A method for dust removal from copper smelting flue gas and comprehensive extraction of valuable metals from the flue gas.

Abstract

This invention provides a method for removing dust from copper smelting flue gas and comprehensively extracting valuable metals from the flue gas. The method includes the following steps: (1) After high-temperature filtration and dust removal, lead-, zinc-, copper-, and iron-containing flue gas is separated from arsenic-containing flue gas; (2) The arsenic-containing flue gas is subjected to electrostatic precipitator to obtain arsenic-containing flue gas; (3) The lead-, zinc-, copper-, and iron-containing flue gas is subjected to alkaline leaching, ammonia leaching, and acid leaching in sequence to achieve stepwise separation and recovery of zinc, copper, iron, and lead. The method of this invention achieves the reduction of arsenic-containing flue gas from copper smelting and the comprehensive extraction and separation of multiple valuable metals. It separates arsenic-containing flue gas from the source, reduces the amount of hazardous waste disposal, and achieves targeted extraction and recovery of valuable metals through a specific leaching sequence, making it suitable for widespread application.

Description

Technical Field

[0001] This invention relates to the fields of non-ferrous metallurgy and solid waste resource recycling technology, and in particular to a method for removing dust from copper smelting flue gas and comprehensively extracting valuable metals from the flue gas. Background Technology

[0002] In recent years, there has been a severe shortage of high-grade copper ore, making it essential to recover and utilize flue gas dust from smelting fumes with a copper content of nearly 10%.

[0003] Current copper smelting flue gas is treated with electrostatic precipitators at approximately 300°C. The collected flue gas contains not only copper but also large amounts of arsenic compounds and elements such as lead, zinc, and iron. These require separate harmless separation and resource recovery to obtain copper concentrate. Existing inventions primarily target the collected high-arsenic flue gas, employing pyrometallurgical, hydrometallurgical, and combined methods for harmless and resource-efficient treatment.

[0004] CN113731048A discloses an arsenic recovery system and method for dioxin-containing smelting flue gas. The system captures metal dust through high-temperature filtration in a primary dust collector, reduces dioxin formation and absorbs SOx through rapid cooling with water and alkaline solution, and then collects arsenic dust through a secondary dust collector, thus achieving source separation of metal dust and arsenic dust. However, the rapid cooling temperature is lower than the sublimation temperature of As2O3, and some As2O3 condenses into the cooling liquid, generating arsenic-containing waste liquid.

[0005] CN218872510U discloses a device for treating arsenic-containing flue gas. The device removes dust using an electrostatic precipitator, followed by a cooling tank. While water is sprayed to cool the gas, As2O3 crystals precipitate and enter a crystallization collection cylinder at the bottom of the tank. Since the dust removal temperature range of the electrostatic precipitator overlaps with the sublimation temperature range of As2O3, the collected dust may still contain arsenic.

[0006] CN107779607A discloses a method for efficiently separating copper and arsenic from high-arsenic flue dust. The method involves pulping the high-arsenic flue dust using appropriate amounts of water, dilute sulfuric acid solution, or a two-stage leaching solution, followed by atmospheric pressure leaching. Metal oxides and salts of arsenic, copper, iron, zinc, and cadmium in the flue dust are leached into the solution, while sulfides such as arsenic and copper, which are difficult to leach, remain in the residue. The leaching residue is then subjected to pressure leaching to further improve the leaching rate of arsenic and copper, achieving efficient removal and recovery of copper and arsenic from the flue dust.

[0007] CN110669941A discloses a method for selective arsenic removal and valuable metal recovery from white smoke dust. The method involves mixing arsenic-containing white smoke dust from copper smelting, sulfuric acid, and additives in a specific ratio, then acidifying the mixture. The acidified material is then calcined at 250-600℃ for 1-6 hours, causing the arsenic in the white smoke dust to volatilize into the smoke dust as arsenic trioxide, while the valuable metals are added to the slag as sulfates, thus achieving arsenic removal. The calcined slag is then leached with water, and copper and zinc are recovered from the filtrate, while other metals are recovered from the filter residue.

[0008] The above methods are for arsenic-containing flue gas and arsenic-containing dust, respectively. Dust removal and cooling of arsenic-containing flue gas may cause arsenic to accumulate in the liquid phase and dust. The original amount of arsenic-containing dust is large, and subsequent arsenic removal is required before valuable elements can be recovered. Moreover, the treatment methods are not very selective for valuable elements. For example, acid leaching causes zinc, copper and iron to leach out at the same time, and ammonia leaching causes zinc and copper to leach out at the same time. Summary of the Invention

[0009] In view of the problems existing in the prior art, the present invention provides a method for removing dust from copper smelting flue gas and comprehensively extracting valuable metals from the flue gas. The method uses two-stage dust removal to recover arsenic-containing flue gas, thereby achieving the separation and recovery of arsenic and the reduction of hazardous waste containing arsenic flue gas. Flue gas containing lead, zinc, copper and iron is subjected to alkaline leaching, ammonia leaching and acid leaching in sequence, thereby achieving the step-by-step separation and recovery of zinc, copper, iron and lead. The separation cost is low and the economic benefits are good.

[0010] To achieve this objective, the present invention adopts the following technical solution:

[0011] This invention provides a method for removing dust from copper smelting flue gas and comprehensively extracting valuable metals from the flue gas, the method comprising the following steps:

[0012] (1) After the copper smelting flue gas is filtered and dust removed at high temperature, the lead-zinc-copper-iron flue gas and the arsenic-containing flue gas are separated; the temperature of the high-temperature filtration and dust removal is 500-600℃.

[0013] (2) The arsenic-containing flue gas is subjected to electrostatic precipitator to obtain arsenic-containing dust; the temperature of the electrostatic precipitator is 240-320℃;

[0014] (3) The lead-, zinc-, copper-, and iron-containing dust is subjected to alkali leaching, ammonia leaching, and acid leaching in sequence to achieve the step-by-step separation and recovery of zinc, copper, iron, and lead.

[0015] Copper smelting flue gas contains not only copper, but also large amounts of arsenic compounds and elements such as lead, zinc, and iron. Arsenic-containing flue gas is classified as hazardous waste, and its treatment and recycling costs are much higher than those for ordinary waste. Therefore, this invention provides a method for dust removal from copper smelting flue gas and comprehensive extraction of valuable metals from the flue gas. First, arsenic in the copper smelting flue gas is separated from other elements, thereby reducing the amount of hazardous waste.

[0016] For the high-temperature flue gas generated by copper smelting furnaces at approximately 1000℃, a slight cooling to 500-600℃ is first performed before high-temperature filtration and dust removal. This saves on cooling costs, and at 500-600℃, arsenic compounds remain in the flue gas as a gaseous state, while lead-, zinc-, copper-, and iron-containing dust is collected in solid form by the dust collector, thus initially separating arsenic compounds from other elements. Subsequently, the arsenic-containing flue gas is further cooled to 240-320℃, at which point the arsenic compounds solidify into particles, which can be collected and recovered by electrostatic precipitator, yielding arsenic-containing dust. Using this two-stage dust removal method, arsenic-containing dust can be efficiently recovered. This arsenic-containing dust has a high As₂O₃ content and can be directly used in arsenic metallurgy. The lead-, zinc-, copper-, and iron-containing dust is then subjected to alkaline leaching, ammonia leaching, and acid leaching sequentially, achieving the step-by-step separation and recovery of zinc, copper, iron, and lead. When lead-, zinc-, copper-, and iron-containing fumes are first acid-leached, zinc, copper, and iron are all leached out, making separation impossible. Similarly, when lead-, zinc-, copper-, and iron-containing fumes are first ammonia-leached, zinc and copper are leached out, also making separation impossible. The method described in this invention separates arsenic fumes at the source, reducing the amount of hazardous waste to be disposed of, and achieves targeted extraction of valuable metals through a specific leaching sequence.

[0017] The high-temperature filtration and dust removal temperature described in this invention is 500-600℃, for example, it can be 500℃, 520℃, 530℃, 550℃, 560℃, 580℃ or 600℃, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0018] The temperature of the electrostatic precipitator is 240-320℃, for example, it can be 240℃, 250℃, 260℃, 280℃, 300℃ or 320℃, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0019] Preferably, the filter material used for high-temperature filtration and dust removal in step (1) includes ceramic membranes or metal filter materials.

[0020] Preferably, the air velocity for high-temperature filtration and dust removal is 0.4 to 0.8 m / min, for example, it can be 0.4 m / min, 0.5 m / min, 0.6 m / min, 0.7 m / min, 0.75 m / min or 0.8 m / min, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0021] Preferably, the dust removal efficiency of the high-temperature filtration dust removal is 95-98%, for example, it can be 95%, 95.5%, 96%, 96.5%, 97%, 97.5% or 98%, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0022] Preferably, the temperature of the high-temperature filtration and dust removal is 550°C.

[0023] Preferably, the electric field wind speed of the electrostatic precipitator in step (2) is 0.4 to 1 m / s, for example, it can be 0.4 m / s, 0.5 m / s, 0.55 m / s, 0.6 m / s, 0.7 m / s, 0.8 m / s or 1 m / s, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 0.6 m / s.

[0024] Preferably, the temperature of the electrostatic precipitator is 280°C.

[0025] Preferably, the dust removal efficiency of the electrostatic precipitator is 90-95%, for example, it can be 90%, 91%, 91.5%, 92%, 92.5%, 93% or 95%, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0026] Preferably, the mass content of As2O3 in the arsenic-containing dust in step (2) is 90% or more, for example, it can be 90%, 91%, 92%, 93% or 95%, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0027] Preferably, the arsenic-containing dust is used directly as a raw material for arsenic metallurgy.

[0028] Preferably, the lead-zinc-copper-iron dust in step (3) is subjected to alkaline leaching to obtain zinc leaching solution and alkaline leaching residue.

[0029] Preferably, the alkaline leaching uses NaOH solution or KOH solution, with NaOH solution being more preferred.

[0030] Preferably, the concentration of the NaOH solution is 1 to 5 mol / L, for example, it can be 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L, 3 mol / L, 4 mol / L or 5 mol / L, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0031] The addition amount is NaOH:Zn = (3~6) mol:1 mol, for example, it can be 3 mol:1 mol, 3.5 mol:1 mol, 4 mol:1 mol, 4.5 mol:1 mol, 5 mol:1 mol, 5.5 mol:1 mol or 6 mol:1 mol, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0032] The leaching time is 3 to 5 hours, for example, it can be 3 hours, 3.5 hours, 4 hours, 4.5 hours, 4.8 hours or 5 hours, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0033] The leaching temperature is 50 to 90°C, for example, 50°C, 55°C, 60°C, 70°C, 80°C, or 90°C, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0034] Preferably, the alkaline leaching residue is subjected to ammonia leaching to obtain copper leaching solution and ammonia leaching residue.

[0035] Preferably, the ammonia leaching is a mixture of ammonia water and ammonium salt solution, with an ammonia / ammonium molar ratio of 1:1.

[0036] Preferably, the ammonia concentration is 5 to 10 mol / L, for example, it can be 5 mol / L, 5.5 mol / L, 6 mol / L, 6.5 mol / L, 7 mol / L, 8 mol / L or 10 mol / L, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0037] The addition amount is NH3·H2O:Cu = (3~5) mol:1 mol; for example, it can be 3 mol:1 mol, 3.5 mol:1 mol, 3.8 mol:1 mol, 4 mol:1 mol, 4.5 mol:1 mol or 5 mol:1 mol, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0038] Preferably, the ammonium salt solution includes any one or a combination of two of ammonium sulfate solution, ammonium carbonate solution, ammonium chloride solution or ammonium acetate solution, wherein typical but non-limiting combinations include a combination of ammonium sulfate solution and ammonium carbonate solution, a combination of ammonium chloride solution and ammonium acetate solution, or a combination of ammonium carbonate solution and ammonium chloride solution.

[0039] Preferably, the concentration of the ammonium salt solution is 5 to 10 mol / L, for example, it can be 5 mol / L, 5.5 mol / L, 6 mol / L, 6.5 mol / L, 7 mol / L, 8 mol / L or 10 mol / L, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0040] Preferably, the leaching time of ammonia leaching in step (3) is 3 to 5 hours, for example, it can be 3 hours, 3.5 hours, 4 hours, 4.5 hours, 4.8 hours or 5 hours, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0041] The leaching temperature is 40 to 70°C, for example, 40°C, 45°C, 50°C, 55°C, 60°C, or 70°C, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0042] Preferably, the ammonia leaching residue is subjected to acid leaching to obtain iron leaching solution and lead-containing slag.

[0043] Preferably, the acid leaching is performed using dilute sulfuric acid or dilute hydrochloric acid, with dilute sulfuric acid being the preferred choice.

[0044] Preferably, the concentration of the dilute sulfuric acid is 5 to 10 mol / L, for example, it can be 5 mol / L, 5.5 mol / L, 6 mol / L, 6.5 mol / L, 7 mol / L, 8 mol / L or 10 mol / L, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0045] The addition amount is H2SO4:(Fe+Pb)=(1.5~2.5)mol:1mol. For example, it can be 1.5mol:1mol, 1.7mol:1mol, 1.9mol:1mol, 2mol:1mol, 2.1mol:1mol, 2.3mol:1mol, or 2.5mol:1mol, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0046] Preferably, the lead-containing slag is used directly as a raw material for lead smelting.

[0047] As a preferred technical solution of the present invention, the method includes the following steps:

[0048] (1) After copper smelting flue gas is filtered and dust removed at high temperature, lead-zinc-copper-iron dust and arsenic-containing flue gas are separated; the temperature of the high-temperature filtration and dust removal is 500-600℃; the filter material used in the high-temperature filtration and dust removal includes ceramic membrane or metal filter material; the wind speed of the high-temperature filtration and dust removal is 0.4-0.8m / min, and the dust removal efficiency is 95-98%;

[0049] (2) The arsenic-containing flue gas is subjected to electrostatic precipitator to obtain arsenic-containing dust; the electric field wind speed of the electrostatic precipitator is 0.4-1m / s, the temperature is 240-320℃, and the dust removal efficiency is 90-95%;

[0050] The arsenic-containing flue dust contains more than 90% As2O3 by mass and can be directly used as a raw material for arsenic metallurgy.

[0051] (3) The lead-zinc-copper-iron flue dust is leached with alkali to obtain zinc leaching solution and alkali leaching residue; the alkali leaching uses NaOH solution or KOH solution, the concentration of NaOH solution is 1-5 mol / L, the addition amount is NaOH:Zn=(3-6)mol:1mol, the leaching time is 3-5h, and the leaching temperature is 50-90℃;

[0052] The alkaline leaching residue is subjected to ammonia leaching to obtain copper leaching solution and ammonia leaching residue; the ammonia leaching uses a mixture of ammonia water and ammonium salt solution, with an ammonia / ammonium molar ratio of 1:1; the concentration of the ammonia water is 5-10 mol / L, and the addition amount is NH3·H2O:Cu = (3-5) mol:1 mol; the ammonium salt solution includes any one or a combination of two of ammonium sulfate solution, ammonium carbonate solution, ammonium chloride solution, or ammonium acetate solution; the concentration of the ammonium salt solution is 5-10 mol / L; the leaching time of the ammonia leaching is 3-5 hours, and the leaching temperature is 40-70℃;

[0053] The ammonia leaching residue is subjected to acid leaching to obtain iron leaching solution and lead-containing slag; the acid leaching uses dilute sulfuric acid or dilute hydrochloric acid, the concentration of the dilute sulfuric acid is 5-10 mol / L, and the addition amount is H2SO4:(Fe+Pb)=(1.5-2.5)mol:1mol; the lead-containing slag is directly used as a raw material for lead smelting to achieve the stepwise separation and recovery of zinc, copper, iron and lead.

[0054] Compared with the prior art, the present invention has at least the following beneficial effects:

[0055] This invention provides a method for dust removal from copper smelting flue gas and comprehensive extraction of valuable metals from the flue gas. The method involves passing the copper smelting flue gas through a high-temperature dust removal process to separate arsenic compounds from lead-, zinc-, copper-, and iron-containing flue gas. The arsenic-containing flue gas is then further cooled and dust removed, achieving the separation and recovery of arsenic and reducing the volume of arsenic-containing flue gas. The lead-, zinc-, copper-, and iron-containing flue gas is then subjected to alkaline leaching, ammonia leaching, and acid leaching in stages, achieving the step-by-step separation and recovery of zinc, copper, iron, and lead. This invention ultimately achieves the reduction of arsenic-containing flue gas from copper smelting and the comprehensive extraction and separation of multiple valuable metals. It separates arsenic-containing flue gas at the source, reducing the volume of hazardous arsenic-containing flue gas, and allows for the targeted recovery and resource utilization of other valuable metals. This reduces the difficulty and cost of dust treatment in copper smelting flue gas and has promising prospects for large-scale application. Attached Figure Description

[0056] Figure 1 This is a flowchart of a method for removing dust from copper smelting flue gas and comprehensively extracting valuable metals from the flue gas, provided by the present invention. Detailed Implementation

[0057] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0058] This invention provides a method for dust removal from copper smelting flue gas and comprehensive extraction of valuable metals from the flue gas, the flowchart of which is shown below. Figure 1 As shown, the method includes the following steps:

[0059] (1) After the copper smelting flue gas is filtered and dust removed at high temperature, the lead-zinc-copper-iron flue gas and the arsenic-containing flue gas are separated; the temperature of the high-temperature filtration and dust removal is 500-600℃.

[0060] (2) The arsenic-containing flue gas is subjected to electrostatic precipitator to obtain arsenic-containing dust; the temperature of the electrostatic precipitator is 240-320℃;

[0061] (3) The lead-, zinc-, copper-, and iron-containing dust is subjected to alkali leaching, ammonia leaching, and acid leaching in sequence to achieve the step-by-step separation and recovery of zinc, copper, iron, and lead.

[0062] The present invention will now be described in further detail. However, the examples described below are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0063] Example 1

[0064] Taking the copper smelting flue gas from a copper smelting enterprise as an example, this paper provides a method for dust removal from copper smelting flue gas and comprehensive extraction of valuable metals from the flue gas. The contents of different metal elements in the copper smelting flue gas are shown in Table 1.

[0065] Table 1

[0066]

[0067] The method includes the following steps:

[0068] (1) After the copper smelting flue gas is filtered and dust removed at high temperature, the lead-zinc-copper-iron dust and the arsenic-containing flue gas are separated; the temperature of the high-temperature filtration and dust removal is 600℃; the filter material used in the high-temperature filtration and dust removal is a ceramic membrane; the wind speed of the high-temperature filtration and dust removal is 0.8m / min, and the dust removal efficiency is 95%.

[0069] (2) Arsenic-containing flue gas is subjected to electrostatic precipitator to obtain arsenic-containing dust; the electric field velocity of the electrostatic precipitator is 1 m / s, the temperature is 320℃, and the dust removal efficiency is 91.3%;

[0070] The arsenic-containing flue dust has an As2O3 content of 92% by mass and can be directly used as a raw material for arsenic metallurgy.

[0071] (3) Lead, zinc, copper and iron dust is leached with NaOH solution to obtain zinc leaching solution and alkali leaching residue; the concentration of NaOH solution is 5 mol / L, the addition amount is NaOH:Zn=3mol:1mol, the leaching time is 3.5h, and the leaching temperature is 50℃.

[0072] (4) The alkaline leaching residue is subjected to ammonia leaching to obtain copper leaching solution and ammonia leaching residue; the ammonia leaching uses a mixture of ammonia water and ammonium salt, with an ammonia / ammonium molar ratio of 1:1; the concentration of the ammonia water is 5 mol / L, and the addition amount is NH3·H2O:Cu = 3 mol: 1 mol; the ammonium salt includes ammonium sulfate; the leaching time of the ammonia leaching is 3.5 h, and the leaching temperature is 50 °C;

[0073] (5) The ammonia leaching residue is acid-leached with dilute sulfuric acid to obtain iron leaching solution and lead-containing slag; the concentration of the dilute sulfuric acid is 5 mol / L, the addition amount is H2SO4:(Fe+Pb)=1.5mol:1mol, the leaching time is 1h, and the leaching temperature is 30℃; the lead-containing slag is directly used as a raw material for lead smelting to realize the stepwise separation and recovery of zinc, copper, iron and lead.

[0074] Example 2

[0075] This embodiment provides a method for removing dust from copper smelting flue gas and extracting valuable metals from the flue gas. Except for the high temperature of 550°C, the wind speed of 0.6m / min and the dust removal efficiency of 97.7% in step (1), the method is the same as that in embodiment 1.

[0076] Example 3

[0077] This embodiment provides a method for removing dust from copper smelting flue gas and extracting valuable metals from the flue gas. Except for step (2), where the electric field wind speed is 0.7 m / s, the temperature is 280℃, and the dust removal efficiency is 93.2%, the method is the same as that in embodiment 1.

[0078] Example 4

[0079] This embodiment provides a method for removing dust from copper smelting flue gas and extracting valuable metals from the flue gas. Except for step (3), where the NaOH concentration is 5 mol / L, the addition amount is calculated as NaOH:Zn = 5 mol: 1 mol, the leaching time is 4.5 h, and the leaching temperature is 90 °C, the rest of the method is the same as in Example 2.

[0080] Example 5

[0081] This embodiment provides a method for removing dust from copper smelting flue gas and extracting valuable metals from the flue gas. Except for step (4), where the ammonia concentration is 8 mol / L, the addition amount is NH3·H2O:Cu=4mol:1mol, the ammonium sulfate concentration is 5 mol / L, the addition amount is (NH4)2SO4:Cu=4mol:1mol, the leaching time is 5h, and the leaching temperature is 70℃, the rest of the method is the same as in Example 2.

[0082] Example 6

[0083] This embodiment provides a method for removing dust from copper smelting flue gas and extracting valuable metals from the flue gas. Except for step (5), where the concentration of dilute sulfuric acid is 5 mol / L, the amount added is H2SO4:(Fe+Pb)=2.5mol:1mol, the leaching time is 2h, and the leaching temperature is 60℃, the rest of the method is the same as in Example 2.

[0084] Comparative Example 1

[0085] This comparative example provides a method for removing dust from copper smelting flue gas and extracting valuable metals from the flue gas. Except for the high-temperature filtration dust removal temperature of 450°C in step (1), the method is the same as that in Example 1.

[0086] Comparative Example 2

[0087] This comparative example provides a method for removing dust from copper smelting flue gas and extracting valuable metals from the flue gas. Except for the high-temperature filtration dust removal temperature of step (1) being 650°C, the method is the same as that in Example 1.

[0088] Comparative Example 3

[0089] This comparative example provides a method for removing dust from copper smelting flue gas and extracting valuable metals from the flue gas. Except for the electrostatic precipitator temperature of 200°C in step (2), the method is the same as that in Example 1.

[0090] Comparative Example 4

[0091] This comparative example provides a method for removing dust from copper smelting flue gas and extracting valuable metals from the flue gas. Except for the electrostatic precipitator temperature of 350°C in step (2), the method is the same as that in Example 1.

[0092] Comparative Example 5

[0093] This comparative example provides a method for removing dust from copper smelting flue gas and extracting valuable metals from the flue gas. Except for the change in the order of steps (3) and (5), the method is the same as that in Example 1, that is, the lead-zinc-copper-iron flue gas is subjected to acid leaching, ammonia leaching and alkali leaching in sequence.

[0094] Comparative Example 6

[0095] This comparative example provides a method for removing dust from copper smelting flue gas and extracting valuable metals from the flue gas. Except for changing the order of steps (3) and (4), the method is the same as in Example 1, that is, the lead-zinc-copper-iron flue gas is subjected to ammonia leaching, acid leaching and alkali leaching in sequence.

[0096] The recovery rates of arsenic, zinc, copper, iron, and lead in the above examples and comparative examples were determined respectively, and the results are shown in Table 2.

[0097] Table 2

[0098]

[0099]

[0100] In Table 2, " / " indicates that the metal cannot be separated and cannot be recovered.

[0101] As can be seen from Table 1:

[0102] (1) As can be seen from the comprehensive examples 1 to 6, the method for removing dust from copper smelting flue gas and extracting valuable metals from the flue gas provided by the present invention achieves the reduction of arsenic-containing flue gas from copper smelting and the comprehensive extraction and separation of various valuable metals. The arsenic recovery rate can reach more than 90.5%, the zinc recovery rate can reach more than 91.4%, the copper recovery rate can reach more than 91.7%, the iron recovery rate can reach more than 90.8%, and the lead recovery rate can reach more than 93.1%.

[0103] (2) It can be seen from the comprehensive comparison of Example 1 and Comparative Examples 1 and 2 that the temperature of high-temperature filtration and dust removal in Comparative Example 1 is relatively low, which causes some arsenic compounds to solidify into particles and be separated together with lead, zinc, copper and iron dust, resulting in an increase in the amount of arsenic-containing hazardous waste after final treatment, an increase in the cost of copper smelting flue gas treatment, and a decrease in the recovery rate of arsenic, zinc, copper, iron and lead; the temperature of high-temperature filtration and dust removal in Comparative Example 2 is relatively high, which has a smaller impact on the separation of arsenic, zinc, copper and iron, but a greater impact on the separation of low-boiling-point lead. However, the excessively high flue gas temperature will shorten the service life of the filter material, which will in turn lead to an increase in the cost of copper smelting flue gas treatment.

[0104] (3) It can be seen from the comprehensive comparison of Example 1 and Comparative Examples 3-4 that the temperature of the electrostatic precipitator in Comparative Example 3 is lower, and the arsenic recovery rate is slightly improved. However, since the flue gas contains a large amount of SO2 and the acid dew point of the flue gas is >200℃, the significant temperature drop will cause corrosion of the electrostatic precipitator equipment, resulting in equipment failure and increasing the cost of copper smelting flue gas treatment. The temperature of the electrostatic precipitator in Comparative Example 4 is higher, which will cause some arsenic compounds to remain in a gaseous state. The arsenic-containing flue gas requires additional equipment for treatment, which increases the cost of copper smelting flue gas treatment.

[0105] (4) It can be seen from the combined examples 1 and 5-6 that in Comparative Example 5, due to the change of the order of steps (3) and (5), the acid leaching efficiency of zinc, copper and iron is 82.3%, 83.4% and 81.9% respectively, but the three elements are mixed and cannot be separated; in Comparative Example 6, due to the change of the order of steps (3) and (4), the ammonia leaching efficiency of zinc and copper is 78.5% and 77.1% respectively, but the two are mixed and cannot be separated. Both of these results in a low recovery rate of valuable metals.

[0106] The applicant declares that 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 conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for removing dust from copper smelting flue gas and comprehensively extracting valuable metals from the flue gas, characterized in that, The method includes the following steps: (1) After the copper smelting flue gas is filtered and dust removed at high temperature, the lead-zinc-copper-iron flue gas and the arsenic-containing flue gas are separated; the temperature of the high-temperature filtration and dust removal is 520-600℃; the filter material used in the high-temperature filtration and dust removal includes ceramic membrane or metal filter material. (2) The arsenic-containing flue gas is subjected to electrostatic precipitator to obtain arsenic-containing dust; the temperature of the electrostatic precipitator is 240-320℃; (3) The lead-, zinc-, copper-, and iron-containing dust is subjected to alkali leaching, ammonia leaching, and acid leaching in sequence to achieve the step-by-step separation and recovery of zinc, copper, iron, and lead.

2. The method according to claim 1, characterized in that, The wind speed for high-temperature filtration and dust removal in step (1) is 0.4 to 0.8 m / min.

3. The method according to claim 1, characterized in that, The dust removal efficiency of the high-temperature filtration dust removal system is 95-98%.

4. The method according to claim 1, characterized in that, The temperature for high-temperature filtration and dust removal is 550℃.

5. The method according to claim 1, characterized in that, The electric field wind speed of the electrostatic precipitator in step (2) is 0.4 to 1 m / s.

6. The method according to claim 5, characterized in that, The electric field wind speed of the electrostatic precipitator in step (2) is 0.6 m / s.

7. The method according to claim 1, characterized in that, The temperature of the electrostatic precipitator is 280℃.

8. The method according to claim 1, characterized in that, The dust removal efficiency of the electrostatic precipitator is 90-95%.

9. The method according to claim 1, characterized in that, The mass content of As2O3 in the arsenic-containing dust in step (2) is above 90%.

10. The method according to claim 1, characterized in that, The arsenic-containing flue dust is used directly as a raw material for arsenic metallurgy.

11. The method according to claim 1, characterized in that, In step (3), the lead-, zinc-, copper-, and iron-containing dust is subjected to alkaline leaching to obtain zinc leaching solution and alkaline leaching residue.

12. The method according to claim 1, characterized in that, The alkaline leaching uses NaOH solution or KOH solution.

13. The method according to claim 12, characterized in that, The alkaline leaching uses NaOH solution.

14. The method according to claim 12, characterized in that, The concentration of the NaOH solution is 1-5 mol / L, the addition amount is NaOH:Zn = (3-6) mol:1 mol, the leaching time is 3-5 h, and the leaching temperature is 50-90℃.

15. The method according to claim 11, characterized in that, The alkaline leaching residue is then subjected to ammonia leaching to obtain copper leaching solution and ammonia leaching residue.

16. The method according to claim 1, characterized in that, The ammonia leaching uses a mixture of ammonia water and ammonium salt solution, with an ammonia / ammonium molar ratio of 1:

1.

17. The method according to claim 16, characterized in that, The concentration of ammonia water is 5-10 mol / L, and the amount added is NH3·H2O:Cu = (3-5) mol:1 mol.

18. The method according to claim 16, characterized in that, The ammonium salt solution includes any one or a combination of two of the following: ammonium sulfate solution, ammonium carbonate solution, ammonium chloride solution, or ammonium acetate solution.

19. The method according to claim 16, characterized in that, The concentration of the ammonium salt solution is 5–10 mol / L.

20. The method according to claim 1, characterized in that, The leaching time for ammonia leaching in step (3) is 3 to 5 hours, and the leaching temperature is 40 to 70°C.

21. The method according to claim 15, characterized in that, The ammonia leaching residue is subjected to acid leaching to obtain iron leaching solution and lead-containing slag.

22. The method according to claim 1, characterized in that, The acid leaching is performed using dilute sulfuric acid or dilute hydrochloric acid.

23. The method according to claim 22, characterized in that, The acid leaching is performed using dilute sulfuric acid.

24. The method according to claim 23, characterized in that, The concentration of the dilute sulfuric acid is 5-10 mol / L, and the amount added is H2SO4:(Fe+Pb)=(1.5-2.5)mol:1mol.

25. The method according to claim 21, characterized in that, The lead-containing slag is used directly as a raw material for lead smelting.

26. The method according to claim 1, characterized in that, The method includes the following steps: (1) After copper smelting flue gas is filtered and dust removed at high temperature, lead-zinc-copper-iron dust and arsenic-containing flue gas are separated; the temperature of the high-temperature filtration and dust removal is 520-600℃; the filter material used in the high-temperature filtration and dust removal includes ceramic membrane or metal filter material; the wind speed of the high-temperature filtration and dust removal is 0.4-0.8m / min, and the dust removal efficiency is 95-98%; (2) Arsenic-containing flue gas is subjected to electrostatic precipitator to obtain arsenic-containing dust; the electric field velocity of the electrostatic precipitator is 0.4-1 m / s, the temperature is 240-320℃, and the dust removal efficiency is 90-95%. The arsenic-containing flue dust contains more than 90% As2O3 by mass and can be directly used as a raw material for arsenic metallurgy. (3) Alkali leaching of lead, zinc, copper and iron dust to obtain zinc leaching solution and alkali leaching residue; the alkali leaching uses NaOH solution or KOH solution, the concentration of NaOH solution is 1-5 mol / L, the addition amount is NaOH:Zn=(3-6)mol:1mol, the leaching time is 3-5h, and the leaching temperature is 50-90℃; The alkaline leaching residue is subjected to ammonia leaching to obtain copper leaching solution and ammonia leaching residue; the ammonia leaching uses a mixture of ammonia water and ammonium salt solution, with an ammonia / ammonium molar ratio of 1:1; the concentration of the ammonia water is 5-10 mol / L, and the addition amount is NH3·H2O:Cu = (3-5) mol:1 mol; the ammonium salt solution includes any one or a combination of two of ammonium sulfate solution, ammonium carbonate solution, ammonium chloride solution, or ammonium acetate solution; the concentration of the ammonium salt solution is 5-10 mol / L; the leaching time of the ammonia leaching is 3-5 hours, and the leaching temperature is 40-70℃; The ammonia leaching residue is subjected to acid leaching to obtain iron leaching solution and lead-containing slag; the acid leaching uses dilute sulfuric acid or dilute hydrochloric acid, the concentration of the dilute sulfuric acid is 5-10 mol / L, and the addition amount is H2SO4:(Fe+Pb)=(1.5-2.5)mol:1mol; the lead-containing slag is directly used as a raw material for lead smelting to achieve the stepwise separation and recovery of zinc, copper, iron and lead.

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