Lead-copper anode slime flue gas treatment device

Abstract

The utility model relates to non ferrous metal smelting waste gas treatment technical field, concretely relates to a kind of lead copper anode slime flue gas treatment device, including the dust removal unit, oxidation unit, water spray tower, alkali spray tower and demisting unit connected in sequence by pipeline;The oxidation unit includes ozone generator and at least two levels of ozone dosing ring, the ozone dosing ring is spaced apart and is arranged on the connecting pipeline between dust removal unit and water spray tower, and the ozone generator supplies ozone to connecting pipeline by ozone dosing ring;Water solution is sprayed in the water spray tower;Alkaline solution is sprayed in the alkali spray tower.The utility model is by using ozone gradient oxidation coupling multistage absorption technology, realizes the multi-pollutant collaborative deep treatment of lead copper anode slime smelting flue gas, improves denitration efficiency, improves the problem that traditional alkali method desulfurization tower accumulates much slag, needs frequent shutdown cleaning.

Description

Technical Field

[0001] This utility model relates to the field of waste gas treatment technology in non-ferrous metal smelting, specifically to a device for treating lead-copper anode mud flue gas. Background Technology

[0002] Lead-copper anode sludge is a byproduct of copper and lead electrolytic refining, typically containing precious metals (such as gold and silver), heavy metals (such as lead, copper, and arsenic), and impurities such as sulfur and fluorine. During pyrometallurgical or hydrometallurgical processes, flue gas containing high concentrations of SO2, NOx (NO, NO2), HF, dust, and heavy metal particles is generated. If these pollutants are not effectively treated, they can cause serious harm to the environment and human health.

[0003] Currently, the treatment of flue gas from lead-copper anode sludge typically employs a combined process of "bag filter dust collection + wet desulfurization (such as limestone-gypsum method, sodium alkali method) + denitrification (such as SCR / SNCR)". In practical applications, traditional wet desulfurization processes have poor absorption efficiency for NOx (especially NO), usually requiring the addition of SCR (selective catalytic reduction) or ozone oxidation to enhance denitrification. This results in low denitrification efficiency and the risk of secondary pollution. Furthermore, the strong acidic gases such as HF and SO3 in the flue gas not only easily corrode equipment but also readily react with desulfurizing agents to form insoluble compounds such as fluorosilicates and sulfates, which crystallize and precipitate within the desulfurization tower, leading to severe scaling and blockage of the packing, spray layer, and pipelines.

[0004] Therefore, there is an urgent need for a flue gas treatment device that can adapt to the characteristics of lead-copper anode mud flue gas and achieve synergistic and efficient removal of multiple pollutants. Summary of the Invention

[0005] This invention addresses the problems of low denitrification efficiency, equipment corrosion, and easy scaling and clogging of lead-copper anode mud flue gas in existing treatment methods. It provides a lead-copper anode mud flue gas treatment device that utilizes ozone gradient oxidation coupled with multi-stage absorption technology to achieve synergistic and in-depth treatment of multiple pollutants in lead-copper anode mud smelting flue gas. This improves denitrification efficiency and alleviates the problems of excessive slag accumulation and frequent shutdowns for cleaning required in traditional alkaline desulfurization towers.

[0006] To achieve the above objectives, the technical solution of this utility model is as follows: A lead-copper anode sludge flue gas treatment device includes a dust removal unit, an oxidation unit, a water spray tower, an alkali spray tower, and a demisting unit connected in sequence by pipelines. The dust removal unit includes a flue gas inlet, through which the lead-copper anode mud flue gas enters the dust removal unit and, after dust removal, enters the oxidation unit. The oxidation unit includes an ozone generator and at least two ozone dosing rings. The ozone dosing rings are spaced apart on the connecting pipe between the dust removal unit and the water spray tower. The ozone generator supplies ozone into the connecting pipe through the ozone dosing rings. The water spray tower sprays an aqueous solution; the alkali spray tower sprays an alkaline solution; the oxidized flue gas passes through the water spray tower and the alkali spray tower, and after being purified by the demisting unit, it leaves from the chimney. By adding ozone in a gradient, the amount of ozone used is reduced, the ozone utilization rate is improved, and the poorly soluble NO is efficiently converted into easily absorbed high-valence nitrogen oxides.

[0007] Furthermore, the dust removal unit is a gradient jet bag filter with a jetting pressure of 0.45–0.55 MPa and a filtration velocity ≤1 m / min. It is used to remove high-concentration flue gas containing toxic heavy metal particles such as lead, copper, and arsenic from lead-copper anode mud smelting flue gas.

[0008] Furthermore, the length of the connecting pipe is 50-100m, and the connecting pipe is equipped with two stages of ozone dosing rings, with a spacing of 20-30m between the ozone dosing rings. This promotes thorough mixing of flue gas and ozone.

[0009] Furthermore, the ozone generator supplies an ozone concentration of 100–120 g / Nm³, the primary ozone dosing ring has a dosing rate of 10–15 kg / h, and the secondary ozone dosing ring has a dosing rate of 5–10 kg / h. This gradient dosing method saves on usage while improving mixing efficiency.

[0010] Furthermore, both the water spray tower and the alkali spray tower are counter-current spray towers. This increases the contact area between the flue gas and the spray liquid, thereby improving the absorption effect.

[0011] Furthermore, the pH value of the circulating aqueous solution in the water spray tower is greater than 1. This is used to maintain the reaction environment of the water spray system and ensure that pollutants are efficiently transferred to the aqueous solution.

[0012] Furthermore, the pH value of the circulating alkaline solution in the alkaline spray tower is 8-9, and the liquid-to-gas ratio is 0.8-1 L / m³. This is used for deep removal of residual SO3, SO2, and acidic aerosols from flue gas, ensuring that the final emitted flue gas achieves ultra-low emissions.

[0013] Furthermore, the demisting unit is a high-frequency pulse electrostatic precipitator with a voltage of 40-60kV. The demisting unit is used to remove tiny droplets and aerosols entrained in the flue gas.

[0014] Furthermore, the water spray tower is equipped with multi-faceted spherical packing material, the flue gas inlet pipe is located at the bottom 1 / 3 of the tower body, and the liquid level of the circulating water solution is no higher than 1 / 4 of the tower body. This improves the purification effect of the water spray tower.

[0015] The beneficial effects of this utility model through the above technical solution are as follows: This invention employs ozone gradient oxidation coupled with multi-stage absorption technology, achieving the synergistic removal of NOx, SO2, HF, and heavy metal particles from flue gas through a combination of dust removal, segmented oxidation, water spraying, alkaline spraying, and demisting. After treatment, the flue gas emission indicators are significantly better than the requirements of the "Emission Standard of Pollutants for Copper, Nickel and Cobalt Industries" (GB 25467-2010).

[0016] This invention employs ozone oxidation for efficient denitrification, fundamentally eliminating the risk of ammonia escape and avoiding secondary pollution. On the other hand, most of the easily scaled substances in the flue gas are pre-removed in the water spray tower, thus completely solving the industry problem of excessive sludge accumulation and frequent shutdowns for cleaning in traditional alkaline desulfurization towers, ensuring the long-term stable operation of the system. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of this utility model; The attached diagram is labeled as follows: 1 is the dust removal unit, 2 is the ozone generator, 3 is the ozone dosing ring, 3-1 is the primary ozone dosing ring, 3-2 is the secondary ozone dosing ring, 4 is the water spray tower, 5 is the alkaline spray tower, 6 is the demisting unit, and 7 is the chimney. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings and specific embodiments: Example 1 like Figure 1 As shown in the figure, this embodiment provides a lead-copper anode sludge flue gas treatment device. The lead-copper anode sludge flue gas is a flue gas containing high concentrations of SO2, NOx (NO, NO2), HF, dust and heavy metal particles. Current lead-copper anode sludge flue gas pollution treatment facilities are simple, and the treatment processes are mainly based on ordinary bag dust collection processes and integrated desulfurization and denitrification processes. The treatment effects of these processes are low and cannot meet the requirements of deep treatment.

[0019] The lead-copper anode sludge flue gas treatment device of this utility model includes a dust removal unit 1, an oxidation unit, a water spray tower 4, an alkali spray tower 5, and a demisting unit 6 connected in sequence by pipelines. The dust removal unit 1 includes a flue gas inlet, through which the lead-copper anode sludge flue gas enters the dust removal unit 1. After dust removal, it sequentially enters the oxidation unit, water spray tower 4, alkali spray tower 5, and demisting unit 6, and is finally discharged from the chimney 7.

[0020] The dust removal unit 1 is used to remove high-concentration flue gas containing toxic heavy metal particles such as lead, copper, and arsenic from the smelting flue gas of lead-copper anode mud. In this embodiment, the dust removal unit 1 is a gradient jet-blown bag filter. Specifically, the dust collector is made of carbon steel, and the filter bags inside the dust collector are made of modified PTFE. The jet pressure is 0.45–0.55 MPa, and the filtration velocity is ≤1 m / min. In actual use, the PTFE filter bags are resistant to high temperatures and acid and alkali corrosion, and can effectively extend the service life of the bag filter at a jet pressure of 0.5 MPa.

[0021] The oxidation unit includes an ozone generator 2 and at least two ozone dosing rings 3. The ozone dosing rings 3 are spaced apart on the connecting pipe between the dust removal unit 1 and the water spray tower 4. The ozone generator 2 supplies ozone into the connecting pipe through the ozone dosing rings 3, oxidizing the water-insoluble NO in the flue gas into water-soluble high-valence nitrogen oxides, making them easier to be absorbed by water or alkaline solution, thus greatly improving the absorption efficiency of nitrogen oxides. Compared with the traditional SCR / SNCR denitrification process, the operating cost is lower and there is no risk of ammonia escape.

[0022] The use of the multi-stage ozone dosing ring 3 reduces the amount of ozone used and improves the ozone utilization rate, enabling NOx removal rates to reach over 95%. Specifically, the ozone dosing ring 3 is used to inject gas into the pipeline. The ozone dosing ring 3 includes an annular pipe arranged around the flue, and the surface of the annular pipe is provided with several nozzles. The nozzles are oriented at a specific angle towards the flue gas flow direction to ensure that ozone covers the entire cross-section of the flue.

[0023] In one possible implementation, the connecting pipe is made of fiberglass and has a length of 50-100m. Two-stage ozone dosing rings 3 are installed on the connecting pipe. Specifically, the dosing rate of the first-stage ozone dosing ring 3-1 is 10-15 kg / h, and the dosing rate of the second-stage ozone dosing ring 3-2 is 5-10 kg / h. The ozone generator 2 supplies an ozone concentration of 100-120 g / Nm³, the distance between the two-stage ozone dosing rings 3 is 20-30m, the flue gas residence time is 8-12 seconds, NO is oxidized to N₂O₅, and the ozone utilization rate is ≥95%.

[0024] The oxidized flue gas enters a water spray tower 4, where a circulating aqueous solution is sprayed. The pH value of the circulating aqueous solution in the water spray tower 4 is controlled to be greater than 1 through water replenishment and sludge discharge to maintain the reaction environment of the water spray system and ensure efficient transfer of pollutants to the aqueous solution for the removal of HF, SO2, and fine dust. Using the aqueous solution to absorb the large amounts of nitric acid and hydrofluoric acid generated after ozone oxidation and dissolve some of the SO2 can significantly reduce alkali consumption in the subsequent alkaline scrubbing tower, while also preventing the formation of difficult-to-treat scale such as calcium sulfate and calcium sulfite in the alkaline scrubbing tower due to excessively high pH. Preferably, the pH value of the circulating aqueous solution in the water spray tower 4 is between 1.5 and 3.5.

[0025] To improve the purification effect of the water spray tower 4, the water spray tower 4 is equipped with multi-faceted spherical packing, the flue gas inlet pipe is located at the bottom 1 / 3 of the tower body, and the liquid level of the circulating water solution is not higher than 1 / 4 of the tower body.

[0026] The washed flue gas is fed into an alkaline spray tower 5, which is configured to spray an alkaline solution. Both the water spray tower 4 and the alkaline spray tower 5 are counter-current spray towers. The pH value of the circulating alkaline solution in the alkaline spray tower 5 is 8-9, and the liquid-to-gas ratio is 0.8-1 L / m³. This solution is used to deeply remove residual SO3, SO2, and acidic aerosols from the flue gas, and to ensure that the final emitted flue gas achieves ultra-low emissions.

[0027] After oxidation, the flue gas passes through water spray tower 4 and alkali spray tower 5, and then enters the demisting unit 6, where it is finally purified. The demisting unit 6 is a high-frequency pulse electrostatic precipitator with an operating voltage of 40-60kV. It can efficiently remove PM2.5 and aerosols, ensuring that the final outlet flue gas temperature is ≤35℃ and the particulate matter concentration is ≤3mg / m³. This reduces the power consumption of the system's induced draft fan while ensuring that the flue gas meets emission standards.

[0028] The working principle of this utility model: I. Pretreatment and Oxidation: The high-temperature flue gas generated from the smelting of lead-copper anode mud first enters a gradient jet bag filter to remove most of the coarse dust containing heavy metals. The flue gas after dust removal enters the oxidation unit, where ozone is added through a two-stage ozone dosing ring to oxidize the water-insoluble nitric oxide (NO) in the flue gas into water-soluble dinitrogen pentoxide (N2O5) and other high-valence nitrogen oxides.

[0029] II. Acidic Absorption and Synergistic Denitrification: The oxidized flue gas enters the counter-current water spray tower 4, where hydrogen fluoride (HF) and sulfur dioxide (SO2) are efficiently and synergistically removed. Nitrogen oxides (such as N2O5) that have been oxidized by ozone are absorbed and converted into nitric acid, achieving efficient denitrification. This process also further captures fine dust.

[0030] III. Alkaline Fine Treatment and Deep Purification: The flue gas after water washing is introduced into the countercurrent alkaline spray tower 5. The alkaline solution deeply removes residual sulfur dioxide (SO2), sulfur trioxide (SO3) and acidic aerosols. Since most pollutants have been removed in the water spray tower 4, the load of this step is significantly reduced, which fundamentally avoids the scaling and clogging problems caused by excessively high reactant concentrations in the traditional alkaline process.

[0031] IV. Terminal Demisting and Standard Emission: Finally, the flue gas enters the high-frequency pulse electrostatic precipitator, where the residual PM2.5, aerosols and fine droplets in the flue gas are removed under the action of a high-voltage electric field, ensuring that the flue gas meets emission standards. The purified flue gas is discharged through chimney 7.

[0032] Example 2 A smelter processes 20,000 tons of lead-copper anode mud annually, with a processing capacity of 6 tons / hour. It processes 100 tons of wet lead-copper anode mud daily, producing 25 tons of flue gas. During smelting, the flue gas volume is 80,000-100,000 m³ / h, the dust collector area is 1700 m², and the flue gas velocity is 15.26 m / s. The pipeline between the ozone dosing ring and the inlet of the water spray tower is made of fiberglass and is 95 m long. The primary and secondary ozone consumption are 10-14 kg / h and 6-9 kg / h, respectively. The water spray tower has a diameter of 4 m and a height of 12 m, discharging approximately 6 m³ per day. The alkali desulfurization tower has a diameter of 5.4 m and a height of 12 m, discharging approximately 18 m³ per day. The electrostatic precipitator operates at 40-60 kV and 300-450 mA. The average nitrogen oxide, sulfur dioxide, and dust content of this unit from January to March 2025 are as follows: Average online data of a smelter from January to March 2025 (unit: mg / m³) The embodiments described above are merely preferred embodiments of this utility model and are not intended to limit the scope of implementation of this utility model. Therefore, all equivalent changes or modifications made to the structure, features and principles described in the patent claims of this utility model should be included within the scope of the patent application of this utility model.

Claims

1. A lead-copper anode slime flue gas treatment device, characterized in that, It includes a dust removal unit (1), an oxidation unit, a water spray tower (4), an alkali spray tower (5), and a demisting unit (6) connected in sequence by pipes. The dust removal unit (1) includes a flue gas inlet, and the lead-copper anode mud flue gas enters the dust removal unit (1) from the flue gas inlet and enters the oxidation unit after dust removal; The oxidation unit includes an ozone generator (2) and at least two ozone dosing rings (3). The ozone dosing rings (3) are spaced apart on the connecting pipe between the dust removal unit (1) and the water spray tower (4). The ozone generator (2) supplies ozone into the connecting pipe through the ozone dosing rings (3). The water spray tower (4) sprays an aqueous solution; the alkali spray tower (5) sprays an alkaline solution; the oxidized flue gas passes through the water spray tower (4) and the alkali spray tower (5), and after being purified by the demisting unit (6), it leaves from the chimney (7).

2. A lead-copper anode slime flue gas treatment device according to claim 1, characterized in that, The dust removal unit (1) is a gradient jet bag filter with a jet pressure of 0.45 to 0.55 MPa and a filtration velocity of ≤1 m / min.

3. A lead-copper anode slime flue gas treatment device according to claim 1, characterized in that, The length of the connecting pipe is 50 to 100 m, and two ozone dosing rings (3) are provided on the connecting pipe, with a spacing of 20 to 30 m between the ozone dosing rings (3).

4. The lead-copper anode sludge flue gas treatment device according to claim 3, characterized in that, The ozone generator (2) supplies an ozone concentration of 100-120 g / Nm³, the first-stage ozone dosing ring (3-1) adds 10-15 kg / h, and the second-stage ozone dosing ring (3-2) adds 5-10 kg / h.

5. A lead-copper anode slime flue gas treatment device according to claim 1, characterized in that, Both the water spray tower (4) and the alkali spray tower (5) are counter-current spray towers.

6. A lead-copper anode slime flue gas treatment device according to claim 1, characterized in that, The pH value of the circulating aqueous solution in the water spray tower (4) is greater than 1.

7. A lead-copper anode slime flue gas treatment device according to claim 1, characterized in that, The pH value of the circulating alkaline solution in the alkaline spray tower (5) is 8-9, and the liquid-to-gas ratio is 0.8-1L / m³.

8. A lead-copper anode slime flue gas treatment device according to claim 1, characterized in that, The demisting unit (6) is a high-frequency pulse electrostatic precipitator with a voltage of 40-60kV.

9. A lead-copper anode slime flue gas treatment device according to claim 1, characterized in that, The water spray tower (4) is equipped with multi-faceted spherical packing, the flue gas inlet pipe is located at the bottom 1 / 3 of the tower body, and the liquid level of the circulating water solution is not higher than 1 / 4 of the tower body.

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