Resourceful treatment method for high-arsenic smoke dust

Abstract

The invention relates to the technical field of resourceful treatment of colored metal metallurgy solid hazardous wastes, in particular to a resourceful treatment method of high-arsenic smoke dust. The resourceful treatment method of the high-arsenic smoke dust comprises the following steps: mixing the high-arsenic smoke dust with an acid solution, carrying out leaching reaction to obtain filtrate and filter residues, and recovering compounds of metal elements of lead, arsenic, copper, cadmium, bismuth, antimony, indium, zinc and silver through a precipitator reaction under the condition that the pH value is-3.0-7.0. According to the method, various elements such as lead, arsenic, copper, cadmium, bismuth, antimony, indium, zinc and silver in the high-arsenic smoke dust are classified and recycled, the recycled products are various in variety and high in additional value, the purpose of comprehensive utilization of resources is truly achieved, the problem that the high-arsenic smoke dust is difficult to treat is solved, and pollution to the environment is reduced.

Description

Technical Field

[0001] This invention relates to the field of solid hazardous waste treatment and utilization technology in non-ferrous metal metallurgy, and in particular to a resource-based treatment method for high-arsenic flue dust. Background Technology

[0002] Arsenic is present in all non-ferrous metal minerals to varying degrees, ranging from a few parts per ten thousand to a few parts per million. Although arsenic is removed as much as possible during the flotation process of non-ferrous metal minerals, 5-20% of the arsenic is still carried into the smelters along with the metal concentrate. In the smelting of non-ferrous metals such as lead, zinc, copper, and tin, most of the arsenic in the furnace charge is oxidized to arsenic trioxide (arsenic trioxide) and volatilizes into the flue gas, resulting in high-arsenic flue dust after dust collection. In addition to arsenic trioxide, high-arsenic flue dust also contains many other volatile elements from the furnace charge in the form of oxides.

[0003] Arsenic is a highly toxic substance and a harmful element that pollutes the environment, especially AsH3, which is even more toxic; inhalation can cause acute poisoning and death. Therefore, when conditions arise that generate AsH3 gas during production processes, arsenic must be treated. Consequently, high-arsenic fumes have become a type of solid hazardous waste produced in large quantities by related industries and posing a serious threat to the environment. The phase composition of arsenic in high-arsenic fumes produced in some metallurgical enterprises is shown in Table 1.

[0004] Table 1. Phase composition of arsenic in flue dust

[0005]

[0006] However, arsenic is also a useful element. Arsenic compounds are mainly used to refine elemental arsenic and manufacture arsenic acid, calcium arsenate, sodium arsenate, lead arsenate, etc. In the metallurgical industry, it is used to refine arsenic alloys; arsenic-lead alloys are used to manufacture bullets, military poisons, and fireworks; arsenic-copper alloys and arsenic-lead alloys are used to manufacture radar and automobile parts. In light industry, it is used to manufacture milky white glass, glass decolorize, wool rinsing, leather tanning agents, and as a wood preservative. In agriculture, it is used as an arsenic-containing pesticide, herbicide, and rodenticide. In the pharmaceutical industry, it can be used as a drug and a strong stimulant. Additionally, arsenic trisulfide can be used to manufacture firecrackers, fireworks, and mosquito coils; it can also be used as a pigment. Therefore, comprehensive arsenic recycling not only turns a potential hazard into a benefit but also meets market demand and creates social wealth.

[0007] The yield of high-arsenic dust is approximately 8-10% of the furnace charge in smelting, indicating a large output and difficulties in resource utilization. Generally, it is disposed of through stockpiling or landfilling. Landfilling is extremely costly, and many factories lack available hazardous waste landfills. This results in existing stockpiles of high-arsenic dust remaining untreated, while newly added dust continues to be stockpiled. This not only consumes significant land, manpower, material resources, and financial resources, but also, due to weathering from sun and rain, the arsenic and metallic elements in the high-arsenic dust cause severe pollution to the surrounding environment. The continuous increase in stockpiles also exacerbates the risk of dam failure, posing a serious threat to the lives and property of people in the surrounding areas.

[0008] Resource-based treatment refers to the use of advanced technologies and processes to treat hazardous waste as a valuable resource, recovering valuable substances from hazardous waste and utilizing them to create economic value and turn waste into treasure.

[0009] In response to the increasingly severe environmental situation, large metallurgical enterprises, related research institutes and universities have successively developed some methods for the treatment and utilization of high-arsenic flue dust. Chinese invention patent CN106893869A discloses a method for treating high-arsenic flue dust, which uses a pyrometallurgical process to obtain elemental arsenic; Chinese invention patent CN111440954A discloses a method for treating high-arsenic flue dust, which uses a pyrometallurgical process to obtain arsenic trioxide; Chinese invention patents CN101798636A and CN102433440A disclose a method for treating high-arsenic flue dust, which uses a combination of wet and pyrometallurgical processes to obtain arsenic trioxide; Chinese invention patent CN114086002A discloses a method for treating high-arsenic flue dust, which uses a wet process to obtain arsenic trioxide and antimony slag; Chinese invention patent CN1789445A discloses a method for treating high-arsenic flue dust, which uses a wet process to obtain arsenic trioxide, and describes a method for separating arsenic, copper, and zinc from the acid leaching solution; Chinese invention patent CN115976326A discloses a method for treating high-arsenic flue dust, which uses a wet process to obtain arsenic trioxide, and describes a method for extracting and separating copper and iron from the leaching solution.

[0010] The above-mentioned treatment methods only recover and utilize arsenic and two or three other elements in the process of treating high-arsenic flue dust, which obviously has the problem of low resource utilization. Moreover, the recovered other elements are not turned into products, resulting in low economic benefits. Summary of the Invention

[0011] The purpose of this invention is to provide a method for the resource utilization of high-arsenic flue dust, which solves the problem of low resource utilization rate of high-arsenic flue dust in the prior art.

[0012] To achieve the above objectives, the resource-based treatment method for high-arsenic flue dust provided by this invention employs the following technical solution:

[0013] A method for resource recovery of high-arsenic flue dust includes the following steps:

[0014] (1) The high-arsenic fume was leached with hydrochloric acid solution at 60-65℃ to obtain filtrate A and filter residue B.

[0015] (2) Add sodium sulfate to A and carry out lead precipitation reaction at 80-85℃ to obtain lead sulfate and filtrate D;

[0016] (3) After adjusting the pH of D to -3.0 to -2.5, add sodium sulfide solution to the pH to -1.5 to -1.2, and then carry out the precipitation of arsenic and copper at 80 to 85℃ to obtain a mixture of arsenic trisulfide and copper sulfide and filtrate F;

[0017] (4) Add sodium sulfide solution to F until the pH is 1.0 to 1.2, and then carry out the cadmium precipitation reaction at 80 to 85°C to obtain cadmium sulfide and filtrate H;

[0018] (5) Add water and sodium hydroxide solution to H until the pH is 2.0 to 2.2, and then carry out the bismuth and antimony precipitation reaction at 40 to 45°C to obtain a mixture of antimony oxychloride and bismuth oxychloride and filtrate J;

[0019] (6) Add sodium hydroxide solution to J until the pH is 3.5-3.7, and then carry out the indium precipitation reaction at 60-65℃ to obtain indium hydroxide and filtrate L;

[0020] (7) Add sodium carbonate solution to L until the pH is 6.8 to 7.0, and then carry out zinc precipitation reaction at 45 to 50°C to obtain basic zinc carbonate.

[0021] The beneficial effects of this invention are as follows: This invention is an improved invention. First, high-arsenic flue dust is mixed with hydrochloric acid to dissolve the compounds of lead, arsenic, copper, cadmium, bismuth, antimony, indium, zinc, and silver elements that react with hydrochloric acid in the high-arsenic flue dust. Then, through solid-liquid separation, substances insoluble in hydrochloric acid, as well as silver chloride precipitate and sulfur, are separated from the high-arsenic flue dust. Next, by controlling the pH value and temperature, and with the addition of a precipitant, lead, arsenic, copper, cadmium, bismuth, antimony, indium, and zinc in the filtrate are precipitated in the form of compounds in sequence, thus achieving the classified recovery of multiple elements such as lead, arsenic, copper, cadmium, bismuth, antimony, indium, zinc, and silver from high-arsenic flue dust.

[0022] This invention prepares a variety of inorganic chemical products, namely lead sulfate, arsenic trioxide, cadmium sulfide, indium hydroxide, and basic zinc carbonate, and separately separates and enriches copper sulfide, antimony oxychloride and bismuth oxychloride, silver chloride and sulfur. The product range is diverse, the process is simple, the equipment investment is low, the operation is easy, the reaction conditions are mild, the production cost is low, the economic benefits are significant, and it meets environmental protection requirements. Moreover, the products have high added value, truly achieving the goal of comprehensive resource utilization, solving the problem of difficult treatment of high arsenic dust, and reducing environmental pollution.

[0023] To facilitate the precipitation of lead, arsenic, and silver compounds in the filter residue that are difficult to dissolve with hydrochloric acid in high-arsenic flue dust, the resource utilization treatment method for filter residue B preferably includes the following steps:

[0024] (a) After mixing filter residue B with water, sodium hydroxide solution was added until the pH was 13.1 to 13.2. Then, an arsenic dissolution reaction was carried out at 60 to 65°C to obtain a mixture of silver chloride, lead sulfide, lead hydroxide and sulfur and filtrate P.

[0025] (b) Add hydrochloric acid solution to P until the pH is -2.2 to -2.0, then add sodium sulfide solution until the pH is -1.0 to -0.8, and then carry out the arsenic precipitation reaction at 80 to 85°C to obtain arsenic trisulfide;

[0026] (c) The mixture of silver chloride, lead sulfide, lead hydroxide and sulfur in step (a) is mixed with water, nitric acid solution is added, and lead dissolution reaction is carried out at 60-65°C to obtain sulfur, silver chloride and filtrate T.

[0027] (d) Add sodium sulfate to T and carry out a lead precipitation reaction at 80-85℃ to obtain lead sulfate.

[0028] In order to enable the metal elements in the solid high-arsenic dust to leach out, preferably, the mass ratio of the high-arsenic dust to the hydrochloric acid solution is 1:(2-4).

[0029] In order to ensure that the metallic elements in the solid high-arsenic dust can be fully reacted and leached, the concentration of the hydrochloric acid solution is preferably 20-26%.

[0030] In order to ensure that the metal elements in the solid high-arsenic dust can fully react and leach out and that the metal elements in the filtrate A can fully precipitate out in the form of compounds, preferably, the leaching reaction time in step (1) is 1.5 to 2 hours; the lead precipitation reaction time in step (2), the arsenic and copper precipitation reaction time in step (3), the cadmium precipitation reaction time in step (4), the bismuth and antimony precipitation reaction time in step (5), the indium precipitation reaction time in step (6), and the zinc precipitation reaction time in step (7) are all 0.5 to 1 hour.

[0031] In order to ensure that the arsenic and lead elements in filter residue B can fully undergo dissolution and precipitation reactions and precipitate out in the form of compounds, preferably, the time for the arsenic dissolution reaction in step (a) and the lead dissolution reaction in step (c) are both 0.5 to 1 hour; the time for the arsenic precipitation reaction in step (b) and the lead precipitation reaction in step (d) are both 0.5 to 1 hour.

[0032] In order to facilitate the adjustment of the pH value of the filtrate and the reaction precipitation of bismuth, antimony and indium elements in high arsenic dust, preferably, the concentration of sodium hydroxide solution in step (5) and sodium hydroxide solution in step (6) is 20-42%.

[0033] In order to facilitate the adjustment of the pH value of the filtrate and the reaction precipitation of arsenic, copper and cadmium elements in high arsenic dust, preferably, the concentration of sodium sulfide solution in step (3) and sodium sulfide solution in step (4) is 15-16%.

[0034] In order to facilitate the adjustment of the pH value of the filtrate and the reaction of zinc element precipitated from high arsenic dust, preferably, the concentration of sodium carbonate solution in step (7) is 25-26%.

[0035] To fully dissolve the lead element in the mixture of silver chloride, lead sulfide, and sulfur, the concentration of the nitric acid solution in step (c) is preferably 62-65%. Attached Figure Description

[0036] Figure 1 This is a flowchart of the resource utilization treatment method for high-arsenic flue dust in Example 1 of the present invention. Detailed Implementation

[0037] Existing technologies for treating high-arsenic flue dust only recover arsenic and two or three other elements, resulting in a low degree of resource utilization. Furthermore, the recovered elements are not converted into products, leading to low economic benefits. This invention proposes a resource-based treatment method for high-arsenic flue dust, comprising the following steps:

[0038] (1) The high-arsenic fume was leached with hydrochloric acid solution at 60-65℃ to obtain filtrate A and filter residue B.

[0039] (2) Add sodium sulfate to A and carry out lead precipitation reaction at 80-85℃ to obtain lead sulfate and filtrate D;

[0040] (3) After adjusting the pH of D to -3.0 to -2.5, add sodium sulfide solution to the pH to -1.5 to -1.2, and then carry out the precipitation of arsenic and copper at 80 to 85℃ to obtain a mixture of arsenic trisulfide and copper sulfide and filtrate F;

[0041] (4) Add sodium sulfide solution to F until the pH is 1.0 to 1.2, and then carry out the cadmium precipitation reaction at 80 to 85°C to obtain cadmium sulfide and filtrate H;

[0042] (5) Add water and sodium hydroxide solution to H until the pH is 2.0 to 2.2, and then carry out the bismuth and antimony precipitation reaction at 40 to 45°C to obtain a mixture of antimony oxychloride and bismuth oxychloride and filtrate J;

[0043] (6) Add sodium hydroxide solution to J until the pH is 3.5-3.7, and then carry out the indium precipitation reaction at 60-65℃ to obtain indium hydroxide and filtrate L;

[0044] (7) Add sodium carbonate solution to L until the pH is 6.8 to 7.0, and then carry out zinc precipitation reaction at 45 to 50°C to obtain basic zinc carbonate.

[0045] The technical concept of this invention is as follows: First, high-arsenic flue dust is mixed with hydrochloric acid to dissolve compounds of lead, arsenic, copper, cadmium, bismuth, antimony, indium, zinc, and silver elements that react with the hydrochloric acid in the high-arsenic flue dust. Then, through solid-liquid separation, substances insoluble in hydrochloric acid, silver chloride precipitate, and sulfur are separated from the high-arsenic flue dust. Next, by controlling the pH and temperature, and with the addition of a precipitating agent, lead, arsenic, copper, cadmium, bismuth, antimony, indium, and zinc in the filtrate are precipitated sequentially as compounds. This invention prepares a variety of inorganic chemical products, namely lead sulfate, arsenic trioxide, cadmium sulfide, indium hydroxide, and basic zinc carbonate, and separately separates and enriches copper sulfide, antimony oxychloride and bismuth oxychloride, silver chloride, and sulfur, resulting in a wide variety of products; simultaneously, the recovery rate of each metal element is high.

[0046] This invention enables the recovery and treatment of metals from high-arsenic flue dust industrial hazardous waste. It offers advantages such as a wide variety of products, high product quality, a simple process flow, low equipment investment, ease of operation, mild reaction conditions, low production costs, and compliance with environmental protection requirements. This invention provides significant economic, environmental, and social benefits, is suitable for industrial production promotion, and has broad application prospects.

[0047] This invention relates to the recovery of valuable metals from high-arsenic flue dust produced in a lead smelting enterprise. The high-arsenic flue dust mainly contains PbO, ZnO, CdO, CuO, Sb₂O₃, Sb₂S₃, Bi₂O₃, In₂O₃, Zn₃(AsO₄)₂, As₂O₃, As₂S₃, PbSO₄, PbS, sulfur, and silver. The content of valuable metal elements is as follows: lead 28.33%, arsenic 16.81%, zinc 10.78%, and cadmium 2.302%. The high-arsenic flue dust contains 0.766% copper, 0.577% antimony, 0.112% indium, 0.0490% bismuth, 0.0124% silver, and other elements such as 2.39% sulfur. Through the following resource-based treatment method for high-arsenic flue dust, lead, arsenic, copper, cadmium, bismuth, antimony, indium, zinc, and silver are precipitated in the form of compounds, achieving the classified recovery of various products including lead sulfate, arsenic trioxide, cadmium sulfide, indium hydroxide, basic zinc carbonate, copper sulfide, antimony oxychloride, bismuth oxychloride, and silver chloride.

[0048] Specifically, the resource utilization method for high-arsenic flue dust includes the following steps:

[0049] (1) Mix high-arsenic flue dust with a 20-26% hydrochloric acid solution, the mass ratio of high-arsenic flue dust to hydrochloric acid solution is 1:(2-4), heat to 60-65℃, react for 1.5-2 hours, then cool to 40-45℃, separate the solid and liquid, and obtain filtrate A and filter residue B. Filter residue B contains silver chloride, lead sulfide, lead sulfate, arsenic trisulfide, arsenic trioxide and sulfur;

[0050] (2) Add solid sodium sulfate to filtrate A, heat to 80-85°C, keep warm for 0.5-1.0 hours until no more precipitation occurs, filter to obtain filter cake C and filtrate D, where filter cake C is lead sulfate;

[0051] (3) Add a 20-42% sodium hydroxide solution to filtrate D until the pH value reaches -3.0 to -2.5, then add a 15-16% sodium sulfide solution until the pH value reaches -1.5 to -1.2. Heat to 80-85℃ and keep warm for 0.5-1.0 hours. Filter to obtain filter cake E and filtrate F. Filter cake E is a mixture of arsenic trisulfide and copper sulfide. At the same time, under the above reaction conditions, a small amount of sulfur is also produced.

[0052] (4) Add a 15-16% sodium sulfide solution to the filtrate F, adjust the pH to 1.0-1.2, heat to 80-85℃, keep warm for 0.5-1.0 hours, filter, and obtain filter cake G and filtrate H. Filter cake G is cadmium sulfide.

[0053] (5) Add 1.8 to 3.0 times the volume of water to the filtrate H and add sodium hydroxide solution with a concentration of 20 to 42% dropwise until the pH value reaches 2.0 to 2.2. Heat to 40 to 45°C and keep warm for 0.5 to 1.0 hours. Filter to obtain filter cake I and filtrate J. Filter cake I is a mixture of antimony oxychloride and bismuth oxychloride.

[0054] (6) Add a 20-42% sodium hydroxide solution to the filtrate J, adjust the pH to 3.5-3.7, heat to 60-65℃, keep warm for 0.5-1.0 hours, filter, and obtain filter cake K and filtrate L. Filter cake K is indium hydroxide.

[0055] (7) Add a 25-26% sodium carbonate solution to the filtrate L until the pH value reaches 6.8-7.0, heat to 45-50℃, keep warm for 0.5-1.0 hours, filter to obtain filter cake M and filtrate N. Filter cake M is basic zinc carbonate; filtrate N is brine, which is sent to the alkali production system.

[0056] (8) Add water at twice the weight of filter residue B to the reaction flask, add filter residue B in portions while stirring at room temperature, and then add 20-42% sodium hydroxide solution dropwise until the pH value is 13.1-13.2. Then heat to 60-65℃ and keep warm for 0.5-1.0 hours. Filter to obtain filter cake O and filtrate P. Filter cake O is a mixture of silver chloride, lead sulfide, lead hydroxide and sulfur. It is then processed in step (10). In this step, sodium hydroxide is used to dissolve arsenic trioxide and arsenic trisulfide. At the same time, sodium hydroxide is used to dissolve lead sulfate and generate lead hydroxide precipitate.

[0057] (9) Add 20-26% hydrochloric acid solution to filtrate P until the pH value is -2.2 to -2.0, then add 15-16% sodium sulfide solution to adjust the pH value to -1.0 to -0.8, heat to 80-85℃, keep warm for 0.5-1.0 hours, filter to obtain filter cake Q and filtrate R. Filter cake Q is arsenic trisulfide and filtrate R is brine, which is sent to the alkali production system.

[0058] (10) Add water equal to the weight of filter cake O to the reaction flask, stir at 50-55℃, and add 62-65% nitric acid solution dropwise until no nitrogen oxide reddish-brown gas is produced. Keep the reaction at 60-65℃ for 0.5-1.0 hours, filter, and obtain filter cake S and filtrate T. Filter cake S is sent to the silver recovery system. The filter cake is silver chloride and sulfur.

[0059] (11) Add solid sodium sulfate to the filtrate T under stirring at room temperature, heat to 80-85°C, keep warm for 0.5-1.0 hours until no more precipitate is produced, filter to obtain filter cake U and filtrate V. Filter cake U is lead sulfate and filtrate V is brine, which is sent to the alkali production system.

[0060] In this invention, the reaction equation in step (1) is:

[0061] PbO + 2HCl → PbCl₂ + H₂O

[0062] ZnO + 2HCl → ZnCl₂ + H₂O

[0063] CdO + 2HCl → CdCl₂ + H₂O

[0064] CuO + 2HCl → CuCl₂ + H₂O

[0065] Sb₂O₃ + 6HCl → 2SbCl₃ + 3H₂O

[0066] Sb₂S₃ + ​​6HCl → 2SbCl₃ + 3H₂S

[0067] Bi₂O₃ + 6HCl → 2BiCl₃ + 3H₂O

[0068] In₂O₃ + 6HCl → 2InCl₃ + H₂O

[0069] Zn3(AsO4)2+6HCl→3ZnCl2+2H3AsO4

[0070] The reaction equation in step (2) is:

[0071] PbCl₂ + Na₂SO₄ → PbSO₄↓ + 2NaCl

[0072] The reaction equation in step (3) is:

[0073] Na₂S + 2HCl → H₂S + 2NaCl

[0074] H3AsO4 + H2S → H3AsO3 + S↓ + H2O

[0075] 2H3AsO3 + 3H2S → As2S3↓ + 6H2O

[0076] CuCl₂ + H₂S → CuS↓ + 2HCl

[0077] The reaction equation in step (4) is:

[0078] Na₂S + 2HCl → H₂S + 2NaCl

[0079] CdCl₂ + H₂S → CdS↓ + 2HCl

[0080] The reaction equation in step (5) is:

[0081] SbCl3 + H2O → SbOCl↓ + 2HCl

[0082] BiCl3 + H2O → BiOCl↓ + 2HCl

[0083] The reaction equation in step (6) is:

[0084] InCl3+3NaOH→In(OH)3↓+3NaCl

[0085] The reaction equation in step (7) is:

[0086] 3ZnCl2 + 3Na2CO3 + 3H2O →

[0087] ZnCO3·2Zn(OH)2·H2O↓+2CO2↑+6NaCl

[0088] The reaction equation in step (8) is:

[0089] As₂O₃ + 6NaOH → 2Na₃AsO₃ + 3H₂O

[0090] As2S3+6NaOH→Na3AsO3+Na3AsS3+3H2O

[0091] PbSO4+2NaOH→Pb(OH)2↓+Na2SO4

[0092] The reaction equation in step (9) is:

[0093] 2HCl + Na₂S → H₂S + 2NaCl

[0094] 2Na3AsO3+3H2S+6HCl→As2S3↓+6H2O+6NaCl

[0095] Na3AsO3+3Na3AsS3+6HCl→As2S3↓+6NaCl+3H2O

[0096] The reaction equation in step (10) is:

[0097] Pb(OH)₂ + 2HNO₃ → Pb(NO₃)₂ + 2H₂O

[0098] 3PbS+8HNO3→3Pb(NO3)2+2NO↑+3S↓+4H2O

[0099] The reaction equation in step (11) is:

[0100] Pb(NO3)2+Na2SO4→PbSO4↓+2NaNO3

[0101] In this invention, to ensure the complete precipitation of valuable metal elements and achieve a high recovery rate, the mass of the precipitant added in each precipitation reaction is controlled in two main ways: First, when the precipitation process is sensitive to the acidity or alkalinity of the filtrate, the mass of the precipitant added is limited according to the pH value during the precipitation reaction. Second, when the precipitant is neutral or amphoteric and added in solid form, the theoretical mass of the corresponding precipitant to be added in each precipitation reaction is calculated based on the component content of the high-arsenic dust used in the experiment, the above reaction equation, and the concentration specifications of the corresponding precipitant. Then, an excess of 20% is added on top of the theoretical mass, which is the actual mass of precipitant added. These methods of precipitant addition ensure that the valuable metal elements in the high-arsenic dust are fully precipitated, achieving a recovery rate of 98-99%.

[0102] The implementation process of the present invention will be described in detail below with reference to specific embodiments.

[0103] In the following examples, apart from the high-arsenic flue dust solids produced by the smelting of a certain lead smelting enterprise mentioned above, all other raw materials are from commercially available conventional raw materials. Where no specific technology or conditions are specified in the examples, they shall be carried out in accordance with the technology or conditions described in the relevant documents or in accordance with the product instructions.

[0104] I. Specific Embodiments of the Resource Utilization Method for High-Arsenic Flue Dust of the Present Invention

[0105] Example 1

[0106] The resource utilization method for high-arsenic flue dust in this embodiment includes the following steps:

[0107] 1. Add 22% hydrochloric acid solution to a 1000 mL flask equipped with a mechanical stirrer, thermometer, and gas absorption device. Heat to 50°C with stirring. Gradually add 200 g of high-arsenic dust in small batches, with a mass ratio of high-arsenic dust to hydrochloric acid solution of 1:2. After addition, maintain the reaction temperature at 60°C for 1.5 hours, then cool to 40°C and filter to obtain filtrate A and residue B. Filtrate A proceeds to step 2; residue B proceeds to step 8, as follows... Figure 1 As shown;

[0108] 2. Add solid sodium sulfate to filtrate A, heat to 80°C, keep warm for 0.5 hours until no more precipitation occurs, cool slightly and filter to obtain filter cake C and filtrate D. Filter cake C is lead sulfate.

[0109] 3. Add a 42% sodium hydroxide solution dropwise to filtrate D until the pH value is -3.0, then add a 15% sodium sulfide solution dropwise until the pH value is -1.5. Heat to 80℃ and keep at that temperature for 0.5 hours. After cooling slightly, filter to obtain filter cake E and filtrate F. Filter cake E is a mixture of arsenic trisulfide and copper sulfide. At the same time, under the above reaction conditions, a small amount of sulfur is also produced.

[0110] 4. Add 15% sodium sulfide solution dropwise to filtrate F until the pH value is 1.0, heat to 80℃, keep warm for 0.5 hours, cool slightly and filter to obtain filter cake G and filtrate H. Filter cake G is cadmium sulfide.

[0111] 5. Add twice the volume of water to the filtrate H and add 42% sodium hydroxide solution dropwise until the pH value is 2.0. Heat to 40°C and keep warm for 0.5 hours. Filter to obtain filter cake I and filtrate J. Filter cake I is a mixture of antimony oxychloride and bismuth oxychloride.

[0112] 6. Add 20% sodium hydroxide solution dropwise to filtrate J until the pH value is 3.5, heat to 60℃, keep warm for 1.0 hour, filter, and obtain filter cake K and filtrate L. Filter cake K is indium hydroxide.

[0113] 7. Add a 25% sodium carbonate solution dropwise to filtrate L until the pH value is 6.8, heat to 45℃, keep warm for 1.0 hour, filter, and obtain filter cake M and filtrate N. Filter cake M is basic zinc carbonate; filtrate N is brine, which is sent to the alkali production system.

[0114] 8. Add water to the reaction flask in quantities twice the weight of filter residue B. While stirring at room temperature, add filter residue B in portions, and then add 42% sodium hydroxide solution dropwise until the pH value reaches 13.1. Then heat to 60°C and keep warm for 1 hour. Filter to obtain filter cake O and filtrate P. Filter cake O is a mixture of silver chloride, lead sulfide, lead hydroxide and sulfur, and proceeds to step 10 for processing. Filtrate P is an arsenite solution.

[0115] 9. Under stirring at room temperature, add 22% hydrochloric acid solution dropwise to filtrate P until the pH value is -2.2. Then add 15% sodium sulfide solution dropwise to adjust the pH value to -1.0. Heat to 80℃ and keep warm for 0.5 hours. After cooling slightly, filter to obtain filter cake Q and filtrate R. Filter cake Q is arsenic trisulfide; filtrate R is brine and is sent to the alkali production system.

[0116] 10. Add water equal to the weight of filter cake O to the reaction flask, and add 65% nitric acid solution dropwise while stirring at 50°C until no reddish-brown gas of nitrogen oxides is produced. Heat to 60°C and keep warm for 0.5 hours. Filter to obtain filter cake S and filtrate T. Filter cake S is sent to the silver recovery system. Filter cake S is silver chloride and sulfur.

[0117] 11. Under stirring at room temperature, add solid sodium sulfate to the filtrate T, heat to 80°C, keep warm for 1 hour until no more precipitate is formed, cool slightly and filter to obtain filter cake U and filtrate V. Filter cake U is lead sulfate; filtrate V is brine, which is sent to the alkali production system.

[0118] Example 2

[0119] The resource utilization method for high-arsenic flue dust in this embodiment includes the following steps:

[0120] 1. Add 26% hydrochloric acid solution to a 1000 mL flask equipped with a mechanical stirrer, thermometer, and gas absorption device. Heat to 50°C with stirring. Gradually add 200 g of high-arsenic dust in small batches, with a mass ratio of high-arsenic dust to hydrochloric acid solution of 1:3. After addition, maintain the reaction temperature at 65°C for 1.5 hours, then cool to 40°C and filter to obtain filtrate A and residue B. Filtrate A proceeds to step 2; residue B proceeds to step 8.

[0121] 2. Add solid sodium sulfate to filtrate A, heat to 82°C, keep warm for 0.5 hours until no more precipitation occurs, cool slightly and filter to obtain filter cake C and filtrate D. Filter cake C is lead sulfate.

[0122] 3. Add a 42% sodium hydroxide solution dropwise to filtrate D until the pH value is -2.5, then add a 15% sodium sulfide solution dropwise until the pH value is -1.3. Heat to 83°C and keep at that temperature for 0.5 hours. After cooling slightly, filter to obtain filter cake E and filtrate F. Filter cake E is a mixture of arsenic trisulfide and copper sulfide. At the same time, under the above reaction conditions, a small amount of sulfur is also produced.

[0123] 4. Add 15% sodium sulfide solution dropwise to filtrate F until the pH value is 1.2, heat to 82℃, keep warm for 0.5 hours, cool slightly and filter to obtain filter cake G and filtrate H. Filter cake G is cadmium sulfide.

[0124] 5. Add 1.8 times the volume of water to filtrate H and add 42% sodium hydroxide solution dropwise until the pH value is 2.0. Heat to 43°C and keep warm for 0.5 hours. Filter to obtain filter cake I and filtrate J. Filter cake I is a mixture of antimony oxychloride and bismuth oxychloride.

[0125] 6. Add 20% sodium hydroxide solution dropwise to filtrate J until the pH value is 3.5, heat to 63℃, keep warm for 1.0 hour, filter, and obtain filter cake K and filtrate L. Filter cake K is indium hydroxide.

[0126] 7. Add a 25% sodium carbonate solution dropwise to filtrate L until the pH value is 6.8, heat to 45℃, keep warm for 1.0 hour, filter, and obtain filter cake M and filtrate N. Filter cake M is basic zinc carbonate; filtrate N is brine, which is sent to the alkali production system.

[0127] 8. Add water to the reaction flask at twice the weight of filter residue B. While stirring at room temperature, add filter residue B in portions, and then add 42% sodium hydroxide solution dropwise until the pH value reaches 13.2. Then heat to 65°C and keep warm for 1 hour. Filter to obtain filter cake O and filtrate P. Filter cake O is a mixture of silver chloride, lead sulfide, lead hydroxide and sulfur, and proceeds to step 10. Filtrate P is an arsenite solution.

[0128] 9. Under stirring at room temperature, add 22% hydrochloric acid solution dropwise to filtrate P until the pH value is -2.0. Then add 15% sodium sulfide solution dropwise to adjust the pH value to -0.8. Heat to 83℃ and keep warm for 0.5 hours. After cooling slightly, filter to obtain filter cake Q and filtrate R. Filter cake Q is arsenic trisulfide; filtrate R is brine and is sent to the alkali production system.

[0129] 10. Add water equal to the weight of filter cake O to the reaction flask, and add 62% nitric acid solution dropwise while stirring at 50°C until no reddish-brown gas of nitrogen oxides is produced. Keep the reaction at 65°C for 0.5 hours, filter, and obtain filter cake S and filtrate T. Filter cake S is sent to the silver recovery system. Filter cake S is silver chloride and sulfur.

[0130] 11. Under stirring at room temperature, add solid sodium sulfate to the filtrate T, heat to 80°C, keep warm for 1 hour until no more precipitate is formed, cool slightly and filter to obtain filter cake U and filtrate V. Filter cake U is lead sulfate; filtrate V is brine, which is sent to the alkali production system.

[0131] Example 3

[0132] The resource utilization method for high-arsenic flue dust in this embodiment includes the following steps:

[0133] 1. Add 20% hydrochloric acid solution to a 1000 mL flask equipped with a mechanical stirrer, thermometer, and gas absorption device. Heat to 50°C with stirring. Gradually add 200 g of high-arsenic dust in small batches, with a mass ratio of high-arsenic dust to hydrochloric acid solution of 1:4. After addition, maintain the reaction temperature at 65°C for 2 hours, then cool to 45°C and filter to obtain filtrate A and residue B. Filtrate A proceeds to step 2; residue B proceeds to step 8.

[0134] 2. Add solid sodium sulfate to filtrate A, heat to 85°C, keep warm for 1 hour until no more precipitation occurs, cool slightly and filter to obtain filter cake C and filtrate D. Filter cake C is lead sulfate.

[0135] 3. Add a 42% sodium hydroxide solution dropwise to filtrate D until the pH value is -2.5, then add a 16% sodium sulfide solution dropwise until the pH value is -1.2. Heat to 85°C and keep at that temperature for 1 hour. After cooling slightly, filter to obtain filter cake E and filtrate F. Filter cake E is a mixture of arsenic trisulfide and copper sulfide. At the same time, under the above reaction conditions, a small amount of sulfur is also produced.

[0136] 4. Add 16% sodium sulfide solution to filtrate F until the pH value is 1.2, heat to 85℃, keep warm for 1.0 hour, cool slightly and filter to obtain filter cake G and filtrate H. Filter cake G is cadmium sulfide.

[0137] 5. Add 3 times the volume of water to filtrate H and add 42% sodium hydroxide solution dropwise until the pH value is 2.2. Heat to 45℃ and keep warm for 1.0 hour. Filter to obtain filter cake I and filtrate J. Filter cake I is a mixture of antimony oxychloride and bismuth oxychloride.

[0138] 6. Add 20% sodium hydroxide solution dropwise to filtrate J until the pH value is 3.7, heat to 65℃, keep warm for 1.0 hour, filter, and obtain filter cake K and filtrate L. Filter cake K is indium hydroxide.

[0139] 7. Add a 26% sodium carbonate solution dropwise to filtrate L until the pH value is 7.0, heat to 50℃, keep warm for 1.0 hour, filter, and obtain filter cake M and filtrate N. Filter cake M is basic zinc carbonate; filtrate N is brine, which is sent to the alkali production system.

[0140] 8. Add water to the reaction flask at twice the weight of filter residue B. While stirring at room temperature, add filter residue B in portions, and then add 42% sodium hydroxide solution dropwise until the pH value reaches 13.2. Then heat to 65°C and keep warm for 1 hour. Filter to obtain filter cake O and filtrate P. Filter cake O is a mixture of silver chloride, lead sulfide, lead hydroxide and sulfur, and proceeds to step 10. Filtrate P is an arsenite solution.

[0141] 9. Under stirring at room temperature, add 22% hydrochloric acid solution dropwise to filtrate P until the pH value is -2.0. Then add 15% sodium sulfide solution dropwise to adjust the pH value to -0.8. Heat to 85℃ and keep warm for 1.0 hour. After cooling slightly, filter to obtain filter cake Q and filtrate R. Filter cake Q is arsenic trisulfide; filtrate R is brine and is sent to the alkali production system.

[0142] 10. Add water equal to the weight of filter cake O to the reaction flask, and add 65% nitric acid solution dropwise while stirring at 55°C until no reddish-brown gas of nitrogen oxides is produced. Keep the reaction at 65°C for 1.0 hour, filter, and obtain filter cake S and filtrate T. Filter cake S is sent to the silver recovery system. Filter cake S is silver chloride and sulfur.

[0143] 11. Under stirring at room temperature, add solid sodium sulfate to the filtrate T, heat to 85°C, keep warm for 1 hour until no more precipitate is formed, cool slightly and filter to obtain filter cake U and filtrate V. Filter cake U is lead sulfate; filtrate V is brine, which is sent to the alkali production system.

[0144] As can be seen from the implementation of the above embodiments, although multiple metal elements exist mixed in high-arsenic flue dust, the implementation of the technical solution of this application can precipitate lead, arsenic, copper, cadmium, bismuth, antimony, indium, zinc, and silver in the high-arsenic flue dust in the form of compounds, realizing the classified recovery of multiple elements such as lead, arsenic, copper, cadmium, bismuth, antimony, indium, zinc, and silver in high-arsenic flue dust. The resulting products are diverse, achieving the goal of comprehensive resource utilization and having broad application prospects.

[0145] The above is a detailed description of the embodiments, but it is not intended to limit the technical solutions of the present invention. Those skilled in the art should understand that any modifications, partial substitutions, and variations can be made to the above embodiments within the scope of the present invention, and all such modifications and variations should be covered within the scope of the present invention.

Claims

1. A method for the resource-based treatment of high-arsenic flue dust, characterized in that, Includes the following steps: (1) The high-arsenic flue dust was leached with hydrochloric acid solution at 60-65℃ to obtain filtrate A and filter residue B; (2) Add sodium sulfate to A and carry out a lead precipitation reaction at 80-85℃ to obtain lead sulfate and filtrate D; (3) After adjusting the pH of D to -3.0 to -2.5, add sodium sulfide solution to the pH to -1.5 to -1.2, and then carry out the precipitation of arsenic and copper at 80 to 85℃ to obtain a mixture of arsenic trisulfide and copper sulfide and filtrate F; (4) Add sodium sulfide solution to F until the pH is 1.0 to 1.2, and then carry out the cadmium precipitation reaction at 80 to 85°C to obtain cadmium sulfide and filtrate H; (5) Add water and sodium hydroxide solution to H until the pH is 2.0 to 2.2, and then carry out the bismuth and antimony precipitation reaction at 40 to 45°C to obtain a mixture of antimony oxychloride and bismuth oxychloride and filtrate J; (6) Add sodium hydroxide solution to J until the pH is 3.5-3.7, and then carry out the indium precipitation reaction at 60-65℃ to obtain indium hydroxide and filtrate L; (7) Add sodium carbonate solution to L until the pH is 6.8 to 7.0, and then carry out zinc precipitation reaction at 45 to 50°C to obtain basic zinc carbonate.

2. The method for resource-based treatment of high-arsenic flue dust according to claim 1, characterized in that, The resource utilization treatment method for filter residue B includes the following steps: (a) After mixing filter residue B with water, sodium hydroxide solution was added until the pH was 13.1 to 13.

2. Then, an arsenic dissolution reaction was carried out at 60 to 65°C to obtain a mixture of silver chloride, lead sulfide, lead hydroxide and sulfur and filtrate P. (b) Add hydrochloric acid solution to P until the pH is -2.2 to -2.0, then add sodium sulfide solution until the pH is -1.0 to -0.8, and then carry out the arsenic precipitation reaction at 80 to 85°C to obtain arsenic trisulfide; (c) The mixture of silver chloride, lead sulfide, lead hydroxide and sulfur in step (a) is mixed with water, nitric acid solution is added, and lead dissolution reaction is carried out at 60-65°C to obtain sulfur, silver chloride and filtrate T. (d) Add sodium sulfate to T and carry out a lead precipitation reaction at 80-85℃ to obtain lead sulfate.

3. The method for resource-based treatment of high-arsenic flue dust according to claim 1, characterized in that, In step (1), the mass ratio of high arsenic dust to hydrochloric acid solution is 1:(2-4).

4. The method for resource-based treatment of high-arsenic flue dust according to claim 3, characterized in that, The concentration of the hydrochloric acid solution is 20-26%.

5. The method for resource-based treatment of high-arsenic flue dust according to claim 1, characterized in that, The leaching reaction time in step (1) is 1.5 to 2 hours; the lead precipitation reaction time in step (2), the arsenic and copper precipitation reaction time in step (3), the cadmium precipitation reaction time in step (4), the bismuth and antimony precipitation reaction time in step (5), the indium precipitation reaction time in step (6), and the zinc precipitation reaction time in step (7) are all 0.5 to 1 hour.

6. The method for resource-based treatment of high-arsenic flue dust according to claim 2, characterized in that, The time for the arsenic dissolution reaction in step (a) and the lead dissolution reaction in step (c) is 0.5 to 1 hour; the time for the arsenic precipitation reaction in step (b) and the lead precipitation reaction in step (d) is 0.5 to 1 hour.

7. The method for resource-based treatment of high-arsenic flue dust according to claim 1, characterized in that, The concentrations of the sodium hydroxide solution in both step (5) and step (6) are 20-42%.

8. The method for resource-based treatment of high-arsenic flue dust according to claim 1, characterized in that, The concentrations of the sodium sulfide solution in step (3) and step (4) are both 15-16%.

9. The method for resource-based treatment of high-arsenic flue dust according to claim 1, characterized in that, The concentration of the sodium carbonate solution in step (7) is 25-26%.

10. The method for resource-based treatment of high-arsenic flue dust according to claim 2, characterized in that, The concentration of the nitric acid solution in step (c) is 62-65%.

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