may reduce the direct contact between copper oxide and Mo2C@SiC-C, thereby affecting the reduction efficiency of copper oxide. In Comparative Example 4, the phosphazene complex was insufficient, resulting in inability to fully adsorb hydrogen chloride.

[0087] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for comprehensive recovery of copper components by combining flameless combustion and pyrolysis of copper-containing sludge, characterized in that: The method comprises: S1, dispersing aniline monomer and silicon carbide nanowires in a hydrochloric acid solution, adding ammonium persulfate to react, obtaining a precursor powder, immersing the precursor powder in an ammonium molybdate solution to react, obtaining a molybdenum-loaded precursor, placing the molybdenum-loaded precursor in a tube furnace, introducing a mixed gas of nitrogen and hydrogen sulfide, raising the temperature to 900-920°C, and maintaining the temperature, to obtain Mo2C@SiC-C; S2, dispersing hexachlorocyclotriphosphazene and hexagonal boron nitride in dimethylformamide, stirring, solidifying, and crushing, and then immersing the crushed powder in a cerium oxide / ferrous sulfide suspension to obtain a composite powder, and mixing the sulfur-modified zeolite with the composite powder to obtain a phosphazene complex; S3, crushing and mixing the dried copper-containing sludge, Mo2C@SiC-C and phosphazene complex, and sequentially carrying out the preheating section, pyrolysis section, reduction section and slag phase stabilization section reaction process, wherein the temperature of the preheating section is 350-400°C, and nitrogen is introduced; the temperature of the pyrolysis section is 550-600°C, and N2 / O2 mixed gas is introduced; the temperature of the reduction section is 800-850°C, and N2 / CO mixed gas is introduced; the temperature of the slag phase stabilization section is 800°C, and nitrogen is introduced; after the reaction is completed, the mixture is cooled to room temperature under nitrogen protection, crushed, and the copper-rich phase is separated and immersed in acid solution, and electrolytic purification is performed to achieve copper recovery.

2. The method for comprehensive recovery of copper components by combining flameless combustion and pyrolysis of copper-containing sludge according to claim 1, characterized in that: In S2, the preparation method of the sulfur-modified zeolite comprises: A1. Place the dried artificial zeolite in a tubular furnace, introduce nitrogen, raise the temperature to 400-420°C, switch to a mixed gas and continue calcining to obtain sulfur-modified zeolite.

3. The method for comprehensive recovery of copper components by combining flameless combustion and pyrolysis of copper-containing sludge according to claim 1, characterized in that: In S1, The mass ratio of the aniline monomer, silicon carbide nanowires and ammonium persulfate is (50-55): (2.5-3.5): (10-13); The mass volume ratio of the precursor powder to the ammonium molybdate solution is 1 g:10 mL.

4. The method for comprehensive recovery of copper components by combining flameless combustion and pyrolysis of copper-containing sludge according to claim 1, characterized in that: In S1, The concentration of the ammonium molybdate solution is 0.5M; The volume ratio of nitrogen to hydrogen sulfide is 98:2, and the total flow rate is 200 mL / min.

5. The method for comprehensive recovery of copper components by combining flameless combustion and pyrolysis of copper-containing sludge according to claim 1, characterized in that: In S2, The mass volume ratio of the hexachlorocyclotriphosphazene, hexagonal boron nitride and cerium oxide / ferrous sulfide suspension is (45-50) g: (5-8) g: 100 mL; The solvent of the cerium oxide / ferrous sulfide suspension is ethanol, the mass ratio of cerium oxide to ferrous sulfide is 5:3, and the mass volume ratio of cerium oxide to ethanol is 2.5 g:100 mL.

6. The method for comprehensive recovery of copper components by combining flameless combustion and pyrolysis of copper-containing sludge according to claim 1, characterized in that: In S2, The mass ratio of the sulfur-modified zeolite to the composite powder is 15:

85.

7. The method for comprehensive recovery of copper components by combining flameless combustion and pyrolysis of copper-containing sludge according to claim 1, characterized in that: In S3, The mass ratio of the dried copper-containing sludge, Mo2C@SiC-C and phosphazene complex is 82:10:

8.

8. The method for comprehensive recovery of copper components by combining flameless combustion and pyrolysis of copper-containing sludge according to claim 1, characterized in that: In S3, In the preheating section, the flow rate of nitrogen is 1L / min, the mixed material is continuously fed at a rate of 500g / min, and the residence time in the preheating section is 20-30min; The pyrolysis section is introduced with N2 / O2 mixed gas, in which O2 accounts for 3% by volume, with a total flow rate of 1L / min, and the residence time in the pyrolysis section is 50-60min.

9. The method for comprehensive recovery of copper components by combining flameless combustion and pyrolysis of copper-containing sludge according to claim 1, characterized in that: In S3, In the reduction section, N2 / CO mixed gas is introduced with a CO volume ratio of 10%, a total flow rate of 1L / min, and a reduction section residence time of 40-50min; The flow rate of nitrogen in the slag phase stabilization section is 1 L / min, and the residence time of the slag phase stabilization section is 30-40 minutes.

10. The method for comprehensive recovery of copper components by combining flameless combustion and pyrolysis of copper-containing sludge according to claim 2, characterized in that: In A1, The mixed gas is H2S / N2 mixed gas, the volume fraction of H2S is 10%, and the total flow rate is 100 mL / min.

Images