A method for preparing arsenic-iron alloy based on secondary smelting of arsenic-containing waste and iron slag and application thereof

Abstract

The application provides a method for preparing arsenic-iron alloy based on secondary smelting of arsenic-containing waste and iron slag and application; the method for preparing arsenic-iron alloy comprises the following steps: S1, providing arsenic-containing waste, iron raw material and reducing agent; S2, first mixing the arsenic-containing waste, the iron raw material and the reducing agent to obtain primary alloy base; S3, first smelting the primary alloy base under the protection of protective atmosphere to obtain initial product alloy; S4, crushing the initial product alloy to obtain alloy powder; second mixing the alloy powder and arsenic raw material to obtain secondary alloy base; S5, second smelting the secondary alloy base under the protection of protective atmosphere to obtain arsenic-iron alloy. The initial product alloy is prepared by using arsenic-containing waste and iron raw material, and the density and arsenic content of the arsenic-iron alloy are improved by remelting, the leaching toxicity is reduced, and remarkable economic benefits are achieved.

Description

Technical Field

[0001] The present invention belongs to the field of alloy material preparation, and in particular relates to a method for preparing arsenic-iron alloy based on secondary smelting of arsenic-containing waste and iron slag and its application. Background Art

[0002] Arsenic, as a co-element, is widely present in various metal minerals and enters the smelting system along with them. However, due to the toxicity of arsenic and its compounds, the market for traditional arsenic products, such as arsenic oxide, has been shrinking year by year. Consequently, the inability to safely remove arsenic from the circuit leads to the massive generation of arsenic-containing waste (hazardous waste) and the extended storage of arsenic products, placing significant environmental pressure on industries like metallurgy. Furthermore, iron slag is a common industrial slag material. Some magnetic separation slags contain ferroferric oxide and ferrous silicate as their primary iron phases, representing a rich iron resource, necessitating effective resource recovery for this slag.

[0003] Arsenic-iron alloys, with their high specific gravity, low production cost, and high environmental stability, hold great potential for application in low-end applications such as counterweights. Therefore, the production of arsenic-iron alloys from arsenic-containing waste and iron slag for use in counterweights has become a viable approach for large-scale utilization. However, existing arsenic-iron alloys, mostly byproducts of smelting processes such as lead smelting, have large fluctuations in density and leaching toxicity, limiting their large-scale application and restricting the large-scale resource recovery of arsenic-containing waste and iron slag (especially arsenic-containing waste) at high arsenic levels.

[0004] In view of this, it is necessary to provide a method and application for preparing arsenic-iron alloy based on secondary smelting of arsenic-containing waste and iron slag, so as to solve or at least alleviate the technical defect of how to prepare high-density and low-leaching toxicity arsenic-iron alloy based on high arsenic content through arsenic-containing waste and iron slag. Summary of the Invention

[0005] The main purpose of the present invention is to provide a method and application for preparing arsenic-iron alloy based on secondary smelting of arsenic-containing waste and iron slag, aiming to solve or at least alleviate the technical problem of how to prepare high-density and low-leaching toxicity arsenic-iron alloy based on high arsenic content by using arsenic-containing waste and iron slag.

[0006] To achieve the above object, the present invention provides a method for preparing ferroarsenic alloy based on secondary smelting of arsenic-containing waste and iron slag, comprising the steps of:

[0007] S1, providing arsenic-containing waste, an iron raw material, and a reducing agent; the arsenic-containing waste contains arsenic, the iron raw material contains iron, and the molar ratio of the arsenic to the iron is 1:0.5-5;

[0008] In the arsenic-containing waste, the arsenic element's occurrence phase includes arsenic oxide; the iron raw material includes iron slag; in the iron slag, the iron element's occurrence phase includes ferrosoferric oxide and ferrous silicate;

[0009] S2, performing a first mixing of the arsenic-containing waste, the iron raw material, and the reducing agent to obtain a primary alloy base material;

[0010] S3, performing a primary smelting of the primary alloy base material under a protective atmosphere to obtain a primary alloy; the primary smelting is performed at a holding temperature of 1000-1400° C. for a holding time of 20-60 minutes;

[0011] S4, crushing the primary alloy to obtain alloy powder; mixing the alloy powder with an arsenic raw material for a second time to obtain a secondary alloy base material; the arsenic raw material includes arsenic powder, and the mass percentage of the arsenic powder to the alloy powder is 5-20%;

[0012] S5, performing secondary smelting on the secondary alloy base material under the protection of a protective atmosphere to obtain an arsenic-iron alloy; the holding temperature of the secondary smelting is 900-1200° C., and the holding time of the secondary smelting is 10-70 minutes.

[0013] Furthermore, the iron raw material also includes iron powder; the mass proportion of the iron element in the iron slag in the total iron is 80-95%, and the total iron is all the iron elements in the iron raw material.

[0014] Furthermore, the reducing agent includes carbon powder; the molar ratio of the carbon powder to the arsenic element is 2 to 5:1.

[0015] Furthermore, the heating rate of the primary smelting is 30-50°C / min.

[0016] Furthermore, the primary smelting is medium frequency induction smelting.

[0017] Furthermore, before the primary smelting, the primary alloy base material is compacted.

[0018] Furthermore, the particle sizes of the arsenic-containing waste, the iron slag and the alloy powder are no larger than the aperture corresponding to a 100-mesh sieve.

[0019] Furthermore, the heating rate of the secondary smelting is 5-20°C / min.

[0020] The present invention also provides an arsenic-iron alloy, which is prepared by any of the above-mentioned methods for preparing the arsenic-iron alloy.

[0021] The present invention also provides an application of any of the above methods for preparing ferroarsenic alloys in treating arsenic-containing hazardous wastes.

[0022] Compared with the prior art, the present invention has at least the following advantages:

[0023] 1. The present invention utilizes primary smelting (medium frequency induction smelting) in a protective atmosphere to prepare a primary alloy using arsenic-containing waste and iron slag as raw materials, and then undergoes secondary high-temperature smelting and modification to significantly improve the density and arsenic content of the ferroarsenic alloy, while ensuring low leaching toxicity, thereby providing it with excellent environmental stability and making it suitable for the field of counterweight materials.

[0024] 2. The present invention effectively avoids the problem of large-scale volatilization of arsenic during the smelting process by increasing the heating rate of the primary smelting (30-50°C / min), making the physical phase of the arsenic-iron alloy product controllable and increasing the arsenic content.

[0025] 3. The present invention adds arsenic powder (metallic arsenic) as an arsenic raw material to the alloy powder. The addition of arsenic powder makes the surface of the arsenic-iron alloy more uniform, increases the content of the arsenic-iron compound phase, and reduces the content of the arsenic-iron solid solution phase. In addition, the addition of arsenic powder causes the elemental iron in the alloy to react secondary with arsenic to form more high-density, high-stability arsenic-iron compounds (ferroarsenide). While increasing the density and arsenic content of the arsenic-iron alloy product, its leaching toxicity is effectively controlled to meet the standard, thereby achieving high-quality arsenic-iron alloy products. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0027] Figure 1 This is a process flow chart for preparing ferroarsenic alloy in the present invention;

[0028] Figure 2 The XRD pattern of the arsenic-containing waste in Example 1 of the present invention;

[0029] Figure 3 The XRD pattern of the iron slag in Example 1 of the present invention;

[0030] Figure 4 This is a finished product image of the ferroarsenic alloy product in Example 1 of the present invention (unpolished);

[0031] Figure 5 This is the XRD pattern of the ferroarsenic alloy product in Example 1 of the present invention;

[0032] Figure 6 This is a SEM-BSE image of the primary alloy in Example 1 of the present invention;

[0033] Figure 7 This is the SEM-BSE image of the ferroarsenic alloy product in Example 1 of the present invention.

[0034] The realization of the objectives, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0035] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0036] Moreover, the technical solutions between the various embodiments of the present invention may be combined with each other, but this must be based on the fact that ordinary technicians in this field can implement them. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0037] When numerical ranges are given in the examples, it should be understood that unless otherwise specified herein, both endpoints of each numerical range and any value between the two endpoints may be used. Unless otherwise defined, all technical and scientific terms used herein are consistent with the prior art as understood by those skilled in the art and the description of the present invention. Any prior art methods, devices, and materials similar or equivalent to those described in the examples of the present invention may also be used to implement the present invention.

[0038] In order to achieve the treatment of arsenic-containing waste and iron slag, obtain arsenic-iron alloy with low leaching toxicity, promote the large-scale disposal of arsenic-containing waste and large-scale synthesis and application of arsenic-iron alloy, and increase the arsenic content and density of arsenic-iron alloy; see Figure 1 It is understood that the present invention provides a method for preparing ferroarsenic alloy based on secondary smelting of arsenic-containing waste and iron slag, comprising the steps of:

[0039] S1, provides arsenic-containing waste, iron raw material and reducing agent.

[0040] In the present invention, the arsenic-containing waste contains arsenic, and the iron raw material contains iron. The molar ratio of the arsenic to the iron is 1:0.5-5; that is, the molar ratio of the arsenic in the arsenic-containing waste to the iron in the iron raw material is 1:0.5-5. Furthermore, the molar ratio of the arsenic to the iron is 1:1-3, preferably 1:1.5-2.5. The mass ratio of the arsenic-containing waste to the iron raw material can be 1:1.5-2.

[0041] In the arsenic-containing waste, the existing phase of the arsenic element includes arsenic oxide (As2O3); the iron raw material includes iron slag; in the iron slag, the existing phase of the iron element includes ferrosoferric oxide (Fe3O4) and ferrous silicate (FeSiO3).

[0042] In the present invention, the mass proportion of arsenic in the arsenic-containing waste can be 45-60%, and the mass proportion of iron in the iron slag can be 40-50%. The arsenic-containing waste can be arsenic-containing calcium sulfate slag, and the iron slag can be magnetic separation iron slag.

[0043] Calculated by mass, the arsenic-containing waste also contains Ca 10-15%, O 15-20%, S 3-6%, Cl 4-7%, F 2-4%, and Sb 0.2-0.5%; calculated by mass, the iron slag also contains Si 7-12%, O 30-35%, Al 2-4%, Na 1-2%, Zn 1-2%, and K 0.8-1.3%.

[0044] In the present invention, the iron raw material further includes iron powder; the iron raw material may specifically be composed of the iron slag and the iron powder; the iron element in the iron slag accounts for 80-95% by mass of the total iron, where the total iron is all the iron elements in the iron raw material. In the iron raw material, the mass ratio of the iron slag to the iron powder may be 15-20:1; and the purity of the iron powder is not less than 99.9%.

[0045] In the present invention, the reducing agent includes or is carbon powder; the molar ratio of the carbon powder to the arsenic element is 2-5:1 or 2.5-3.5:1, the carbon powder can be understood as carbon element, and the molar amount of the carbon powder is calculated based on the carbon element.

[0046] As a further description of the arsenic-containing waste and the iron slag, the particle sizes of the arsenic-containing waste and the iron slag are no greater than the aperture corresponding to the 100-mesh sieve; that is, the arsenic-containing waste and the iron slag can both pass through the 100-mesh sieve.

[0047] S2, performing a first mixing of the arsenic-containing waste, the iron raw material and the reducing agent to obtain a primary alloy base material.

[0048] In the present invention, the first mixing is performed under a protective atmosphere. The first mixing process may include: mixing the arsenic-containing waste, the iron raw material, and the reducing agent at a rotation speed of 20 to 40 rpm for 10 to 14 hours at room temperature and pressure under the protective atmosphere.

[0049] Specifically, the arsenic-containing waste, the iron raw material and the reducing agent can be mixed and placed in a container in an argon glove box, and then the container containing the arsenic-containing waste, the iron raw material and the reducing agent is placed on a tumbling oscillator with a rotation speed of 20 to 40 rpm under normal temperature and pressure and protective atmosphere protection for 10 to 14 hours to obtain the primary alloy base material.

[0050] S3, performing a primary smelting of the primary alloy base material under a protective atmosphere to obtain a primary alloy. In the present invention, after the primary smelting, the upper slag phase needs to be knocked off to obtain the smelting slag and the primary alloy. The primary smelting is performed at a holding temperature of 1000-1400°C for 20-60 minutes. Furthermore, the primary smelting is performed at a holding temperature of 1100-1300°C for 20-40 minutes.

[0051] In the present invention, in order to reduce the volatilization of arsenic during the smelting and heating process, the primary smelting adopts medium frequency induction smelting with a heating rate of 30-50°C / min; in order to make the raw materials react fully, the primary alloy base material is compacted before the primary smelting.

[0052] Specifically, the primary alloy base material can be placed in a graphite crucible and compacted; the material can be discharged according to the operating requirements of the medium frequency furnace, and high-temperature smelting can be performed under an argon atmosphere.

[0053] S4, crushing the primary alloy to obtain alloy powder; and mixing the alloy powder with arsenic raw material for a second time to obtain a secondary alloy base material.

[0054] In the present invention, the addition of the arsenic raw material can make the surface of the arsenic-iron alloy more uniform, increase the content of the arsenic-iron compound phase, and reduce the content of the arsenic-iron solid solution phase; the addition of the arsenic raw material causes the elemental iron in the alloy to react with arsenic secondary to form more high-density arsenic-iron compounds, thereby modifying and improving the arsenic content and density of the arsenic-iron alloy.

[0055] In the present invention, the arsenic raw material includes or is arsenic powder (metallic arsenic). The selection of the arsenic raw material has an important influence on the technical effect of the present invention; the mass percentage of the arsenic powder and the alloy powder is 5-20%, further 5-16% or 8-12%.

[0056] In the present invention, after the crushing process, the alloy powder may be sieved; the particle size of the alloy powder is not greater than the aperture corresponding to a 100-mesh sieve.

[0057] Specifically, the primary alloy is crushed by a vibration mill and then passed through a 100-mesh sieve to obtain the alloy powder; the particle size of the primary alloy is appropriately reduced, which increases its heating area during high-temperature smelting, thereby accelerating its transition to a molten state at high temperature, which is beneficial to the synthesis of high-density arsenic-iron alloy after resmelting.

[0058] In the present invention, the second mixing is carried out under the protection of a protective atmosphere; the second mixing process may include: at room temperature and pressure and under the protection of a protective atmosphere, shaking and mixing the alloy powder and the arsenic raw material at a speed of 20 to 40 rpm for 10 to 14 hours.

[0059] Specifically, the alloy powder and the arsenic raw material can be mixed and placed in a sealed container in an argon glove box. Then, the container containing the alloy powder and the arsenic raw material is placed on a tumbling oscillator at a rotation speed of 20 to 40 rpm under normal temperature and pressure and protective atmosphere for 10 to 14 hours to obtain the secondary alloy base material.

[0060] S5, performing secondary smelting on the secondary alloy base material under the protection of a protective atmosphere to obtain an arsenic-iron alloy; in the present invention, after the secondary smelting, the surface carbon needs to be knocked off and the surface impurities are removed to obtain the arsenic-iron alloy.

[0061] In the present invention, the holding temperature of the secondary smelting is 900-1200°C, and the holding time of the secondary smelting is 10-70 minutes; further, the holding temperature of the secondary smelting is 1000-1200°C, and the holding time of the secondary smelting is 20-40 minutes; the heating rate of the secondary smelting is 5-20°C / min.

[0062] In the present invention, before the secondary smelting, the secondary alloy base material can be transferred under the protection of a protective atmosphere to avoid the toxic leaching effect of the oxidizing environment on the alloy base material. In the present invention, the protective atmosphere in any step can be an inert atmosphere, specifically argon.

[0063] The present invention is a method for preparing ferroarsenic alloy by secondary smelting of arsenic-containing waste and iron slag. The ferroarsenic alloy is prepared by using volatile arsenic-containing waste and difficult-to-reduced iron slag, and by adding arsenic powder for remelting, the density and arsenic content of the ferroarsenic alloy are improved, and low leaching toxicity is ensured, thereby having significant economic benefits.

[0064] The present invention utilizes the synergy of raw material preparation, medium-frequency induction smelting with a high heating rate, secondary high-temperature smelting of arsenic powder, and parameter control to prepare a high-density ferroarsenic alloy with high density, high arsenic content, and low toxicity, thereby achieving safe and efficient modification of the ferroarsenic alloy and effectively improving its physical and chemical properties.

[0065] The details are as follows:

[0066] High density: The primary alloy is added with arsenic powder for remelting and modification to synthesize a high-density arsenic-iron alloy with a dense surface and more high-density arsenic-iron compounds. The density of the arsenic-iron alloy can reach 7.21-7.33 g / cm 3 ; such as 7.33g / cm 3 .

[0067] High arsenic content: By adding arsenic powder and remelting and modifying, the arsenic content of the ferroarsenic alloy can reach 20-26% or 21.62-25.33%, such as 21.62% or 25.33%. The arsenic content in this invention refers to the mass percentage of arsenic in the ferroarsenic alloy.

[0068] Low toxicity: Leaching toxicity analysis of the ferroarsenic alloy using the acetic acid method (TCLP) and the sulfuric acid and nitric acid method (HJ / T 299-2007) demonstrated low toxicity. The arsenic leaching toxicity of the ferroarsenic alloy using the HJ / T 299-2007 leaching procedure was less than 1 mg / L, and the TCLP leaching procedure also showed less than 1 mg / L.

[0069] The TCLP leaching procedure is as follows: the leaching liquid is acetic acid solution. At a temperature of 23±2°C, glacial acetic acid is added to deionized water to adjust the pH to 2.88±0.05. The sample is then placed in the leaching liquid at a liquid-to-solid ratio of 20:1 and shaken at 30±2 r / min for 18±2 h. The arsenic concentration is determined after filtering using a 0.45μm filter membrane.

[0070] The leaching procedure of HJ / T 299-2007 is as follows: the leaching solution is a mixture of sulfuric acid and nitric acid, and the mixture is prepared at a temperature of 23±2℃. 硫酸 :m 硝酸 =1:2 mixture and add it to deionized water to adjust the pH to 3.20±0.05. Place the sample in the extract at a liquid-to-solid ratio of 10:1, shake at 30±2 r / min for 18±2 h, and determine the arsenic concentration after filtering through a 0.45 μm filter membrane.

[0071] The present invention also provides an arsenic-iron alloy, which is prepared by any of the above-mentioned methods for preparing arsenic-iron alloys. The high-density arsenic-iron alloy phase includes ferroarsenide; the high-density arsenic-iron alloy has a density of 7.21 to 7.33 g / cm 3 , such as 7.33g / cm 3 The arsenic content of the high-density arsenic-iron alloy can reach 20-26% or 21.62-25.33%, such as 21.62% or 25.33%.

[0072] The present invention also provides an application of any of the above methods for preparing ferroarsenic alloys in treating arsenic-containing hazardous wastes.

[0073] The following are specific examples of the present invention:

[0074] Example 1

[0075] 1. In this embodiment, the steps for preparing the ferroarsenic alloy product are as follows:

[0076] S1. In an argon atmosphere glove box, 10 g of arsenic-containing waste, 16.15 g of iron slag, 0.86 g of iron powder, and 2.56 g of reducing agent powder were placed in a transparent glass bottle and sealed.

[0077] In this embodiment, the reducing agent powder is carbon powder; the arsenic-containing waste and the iron slag can both pass through a 100-mesh sieve; the elemental analysis of the arsenic-containing waste is shown in Table 1, and the elemental analysis of the iron slag is shown in Table 2.

[0078] Table 1 Elemental analysis of arsenic-containing waste (wt%)

[0079]

[0080] Table 2 Elemental analysis of iron slag (wt%)

[0081]

[0082] In this embodiment, the arsenic-containing waste material is arsenic-containing calcium sulfate slag produced by a large gold smelter in Henan Province; Figure 2 As shown in FIG, the main phase of arsenic-containing waste is arsenic oxide. In this embodiment, the iron slag is: magnetic separation iron slag from a large gold smelter in Henan; Figure 3 As shown, the main phases in the iron slag are ferroferric oxide and ferrous silicate. The iron powder in this embodiment is 99.9% analytically pure elemental iron powder, provided by Aladdin (Reagent) Shanghai Co., Ltd. In this embodiment, the iron slag and iron powder together constitute the iron raw material.

[0083] S2, placing the glass bottle containing the arsenic-containing waste, iron slag, iron powder and reducing agent on a tumbling shaker at a rotation speed of 30 rpm under normal temperature and pressure and argon protection for 12 hours to obtain a primary alloy base material.

[0084] S3, put the above-mentioned primary alloy base material into a 2L graphite crucible and compact it, discharge it according to the operating requirements of the medium frequency furnace, and perform a single smelting under an argon atmosphere; the medium frequency furnace used in this embodiment is a medium frequency induction furnace, the manufacturer is the Great Wall Electric Furnace Factory in Yuhua District, Changsha City, model number is IKAYXQM-4.

[0085] In this embodiment, during the first smelting, the temperature was raised to 1200° C. at a rate of 30° C. / min and then kept at that temperature for 30 minutes for smelting. After the furnace body naturally cooled to room temperature, the upper slag phase of the obtained sample was knocked off to obtain a primary alloy (primary arsenic-iron alloy).

[0086] S4, crushing the primary alloy into powder using a vibration mill, and then passing it through a 100-mesh sieve to obtain alloy powder; then, mixing the alloy powder with an arsenic raw material to obtain a secondary alloy base material; the arsenic raw material in this embodiment is metallic arsenic powder.

[0087] The process of mixing the alloy powder and the arsenic raw material is as follows: in an argon atmosphere glove box, 5 g of alloy powder and 0.5054 g of arsenic raw material are taken into a transparent glass bottle and sealed; the glass bottle containing the arsenic-iron alloy powder and the arsenic raw material is placed on a tumbling shaker with a rotation speed of 30 rpm at room temperature and pressure under argon protection conditions and tumbled and shaken for 12 hours to obtain a secondary alloy base material.

[0088] S5. Place the above-mentioned secondary alloy base material into a graphite ark and place it in a tubular furnace (manufacturer: Hefei Kejing Material Technology Co., Ltd., model: OTF-1200X-Ⅲ-80VT) for secondary smelting; during the secondary smelting, heat the temperature to 1100°C at a rate of 10°C / min under an argon atmosphere and then keep the temperature for 30 minutes for smelting. After the furnace body naturally cools to room temperature, knock off the carbon on the surface of the sample to obtain an arsenic-iron alloy product.

[0089] 2. The experimental results of this embodiment are as follows:

[0090] 1. The arsenic content of the primary alloy is 13.9%. The As leaching toxicity of the arsenic-iron alloy measured by the HJ / T 299-2007 leaching procedure is 0.52 mg / L. The density of the arsenic-iron alloy is 6.8 g / cm 3 .

[0091] 2. The arsenic content of the ferroarsenic alloy product is 21.62%. The As leaching toxicity of the ferroarsenic alloy product measured by the HJ / T 299-2007 leaching procedure is 0.25 mg / L. In addition, the As leaching toxicity of the ferroarsenic alloy product measured by the TCLP leaching procedure is 0.51 mg / L. The density of the ferroarsenic alloy product is 7.33 g / cm 3 .

[0092] 3. Actual pictures of arsenic iron alloy products are as follows: Figure 4 As shown; the XRD pattern of arsenic iron alloy products is as follows Figure 5 As shown; SEM-BSE images of ferroarsenic alloys (primary alloys and ferroarsenic alloy products) before and after remelting are shown Figure 6 、 Figure 7 shown.

[0093] The XRD diagram shows that the physical phases of the ferroarsenic alloy product are Fe and Fe2As; the SEM-BSE diagram shows that after adding 10% metallic arsenic for secondary smelting, the surface of the ferroarsenic alloy becomes dense and uniform, the light gray ferroarsenic solid solution is significantly reduced, and the silvery white ferroarsenic compound phase increases significantly, changing from irregular blocks to long strips, and the dark gray ferrosulfur phase does not change significantly. The metallic arsenic combines with the elemental iron in the ferroarsenic solid solution to form ferroarsenic compounds.

[0094] Comparative Example 1

[0095] 1. In this comparative example, the steps for preparing the ferroarsenic alloy product are as follows:

[0096] Compared with Example 1, in this comparative example, the alloy powder and the arsenic raw material were not mixed in step S4, and the alloy powder was directly used as the secondary alloy base material (the arsenic raw material was omitted). Other conditions remained unchanged to obtain an arsenic-iron alloy product.

[0097] 2. The experimental results of this comparative example are as follows:

[0098] The arsenic content of the ferroarsenic alloy product is 11.3%. The As leaching toxicity of the ferroarsenic alloy measured by the HJ / T 299-2007 leaching procedure is 0.91 mg / L. The density of the ferroarsenic alloy is 6.91 g / cm 3 .

[0099] Comparative Example 2

[0100] 1. In this comparative example, the steps for preparing the ferroarsenic alloy product are as follows:

[0101] Compared with Example 1, in this comparative example, the arsenic raw material was changed from metallic arsenic powder to arsenic sulfide powder, and the amount of arsenic sulfide powder added was adjusted to 0.8951 g, while other conditions remained unchanged, to obtain an arsenic-iron alloy product.

[0102] 2. The experimental results of this comparative example are as follows:

[0103] The arsenic content of the ferroarsenic alloy product is 13.26%. The As leaching toxicity of the ferroarsenic alloy product measured by the HJ / T 299-2007 leaching procedure is 4.50 mg / L. The density of the ferroarsenic alloy product is 6.49 g / cm 3 .

[0104] Comparative Example 3

[0105] 1. In this comparative example, the steps for preparing the ferroarsenic alloy product are as follows:

[0106] Compared with Example 1, in this comparative example, the arsenic raw material was changed from metallic arsenic powder to arsenic sulfide powder, and the amount of arsenic sulfide powder added was adjusted to 1.3427 g, while other conditions remained unchanged, to obtain an arsenic-iron alloy product.

[0107] 2. The experimental results of this comparative example are as follows:

[0108] The arsenic content of the ferroarsenic alloy product is 15.23%. The As leaching toxicity of the ferroarsenic alloy product measured by the HJ / T 299-2007 leaching procedure is 8.38 mg / L. The density of the ferroarsenic alloy product is 6.32 g / cm 3 .

[0109] Example 2

[0110] 1. In this comparative example, the steps for preparing the ferroarsenic alloy product are as follows:

[0111] Compared with Example 1, in this comparative example, the addition amount of the arsenic raw material (metallic arsenic powder) was adjusted to 0.7851, and other conditions remained unchanged to obtain an arsenic-iron alloy product.

[0112] 2. The experimental results of this comparative example are as follows:

[0113] The arsenic content of the ferroarsenic alloy product is 25.33%. The As leaching toxicity of the ferroarsenic alloy product measured by the HJ / T 299-2007 leaching procedure is 0.17 mg / L. The density of the ferroarsenic alloy product is 7.21 g / cm 3 .

[0114] Example 3

[0115] 1. In this comparative example, the steps for preparing the ferroarsenic alloy product are as follows:

[0116] In this comparative example, compared with Example 1, the amount of arsenic raw material (metallic arsenic powder) added was adjusted to 0.2527 g, and other conditions remained unchanged to obtain an arsenic-iron alloy product.

[0117] 2. The experimental results of this comparative example are as follows:

[0118] The arsenic content of the ferroarsenic alloy product is 15.23%. The As leaching toxicity of the ferroarsenic alloy product measured by the HJ / T 299-2007 leaching procedure is 0.91 mg / L. The density of the ferroarsenic alloy product is 7.24 g / cm 3 .

[0119] The above technical solutions of the present invention are only preferred embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention's description and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for preparing ferroarsenic alloy based on secondary smelting of arsenic-containing waste and iron slag, characterized in that: Including steps: S1, providing arsenic-containing waste, an iron raw material, and a reducing agent; the arsenic-containing waste contains arsenic, the iron raw material contains iron, and the molar ratio of the arsenic to the iron is 1:0.5-5; In the arsenic-containing waste, the arsenic element's occurrence phase includes arsenic oxide; the iron raw material includes iron slag; in the iron slag, the iron element's occurrence phase includes ferrosoferric oxide and ferrous silicate; S2, performing a first mixing of the arsenic-containing waste, the iron raw material, and the reducing agent to obtain a primary alloy base material; S3, performing a primary smelting of the primary alloy base material under a protective atmosphere to obtain a primary alloy; the primary smelting is performed at a holding temperature of 1000-1400° C. for a holding time of 20-60 minutes; S4, crushing the primary alloy to obtain alloy powder; mixing the alloy powder with an arsenic raw material for a second time to obtain a secondary alloy base material; the arsenic raw material includes arsenic powder, and the mass percentage of the arsenic powder to the alloy powder is 5-20%; S5, performing secondary smelting on the secondary alloy base material under the protection of a protective atmosphere to obtain an arsenic-iron alloy; the holding temperature of the secondary smelting is 900-1200° C., and the holding time of the secondary smelting is 10-70 minutes.

2. The method for preparing ferroarsenic alloy according to claim 1, characterized in that: The iron raw material also includes iron powder; the mass proportion of the iron element in the iron slag in the total iron is 80-95%, and the total iron is all the iron elements in the iron raw material.

3. The method for preparing ferroarsenic alloy according to claim 1, characterized in that: The reducing agent includes carbon powder; the molar ratio of the carbon powder to the arsenic element is 2 to 5:

1.

4. The method for preparing ferroarsenic alloy according to claim 1, characterized in that: The heating rate of the primary smelting is 30-50°C / min.

5. The method for preparing ferroarsenic alloy according to claim 1, characterized in that: The primary smelting is medium frequency induction smelting.

6. The method for preparing ferroarsenic alloy according to claim 1, characterized in that: Before the primary smelting, the primary alloy base material is compacted.

7. The method for preparing ferroarsenic alloy according to claim 1, characterized in that: The particle sizes of the arsenic-containing waste, the iron slag and the alloy powder are all no larger than the aperture corresponding to a 100-mesh sieve.

8. The method for preparing ferroarsenic alloy according to claim 1, characterized in that: The heating rate of the secondary smelting is 5-20°C / min.

9. An arsenic-iron alloy, characterized in that: The ferroarsenic alloy is prepared by the method for preparing the ferroarsenic alloy according to any one of claims 1 to 8.

10. Use of the method for preparing ferroarsenic alloy according to any one of claims 1 to 8 in treating arsenic-containing hazardous waste.

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