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

Abstract

The invention provides a method for preparing an arsenic-iron alloy based on secondary smelting of arsenic-containing waste and iron slag and application. The method for preparing the arsenic-iron alloy comprises the following steps: S1, providing an arsenic-containing waste material, an iron raw material and a reducing agent; s2, the arsenic-containing waste, the iron raw material and the reducing agent are mixed for the first time, and a primary alloy base material is obtained; s3, the primary alloy base material is subjected to primary smelting under the protection of the protective atmosphere, and a primary alloy product is obtained; s4, the primary alloy is crushed, and alloy powder is obtained; carrying out secondary mixing on the alloy powder and an arsenic raw material to obtain a secondary alloy base material; and S5, the secondary alloy base material is subjected to secondary smelting under the protection of the protective atmosphere, and the arsenic-iron alloy is obtained. According to the method, the primary alloy is prepared from the arsenic-containing waste and the iron raw material, the density and the arsenic content of the arsenic-iron alloy are improved through re-smelting, the leaching toxicity is reduced, and remarkable economic benefits are achieved.

Description

Technical Field

[0001] The 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 application thereof. Background Art

[0002] Arsenic, as a co-element, is widely present in various metal minerals and will enter the smelting system along with the metal minerals. However, due to the toxicity of arsenic and its compounds, the market for traditional arsenic products such as arsenic oxide is shrinking year by year. Therefore, since arsenic cannot be safely removed from the circuit, a large amount of arsenic-containing waste (hazardous waste) is generated and arsenic products are stored beyond the expiration date, causing great environmental pressure on industries such as metallurgy. In addition, iron slag is a common slag material in industry. The main iron phases of some magnetically separated iron slag are ferroferric oxide and ferrous silicate, which are rich in iron resources, resulting in an urgent need for effective resource processing of iron slag.

[0003] Arsenic iron alloy has the characteristics of high specific gravity, low preparation cost and high environmental stability, and has great application potential in low-end fields such as counterweights. Therefore, the preparation of arsenic iron alloy from arsenic-containing waste and iron slag for use in the preparation of counterweights has become a feasible way to consume in bulk. However, most of the existing arsenic iron alloys are by-products of smelting processes such as lead smelting, and their density and leaching toxicity fluctuate greatly, which limits the large-scale application of arsenic iron alloys; and also limits the large-scale resource treatment of arsenic-containing waste and iron slag (especially arsenic-containing waste) under high arsenic content.

[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 through arsenic-containing waste and iron slag on the basis of high arsenic content. 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 through 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 existing phase of the arsenic element includes arsenic oxide; the iron raw material includes iron slag; in the iron slag, the existing phase of the iron element 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 the protection of a protective atmosphere to obtain a primary alloy; the primary smelting is performed at a holding temperature of 1000 to 1400° C. and a holding time of 20 to 60 minutes;

[0011] S4, crushing the primary alloy to obtain alloy powder; mixing the alloy powder and 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 and 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 insulation temperature of the secondary smelting is 900-1200° C., and the insulation 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 to 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) to prepare a primary alloy using arsenic-containing waste and iron slag as raw materials under a protective atmosphere, and performs secondary high-temperature smelting modification to significantly improve the density and arsenic content of the ferroarsenic alloy, and ensure low leaching toxicity, so that the alloy has excellent environmental stability and is 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 ferroarsenic 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 ferroarsenic alloy more uniform, increases the content of the ferroarsenic compound phase, and reduces the content of the ferroarsenic solid solution phase. In addition, the addition of arsenic powder causes the elemental iron in the alloy to react with arsenic for a second time to form more high-density, high-stability ferroarsenic compounds (ferroarsenide), thereby effectively controlling the leaching toxicity to meet the standard while increasing the density and arsenic content of the ferroarsenic alloy product, thereby achieving high-quality ferroarsenic 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 drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 creative work.

[0027] Figure 1 The process flow chart of preparing ferroarsenic alloy in the present invention;

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

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

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

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

[0032] Figure 6 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 purpose, functional features and advantages of the present invention will be further explained in conjunction with the implementation methods and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention.

[0036] Furthermore, 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 they can be implemented by ordinary technicians in the field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such 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 embodiments, it should be understood that, unless otherwise specified in the present invention, both endpoints of each numerical range and any value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention are familiar to those skilled in the art and the description of the present invention, and any methods, equipment and materials of the prior art similar or equivalent to the methods, equipment and materials described in the embodiments of the present invention can 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 the 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, providing arsenic-containing waste, iron raw material and reducing agent.

[0040] In the present invention, 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; 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; further, 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 magnetically separated iron slag.

[0043] In terms of mass percentage, 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%; in terms of mass percentage, 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 also includes iron powder; the iron raw material can be specifically composed of the iron slag and the 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. In the iron raw material, the mass ratio of the iron slag to the iron powder can be 15-20:1; 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 the protection of 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 normal temperature and pressure under the protection of a protective atmosphere.

[0049] Specifically, the arsenic-containing waste, the iron raw material and the reducing agent can be mixed and loaded into 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 at a rotation speed of 20 to 40 rpm for 10 to 14 hours at room temperature and pressure under protective atmosphere to obtain the primary alloy base material.

[0050] S3, the primary alloy base material is melted once under the protection of a protective atmosphere to obtain a primary alloy; in the present invention, the upper slag phase needs to be knocked off after the primary melting to obtain smelting slag and primary alloy. The insulation temperature of the primary melting is 1000-1400°C, and the insulation time of the primary melting is 20-60 minutes; further, the insulation temperature of the primary melting is 1100-1300°C, and the insulation time of the primary melting is 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 put into a graphite crucible and compacted; the material is discharged according to the operating requirements of the medium frequency furnace, and high-temperature smelting is performed in an argon atmosphere.

[0053] S4, crushing the primary alloy to obtain alloy powder; and mixing the alloy powder and 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 to form more high-density arsenic-iron compounds, thereby 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 the 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 transformation to a molten state at high temperature, which is beneficial to the synthesis of high-density arsenic-iron alloy after re-smelting.

[0058] In the present invention, the second mixing is performed 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 loaded into a container in an argon glove box, and 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 for 10 to 14 hours at room temperature and pressure under protective atmosphere 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 carbon on the surface needs to be knocked off, and the surface impurities are removed to obtain the arsenic-iron alloy.

[0061] In the present invention, the insulation temperature of the secondary smelting is 900-1200°C, and the insulation time of the secondary smelting is 10-70min; further, the insulation temperature of the secondary smelting is 1000-1200°C, and the insulation time of the secondary smelting is 20-40min; 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 link can be an inert atmosphere, specifically argon.

[0063] The invention discloses a method for preparing ferroarsenic alloy based on secondary smelting of arsenic-containing waste and iron slag, wherein the ferroarsenic alloy is prepared by utilizing volatile arsenic-containing waste and hard-to-reducible 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 coordinated technical means 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 arsenic-iron alloy with high density, high arsenic content and low toxicity, thereby achieving safe and efficient modification of the arsenic-iron 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 for remelting and modification, 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 the present invention refers to the mass proportion of arsenic element in the ferroarsenic alloy.

[0068] Low toxicity: The leaching toxicity analysis of arsenic iron alloy using the leaching procedures of acetic acid method (TCLP) and sulfuric acid and nitric acid method (HJ / T 299-2007) showed low leaching toxicity. The As leaching toxicity of arsenic iron alloy corresponding to the HJ / T 299-2007 leaching procedure is less than 1mg / L, and the As leaching toxicity of arsenic iron alloy corresponding to the TCLP leaching procedure is less than 1mg / L.

[0069] The TCLP leaching procedure is as follows: the leaching solution 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 solution at a liquid-to-solid ratio of 20:1, and shaken at 30±2r / min for 18±2h. The arsenic concentration is determined after filtering with 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 temperature is 23±2℃, and the mixture is mixed with m 硫酸 :m 硝酸 =1:2 mixed solution and added into deionized water to adjust the pH to 3.20±0.05, the sample was placed in the extract at a liquid-to-solid ratio of 10:1, and oscillated at 30±2r / min for 18±2h. The arsenic concentration was determined after filtering with a 0.45μm 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 7.21-7.33 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, take 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 into a transparent glass bottle and seal it.

[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. 1 , the main phase in the arsenic-containing waste is arsenic oxide. In this embodiment, the iron slag is: magnetic separation iron slag from a large gold smelter in Henan; see 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 oscillator 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 for compaction, discharge the material according to the operating requirements of the medium frequency furnace, and perform a smelting in an argon atmosphere; the medium frequency furnace used in this embodiment is a medium frequency induction furnace, the manufacturer is Changsha Yuhua District Great Wall Electric Furnace Factory, model 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 was 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 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 the alloy powder and 0.5054 g of the arsenic raw material are put 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 oscillator at a speed of 30 rpm at room temperature and pressure under argon protection conditions for 12 hours to obtain a secondary alloy base material.

[0088] S5, put the above 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 in an argon atmosphere and then keep it warm for 30 minutes for smelting. After the furnace body is naturally cooled to room temperature, the carbon on the surface of the sample is knocked off to obtain an arsenic-iron alloy product.

[0089] Second, 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; and 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. The actual picture of arsenic iron alloy products is 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, the silvery white ferroarsenic compound phase increases significantly, and changes from irregular blocks to long strips. The dark gray ferrosulfide phase does not change significantly, and 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 are not mixed in step S4, and the alloy powder is directly used as the secondary alloy base material (the arsenic raw material is omitted), and other conditions remain 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 is adjusted from metallic arsenic powder to arsenic sulfide powder, and the added amount of arsenic sulfide powder is adjusted to 0.8951 g, while other conditions remain 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 is adjusted from metallic arsenic powder to arsenic sulfide powder, and the added amount of arsenic sulfide powder is adjusted to 1.3427 g, while other conditions remain 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 arsenic raw material (metal arsenic powder) is adjusted to 0.7851, and other conditions remain 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] Compared with Example 1, in this comparative example, the amount of arsenic raw material (metal 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 the patent scope of the present invention is not limited thereto. All equivalent structural changes made by using the contents of the present invention specification 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: Includes 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 existing phase of the arsenic element includes arsenic oxide; the iron raw material includes iron slag; in the iron slag, the existing phase of the iron element 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 the protection of a protective atmosphere to obtain a primary alloy; the primary smelting is performed at a holding temperature of 1000 to 1400° C. and a holding time of 20 to 60 minutes; S4, crushing the primary alloy to obtain alloy powder; mixing the alloy powder and 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 and 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 insulation temperature of the secondary smelting is 900-1200° C., and the insulation 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 the 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 as described in 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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