Comprehensive recycling method for sulfur-containing metallurgical flue gas
By introducing organic matter to the metallurgical flue gas to pyrolysis to generate reducing gas, the problems of complex purification process and waste of resources are solved, efficient recycling of valuable metals and inhibiting the formation of polluted acids, and environmental pollution is reduced.
Patent Information
- Application Number
- CN202510719973.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-30
- Publication Date
- 2025-08-12
AI Technical Summary
The existing smelting flue gas purification technology process is complex, requires additional heating, and it is difficult to effectively remove sulfur trioxide, arsenic oxide and non-ferrous metal oxides, resulting in high acidity, large acid content, and rich in ferrous metals.
High-temperature metallurgical flue gas is passed into the organic matter furnace body, and reducing the reducing metal is achieved by pyrolysis of organic matter, so as to achieve rapid condensation of valuable metals and reduce the flue gas. The reducing gas is used to separate the valuable metals and flue gas, and then gas separation and oxidation are performed to generate sulfuric acid.
It realizes efficient recycling of valuable metals, reduces flue gas temperature, inhibits the formation of polluted acids, reduces environmental pollution, and improves resource utilization.
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Abstract
Description
Technical Field
[0001] The invention relates to a comprehensive recovery and utilization method of sulfur-containing metallurgical flue gas, belonging to the technical field of metallurgy. Background Art
[0002] After dust removal, smelting flue gas still contains nitrogen, sulfur dioxide, oxygen, and solid and gaseous harmful impurities. Therefore, purification is required before acid production. Solid harmful impurities in flue gas include ferroferric oxide, gangue particles, and iron oxide; gaseous harmful impurities include water vapor, trifluoride, selenium dioxide, sulfur trioxide, arsenic oxide, non-ferrous metal oxides, carbon monoxide, and carbon dioxide. The presence of these substances can cause numerous problems in the acid production process, such as catalyst deactivation and reduced conversion efficiency; residual coloring or toxic elements, affecting the quality of sulfuric acid products; carryover of fluorine and chlorine, causing corrosion of production, storage, and transportation equipment; and increased complexity of the acid production exhaust, affecting the ability of the acid production process to meet emission standards.
[0003] The acid purification process for smelting flue gas, both domestically and internationally, primarily utilizes countercurrent contact wet scrubbing for purification and cooling. This technology aims to cool and remove dust from the flue gas, thereby producing pure sulfur dioxide gas. In recent years, this technology has generally employed dynamic wave scrubbing combined with electrostatic demisting to achieve flue gas cooling and purification. However, even under policies requiring comprehensive reduction of contaminated acid wastewater emissions, the use of recycled dilute acid as a scrubbing fluid still presents challenges such as high disposal costs, significant resource consumption, and significant environmental risks associated with the storage of hazardous waste residues.
[0004] After purification, smelting flue gas can be converted to sulfuric acid. Based on the conversion principle of flue gas acidification and the optimal reaction temperature of the catalyst, the temperature entering the conversion process is generally required to be around 425°C. This not only facilitates the reaction but also facilitates heat recovery. Currently, the industry has widely adopted a "two-conversion, two-absorption" process to replace the traditional "one-conversion, one-absorption" process. This improves SO2 conversion rates and reduces exhaust gas content. Although this has reached the emission mass concentration limit, there are still some issues such as complex processes and the need for additional heating, which wastes resources.
[0005] Currently, this type of research primarily focuses on high-temperature filtration to achieve flue gas purification, using filters of various structures and materials, such as high-temperature metal membranes, fiber fabrics, and catalyst-loaded fiber membranes. While these methods address the issue of fine solid particles in flue gas to some extent, they still cannot significantly reduce sulfur trioxide, arsenic oxide, and non-ferrous metal oxides, leading to high acidity, high acid content, and a high concentration of non-ferrous metals in the waste gas. Summary of the Invention
[0006] In response to the problems of complex processes and the need for additional heating in the existing recovery of valuable metals and flue gas purification in sulfur-containing metallurgical flue gas, the present invention proposes a comprehensive recovery and utilization method for sulfur-containing metallurgical flue gas. High-temperature smelting flue gas is introduced into organic matter to achieve rapid condensation of valuable metal elements and reduction of flue gas with organic matter cracking products, thereby increasing the melting point of valuable metals and achieving the purpose of purifying flue gas.
[0007] A comprehensive recovery and utilization method for sulfur-containing metallurgical flue gas, comprising the following specific steps: (1) High-temperature metallurgical flue gas containing SO3 is introduced into a furnace containing organic matter. The organic matter absorbs heat and pyrolyzes to generate reducing pyrolysis gas. The SO3 in the metallurgical flue gas is reduced to SO2, and the temperature is lowered to maintain the reducing property of the metallurgical flue gas. At the same time, the valuable metals in the metallurgical flue gas are quickly condensed into a metal condensed phase and separated from the flue gas. (2) The flue gas obtained from the reaction in step (1) is subjected to dust removal treatment to remove ash from the flue gas; (3) Separating the reducing pyrolysis gas and SO2 gas from the gas subjected to the dust removal treatment in step (2), and collecting the reducing pyrolysis gas; (4) Oxidizing the SO2 gas obtained in step (3) to generate SO3 gas for acid production to obtain sulfuric acid (using 98.3% concentrated sulfuric acid to absorb the SO3 gas, and then diluting it with deionized water or dilute sulfuric acid to produce sulfuric acid of the required concentration).
[0008] The temperature of the high-temperature SO3-containing metallurgical flue gas in step (1) is 1423-1523K.
[0009] The reducing pyrolysis gas in step (1) is H2, CO and CH4.
[0010] The reducing pyrolysis gas contains 5-20 vol.% H, 30-90 vol.% CO and 5-20 vol.% CH.
[0011] Since the flue gas changes from oxidizing to reducing, sulfuric acid is not easily generated when it comes into contact with water during the dust removal process. Therefore, dust removal can be carried out under certain moisture conditions. Preferably, the dust removal method in step (2) is spray dust removal, gravity dust removal, inertial dust removal, cyclone dust removal, bag dust removal, electrostatic dust removal, explosion-proof dust removal or electrostatic dust removal. Taking into account the dust removal conditions and dust removal efficiency, it is more preferred that the dust removal method in step (2) is bag dust removal, electrostatic dust removal or spray dust removal.
[0012] Preferably, the gas separation method in step (3) is adsorption, deep freezing, membrane separation or low-temperature pressurized distillation. The adsorption method relies on the difference in adsorption capacity of solid adsorbents for each component. The adsorbent can be activated carbon, silica gel, activated alumina and zeolite molecular sieve. The adsorption method can not only effectively separate gases, but also convert low-concentration SO2 into SO3; the deep freezing method liquefies the flue gas, resulting in the separation of gas and liquid concentrations; the membrane separation method uses the different permeation effects of various substances in the raw gas on the membrane material to achieve gas separation with the pressure difference of the gas on both sides of the membrane as the actual power; the low-temperature pressurized distillation method pressurizes the raw air through an air compressor, and then removes water, carbon dioxide and other substances that are solid at low temperatures through a molecular sieve. After the high-pressure air is isentropically expanded by an expander, the temperature is reduced, and multiple streams of air in different temperature and pressure states enter the distillation tower to achieve gas separation.
[0013] Preferably, the oxidation method in step (4) is: introducing oxygen into the SO2 gas, and catalytically oxidizing it under the action of a catalyst to generate SO3 gas.
[0014] Preferably, the catalyst can be selected from vanadium pentoxide, metallic platinum, iron oxide, cesium oxide modified vanadium catalyst, cerium oxide, chromium oxide, titanium oxide supported catalyst or copper oxide.
[0015] The acid production method is as follows: for low-concentration flue gas with a SO2 mass fraction of 0.05% to 4%, a non-steady-state conversion technology is used to directly produce acid; for high-concentration flue gas with a SO2 mass fraction greater than 20% generated during oxygen-enriched enhanced smelting, acid is produced by mixing partially reacted SO3 into the circulating flue gas entering the converter.
[0016] Principle of organic matter reduction of flue gas: When the temperature is higher than 200℃, organic matter undergoes pyrolysis to generate reducing gases such as CO2, H2, CO and CH4; the generated pyrolysis gases include CO2, CO, H2, CH4, etc., among which CO, H2, CH4, etc. can be used as gaseous reducing agents for reduction. At the same time, as the pyrolysis temperature increases, the proportion of reducing gases CO and CH4 increases significantly, and the gaseous reducing agents generated by the pyrolysis of organic matter react with the oxidizing flue gas to undergo a reduction reaction; the reactions involved in the reduction process are thermodynamically calculated to obtain the relationship curve between the reaction Gibbs free energy and the reaction temperature, as shown in the figure. Figures 1-3 ; Calculation of the Gibbs free energy of the reaction shows that gaseous reducing agents such as H2, CH4, and CO produced by the pyrolysis of organic matter have the ability to reduce polluted acid at low temperatures.
[0017] The present invention comprehensively recycles and utilizes the flue gas before the generation of waste acid, and uses gaseous reducing agents such as H2, CH4, and CO generated by the thermal decomposition of organic matter to reduce the impurity elements in the flue gas. Compared with conventional waste acid treatment and waste acid reduction modes, the invention uses cheap organic matter to generate usable gas reducing agents, and at the same time uses gases such as H2, CH4, and CO to reduce SO3 in the flue gas to obtain a large amount of SO2 without generating other harmful gases. The thermal decomposition of organic matter absorbs heat to cool the flue gas, forcing the valuable elements to quickly condense into a metal condensed phase to separate from the flue gas. This process does not require additional heat, and arsenic and lead are easy to recover and have a high recovery rate. At a temperature of 400~600℃ and in the presence of a catalyst (optionally vanadium pentoxide), SO2 can be oxidized by O2 to SO3. The reaction formula for the generation of SO3 in flue gas is: 2SO2(g)+O2(g)=2SO3(g). The equilibrium curve for the conversion of SO2 to SO3 is shown as follows: Figure 4 .
[0018] The beneficial effects of the present invention are: (1) The present invention absorbs flue gas with organic matter, causing the temperature to drop rapidly and arsenic and lead to condense quickly, thereby facilitating the recovery of heavy metal elements and reducing the amount of arsenic-containing waste, thereby realizing resource utilization of arsenic elements; (2) The present invention reduces SO3 in the flue gas by generating reducing gas through pyrolysis of organic matter and lowering the temperature to maintain the reducing property of the metallurgical flue gas, thereby inhibiting the conversion of SO2 into SO3 and suppressing the generation of polluted acid from the source; (3) The present invention utilizes the characteristics of organic matter pyrolysis to absorb heat and provide a reducing atmosphere, thereby reducing the temperature and oxidizing properties of smelting flue gas, avoiding pollution to the environment, and achieving efficient and rapid recovery of valuable metal elements and recycling of sulfur elements. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 Thermodynamic calculation of the reduction process of reducing gas H2; Figure 2 Thermodynamic calculation of the reduction process of reducing gas CH4; Figure 3 Thermodynamic calculation of the reduction process of reducing gas CO; Figure 4 is the equilibrium curve for the conversion of SO2 to SO3; Figure 5 This is a phase analysis diagram of arsenic-containing flue gas at a reaction temperature of 700°C in Example 1; Figure 6 is the arsenic removal rate of flue gas at different reaction temperatures in Example 1; Figure 7 This is a graph showing the direct yield of valuable elements in flue gas at different reaction temperatures in Example 1. DETAILED DESCRIPTION
[0020] The present invention will be further described in detail below in conjunction with specific embodiments, but the protection scope of the present invention is not limited to the contents described above.
[0021] Example 1: The metallurgical flue gas containing SO3 in this example (main components are shown in Table 1) is the flue gas generated by copper flash smelting; Table 1 Main components of metallurgical flue gas containing SO3 in this embodiment element As Pb Zn S Bi Sn Cu Fe Si K Sb content(%) 14.14 12.33 15.00 6.59 4.33 1.06 3.31 4.60 0.69 0.38 0.24 A comprehensive recovery and utilization method for sulfur-containing metallurgical flue gas, comprising the following specific steps: (1) Under normal pressure, high-temperature (1423-1523K) metallurgical flue gas containing SO3 is introduced into a furnace filled with organic matter (pine wood chips). The ambient temperature in the furnace is controlled at 400℃, 500℃, 600℃, 700℃, and 800℃, respectively. The organic matter absorbs heat and pyrolyzes to generate reducing pyrolysis gas (5.27vol% H2, 55.50vol% CO, 8.89vol% CH4 in the pyrolysis gas, and the rest is CO2). The SO3 in the metallurgical flue gas is reduced to SO2, and the temperature is lowered to maintain the reducing property of the metallurgical flue gas. At the same time, the valuable metals in the metallurgical flue gas are quickly condensed into a metal condensed phase and separated from the flue gas. (2) The flue gas obtained from the reaction in step (1) is subjected to dust removal treatment (bag dust collector) to remove ash from the flue gas; (3) performing gas separation (using activated carbon as adsorbent) on the reducing pyrolysis gas (H2, CO and CH4) and SO2 gas in the gas subjected to dust removal in step (2), and collecting the reducing pyrolysis gas; (4) introducing the SO2 gas obtained by desorption in step (3) into a reactor body containing a vanadium pentoxide catalyst, introducing oxygen, and oxidizing it at a temperature of 673-773 K to generate SO3 gas, using concentrated sulfuric acid with a mass concentration of 98.3% to absorb SO3 for acid production, and then cooling and diluting it with deionized water or dilute sulfuric acid to obtain sulfuric acid of the desired concentration; The arsenic removal rate of flue gas at different reaction temperatures in this embodiment is shown in Figure 6 , the direct yield of valuable elements in flue gas at different reaction temperatures is shown in the figure Figure 7 ;from Figure 6 It can be seen that as the temperature increases, the weight loss rate increases, but the arsenic removal rate reaches the maximum at 700 degrees Celsius; Figure 7 It can be seen that the direct recovery rates of Pb, Zn, and Bi show a trend of first decreasing and then increasing with increasing temperature, while the direct recovery rates of Cu and Sn show a trend of first increasing and then decreasing with increasing temperature. In summary, at 700℃, the direct recovery rates of various elements are relatively high; Therefore, the optimal reaction temperature of the biomass pyrolysis reducing gas and metallurgical flue gas in this embodiment is 700° C., the arsenic removal rate of the flue gas can reach 95.18%, and the direct recovery rate of lead can reach 98.24%.
[0022] Example 2: The metallurgical flue gas containing SO3 in this example (see Table 2 for main components) is the flue gas generated during the oxygen-enriched top-blown smelting process of copper; Table 2 Main components of metallurgical flue gas containing SO3 in this embodiment element As Pb Zn S Bi Sn Cu Fe Si K Sb content(%) 14.12 12.66 15.89 7.59 3.33 1.68 3.38 4.60 0.79 0.39 0.27 A comprehensive recovery and utilization method for sulfur-containing metallurgical flue gas, comprising the following specific steps: (1) Under normal pressure, high-temperature (1423-1523K) metallurgical flue gas containing SO3 is introduced into a furnace containing organic matter (rice husk). The ambient temperature inside the furnace is controlled at 700℃. The organic matter absorbs heat and pyrolyzes to generate reducing pyrolysis gas (4.87vol% H2, 45.50vol% CO, 5.89vol% CH4, and the rest is CO2 in the pyrolysis gas). The SO3 in the metallurgical flue gas is reduced to SO2, and the temperature is lowered to maintain the reducing property of the metallurgical flue gas. At the same time, the valuable metals in the metallurgical flue gas are quickly condensed into a metal condensed phase and separated from the flue gas. (2) The flue gas obtained from the reaction in step (1) is subjected to dust removal treatment (spray dust removal) to remove ash from the flue gas; (3) The reducing pyrolysis gas (H2, CO and CH4) and SO2 gas in the dust removal treatment of step (2) are separated (deep freezing method), and the reducing pyrolysis gas is collected; the specific steps of the deep freezing method are: 1) The gas is pressurized to 5-6 MPa by the compressor; 2) The compressed gas enters the main heat exchanger and exchanges heat with the returning low-temperature product gas (nitrogen, oxygen) to cool down to below -160°C; 3) Part of the high-pressure gas is adiabatically expanded to 0.5 MPa in the turbine expander, and the temperature drops sharply to below -190°C to provide cooling; 4) The remaining high-pressure gas is depressurized and liquefied through the throttle valve, and the refrigeration of the expander is coordinated to achieve overall liquefaction of the gas; 5) Liquid gas is initially separated in a high-pressure tower (0.5-0.6 MPa); 6) Distillation is carried out in a low-pressure tower (0.1-0.15MPa), with reducing gas produced at the bottom and high-purity SO2 at the top; 7) The separated gas is reheated to room temperature through the main heat exchanger and output in gaseous form or stored in low-temperature liquid form; (4) The SO2 gas separated in step (3) is introduced into a reactor body containing a platinum catalyst, oxygen is introduced, and SO3 gas is oxidized at a temperature of 673-773 K. Concentrated sulfuric acid with a mass concentration of 98.3% is used to absorb SO3 for acid production. After cooling, the gas is diluted with deionized water or dilute sulfuric acid to obtain sulfuric acid of the desired concentration; In this embodiment, the reaction temperature of the biomass pyrolysis reducing gas and the metallurgical flue gas is 700° C., the arsenic removal rate of the flue gas can reach 94.2%, and the direct recovery rate of lead can reach 96.6%.
[0023] Example 3: The metallurgical flue gas containing SO3 in this example (see Table 3 for main components) is the flue gas generated during the lead oxygen-enriched blown smelting process; Table 3 Main components of metallurgical flue gas containing SO3 in this embodiment element As Pb Zn S Bi Sn Cu Fe Si K Sb content(%) 12.42 2.66 3.89 6.88 3.54 2.43 13.82 4.60 0.39 0.33 0.17 A comprehensive recovery and utilization method for sulfur-containing metallurgical flue gas, comprising the following specific steps: (1) Under normal pressure, high-temperature (1423-1523K) metallurgical flue gas containing SO3 is introduced into a furnace containing organic matter (sugar cane). The ambient temperature in the furnace is controlled at 700℃. The organic matter absorbs heat and pyrolyzes to generate reducing pyrolysis gas (19.44vol% H2, 30.34vol% CO, 5.58vol% CH4, and the rest is CO2 in the pyrolysis gas). The SO3 in the metallurgical flue gas is reduced to SO2, and the temperature is lowered to maintain the reducing property of the metallurgical flue gas. At the same time, the valuable metals in the metallurgical flue gas are quickly condensed into a metal condensed phase and separated from the flue gas. (2) The flue gas obtained from the reaction in step (1) is subjected to dust removal treatment (electrostatic precipitator) to remove ash from the flue gas; (3) Separating the reducing pyrolysis gas (H2, CO and CH4) from the SO2 gas in the dust removal treatment of step (2) (low temperature pressurized distillation method) and collecting the reducing pyrolysis gas; The specific steps of the low temperature pressure distillation method are: 1) Pressurize the gas to 2.0–3.0 MPa to increase the boiling point of the components; 2) The compressed gas is pre-cooled to -30℃ to -50℃ through the heat exchanger; 3) The pre-cooled air enters the refrigeration unit and is further cooled to below -100°C, liquefying most of the components; 4) The liquefied mixed gas is separated in a high-pressure distillation tower (-90℃~-60℃), and methane and hydrogen gases are produced at the top of the tower; 5) The bottom liquid is sent to the medium-pressure tower to separate the SO2 gas; (4) The SO2 gas separated in step (3) is introduced into a reactor body containing a catalyst, iron oxide, and oxygen is introduced to oxidize the SO3 gas at a temperature of 673-773 K. The SO3 gas is absorbed by concentrated sulfuric acid with a mass concentration of 98.3% to produce acid. After cooling, the gas is diluted with deionized water or dilute sulfuric acid to obtain sulfuric acid of the desired concentration. In this embodiment, the reaction temperature of the biomass pyrolysis reducing gas and the metallurgical flue gas is 700° C., the arsenic removal rate of the flue gas can reach 94.6%, and the direct recovery rate of lead can reach 97.8%.
[0024] Example 4: The metallurgical flue gas containing SO3 in this example (main components are shown in Table 4) is the flue gas generated during the boiling roasting process of zinc; Table 4 Main components of metallurgical flue gas containing SO3 in this embodiment element As Pb Zn S Bi Sn Cu Fe Si K Sb content(%) 15.33 2.54 5.23 7.59 3.33 1.68 12.38 2.57 0.99 1.21 0.56 A comprehensive recovery and utilization method for sulfur-containing metallurgical flue gas, comprising the following specific steps: (1) Under normal pressure, high-temperature (1423~1523K) metallurgical flue gas containing SO3 is introduced into a furnace body filled with organic matter (waste gas grease), and the ambient temperature in the furnace body is controlled at 700℃. The organic matter absorbs heat and pyrolyzes to generate reducing pyrolysis gas (5.34vol%H2, 30.50vol%CO, 19.67vol%CH4 in the pyrolysis gas, and the rest is CO2). The SO3 in the metallurgical flue gas is reduced to SO2 and the temperature is lowered to maintain the reducing property of the metallurgical flue gas. At the same time, the valuable metals in the metallurgical flue gas are quickly condensed into a metal condensed phase and separated from the flue gas. (2) The flue gas obtained from the reaction in step (1) is subjected to dust removal treatment (cyclone dust removal) to remove ash from the flue gas; (3) performing gas separation (membrane separation method) on the reducing pyrolysis gas (H2, CO and CH4) and SO2 gas in the gas subjected to the dust removal treatment in step (2), and collecting the reducing pyrolysis gas; The specific steps of the membrane separation method are: 1) The mixed gas passes through the dust removal and demisting device to remove solid particles and droplets to avoid clogging of the membrane components; 2) Gas pressurization to 0.5–2.0 MPa drives the separation process and increases the permeation rate; 3) When the mixed gas passes through the polyimide or cellulose acetate membrane, SO2 preferentially dissolves and diffuses through the membrane layer, while the reducing gas is retained on the high-pressure side due to its low permeability; 4) The low-pressure side of the membrane produces SO2-rich gas (concentration increased to 30-60%) and enters the subsequent recovery system; 5) The high-pressure side outputs the retained gas containing high-purity reducing gases (such as H2S, CO), with residual SO2 < 0.1%; (4) introducing the SO2 gas separated in step (3) into a reactor containing a cesium oxide-modified vanadium catalyst, introducing oxygen, and oxidizing it at a temperature of 673-773 K to generate SO3 gas, using concentrated sulfuric acid with a mass concentration of 98.3% to absorb SO3 for acid production, and then cooling and diluting it with deionized water or dilute sulfuric acid to obtain sulfuric acid of the desired concentration; In this embodiment, the reaction temperature of the biomass pyrolysis reducing gas and the metallurgical flue gas is 700° C., the arsenic removal rate of the flue gas can reach 94.8%, and the direct recovery rate of lead can reach 97.5%.
[0025] Example 5: The metallurgical flue gas containing SO3 in this example (see Table 5 for main components) is the flue gas generated during the oxygen-enriched top-blown smelting process of nickel matte; Table 5 Main components of metallurgical flue gas containing SO3 in this embodiment element As Pb Zn S Bi Sn Cu Fe Si K Sb content(%) 14.12 13.66 14.89 7.59 3.33 1.68 13.38 2.60 0.79 0.39 0.27 A comprehensive recovery and utilization method for sulfur-containing metallurgical flue gas, comprising the following specific steps: (1) Under normal pressure, high-temperature (1423-1523K) metallurgical flue gas containing SO3 is introduced into a furnace containing organic matter (Miscanthus sinensis). The ambient temperature inside the furnace is controlled at 700℃. The organic matter absorbs heat and pyrolyzes to generate reducing pyrolysis gas (19.27vol% H2, 69.50vol% CO, 5.89vol% CH4, and the rest is CO2 in the pyrolysis gas). The SO3 in the metallurgical flue gas is reduced to SO2, and the temperature is lowered to maintain the reducing property of the metallurgical flue gas. At the same time, the valuable metals in the metallurgical flue gas are quickly condensed into a metal condensed phase and separated from the flue gas. (2) The flue gas obtained from the reaction in step (1) is subjected to dust removal treatment (electrostatic separator dust removal) to remove ash from the flue gas; (3) performing gas separation (using adsorbent silica gel) on the reducing pyrolysis gas (H2, CO and CH4) and SO2 gas in the gas subjected to dust removal in step (2), and collecting the reducing pyrolysis gas; (4) The SO2 gas separated in step (3) is introduced into a reactor body containing a cerium oxide catalyst, and oxygen is introduced to oxidize the SO3 gas at a temperature of 673-773 K. The SO3 gas is absorbed by concentrated sulfuric acid with a mass concentration of 98.3% to produce acid. After cooling, the gas is diluted with deionized water or dilute sulfuric acid to obtain sulfuric acid of the desired concentration. In this embodiment, the reaction temperature of the biomass pyrolysis reducing gas and the metallurgical flue gas is 700° C., the arsenic removal rate of the flue gas can reach 95.18%, and the direct recovery rate of lead can reach 98.24%.
[0026] Example 6: The metallurgical flue gas containing SO3 in this example (main components are shown in Table 6) is the flue gas generated during the smelting process of cobalt sulfide ore; Table 6 Main components of metallurgical flue gas containing SO3 in this embodiment element As Pb Zn S Co Sn Cu Fe Si K Sb content(%) 14.12 12.34 15.25 7.59 3.23 1.68 13.38 4.60 0.79 0.39 0.27 A comprehensive recovery and utilization method for sulfur-containing metallurgical flue gas, comprising the following specific steps: (1) Under normal pressure, high-temperature (1423-1523K) metallurgical flue gas containing SO3 is introduced into a furnace containing organic matter (soybean). The ambient temperature in the furnace is controlled at 700℃. The organic matter absorbs heat and pyrolyzes to generate reducing pyrolysis gas (5.45vol%H2, 79.85vol%CO, 19.63vol%CH4, and the rest is CO2 in the pyrolysis gas). The SO3 in the metallurgical flue gas is reduced to SO2, and the temperature is lowered to maintain the reducing property of the metallurgical flue gas. At the same time, the valuable metals in the metallurgical flue gas are quickly condensed into a metal condensed phase and separated from the flue gas. (2) The flue gas obtained from the reaction in step (1) is subjected to dust removal treatment (bag dust removal) to remove ash from the flue gas; (3) performing gas separation (using adsorbent silica gel) on the reducing pyrolysis gas (H2, CO and CH4) and SO2 gas in the gas subjected to dust removal in step (2), and collecting the reducing pyrolysis gas; (4) The SO2 gas separated in step (3) is introduced into a reactor body containing a chromium oxide catalyst, oxygen is introduced, and SO3 gas is oxidized at a temperature of 673-773 K. Concentrated sulfuric acid with a mass concentration of 98.3% is used to absorb SO3 for acid production. After cooling, the gas is diluted with deionized water or dilute sulfuric acid to obtain sulfuric acid of the desired concentration; In this embodiment, the reaction temperature of the biomass pyrolysis reducing gas and the metallurgical flue gas is 700° C., the arsenic removal rate of the flue gas can reach 95.3%, and the direct recovery rate of lead can reach 97.2%.
[0027] Example 7: The metallurgical flue gas containing SO3 in this example (the main components are shown in Table 7) is the flue gas generated during the antimony vortex smelting process; Table 7 Main components of metallurgical flue gas containing SO3 in this embodiment element As Pb Zn S Bi Sn Cu Fe Si K Sb content(%) 13.12 11.99 16.89 7.59 3.33 1.68 13.38 4.60 0.79 0.39 3.27 A comprehensive recovery and utilization method for sulfur-containing metallurgical flue gas, comprising the following specific steps: (1) Under normal pressure, high-temperature (1423-1523K) metallurgical flue gas containing SO3 is introduced into a furnace containing organic matter (pig excrement). The ambient temperature inside the furnace is controlled at 700℃. The organic matter absorbs heat and pyrolyzes to generate reducing pyrolysis gas (5.12vol% H2, 70.50vol% CO, 19.84vol% CH4, and the rest is CO2 in the pyrolysis gas). The SO3 in the metallurgical flue gas is reduced to SO2, and the temperature is lowered to maintain the reducing property of the metallurgical flue gas. At the same time, the valuable metals in the metallurgical flue gas are quickly condensed into a metal condensed phase and separated from the flue gas. (2) The flue gas obtained from the reaction in step (1) is subjected to dust removal treatment (bag dust removal) to remove ash from the flue gas; (3) performing gas separation (using activated alumina as adsorbent) on the reducing pyrolysis gas (H2, CO and CH4) and SO2 gas in the gas subjected to dust removal in step (2), and collecting the reducing pyrolysis gas; (4) introducing the SO2 gas separated in step (3) into a reactor containing a titanium oxide-supported catalyst, introducing oxygen, and oxidizing it at a temperature of 673-773 K to generate SO3 gas, using concentrated sulfuric acid with a mass concentration of 98.3% to absorb SO3 for acid production, and then cooling and diluting it with deionized water or dilute sulfuric acid to obtain sulfuric acid of the desired concentration; In this embodiment, the reaction temperature of the biomass pyrolysis reducing gas and the metallurgical flue gas is 700° C., the arsenic removal rate of the flue gas can reach 95.18%, and the direct recovery rate of lead can reach 98.24%.
[0028] Example 8: The metallurgical flue gas containing SO3 in this example (see Table 8 for main components) is the flue gas generated during the boiling roasting process of mercury ore; Table 8 Main components of metallurgical flue gas containing SO3 in this embodiment element As Pb Zn S Hg Sn Cu Fe Si K Sb content(%) 13.08 11.54 13.24 8.14 4.23 1.68 9.77 4.24 0.52 0.23 0.33 A comprehensive recovery and utilization method for sulfur-containing metallurgical flue gas, comprising the following specific steps: (1) Under normal pressure, high-temperature (1423-1523K) metallurgical flue gas containing SO3 is introduced into a furnace containing organic matter (fruit shells). The ambient temperature in the furnace is controlled at 700℃. The organic matter absorbs heat and pyrolyzes to generate reducing pyrolysis gas (5.89vol% H2, 80.34vol% CO, 5.66vol% CH4, and the rest is CO2 in the pyrolysis gas). The SO3 in the metallurgical flue gas is reduced to SO2, and the temperature is lowered to maintain the reducing property of the metallurgical flue gas. At the same time, the valuable metals in the metallurgical flue gas are quickly condensed into a metal condensed phase and separated from the flue gas. (2) The flue gas obtained from the reaction in step (1) is subjected to dust removal treatment (bag dust removal) to remove ash from the flue gas; (3) performing gas separation (using adsorbent zeolite molecular sieve) on the reducing pyrolysis gas (H2, CO and CH4) and SO2 gas in the gas subjected to dust removal in step (2), and collecting the reducing pyrolysis gas; (4) The SO2 gas separated in step (3) is introduced into a reactor body containing a copper oxide catalyst, oxygen is introduced, and SO3 gas is oxidized at a temperature of 673-773 K. Concentrated sulfuric acid with a mass concentration of 98.3% is used to absorb SO3 for acid production. After cooling, the gas is diluted with deionized water or dilute sulfuric acid to obtain sulfuric acid of the desired concentration; In this embodiment, the reaction temperature of the biomass pyrolysis reducing gas and the metallurgical flue gas is 700° C., the arsenic removal rate of the flue gas can reach 95.3%, and the direct recovery rate of lead can reach 97.2%.
[0029] The above describes the specific embodiments of the present invention in detail, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in this field without departing from the scope of the present invention.
Claims
1. A comprehensive recovery and utilization method for sulfur-containing metallurgical flue gas, characterized in that: The specific steps are as follows: (1) High-temperature metallurgical flue gas containing SO3 is introduced into a furnace containing organic matter. The organic matter absorbs heat and pyrolyzes to generate reducing pyrolysis gas. The SO3 in the metallurgical flue gas is reduced to SO2, and the temperature is lowered to maintain the reducing property of the metallurgical flue gas. At the same time, the valuable metals in the metallurgical flue gas are quickly condensed into a metal condensed phase and separated from the flue gas. (2) The flue gas obtained from the reaction in step (1) is subjected to dust removal treatment to remove ash from the flue gas; (3) Separating the reducing pyrolysis gas and SO2 gas from the gas subjected to the dust removal treatment in step (2), and collecting the reducing pyrolysis gas; (4) The SO2 gas obtained in step (3) is oxidized to generate SO3 gas for acid production to obtain sulfuric acid.
2. The comprehensive recovery and utilization method of sulfur-containing metallurgical flue gas according to claim 1, characterized in that: The temperature of the high-temperature SO3-containing metallurgical flue gas in step (1) is 1423~1523K.
3. The comprehensive recovery and utilization method of sulfur-containing metallurgical flue gas according to claim 1, characterized in that: The reducing pyrolysis gases in step (1) are H2, CO and CH4.
4. The comprehensive recovery and utilization method of sulfur-containing metallurgical flue gas according to claim 3, characterized in that: The reducing pyrolysis gas contains H25~20vol.%, CO30~90vol.% and CH45~20vol.%.
5. The comprehensive recovery and utilization method of sulfur-containing metallurgical flue gas according to claim 1, characterized in that: The dust removal method in step (2) is spray dust removal, gravity dust collector dust removal, inertial dust collector dust removal, cyclone separator dust removal, bag dust collector dust removal, electrostatic dust collector dust removal, explosion-proof dust collector dust removal or electric dust collector dust removal.
6. The comprehensive recovery and utilization method of sulfur-containing metallurgical flue gas according to claim 1, characterized in that: The gas separation method in step (3) is adsorption, deep freezing, membrane separation or low-temperature pressure distillation.
7. The comprehensive recovery and utilization method of sulfur-containing metallurgical flue gas according to claim 1, characterized in that: The oxidation method in step (4) is as follows: oxygen is introduced into the SO2 gas, and catalytic oxidation is performed under the action of a catalyst to generate SO3 gas.